996 Engine Case Reman - Bullet Proof
08-16-2017, 04:35 PM
#61
The value of the car is completely unrelated to the availability and cost of rebuild options. Nobody owes m96 owners a cheap rebuild option that's proven to be reliable. It may be something people want, but if the technology isn't there, it's simply a reality that must be accepted.
It's nice of Charles to share some details on why variant options from the Nickies approach can be problematic, and fundamentally I think they charge a very reasonable fee for the services offered. $4-5k for a properly re-sleeved block is understandable.
One of the main problems with the m96 is that rebuilding requires new c-rods due to inferior OEM part quality. Same goes for the timing chains. When you break down the costs involved in a $20k rebuild, I see an expensive solution to a range of problems with the OEM design. If the c-rods were good to reuse and/or the timing chains didn't have issues with reliability & stretching, the rebuild costs could be materially lower. The high cost seems a direct result of Porsche's decision making & not that of independent builders. We should be thankful 996s depreciated to the level they're at & that high-quality rebuilds can be done a la carte based on the owner's preference.
It's nice of Charles to share some details on why variant options from the Nickies approach can be problematic, and fundamentally I think they charge a very reasonable fee for the services offered. $4-5k for a properly re-sleeved block is understandable.
One of the main problems with the m96 is that rebuilding requires new c-rods due to inferior OEM part quality. Same goes for the timing chains. When you break down the costs involved in a $20k rebuild, I see an expensive solution to a range of problems with the OEM design. If the c-rods were good to reuse and/or the timing chains didn't have issues with reliability & stretching, the rebuild costs could be materially lower. The high cost seems a direct result of Porsche's decision making & not that of independent builders. We should be thankful 996s depreciated to the level they're at & that high-quality rebuilds can be done a la carte based on the owner's preference.
it's all the other things that add up. The timing chains are cheap compared to everything else that needs to be replaced in a rebuild.
08-16-2017, 04:37 PM
#62
Charles, what is the "NSC Recond." option on your website? I don't remember that being there before.
https://lnengineering.com/products/w...-included.html
https://lnengineering.com/products/w...-included.html
08-16-2017, 07:10 PM
#63
If that's true, what are we arguing about this? Dry iron sleeves for 1600, wet iron sleeves for 1800-2000 (guessing), and 2265 for Nickies.
Comparing sleeving processes alone, it seems like an easy decision to make. Pistons are another story.
Comparing sleeving processes alone, it seems like an easy decision to make. Pistons are another story.
08-16-2017, 07:15 PM
#64
Burning Brakes
Yeah exactly, even a cheapskate like me would spend the extra $665 for nickies Vs dry iron sleeves etc
08-16-2017, 08:38 PM
#65
Rennlist Member
Charles, what is the "NSC Recond." option on your website? I don't remember that being there before.
https://lnengineering.com/products/w...-included.html
https://lnengineering.com/products/w...-included.html
04-06-2018, 11:00 AM
#67
Rennlist Member
04-06-2018, 02:44 PM
#68
Rennlist Member
But yah I don’t know what I’m talking about.
A lot of auto enthusiasts demand proof no one can provide due to economic constraints but internet blow yards can still insist on it for proof..... doing it is something else entirely.
04-09-2018, 06:30 AM
#69
I think I must have missed this original post and am a bit shocked by some of the content.There seems to be a debate about different liner suppliers, costs and technical solutions that I would like to contribute to. The problem is the more you know about the subject the longer the answer can be. Too short and you are open to all sorts of unhelpful responses – too long and no one reads it or you are accused of confusing readers.
Here is the short answer.
Manufacturers use Nikasil alloy bores for a lot of good technical reasons and because they are a better technical solution than ferrous liners. However in many applications ferrous replacement liners provide a good moderate cost solution to bore problems. This particular cylinder block design and dimensions (being open deck with thin alloy cylinder tubes) is not best suited to a ferrous dry liner solution and makes the quality of the machining and fitting of the liners crucial – and can still cause problems later. A Nikasil alloy dry replacement liner is a better solution (but more expensive) and a wet Nikasil alloy replacement cylinder that converts the design to a closed deck is even better (but also more expensive). Compared to the cost of the whole repair the extra cost of a better solution is minimal but for some can still too much when ferrous liners may well provide a cheaper way out with a slightly higher risk.
At Hartech we cannot handle any more cylinder work and will not compromise on our solution but if owners prefer to use alternatives - that is their choice.
Here is the long answer.
(1) Unlike manufacturers of ferrous liners - we are an Independent Porsche specialist and so have no liner product type or material to promote or champion. We weighed up all the technical issues and costs and decided that because we wanted to provide the best solution for our customers – we would only use Nikasil plated alloy cylinders.
(2) The M96/7 996/7 blocks required high pressure casting to force the molten aluminium into the porous Lokasil preform and the way the metal moulds were made allowed for this resulting in a very accurate castings but the downside was a central cylinder tube being free and unrestrained at the top and bottom and only held in the centre to the exterior block part of the casting (like a thin tube being held between fingers in the middle – say).
(3) From 2.5, 2.7 and 3.2 engines this cylinder tube was thicker, the bores reasonably stable and good space for coolant - but increasing the bore size to make the 3.4 & 3.6 and 3.8 engines in the same cylinder spacing and overall block size inevitably reduced the space for coolant and later on the cylinders were made thinner to compensate. This meant that they were less stable with earlier examples going oval over time under the forces of the bigger pistons and eventually cracked (“D” chunked).
(4) Probable changes to the Lokasil silicon particle size and mix increased cylinder strength in later engines but changes to piston coatings then resulting in scoring.
(5) Both the above usually required cylinder replacement to repair but if the original block was just re-plated it retained the original weak cylinder walls.
(6) With any liner material the quality of the result requires precise machining and fitting.
