944 S2 Engine rebuild info: Doc?
09-13-2008, 12:09 PM
#16
Rennlist Member
I can elaborate on the Diamond pistons and the build decisions.
My fundamental philosophy was to bring the car back to what would have been delivered from the factory in the most economical, reliable and robust manner, with perhaps some hidden tweaks. Nothing ostentatious. You shouldn't be able to tell that there is anything special about this car when you see it on the road or parked. I use this car for DE sessions at Waterford and much more so for street driving.
The initial state was that cylinders 2 and 3 had some deep scratches / gouges which was not good. So the bores had to be redone. No surprise for an engine that has 185K MIs on it.
The choices to address this are 1). replace the block with a good / used, 2). steel sleeve the bores, and 3). Nikasil plate the bores and hone them.
Steel sleeve inserts, in my opinion would cause temperature related expansion / contraction issues. Yes, I know that GM does this on all / most of their aluminum engines and it works, but still, a Porsche engine?
If you choose a good used, you really never know what you are going to end up with, it may need more work that what you started out with. I wanted to keep the same engine serial number with the chassis serial number, in the, perhaps foolish hope, that this would matter for the value of the car later on.
911 engines are Nikasil coated from the get go. Nikasil is a harder substance than the Alusil finishing that the engine was manufactured with.
I chose to Nikasil coat the bores, and have them hones to the pistons. The shop that did this was US Chrome http://www.usnicom.com. Cost was around $1200, and they needed the pistons to hone the cylinder for fitment.
When the old pistons arrived at US chrome, they said they were wore out and were unsuitable for going forward.
I priced out Porsche pistons and they were $395 each. Ouch!. I called Lindsey Racing, and they quoted me $1K on the phone for a set of JE pistons. Still Ouch!. I called Diamond racing, and they quoted me custom manufactured pistons for $700. OK. Part of the options was some mild lightening and a molly coated skirt so that there would be fewer friction losses. The material used is stronger than OEM, so it could stand some lightening without losing strength.
Since I was not interested in over boring, I held to the 104mm tolerance group 0 bore size. For purity's sake, I wanted to keep the engine as close to factory fresh as I could get.
When the pistons and block came back from honing I weighed them. It turned out that each piston was on average 37g lighter than the stock ones. Cool.
I sent the crank, rods, pistons, pins and rings for balancing and pin weighting to Crankshaft Craftsmen in Detroit (close by). This was relatively inexpensive to do. I think I paid a total of $130, but I believe that it'll be well worth it.
They found that Porsche did a good job of balancing the crank, but made some very minor adjustments. They pin weighted each rod and weight matched it to the pistons, rings and pins so that the weight difference from min to max across all the cylinders was a mere .1g, so the engine will be very balanced.
So now, Vaughan and I will be starting the build process tomorrow, Sunday, with putting the bottom end back together.
This is the path that I have chosen. Other may choose other paths, and that's just fine. Each of these cars is an expression of the individual's needs / wants / desires / priorities, so they'll all end up being different and a reflection of their owners.
My fundamental philosophy was to bring the car back to what would have been delivered from the factory in the most economical, reliable and robust manner, with perhaps some hidden tweaks. Nothing ostentatious. You shouldn't be able to tell that there is anything special about this car when you see it on the road or parked. I use this car for DE sessions at Waterford and much more so for street driving.
The initial state was that cylinders 2 and 3 had some deep scratches / gouges which was not good. So the bores had to be redone. No surprise for an engine that has 185K MIs on it.
The choices to address this are 1). replace the block with a good / used, 2). steel sleeve the bores, and 3). Nikasil plate the bores and hone them.
Steel sleeve inserts, in my opinion would cause temperature related expansion / contraction issues. Yes, I know that GM does this on all / most of their aluminum engines and it works, but still, a Porsche engine?
If you choose a good used, you really never know what you are going to end up with, it may need more work that what you started out with. I wanted to keep the same engine serial number with the chassis serial number, in the, perhaps foolish hope, that this would matter for the value of the car later on.
