Stroker Cranshafts
02-28-2002, 11:15 AM
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Stroker Cranshafts
Just to let those of you know...
928 International has announced that they will be placing an order for the Scat Industries 928 Stroker Crankshaft.
These are rare items, and they are only ordered seldomly. A deposit of $1500 up front, with the delivery of an additional $1500 due in 12-14 weeks for a total cost of $3000.
Just thought I'd pass it on to all of you who may be pondering this option.
<img src="graemlins/burnout.gif" border="0" alt="[burnout]" />
928 International has announced that they will be placing an order for the Scat Industries 928 Stroker Crankshaft.
These are rare items, and they are only ordered seldomly. A deposit of $1500 up front, with the delivery of an additional $1500 due in 12-14 weeks for a total cost of $3000.
Just thought I'd pass it on to all of you who may be pondering this option.
<img src="graemlins/burnout.gif" border="0" alt="[burnout]" />
02-28-2002, 08:18 PM
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A Cranshaft? Would this be a new product by Ocean Spray?
I really like their Cranapple flavour <img src="graemlins/roflmao.gif" border="0" alt="[hiha]" /> !
I really like their Cranapple flavour <img src="graemlins/roflmao.gif" border="0" alt="[hiha]" /> !
02-28-2002, 11:18 PM
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Good one Randy. 
Actually, after I sent the topic out, I then noticed that my fat fingers had helped me out again.
Even tried the delete post option - only to find out that I can't do that - and I can't edit the topic title. Oh well, won't be the first time I looked like a boob (hey....you don't chime in here THAT fast!)
Actually, after I sent the topic out, I then noticed that my fat fingers had helped me out again.
Even tried the delete post option - only to find out that I can't do that - and I can't edit the topic title. Oh well, won't be the first time I looked like a boob (hey....you don't chime in here THAT fast!)
03-01-2002, 01:30 AM
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I haven't been in the game long, so I'll ask: what's the poop on Scat Industries crakshafts? I.E. significant horsepower gain, better made, particular 928 history?
03-01-2002, 08:24 AM
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Flint-
The Crankshafts will increase displacement...for the 5.0L - with no boring add the Crankshaft and you get a 6.0L motor.
Increase the bore size from 100 mm to 104 mm and displacement goes to ~ 6.5L. An increase from 302.5 cubic inches to ~392 cubic inches.
The owners of DEVEK and 928 International (along with a few others - including our own Sterling Gee here) have performed the Stroker Modification with apparently great results in the increased peformance department.
<img src="graemlins/burnout.gif" border="0" alt="[burnout]" />
The Crankshafts will increase displacement...for the 5.0L - with no boring add the Crankshaft and you get a 6.0L motor.
Increase the bore size from 100 mm to 104 mm and displacement goes to ~ 6.5L. An increase from 302.5 cubic inches to ~392 cubic inches.
The owners of DEVEK and 928 International (along with a few others - including our own Sterling Gee here) have performed the Stroker Modification with apparently great results in the increased peformance department.
<img src="graemlins/burnout.gif" border="0" alt="[burnout]" />
03-01-2002, 09:22 AM
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For what it is worth, I have priced out getting a Scat crank through my engine builder here in town, who does not exactly do many Porsche motors. The cost through him would also be $3k and same deal for me, I would have to put down 50% and have to wait till Scat had 6 or more total orders before they would make any. So the 928Intl crank is a Scat as well?
03-01-2002, 09:36 AM
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This is the actual post on the email list...
Jim Bailey at 928 International wrote:
For those who may be interested in building a stroker engine we have a
commitment from a major crankshaft manufacturer for billet forged cranks in
the popular 95.25 mm stroke designed to use the " Chevy rods 5.85 inch "
This is based on the GTS eight counter weight crank . Delivery is forecasted
at 12-14 weeks from the date an order is entered . The cranks will sell for
$3,000 we are requiring a 50 % deposit with the order . It has been two
years since these were last manufactured . Using the 100 mm piston gives a 6
liter , 104 mm 968 pistons makes a 6.5 liter engine . Please note you need
to run custom rods and short GTS or 968 pistons for clearance from the
counter weights to piston skirt . It is also very important to carefully
measure and calculate for the desired compression ratio . The new Kelly Moss
engine has this crank and is the same as run in one of our road race cars .