(7) Dry liners work best on closed deck blocks because the material outside the liner is more stable.
(8) Fitting dry liners inside a different material block inevitably can result in different bore sizes during thermal expansion and contraction and with a thin flat steel head gasket can result in some problems with head sealing which is not present if the liner and block are the same material with the same expansion coefficient.
(9) These different expansion rates working in combination with the resulting interference fit - influence the running size of the bores from cold to hot.
(10) The expansion from cold to hot is a function of the bore size as well and so smaller cylinders (in multi-cylinder engines of the same capacity) suit differential expansion cylinder liners better than larger bores when using the same material becomes more beneficial especially if it is similar to the piston material which provides the best piston clearances for all engine temperatures and conditions.
(11) It is a fact of mechanical science that fitting a dry liner inside an open deck tube results in both being weaker than one wet solid cylinder of the same overall inside and outside diameter and we have found that many ferrous liners fitted inside thin alloy tubes while being stable in their own right still gradually press against the thinner outer alloy tube and work the original interference fit loose allowing it to rock and potentially sink leading eventually to head sealing problems or coolant ingression and failure.
(12) Most of the failures we have seen of ferrous liners relate to poor design, machining inaccuracy or incorrect fitting (especially regarding the slip in vertical fit on cooling down the heated block).
(13) These cylinder blocks cannot be bored out at the top to enable the top of all the liners/new cylinders to fit in a machined recess by a tool that generates a full circle cut and can only be done by some form of circular interpolation that most liner fitting machine shops do not have the equipment to achieve – so very few can create an accurately fitting a top hat to stabilise the cylinder in use. If it did the diameter of the top hat is quite large and would require a very thick original ferrous liner and a lot of machining – adding to liner cost.
(14) It is no coincidence that manufacturers of performance engines using large cylinder bore diameters try to use a form of aluminium throughout the design to maintain tight cylinder clearances in all running conditions. Typically relevant examples are the GT3 and turbo versions of these engines that use aluminium cylinders with Nikasil plated bores fitted to precision machined bores throughout their height - despite their extra cost - creating a superior closed deck outcome.
(15) Because racing is at one predictable flat out coolant temperature, properly fitted ferrous liners in cylinder blocks with adequate coolant volumes and stability can be perfectly acceptable.
(16) In application in which ferrous liners would be the best solution we would be perfectly happy to use them and obtain them from the various suppliers mentioned - including Westwood who have a very good reputation. For supplying iron liners
(17) It is clear that some suppliers are managing to fit ferrous liners that work acceptably in the short term and as yet it is impossible (as rightly pointed out by AnthonyGS) to establish the long term reliability until more time passes and mileages increase.
(18) Our liners are more properly called “new cylinders” (because they do not fit inside another bore at the business end) and are manufactured under licence by a reputable F1 supplier and machined by us “IN-HOUSE” using brand new multi axis CNC machinery with diamond tooling that creates incredible accuracy with each individually fitted. We do not use interference fits (so no distortion or thermal expansion issues), are ribbed (for additional cooling surface area in the restricted coolant volumes present), and have a precision machined top hat fit in the cylinder block (converting the block to a closed deck).
(19) We are not saying there are not other solutions that might work perfectly well but we would claim that by any investigation our solution is the best technically and it is no surprise then that we enjoy a superb reputation for quality and long life.
(20) Really our way of doing things should be prohibitively expensive (and only for perfectionists) but because we do it all in house with specially manufactured and fixed tooling in new state of the art machinery and within a production process that is a small scale production line right from car (or engine or crankcase set) in to out again – we have managed to provide this solution at very similar prices (often even less) than competitors with different technical offerings. For example fitting 6 aerospace alloy Nikasil plated cylinders is £2,500 (plus any applicable taxes).
(21) We also make other coolant flow adjustments at the same time (after extensive testing and development) and other products included (for example re-coated original pistons where available).
(22) From car in to car out with a full rebuild with 6 Hartech cylinders, re-coated pistons upgraded IMS bearing (where required), new chains and runners, new crankshaft bearings, gaskets and seals etc usually runs out around £8,500 to £9,500. Just engines or crankcases obviously less. Video’s on our web site demonstrate this process www.hartech.org .
(23) Owners struggling to afford a comprehensive rebuild may find some suppliers using ferrous liners can offer a solution that they can afford and that works acceptably, but it does require exceptional machining and fitting quality which is often undertaken by a variety of specialists with varying capabilities and therefore different success rates.
(24) Owners wanting the best technical solution from a supplier with a superb reliability record for many years covering thousands of cylinders and who carries out the whole process in-house - may decide any small additional cost is well worth paying (and it does impact on eventual re-sale values).
(25) I have numbered these points and am happy to respond to any arguments that anyone wants to raise and to defend the points I have made on this medium or any other.
Baz
Here is the short answer.
Manufacturers use Nikasil alloy bores for a lot of good technical reasons and because they are a better technical solution than ferrous liners. However in many applications ferrous replacement liners provide a good moderate cost solution to bore problems. This particular cylinder block design and dimensions (being open deck with thin alloy cylinder tubes) is not best suited to a ferrous dry liner solution and makes the quality of the machining and fitting of the liners crucial – and can still cause problems later. A Nikasil alloy dry replacement liner is a better solution (but more expensive) and a wet Nikasil alloy replacement cylinder that converts the design to a closed deck is even better (but also more expensive). Compared to the cost of the whole repair the extra cost of a better solution is minimal but for some can still too much when ferrous liners may well provide a cheaper way out with a slightly higher risk.
At Hartech we cannot handle any more cylinder work and will not compromise on our solution but if owners prefer to use alternatives - that is their choice.
Here is the long answer.
(1) Unlike manufacturers of ferrous liners - we are an Independent Porsche specialist and so have no liner product type or material to promote or champion. We weighed up all the technical issues and costs and decided that because we wanted to provide the best solution for our customers – we would only use Nikasil plated alloy cylinders.