911 engines are Nikasil coated from the get go. Nikasil is a harder substance than the Alusil finishing that the engine was manufactured with.
I chose to Nikasil coat the bores, and have them hones to the pistons. The shop that did this was US Chrome http://www.usnicom.com. Cost was around $1200, and they needed the pistons to hone the cylinder for fitment.
When the old pistons arrived at US chrome, they said they were wore out and were unsuitable for going forward.
I priced out Porsche pistons and they were $395 each. Ouch!. I called Lindsey Racing, and they quoted me $1K on the phone for a set of JE pistons. Still Ouch!. I called Diamond racing, and they quoted me custom manufactured pistons for $700. OK. Part of the options was some mild lightening and a molly coated skirt so that there would be fewer friction losses. The material used is stronger than OEM, so it could stand some lightening without losing strength.
Since I was not interested in over boring, I held to the 104mm tolerance group 0 bore size. For purity's sake, I wanted to keep the engine as close to factory fresh as I could get.
When the pistons and block came back from honing I weighed them. It turned out that each piston was on average 37g lighter than the stock ones. Cool.
I sent the crank, rods, pistons, pins and rings for balancing and pin weighting to Crankshaft Craftsmen in Detroit (close by). This was relatively inexpensive to do. I think I paid a total of $130, but I believe that it'll be well worth it.
They found that Porsche did a good job of balancing the crank, but made some very minor adjustments. They pin weighted each rod and weight matched it to the pistons, rings and pins so that the weight difference from min to max across all the cylinders was a mere .1g, so the engine will be very balanced.
So now, Vaughan and I will be starting the build process tomorrow, Sunday, with putting the bottom end back together.
This is the path that I have chosen. Other may choose other paths, and that's just fine. Each of these cars is an expression of the individual's needs / wants / desires / priorities, so they'll all end up being different and a reflection of their owners.
09-13-2008, 12:45 PM
#17
Nordschleife Master
Thread Starter
I can elaborate on the Diamond pistons and the build decisions.
My fundamental philosophy was to bring the car back to what would have been delivered from the factory in the most economical, reliable and robust manner, with perhaps some hidden tweaks. Nothing ostentatious. You shouldn't be able to tell that there is anything special about this car when you see it on the road or parked. I use this car for DE sessions at Waterford and much more so for street driving...
My fundamental philosophy was to bring the car back to what would have been delivered from the factory in the most economical, reliable and robust manner, with perhaps some hidden tweaks. Nothing ostentatious. You shouldn't be able to tell that there is anything special about this car when you see it on the road or parked. I use this car for DE sessions at Waterford and much more so for street driving...
Could you PM me a contact number to discuss this at length?
C.
09-13-2008, 07:58 PM
#18
Rennlist Member
Here's a couple more things to add to your list.
Oil pump drive gear.
Balance shaft sleeves.
These get wear grooves in them after many miles and can be a source of leaks.
You might as well add a
water pump
thermostat
timing belt
balance belt
cam chain tensioner
motor mounts
injectors cleaned and flow matched
any vacuum hoses that are cracked
all new coolant hoses.
Oil pump drive gear.
Balance shaft sleeves.
These get wear grooves in them after many miles and can be a source of leaks.
You might as well add a
water pump
thermostat
timing belt
balance belt
cam chain tensioner
motor mounts
injectors cleaned and flow matched
any vacuum hoses that are cracked
all new coolant hoses.
09-13-2008, 08:45 PM
#19
Nordschleife Master
Thread Starter
Here's a couple more things to add to your list.
Oil pump drive gear.
Balance shaft sleeves.
These get wear grooves in them after many miles and can be a source of leaks.
You might as well add a
water pump
thermostat
timing belt
balance belt
cam chain tensioner
motor mounts
injectors cleaned and flow matched
any vacuum hoses that are cracked
all new coolant hoses.
Oil pump drive gear.
Balance shaft sleeves.
These get wear grooves in them after many miles and can be a source of leaks.