This window will close quickly and it may be years before we put together
another batch of orders , especially at this price . Mark Anderson decided
to build a " spare engine " for the speed vision car and that was the
catalyst for this batch of stroker cranks . We have several commitments from
customers who want one . This is one case where bigger is BETTER ... $1,500
reserves a crank , balance due before delivery . They do make excellent
coffee tables if you plan to start accumulating parts for the stroker
rebuild .... Honest Dear it is Home Decor !! They will be delivered in plain
brown paper boxes your neighbors will never know . For every 100 people who
talk about it, seems only about one ever lives the dream .
Jim Bailey
928 International
Jim@928intl.com
<a href="http://www.928intl.com" target="_blank">www.928intl.com</a>
(714)632-9288
I spoke with Jim directly and understood him to indicate that the crankshafts are from Scat Industries.
hth-
Jim Bailey at 928 International wrote:
For those who may be interested in building a stroker engine we have a
commitment from a major crankshaft manufacturer for billet forged cranks in
the popular 95.25 mm stroke designed to use the " Chevy rods 5.85 inch "
This is based on the GTS eight counter weight crank . Delivery is forecasted
at 12-14 weeks from the date an order is entered . The cranks will sell for
$3,000 we are requiring a 50 % deposit with the order . It has been two
years since these were last manufactured . Using the 100 mm piston gives a 6
liter , 104 mm 968 pistons makes a 6.5 liter engine . Please note you need
to run custom rods and short GTS or 968 pistons for clearance from the
counter weights to piston skirt . It is also very important to carefully
measure and calculate for the desired compression ratio . The new Kelly Moss
engine has this crank and is the same as run in one of our road race cars .
This window will close quickly and it may be years before we put together
another batch of orders , especially at this price . Mark Anderson decided
to build a " spare engine " for the speed vision car and that was the
catalyst for this batch of stroker cranks . We have several commitments from
customers who want one . This is one case where bigger is BETTER ... $1,500
reserves a crank , balance due before delivery . They do make excellent
coffee tables if you plan to start accumulating parts for the stroker
rebuild .... Honest Dear it is Home Decor !! They will be delivered in plain
brown paper boxes your neighbors will never know . For every 100 people who
talk about it, seems only about one ever lives the dream .
Jim Bailey
928 International
Jim@928intl.com
<a href="http://www.928intl.com" target="_blank">www.928intl.com</a>
(714)632-9288
I spoke with Jim directly and understood him to indicate that the crankshafts are from Scat Industries.
hth-
Trending Topics
08-03-2002, 10:56 PM
#8
Hi Jay have you been able to determine what length conrods are to be used in the stroker motors? I did some quick math and found that it didn't make any sense to use the 5.85" rod unless the piston pin is placed significantly higher in the replacement piston. I would have thought that the most likely rod used was the 5.7" inch rod with a custom short skirt JE piston that has a higher than Porsche original wrist pin placement. Anybody know anything different? All the best
<img src="graemlins/drink.gif" border="0" alt="[cherrsagai]" />
<img src="graemlins/drink.gif" border="0" alt="[cherrsagai]" />
08-04-2002, 04:30 AM
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[quote]Originally posted by 928s:
<strong>I did some quick math and found that it didn't make any sense to use the 5.85" rod unless the piston pin is placed significantly higher in the replacement piston. I would have thought that the most likely rod used was the 5.7" inch rod with a custom short skirt JE piston that has a higher than Porsche original wrist pin placement. Anybody know anything different?</strong><hr></blockquote>
Greg,
The reference is not being made to actual Chevy part # rods here. Custom
aftermarket rods will still be required. A longer center-to-center rod
length is better as it decreases the angle the rod must "swing" through,
which lessens the stress on the rod. Then you can build a rod with less
material in the beam section, resulting in a lighter rod with lowered
reciprocating weight and better rpm potential. You are correct about
having to utilize a higher wristpin location in the piston, but both the
GTS and the 968 pistons have this because they were designed for longer
stroke engines. These "factory" OEM pistons are compatible with the high
silicon content in the Reynolds alloy block bores. Aftermarket
pistons, such as the JE and others, will not last in the hard bores. You
must overbore the block and install cast iron sleeves in the bores to
be able to use non-OEM pistons. This *is* the approach some have taken.