(2) The M96/7 996/7 blocks required high pressure casting to force the molten aluminium into the porous Lokasil preform and the way the metal moulds were made allowed for this resulting in a very accurate castings but the downside was a central cylinder tube being free and unrestrained at the top and bottom and only held in the centre to the exterior block part of the casting (like a thin tube being held between fingers in the middle – say).
(3) From 2.5, 2.7 and 3.2 engines this cylinder tube was thicker, the bores reasonably stable and good space for coolant - but increasing the bore size to make the 3.4 & 3.6 and 3.8 engines in the same cylinder spacing and overall block size inevitably reduced the space for coolant and later on the cylinders were made thinner to compensate. This meant that they were less stable with earlier examples going oval over time under the forces of the bigger pistons and eventually cracked (“D” chunked).
(4) Probable changes to the Lokasil silicon particle size and mix increased cylinder strength in later engines but changes to piston coatings then resulting in scoring.
(5) Both the above usually required cylinder replacement to repair but if the original block was just re-plated it retained the original weak cylinder walls.
(6) With any liner material the quality of the result requires precise machining and fitting.
(7) Dry liners work best on closed deck blocks because the material outside the liner is more stable.
(8) Fitting dry liners inside a different material block inevitably can result in different bore sizes during thermal expansion and contraction and with a thin flat steel head gasket can result in some problems with head sealing which is not present if the liner and block are the same material with the same expansion coefficient.
(9) These different expansion rates working in combination with the resulting interference fit - influence the running size of the bores from cold to hot.
(10) The expansion from cold to hot is a function of the bore size as well and so smaller cylinders (in multi-cylinder engines of the same capacity) suit differential expansion cylinder liners better than larger bores when using the same material becomes more beneficial especially if it is similar to the piston material which provides the best piston clearances for all engine temperatures and conditions.
(11) It is a fact of mechanical science that fitting a dry liner inside an open deck tube results in both being weaker than one wet solid cylinder of the same overall inside and outside diameter and we have found that many ferrous liners fitted inside thin alloy tubes while being stable in their own right still gradually press against the thinner outer alloy tube and work the original interference fit loose allowing it to rock and potentially sink leading eventually to head sealing problems or coolant ingression and failure.
(12) Most of the failures we have seen of ferrous liners relate to poor design, machining inaccuracy or incorrect fitting (especially regarding the slip in vertical fit on cooling down the heated block).
(13) These cylinder blocks cannot be bored out at the top to enable the top of all the liners/new cylinders to fit in a machined recess by a tool that generates a full circle cut and can only be done by some form of circular interpolation that most liner fitting machine shops do not have the equipment to achieve – so very few can create an accurately fitting a top hat to stabilise the cylinder in use. If it did the diameter of the top hat is quite large and would require a very thick original ferrous liner and a lot of machining – adding to liner cost.
(14) It is no coincidence that manufacturers of performance engines using large cylinder bore diameters try to use a form of aluminium throughout the design to maintain tight cylinder clearances in all running conditions. Typically relevant examples are the GT3 and turbo versions of these engines that use aluminium cylinders with Nikasil plated bores fitted to precision machined bores throughout their height - despite their extra cost - creating a superior closed deck outcome.
(15) Because racing is at one predictable flat out coolant temperature, properly fitted ferrous liners in cylinder blocks with adequate coolant volumes and stability can be perfectly acceptable.
(16) In application in which ferrous liners would be the best solution we would be perfectly happy to use them and obtain them from the various suppliers mentioned - including Westwood who have a very good reputation. For supplying iron liners
(17) It is clear that some suppliers are managing to fit ferrous liners that work acceptably in the short term and as yet it is impossible (as rightly pointed out by AnthonyGS) to establish the long term reliability until more time passes and mileages increase.
(18) Our liners are more properly called “new cylinders” (because they do not fit inside another bore at the business end) and are manufactured under licence by a reputable F1 supplier and machined by us “IN-HOUSE” using brand new multi axis CNC machinery with diamond tooling that creates incredible accuracy with each individually fitted. We do not use interference fits (so no distortion or thermal expansion issues), are ribbed (for additional cooling surface area in the restricted coolant volumes present), and have a precision machined top hat fit in the cylinder block (converting the block to a closed deck).
(19) We are not saying there are not other solutions that might work perfectly well but we would claim that by any investigation our solution is the best technically and it is no surprise then that we enjoy a superb reputation for quality and long life.
(20) Really our way of doing things should be prohibitively expensive (and only for perfectionists) but because we do it all in house with specially manufactured and fixed tooling in new state of the art machinery and within a production process that is a small scale production line right from car (or engine or crankcase set) in to out again – we have managed to provide this solution at very similar prices (often even less) than competitors with different technical offerings. For example fitting 6 aerospace alloy Nikasil plated cylinders is £2,500 (plus any applicable taxes).
(21) We also make other coolant flow adjustments at the same time (after extensive testing and development) and other products included (for example re-coated original pistons where available).
(22) From car in to car out with a full rebuild with 6 Hartech cylinders, re-coated pistons upgraded IMS bearing (where required), new chains and runners, new crankshaft bearings, gaskets and seals etc usually runs out around £8,500 to £9,500. Just engines or crankcases obviously less. Video’s on our web site demonstrate this process www.hartech.org .
(23) Owners struggling to afford a comprehensive rebuild may find some suppliers using ferrous liners can offer a solution that they can afford and that works acceptably, but it does require exceptional machining and fitting quality which is often undertaken by a variety of specialists with varying capabilities and therefore different success rates.
(24) Owners wanting the best technical solution from a supplier with a superb reliability record for many years covering thousands of cylinders and who carries out the whole process in-house - may decide any small additional cost is well worth paying (and it does impact on eventual re-sale values).