You might as well add a
water pump
thermostat
timing belt
balance belt
cam chain tensioner
motor mounts
injectors cleaned and flow matched
any vacuum hoses that are cracked
all new coolant hoses.
All good stuff, but don't forget. We're on a budget here.
C.
09-13-2008, 09:08 PM
#20
Rennlist Member
Yea, but the trouble is that once it's this far apart, it's easier to replace it now, rather than tearing it all apart again to change it later.
It's a balance thing between how bad the part is now, money and time that's available now. Everybody has to make their own choices.
One thing that I've learned so far in this thread is that I'm going to look over that oil pump gear once more for grooves!
I've already replaced the top pad from the cam chain tensioner and the cam teeth look good, so I figure that'll be OK.
It's already got a set of fresh rod bearings, so that's OK.
I know that the waterpump was just replaced at 165K MI, so I'm not going to replace that. Motor mounts already done 2 years ago - upgraded to turbo ones.
I know that I porbably should have the injectors checked and flow matched, but I wonder about the price of that operation, and I know that I have to replace the injector seals.
It's a balance thing between how bad the part is now, money and time that's available now. Everybody has to make their own choices.
One thing that I've learned so far in this thread is that I'm going to look over that oil pump gear once more for grooves!
I've already replaced the top pad from the cam chain tensioner and the cam teeth look good, so I figure that'll be OK.
It's already got a set of fresh rod bearings, so that's OK.
I know that the waterpump was just replaced at 165K MI, so I'm not going to replace that. Motor mounts already done 2 years ago - upgraded to turbo ones.
I know that I porbably should have the injectors checked and flow matched, but I wonder about the price of that operation, and I know that I have to replace the injector seals.
09-14-2008, 02:54 PM
#21
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Don't forget the S2 has an additonal timing belt roller on the tensioner (in addition to the toothed roller), so there are actually 3 rollers you need for the timing belt, plus 2 for the balance shaft belt. Part number 944.105.241.02
Cam Chain: 944.105.501.01
As was stated earlier, the oil pump drive sleeve, spacer sleeves, waterpump/thermostat, motor mounts, vacuum lines, injectors at minimum resealed, coolant hoses.
Multiple oil filters for breaking in the motor
Cylinder head washers, and nuts
Clutch and related hardware. If not replacing, then at least new flywheel and pressure plate bolts. Flywheel bolts are 1 time use, and i consider the pressure plate bolts one time use as well, just due to the allen or cheesehead tool design.
All new hose clamps, etc
Heater control valve if it hasn't been replaced recently.
DME temp sensor
Cam Chain: 944.105.501.01
As was stated earlier, the oil pump drive sleeve, spacer sleeves, waterpump/thermostat, motor mounts, vacuum lines, injectors at minimum resealed, coolant hoses.
Multiple oil filters for breaking in the motor
Cylinder head washers, and nuts
Clutch and related hardware. If not replacing, then at least new flywheel and pressure plate bolts. Flywheel bolts are 1 time use, and i consider the pressure plate bolts one time use as well, just due to the allen or cheesehead tool design.
All new hose clamps, etc
Heater control valve if it hasn't been replaced recently.