(25) I have numbered these points and am happy to respond to any arguments that anyone wants to raise and to defend the points I have made on this medium or any other.
Baz
Last edited by bazhart; 04-09-2018 at 06:32 AM. Reason: spacing wrong
04-09-2018, 11:08 AM
#70
Burning Brakes
I think I must have missed this original post and am a bit shocked by some of the content.There seems to be a debate about different liner suppliers, costs and technical solutions that I would like to contribute to. The problem is the more you know about the subject the longer the answer can be. Too short and you are open to all sorts of unhelpful responses – too long and no one reads it or you are accused of confusing readers.
Here is the short answer.
Manufacturers use Nikasil alloy bores for a lot of good technical reasons and because they are a better technical solution than ferrous liners. However in many applications ferrous replacement liners provide a good moderate cost solution to bore problems. This particular cylinder block design and dimensions (being open deck with thin alloy cylinder tubes) is not best suited to a ferrous dry liner solution and makes the quality of the machining and fitting of the liners crucial – and can still cause problems later. A Nikasil alloy dry replacement liner is a better solution (but more expensive) and a wet Nikasil alloy replacement cylinder that converts the design to a closed deck is even better (but also more expensive). Compared to the cost of the whole repair the extra cost of a better solution is minimal but for some can still too much when ferrous liners may well provide a cheaper way out with a slightly higher risk.
At Hartech we cannot handle any more cylinder work and will not compromise on our solution but if owners prefer to use alternatives - that is their choice.
Here is the long answer.
(1) Unlike manufacturers of ferrous liners - we are an Independent Porsche specialist and so have no liner product type or material to promote or champion. We weighed up all the technical issues and costs and decided that because we wanted to provide the best solution for our customers – we would only use Nikasil plated alloy cylinders.
(2) The M96/7 996/7 blocks required high pressure casting to force the molten aluminium into the porous Lokasil preform and the way the metal moulds were made allowed for this resulting in a very accurate castings but the downside was a central cylinder tube being free and unrestrained at the top and bottom and only held in the centre to the exterior block part of the casting (like a thin tube being held between fingers in the middle – say).
(3) From 2.5, 2.7 and 3.2 engines this cylinder tube was thicker, the bores reasonably stable and good space for coolant - but increasing the bore size to make the 3.4 & 3.6 and 3.8 engines in the same cylinder spacing and overall block size inevitably reduced the space for coolant and later on the cylinders were made thinner to compensate. This meant that they were less stable with earlier examples going oval over time under the forces of the bigger pistons and eventually cracked (“D” chunked).
(4) Probable changes to the Lokasil silicon particle size and mix increased cylinder strength in later engines but changes to piston coatings then resulting in scoring.
(5) Both the above usually required cylinder replacement to repair but if the original block was just re-plated it retained the original weak cylinder walls.
(6) With any liner material the quality of the result requires precise machining and fitting.
(7) Dry liners work best on closed deck blocks because the material outside the liner is more stable.
(8) Fitting dry liners inside a different material block inevitably can result in different bore sizes during thermal expansion and contraction and with a thin flat steel head gasket can result in some problems with head sealing which is not present if the liner and block are the same material with the same expansion coefficient.
(9) These different expansion rates working in combination with the resulting interference fit - influence the running size of the bores from cold to hot.
(10) The expansion from cold to hot is a function of the bore size as well and so smaller cylinders (in multi-cylinder engines of the same capacity) suit differential expansion cylinder liners better than larger bores when using the same material becomes more beneficial especially if it is similar to the piston material which provides the best piston clearances for all engine temperatures and conditions.
(11) It is a fact of mechanical science that fitting a dry liner inside an open deck tube results in both being weaker than one wet solid cylinder of the same overall inside and outside diameter and we have found that many ferrous liners fitted inside thin alloy tubes while being stable in their own right still gradually press against the thinner outer alloy tube and work the original interference fit loose allowing it to rock and potentially sink leading eventually to head sealing problems or coolant ingression and failure.
(12) Most of the failures we have seen of ferrous liners relate to poor design, machining inaccuracy or incorrect fitting (especially regarding the slip in vertical fit on cooling down the heated block).
(13) These cylinder blocks cannot be bored out at the top to enable the top of all the liners/new cylinders to fit in a machined recess by a tool that generates a full circle cut and can only be done by some form of circular interpolation that most liner fitting machine shops do not have the equipment to achieve – so very few can create an accurately fitting a top hat to stabilise the cylinder in use. If it did the diameter of the top hat is quite large and would require a very thick original ferrous liner and a lot of machining – adding to liner cost.
(14) It is no coincidence that manufacturers of performance engines using large cylinder bore diameters try to use a form of aluminium throughout the design to maintain tight cylinder clearances in all running conditions. Typically relevant examples are the GT3 and turbo versions of these engines that use aluminium cylinders with Nikasil plated bores fitted to precision machined bores throughout their height - despite their extra cost - creating a superior closed deck outcome.
(15) Because racing is at one predictable flat out coolant temperature, properly fitted ferrous liners in cylinder blocks with adequate coolant volumes and stability can be perfectly acceptable.
(16) In application in which ferrous liners would be the best solution we would be perfectly happy to use them and obtain them from the various suppliers mentioned - including Westwood who have a very good reputation. For supplying iron liners
(17) It is clear that some suppliers are managing to fit ferrous liners that work acceptably in the short term and as yet it is impossible (as rightly pointed out by AnthonyGS) to establish the long term reliability until more time passes and mileages increase.
(18) Our liners are more properly called “new cylinders” (because they do not fit inside another bore at the business end) and are manufactured under licence by a reputable F1 supplier and machined by us “IN-HOUSE” using brand new multi axis CNC machinery with diamond tooling that creates incredible accuracy with each individually fitted. We do not use interference fits (so no distortion or thermal expansion issues), are ribbed (for additional cooling surface area in the restricted coolant volumes present), and have a precision machined top hat fit in the cylinder block (converting the block to a closed deck).