DME temp sensor
09-14-2008, 05:12 PM
#22
Nordschleife Master
Thread Starter
Good stuff all...many thanks. Here's my list as of today:
Engine Parts / services needed:
Con Rods Opt 1
4 – Forged Carrillo rods……………………………………....……….$1200.00
Con Rods Opt 2
4 – Used Forged 968 rods (Low miles only)……………...……...$380.00
Piston options (TBD - once inspection is complete)
New Diamond Racing pistons (confirm compatibility)…….......$700.00
New LN Engineering / J&E Pistons……….........……..………....……$890.00
Used Forged 968 Pistons (OE size 104mm)..……..………...……TBD
Engine rebuild kit: (Source Vertex Auto)……………..………..……$890.00
1 Rod Bearing Set (Standard) - 92810314315
1 Main Bearing Set (Standard) - 94410190100
1 Piston Ring Set - 94410390260
1 Balance Shaft Belt - 94410221902
1 Timing Belt - 94410532302
16 Valve Guides - 94410432700
1 Head Gasket Set (Upper) - 94410090106
1 Case Gasket Set (Lower) - 94410090103
8 Connecting Rod Nuts - 92810317202
1 Front Engine Seal Kit - 94410100000
1 Loctite 574 Sealant 50 ml Tube - 00004301000
Balance shaft bearing (x4)…..94410112110…...………..…….….$65.00
Balance tensioner…………….94410202507…...……….....….….….$25.00
Balance roller………………….94410227706…...………..…....….….$29.00
Timing belt roller……………....94410524102…...……..…..…….….$29.00
Timing belt roller 46.2 ..……...94410524103…...………..…….….$29.00
Cam Hall Sensor ……………...94460612500M14.…..…....…..…...$21.50
Block machine work……..………....……………….….…..…...………$1000.00
(to include - honing cylinders to spec, machining piston oil squirters, cleaning block, and balancing crank
Refurb / Machine Head work……………………………....……....…..$800.00
Timing chain tensioner……….94410504901…...……..…..………$359.00
Exhaust valve (x8)…………….92810564206…...……….....………$272.00
Valve guides (x16)……………94410432700…...……….....…..……$79.20
Valve stem seal (x16)…………92810460107…...………..…..…....$47.84
Cam Hall Sensor ……………...94460617002M14.…...…..…..….$139.75
Oil Pump Sleeve……………….94410716102M260..………..……...$35.50
Oil Pump Spacer……………….94410791101M100..………..….….$10.50
Grand Total (rod Opt2, Diamond piston Opt): $4932.29
NOTES: Water pump and belts are new as of 5K ago. I also have a new Cam chain that came with the car. The flywheel, clutch and related parts are going into my drive train rebuild list. At the moment, that also includes my track suspension, torque tube rebuild, and bushings. A clutch is definitely on the list.
I am going to try and shoot for 104mm pistons. However, I will know more info once I crack open the motor and do some measurements of the cylinder bores. If I have to go 104.5mm, finding pistons for a reasonable price may become difficult. I am sure more components will come up as I go further into the build.
FWIW - I also found this engine repair site. Great information (very general, but still very good).
Engine Rebuild Tips and Info
More to come, stay tuned.
C.
Engine Parts / services needed:
Con Rods Opt 1
4 – Forged Carrillo rods……………………………………....……….$1200.00
Con Rods Opt 2
4 – Used Forged 968 rods (Low miles only)……………...……...$380.00
Piston options (TBD - once inspection is complete)
New Diamond Racing pistons (confirm compatibility)…….......$700.00
New LN Engineering / J&E Pistons……….........……..………....……$890.00
Used Forged 968 Pistons (OE size 104mm)..……..………...……TBD
Engine rebuild kit: (Source Vertex Auto)……………..………..……$890.00
1 Rod Bearing Set (Standard) - 92810314315
1 Main Bearing Set (Standard) - 94410190100
1 Piston Ring Set - 94410390260
1 Balance Shaft Belt - 94410221902
1 Timing Belt - 94410532302
16 Valve Guides - 94410432700
1 Head Gasket Set (Upper) - 94410090106
1 Case Gasket Set (Lower) - 94410090103
8 Connecting Rod Nuts - 92810317202
1 Front Engine Seal Kit - 94410100000
1 Loctite 574 Sealant 50 ml Tube - 00004301000
Balance shaft bearing (x4)…..94410112110…...………..…….….$65.00
Balance tensioner…………….94410202507…...……….....….….….$25.00
Balance roller………………….94410227706…...………..…....….….$29.00
Timing belt roller……………....94410524102…...……..…..…….….$29.00
Timing belt roller 46.2 ..……...94410524103…...………..…….….$29.00
Cam Hall Sensor ……………...94460612500M14.…..…....…..…...$21.50
Block machine work……..………....……………….….…..…...………$1000.00
(to include - honing cylinders to spec, machining piston oil squirters, cleaning block, and balancing crank
Refurb / Machine Head work……………………………....……....…..$800.00
Timing chain tensioner……….94410504901…...……..…..………$359.00
Exhaust valve (x8)…………….92810564206…...……….....………$272.00
Valve guides (x16)……………94410432700…...……….....…..……$79.20
Valve stem seal (x16)…………92810460107…...………..…..…....$47.84
Cam Hall Sensor ……………...94460617002M14.…...…..…..….$139.75
Oil Pump Sleeve……………….94410716102M260..………..……...$35.50
Oil Pump Spacer……………….94410791101M100..………..….….$10.50
Grand Total (rod Opt2, Diamond piston Opt): $4932.29
NOTES: Water pump and belts are new as of 5K ago. I also have a new Cam chain that came with the car. The flywheel, clutch and related parts are going into my drive train rebuild list. At the moment, that also includes my track suspension, torque tube rebuild, and bushings. A clutch is definitely on the list.