(19) We are not saying there are not other solutions that might work perfectly well but we would claim that by any investigation our solution is the best technically and it is no surprise then that we enjoy a superb reputation for quality and long life.
(20) Really our way of doing things should be prohibitively expensive (and only for perfectionists) but because we do it all in house with specially manufactured and fixed tooling in new state of the art machinery and within a production process that is a small scale production line right from car (or engine or crankcase set) in to out again – we have managed to provide this solution at very similar prices (often even less) than competitors with different technical offerings. For example fitting 6 aerospace alloy Nikasil plated cylinders is £2,500 (plus any applicable taxes).
(21) We also make other coolant flow adjustments at the same time (after extensive testing and development) and other products included (for example re-coated original pistons where available).
(22) From car in to car out with a full rebuild with 6 Hartech cylinders, re-coated pistons upgraded IMS bearing (where required), new chains and runners, new crankshaft bearings, gaskets and seals etc usually runs out around £8,500 to £9,500. Just engines or crankcases obviously less. Video’s on our web site demonstrate this process www.hartech.org .
(23) Owners struggling to afford a comprehensive rebuild may find some suppliers using ferrous liners can offer a solution that they can afford and that works acceptably, but it does require exceptional machining and fitting quality which is often undertaken by a variety of specialists with varying capabilities and therefore different success rates.
(24) Owners wanting the best technical solution from a supplier with a superb reliability record for many years covering thousands of cylinders and who carries out the whole process in-house - may decide any small additional cost is well worth paying (and it does impact on eventual re-sale values).
(25) I have numbered these points and am happy to respond to any arguments that anyone wants to raise and to defend the points I have made on this medium or any other.
Baz
Here is the short answer.
Manufacturers use Nikasil alloy bores for a lot of good technical reasons and because they are a better technical solution than ferrous liners. However in many applications ferrous replacement liners provide a good moderate cost solution to bore problems. This particular cylinder block design and dimensions (being open deck with thin alloy cylinder tubes) is not best suited to a ferrous dry liner solution and makes the quality of the machining and fitting of the liners crucial – and can still cause problems later. A Nikasil alloy dry replacement liner is a better solution (but more expensive) and a wet Nikasil alloy replacement cylinder that converts the design to a closed deck is even better (but also more expensive). Compared to the cost of the whole repair the extra cost of a better solution is minimal but for some can still too much when ferrous liners may well provide a cheaper way out with a slightly higher risk.
At Hartech we cannot handle any more cylinder work and will not compromise on our solution but if owners prefer to use alternatives - that is their choice.
Here is the long answer.
(1) Unlike manufacturers of ferrous liners - we are an Independent Porsche specialist and so have no liner product type or material to promote or champion. We weighed up all the technical issues and costs and decided that because we wanted to provide the best solution for our customers – we would only use Nikasil plated alloy cylinders.
(2) The M96/7 996/7 blocks required high pressure casting to force the molten aluminium into the porous Lokasil preform and the way the metal moulds were made allowed for this resulting in a very accurate castings but the downside was a central cylinder tube being free and unrestrained at the top and bottom and only held in the centre to the exterior block part of the casting (like a thin tube being held between fingers in the middle – say).
(3) From 2.5, 2.7 and 3.2 engines this cylinder tube was thicker, the bores reasonably stable and good space for coolant - but increasing the bore size to make the 3.4 & 3.6 and 3.8 engines in the same cylinder spacing and overall block size inevitably reduced the space for coolant and later on the cylinders were made thinner to compensate. This meant that they were less stable with earlier examples going oval over time under the forces of the bigger pistons and eventually cracked (“D” chunked).
(4) Probable changes to the Lokasil silicon particle size and mix increased cylinder strength in later engines but changes to piston coatings then resulting in scoring.
(5) Both the above usually required cylinder replacement to repair but if the original block was just re-plated it retained the original weak cylinder walls.
(6) With any liner material the quality of the result requires precise machining and fitting.
(7) Dry liners work best on closed deck blocks because the material outside the liner is more stable.
(8) Fitting dry liners inside a different material block inevitably can result in different bore sizes during thermal expansion and contraction and with a thin flat steel head gasket can result in some problems with head sealing which is not present if the liner and block are the same material with the same expansion coefficient.
(9) These different expansion rates working in combination with the resulting interference fit - influence the running size of the bores from cold to hot.
(10) The expansion from cold to hot is a function of the bore size as well and so smaller cylinders (in multi-cylinder engines of the same capacity) suit differential expansion cylinder liners better than larger bores when using the same material becomes more beneficial especially if it is similar to the piston material which provides the best piston clearances for all engine temperatures and conditions.
(11) It is a fact of mechanical science that fitting a dry liner inside an open deck tube results in both being weaker than one wet solid cylinder of the same overall inside and outside diameter and we have found that many ferrous liners fitted inside thin alloy tubes while being stable in their own right still gradually press against the thinner outer alloy tube and work the original interference fit loose allowing it to rock and potentially sink leading eventually to head sealing problems or coolant ingression and failure.
(12) Most of the failures we have seen of ferrous liners relate to poor design, machining inaccuracy or incorrect fitting (especially regarding the slip in vertical fit on cooling down the heated block).
(13) These cylinder blocks cannot be bored out at the top to enable the top of all the liners/new cylinders to fit in a machined recess by a tool that generates a full circle cut and can only be done by some form of circular interpolation that most liner fitting machine shops do not have the equipment to achieve – so very few can create an accurately fitting a top hat to stabilise the cylinder in use. If it did the diameter of the top hat is quite large and would require a very thick original ferrous liner and a lot of machining – adding to liner cost.
(14) It is no coincidence that manufacturers of performance engines using large cylinder bore diameters try to use a form of aluminium throughout the design to maintain tight cylinder clearances in all running conditions. Typically relevant examples are the GT3 and turbo versions of these engines that use aluminium cylinders with Nikasil plated bores fitted to precision machined bores throughout their height - despite their extra cost - creating a superior closed deck outcome.
(15) Because racing is at one predictable flat out coolant temperature, properly fitted ferrous liners in cylinder blocks with adequate coolant volumes and stability can be perfectly acceptable.
(16) In application in which ferrous liners would be the best solution we would be perfectly happy to use them and obtain them from the various suppliers mentioned - including Westwood who have a very good reputation. For supplying iron liners
(17) It is clear that some suppliers are managing to fit ferrous liners that work acceptably in the short term and as yet it is impossible (as rightly pointed out by AnthonyGS) to establish the long term reliability until more time passes and mileages increase.
(18) Our liners are more properly called “new cylinders” (because they do not fit inside another bore at the business end) and are manufactured under licence by a reputable F1 supplier and machined by us “IN-HOUSE” using brand new multi axis CNC machinery with diamond tooling that creates incredible accuracy with each individually fitted. We do not use interference fits (so no distortion or thermal expansion issues), are ribbed (for additional cooling surface area in the restricted coolant volumes present), and have a precision machined top hat fit in the cylinder block (converting the block to a closed deck).
(19) We are not saying there are not other solutions that might work perfectly well but we would claim that by any investigation our solution is the best technically and it is no surprise then that we enjoy a superb reputation for quality and long life.
(20) Really our way of doing things should be prohibitively expensive (and only for perfectionists) but because we do it all in house with specially manufactured and fixed tooling in new state of the art machinery and within a production process that is a small scale production line right from car (or engine or crankcase set) in to out again – we have managed to provide this solution at very similar prices (often even less) than competitors with different technical offerings. For example fitting 6 aerospace alloy Nikasil plated cylinders is £2,500 (plus any applicable taxes).
(21) We also make other coolant flow adjustments at the same time (after extensive testing and development) and other products included (for example re-coated original pistons where available).
(22) From car in to car out with a full rebuild with 6 Hartech cylinders, re-coated pistons upgraded IMS bearing (where required), new chains and runners, new crankshaft bearings, gaskets and seals etc usually runs out around £8,500 to £9,500. Just engines or crankcases obviously less. Video’s on our web site demonstrate this process www.hartech.org .
(23) Owners struggling to afford a comprehensive rebuild may find some suppliers using ferrous liners can offer a solution that they can afford and that works acceptably, but it does require exceptional machining and fitting quality which is often undertaken by a variety of specialists with varying capabilities and therefore different success rates.
(24) Owners wanting the best technical solution from a supplier with a superb reliability record for many years covering thousands of cylinders and who carries out the whole process in-house - may decide any small additional cost is well worth paying (and it does impact on eventual re-sale values).
(25) I have numbered these points and am happy to respond to any arguments that anyone wants to raise and to defend the points I have made on this medium or any other.
Baz
04-09-2018, 01:49 PM
#71
The difficulty with all cylinder liner replacements is that the quality of the result depends mainly on the skill, experience and equipment available to the people carrying out the work.This engine type demands more accuracy, different design parameters, tighter tolerances and different equipment than the type used perfectly well for most cylinder liner replacements and liner types.
It is in our opinion less suitable for ferrous dry liners than aluminium Nikasil plated ones and better still alloy Nikasil plated ones fitted in a wet liner design with closed deck top fitting applied. Because of this we prefer to limit the supply to that which we can do ourselves or under licence strictly applying our technology with people of similar mentality and this we are doing with Alpine Autowerks in Canada.
We have had numerous requests to sell our cylinders in the USA but although it would recover some valuable investment – we have yet to find a suitable outlet that understands the need to adopt our systems, quality limits, machinery and processes or are willing to enter into a technology agreement because they assume it is easy to fit them and that they don’t need any of our support or advice.
We know that this attitude could damage the outcome and our reputation and prefer not to do so until and unless we find a suitable technology partner in the USA. Meanwhile we do have some crankcase sets that we might be able to use on an exchange basis but there is little option or alternative otherwise than to send them to the UK and back (or contact Alpine in Canada) which I appreciate is less than ideal.
Can I just make it clear however that we are not claiming that our method and technology is the only one that works nor that there are not other specialists in the USA who can do a good job – it is just that this particular engine crankcase design presents additional problems that most other types do not and that as a result the success of various previously good suppliers getting involved in solutions can be variable and leads to problems and arguments over the Internet that are unfortunate. That is why I have tried to explain in more detail exactly why we think our solution is the best and that doing all the work ourselves, “IN HOUSE” and under our total control – is the best way to liberate that superior technology (or anywhere else that strictly adopts the same process – as Alpine are doing).
We (like many USA specialists with many years of experience successfully repairing these engines) have experienced unfortunate owners who tried other solutions only to have them fail (and have the evidence to prove it but prefer not to expose other suppliers trying their best and in so doing incurring all the adverse feedback that such a mistakenly perceived attack would unravel). We have all had to do the job again properly after other solutions and suppliers have been tried to save some money - while the unfortunate owner then incurs the cost all over again – and it is this fact that leads good suppliers to appear critical when Internet posts suggest newcomers already have it all sorted out.
This engine type is not as straightforward as most other types and reliable solutions require a lot of knowledge, experience and special equipment – which is why – rather than getting immersed in direct arguments with others I have preferred to just try and list facts and allow owners in need of rebuilds to make their own decisions about where to go and what solution to adopt.
We are flat out supplying the European demand for our top quality rebuilds employing several specialists in a flow production process that is so efficient it allows us to supply superior quality at competitive prices (in Europe) and the only way we could expand would be to double the whole process which the lifespan of this type of engine repair would not justify.