I am going to try and shoot for 104mm pistons. However, I will know more info once I crack open the motor and do some measurements of the cylinder bores. If I have to go 104.5mm, finding pistons for a reasonable price may become difficult. I am sure more components will come up as I go further into the build.
FWIW - I also found this engine repair site. Great information (very general, but still very good).
Engine Rebuild Tips and Info
More to come, stay tuned.
C.
09-15-2008, 09:20 AM
#23
Addict
Rennlist Member
Rennlist Member
VALVE SPRINGS!!!!
We got Erik's bottom end back together yesterday... I think he's happy to finally see bits going back together!!
Put a crank scraper in - cheap HP. I've been using one in my racecar for some time now, helps control oil flow too.
Don't forget to chase all the threads in the block and head. Took us 2 hrs just to do the block alone, but it was worth it!
We got Erik's bottom end back together yesterday... I think he's happy to finally see bits going back together!!
Put a crank scraper in - cheap HP. I've been using one in my racecar for some time now, helps control oil flow too.
Don't forget to chase all the threads in the block and head. Took us 2 hrs just to do the block alone, but it was worth it!
09-15-2008, 08:59 PM
#24
Rennlist Member
Vauhan,
You got that right. I'm starting to believe that it will actually run again, and before winter sets in too hard (hope hope).
Can't thank you enough for all the help. Owe you big time.
Erik.
You got that right. I'm starting to believe that it will actually run again, and before winter sets in too hard (hope hope).
Can't thank you enough for all the help. Owe you big time.
Erik.
09-16-2008, 02:53 PM
#25
Drifting
Give Scott Gomes of UnderPressure Performance a call. I remember a quote of about $5999 for a fully rebuilt long block with all wear & tear items replaced and other items rebuilt as needed. Can't hurt to give him a call for that price...
09-16-2008, 05:02 PM
#26
Not Special
Rennlist Member
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Someone mentioned the cost of fuel injectors being cleaned and flow matched...check out WitchHunter. Great turnaround, under $100 for cleaning, new seals, flow matching, and return postage.
09-16-2008, 05:52 PM
#27
Nordschleife Master
Thread Starter
09-16-2008, 05:54 PM
#28
Not Special
Rennlist Member
Rennlist Member
http://www.witchhunter.com/
In case anyone wondered, $18/injector. I should mention that you should only do this if you're planning on putting them right back in, apparently they can lock up if left out of the engine for a long time. I did mine while on vacation - pulled them the day before, mailed them the day I left, they were waiting for me when I arrived. Put them back in right after getting home. With a beer!
In case anyone wondered, $18/injector. I should mention that you should only do this if you're planning on putting them right back in, apparently they can lock up if left out of the engine for a long time. I did mine while on vacation - pulled them the day before, mailed them the day I left, they were waiting for me when I arrived. Put them back in right after getting home. With a beer!
09-16-2008, 10:24 PM
#29
Addict
Rennlist Member
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2nd the vote for witchhunter.