So our advice is not because we are trying to drum up more business nor to discredit what anyone else is doing and our reluctance in supplying our cylinders is purely because we value our reputation more than we seek expansion at a cost. Some USA specialists seem to be coping well and I do not want to get involved in arguments with anyone over there about what they do and who is better or not. I just hope that by providing the facts I have – that it stops some of the inaccurate responses I have read on the subject that simply confuse owners and can result in them making a poor choice that they might regret.
Baz
It is in our opinion less suitable for ferrous dry liners than aluminium Nikasil plated ones and better still alloy Nikasil plated ones fitted in a wet liner design with closed deck top fitting applied. Because of this we prefer to limit the supply to that which we can do ourselves or under licence strictly applying our technology with people of similar mentality and this we are doing with Alpine Autowerks in Canada.
We have had numerous requests to sell our cylinders in the USA but although it would recover some valuable investment – we have yet to find a suitable outlet that understands the need to adopt our systems, quality limits, machinery and processes or are willing to enter into a technology agreement because they assume it is easy to fit them and that they don’t need any of our support or advice.
We know that this attitude could damage the outcome and our reputation and prefer not to do so until and unless we find a suitable technology partner in the USA. Meanwhile we do have some crankcase sets that we might be able to use on an exchange basis but there is little option or alternative otherwise than to send them to the UK and back (or contact Alpine in Canada) which I appreciate is less than ideal.
Can I just make it clear however that we are not claiming that our method and technology is the only one that works nor that there are not other specialists in the USA who can do a good job – it is just that this particular engine crankcase design presents additional problems that most other types do not and that as a result the success of various previously good suppliers getting involved in solutions can be variable and leads to problems and arguments over the Internet that are unfortunate. That is why I have tried to explain in more detail exactly why we think our solution is the best and that doing all the work ourselves, “IN HOUSE” and under our total control – is the best way to liberate that superior technology (or anywhere else that strictly adopts the same process – as Alpine are doing).
We (like many USA specialists with many years of experience successfully repairing these engines) have experienced unfortunate owners who tried other solutions only to have them fail (and have the evidence to prove it but prefer not to expose other suppliers trying their best and in so doing incurring all the adverse feedback that such a mistakenly perceived attack would unravel). We have all had to do the job again properly after other solutions and suppliers have been tried to save some money - while the unfortunate owner then incurs the cost all over again – and it is this fact that leads good suppliers to appear critical when Internet posts suggest newcomers already have it all sorted out.
This engine type is not as straightforward as most other types and reliable solutions require a lot of knowledge, experience and special equipment – which is why – rather than getting immersed in direct arguments with others I have preferred to just try and list facts and allow owners in need of rebuilds to make their own decisions about where to go and what solution to adopt.
We are flat out supplying the European demand for our top quality rebuilds employing several specialists in a flow production process that is so efficient it allows us to supply superior quality at competitive prices (in Europe) and the only way we could expand would be to double the whole process which the lifespan of this type of engine repair would not justify.
So our advice is not because we are trying to drum up more business nor to discredit what anyone else is doing and our reluctance in supplying our cylinders is purely because we value our reputation more than we seek expansion at a cost. Some USA specialists seem to be coping well and I do not want to get involved in arguments with anyone over there about what they do and who is better or not. I just hope that by providing the facts I have – that it stops some of the inaccurate responses I have read on the subject that simply confuse owners and can result in them making a poor choice that they might regret.
Baz
Last edited by bazhart; 04-09-2018 at 01:53 PM. Reason: spacing wrong
04-09-2018, 03:08 PM
#72
Three Wheelin'
Join Date: Jun 2016
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"Alpine Autowerks wants to announce a new partnership with Hartech Auto as an agent for their M96/M97 cylinder replacement."
04-09-2018, 11:54 PM
#73
Rennlist Member
BAZ, are you still doing the cylinder support ring and re-rounding procedures? Or do you replace the cylinders on all your rebuilds now with the Alloy/Nickasil cylinders. I think this is a very frugal and an upgrade/preventative mod to extend the life of the factory blocks that have an otherwise perfect bore ( with no scoring). I think any m96/7 bore of 96mm or 99mm factory case if disassembled should get the support rings/re-round procedure as part of a refresh or rebuild. No telling how long the Lokasil surface will last if no scoring occures, they sure don't ever show any signs of ring wear.
04-10-2018, 06:05 AM
#74
The difference in why the same bore surface lasts longer on bank 1 than bank 2 is a combination of various factors like the hotter thrust surface of the bore on bank 2 reducing the oil viscosity and making the oil film thinner and hence allowing loose silicon particles to impact on the piston plastic coating more, the oil draining from the thrust face after stopping on bank 2 but dripping onto the thrust face on bank 1 ready for an oil rich start up etc.
Rather like a pot hole in a road – once a few pieces of silicon become free and rub up and down the bore and over the small hole they leave the impact of them on the original bore grows the score until there is too much loose silicon stuck on the piston and the bore gets severely scored.
Furthermore the porous surface of Lokasil is (in our opinion) subject to fatigue and releases more silicon particles with age. The bonding is variable and we have seen some engines in which whole areas of Lokasil have been washed away by the oil – over time
The piston coating also becomes less bonded to the piston surface with age and is more likely to peel off. Taking all this into account and bearing in mind that new buyers will usually pay a premium if all 6 cylinders were changed – the public have generally come to terms with the benefits of changing all 6 cylinders and fitting support rings has become relatively rare.
However we still reluctantly try to help those unfortunate owners that experienced a failure that they simply struggle to afford to fix properly - for whom the support rings can make a difference.
Baz
Rather like a pot hole in a road – once a few pieces of silicon become free and rub up and down the bore and over the small hole they leave the impact of them on the original bore grows the score until there is too much loose silicon stuck on the piston and the bore gets severely scored.
Furthermore the porous surface of Lokasil is (in our opinion) subject to fatigue and releases more silicon particles with age. The bonding is variable and we have seen some engines in which whole areas of Lokasil have been washed away by the oil – over time
The piston coating also becomes less bonded to the piston surface with age and is more likely to peel off. Taking all this into account and bearing in mind that new buyers will usually pay a premium if all 6 cylinders were changed – the public have generally come to terms with the benefits of changing all 6 cylinders and fitting support rings has become relatively rare.
However we still reluctantly try to help those unfortunate owners that experienced a failure that they simply struggle to afford to fix properly - for whom the support rings can make a difference.
Baz
Last edited by bazhart; 04-10-2018 at 06:07 AM. Reason: spacing wrong
01-07-2019, 10:36 AM
#75
Rennlist Member
Rokket built me a Rocket....
Soooooo.... A year plus later, I can finally report back that Rocket built me a fantastic short block! It took so long because of many reasons. Some of the time-killer highlights included a patient search for a low-miles crank shaft & basket (which took a good month or so); once decision was made to go to 3.6L we had to wait almost three months for Woessner to ship us the new pistons & rings; my mechanic's shop moved three times in the last 9 months due to life dynamics; and I ended up having back issues and resulting surgery for most of 2018. None of the delays are Rokket's fault. Instead, they were more contributed by forced patience as I looked for the parts he told me we needed (the crank & basket came from same car, a wrecked low-miles 2000 Boxster S that uses same crank part number). One other delay came when we spun my engine's IMS shaft on a lathe, and found it to have 0.004" of rollout. I bought two more IMS shafts for us to test and cherry pick, and ended up with one that had only 0.001" rollout, which is now in my engine.
The short-block was sleeved using Rokket's described process at the beginning of this thread, and his shop also fully re-built my heads. Rocket offered to port and polish my exhaust ports, as that's a proven internal enhancement that can make a noticeable difference, but my budget simply didn't allow for that. Instead, I opted for simpler gasket-matching the exhaust ports (the next best thing) and dynamic balancing of the entire rotating assembly. I also bought a lightweight flywheel to be spun and balanced with the rest of the engine bits.
Rokket buys a lot of P-car parts and also helped me shave about $700 off the eye-opening list of accessories and new bits that we needed in order to really do this properly (chains, tensioners, guide rails, water pump, AOS, oil cooler, etc, etc, etc, etc).
So, once everything finally got put back together and installed in the car, the engine started on my mechanic's first key turn. He told me he just stayed on the ignition and watched the oil pressure build, then the compression build and when he let go of the key it chugged to life and settled into a steady idle. Even he was floored by how smooth this engine runs. It has been running smooth for about 600 miles now, running Royal Purple break-in oil.
So, I now have a balanced and blueprinted 3.6L instead of a stock 3.4, with gasket-matched port work done to the heads, and a lightweight flywheel. I also added the 200 cell cross-pipes from TopGear UK to my Agency Power headers and cans and the car runs like a raped ape. No check-engine lights.
Rokket has been sending these blocks out of town when he does them, so with me being local I have promised to bring him the car after it's broken in so we can put it on his dyno. The car feels a fair bit stronger than it did before, and stronger than my brother's '99 (w/ Fabspeed x-pipe Cat setup) and on par with my neighbors '06 997 C2 cabriolet (w/Fabspeed muffler-bypass). My butt-dyno tells me that my C4 is definitely C2 fast now.., but we are going to get proof.
Rokket, thanks a ton for building me a fantastic engine. I'm happy to be the first of your customers to report to this thread and I apologize it has taken so long. I'm also grateful for letting us use that engine-stand bracket for longer than any of us thought it would take. I'll see you either at your shop, or when you're flogging one of your cars around Sebring later this year.
The short-block was sleeved using Rokket's described process at the beginning of this thread, and his shop also fully re-built my heads. Rocket offered to port and polish my exhaust ports, as that's a proven internal enhancement that can make a noticeable difference, but my budget simply didn't allow for that. Instead, I opted for simpler gasket-matching the exhaust ports (the next best thing) and dynamic balancing of the entire rotating assembly. I also bought a lightweight flywheel to be spun and balanced with the rest of the engine bits.
Rokket buys a lot of P-car parts and also helped me shave about $700 off the eye-opening list of accessories and new bits that we needed in order to really do this properly (chains, tensioners, guide rails, water pump, AOS, oil cooler, etc, etc, etc, etc).
So, once everything finally got put back together and installed in the car, the engine started on my mechanic's first key turn. He told me he just stayed on the ignition and watched the oil pressure build, then the compression build and when he let go of the key it chugged to life and settled into a steady idle. Even he was floored by how smooth this engine runs. It has been running smooth for about 600 miles now, running Royal Purple break-in oil.
So, I now have a balanced and blueprinted 3.6L instead of a stock 3.4, with gasket-matched port work done to the heads, and a lightweight flywheel. I also added the 200 cell cross-pipes from TopGear UK to my Agency Power headers and cans and the car runs like a raped ape. No check-engine lights.
Rokket has been sending these blocks out of town when he does them, so with me being local I have promised to bring him the car after it's broken in so we can put it on his dyno. The car feels a fair bit stronger than it did before, and stronger than my brother's '99 (w/ Fabspeed x-pipe Cat setup) and on par with my neighbors '06 997 C2 cabriolet (w/Fabspeed muffler-bypass). My butt-dyno tells me that my C4 is definitely C2 fast now.., but we are going to get proof.
Rokket, thanks a ton for building me a fantastic engine. I'm happy to be the first of your customers to report to this thread and I apologize it has taken so long. I'm also grateful for letting us use that engine-stand bracket for longer than any of us thought it would take. I'll see you either at your shop, or when you're flogging one of your cars around Sebring later this year.