Brad
'78 euro 5 speed
928 Owners Club
Rennlist #020804-2937
<strong>I did some quick math and found that it didn't make any sense to use the 5.85" rod unless the piston pin is placed significantly higher in the replacement piston. I would have thought that the most likely rod used was the 5.7" inch rod with a custom short skirt JE piston that has a higher than Porsche original wrist pin placement. Anybody know anything different?</strong><hr></blockquote>
Greg,
The reference is not being made to actual Chevy part # rods here. Custom
aftermarket rods will still be required. A longer center-to-center rod
length is better as it decreases the angle the rod must "swing" through,
which lessens the stress on the rod. Then you can build a rod with less
material in the beam section, resulting in a lighter rod with lowered
reciprocating weight and better rpm potential. You are correct about
having to utilize a higher wristpin location in the piston, but both the
GTS and the 968 pistons have this because they were designed for longer
stroke engines. These "factory" OEM pistons are compatible with the high
silicon content in the Reynolds alloy block bores. Aftermarket
pistons, such as the JE and others, will not last in the hard bores. You
must overbore the block and install cast iron sleeves in the bores to
be able to use non-OEM pistons. This *is* the approach some have taken.
Brad
'78 euro 5 speed
928 Owners Club
Rennlist #020804-2937
08-04-2002, 10:21 AM
#10
Hi Brad and thanks for responding, I generally agree with what you said, all I would add is that you could ask ten different engine builders and get ten different answers about rod length.
I think I would go with a longer rod length if possible, for the reasons you quoted, also there is less pressure exerted on the skirt of the piston with a longer rod length. I can't quite remember but I think shorter rods produce quicker speeds away from tdc and thus higher loads on recipricating components. I did read a case for shorter rods but I couldn't find it to post it so sorry.
I will use JE custom pistons regardless because with a stroker crankshaft the piston speed will increase, JEs are light, this will reduce loads also, I will of course deal with the coating issue. I have done a bit of research on this topic already. My engineer who is faboulus to deal with by the way, is a JE distributor he will sell me the JEs at his cost plus a $100 dollars. Bargain I say. Also tomorrow I'm ringing a fellow in this country who does, or so I been told Nicasil coatings. So what might develop is a Custom JEs and a nicasil block running genuine Porsche rings. N.B no problem with sulphur fuels here. Maybe he has a piston coating process also. For anybody reading this post that is not familiar with nicasil it is used in BMWs and many 911s it is a type of chrome. Now the original piston coating that came on the alusil type motors was iron, the coating from memory was called Feron.
The coating from my knowledge does not have to be iron it just has to be not aluminium to prevent the galling. The process I am familiar with is chroming. Remember that the rings in an alusil block are chrome. In a nicasil block they are not. Can't run chrome on chrome, otherwise more galling. There seems to be no easy solution, because if I got the JEs chromed which costs about $250 then I have to use the really expensive rings that run on the alusil the're about $800 as apposed to $400 for rings that run on nicasil, the other end of the spectrum is rings that run on a steel bore they cost $150 but you need a steel bore, aaaaahhhhhh.
So I will know more tommorow. How much are titanium conrods in the States does anybody know?
Brad I would have thought that given the stroker crank is made from scratch why not use a standard chevy journal so that custom rods aren't required.
Incidently I had thought of making my own custom stroker crank, I had a quote and it would be made from en26 so I'm sure you know what that is and it is cheaper than any of the big three by a margin of 25%. It would be probably lighter also due to less material being needed but I'm not trying to reinvent the wheel here and I think that we should support them when we can, and pay for their knowledge as long as it is worth paying for that is.
<img src="graemlins/c.gif" border="0" alt="[ouch]" /> <img src="graemlins/drink.gif" border="0" alt="[cherrsagai]" /> <img src="graemlins/beerchug.gif" border="0" alt="[cheers]" />
I think I would go with a longer rod length if possible, for the reasons you quoted, also there is less pressure exerted on the skirt of the piston with a longer rod length. I can't quite remember but I think shorter rods produce quicker speeds away from tdc and thus higher loads on recipricating components. I did read a case for shorter rods but I couldn't find it to post it so sorry.
I will use JE custom pistons regardless because with a stroker crankshaft the piston speed will increase, JEs are light, this will reduce loads also, I will of course deal with the coating issue. I have done a bit of research on this topic already. My engineer who is faboulus to deal with by the way, is a JE distributor he will sell me the JEs at his cost plus a $100 dollars. Bargain I say. Also tomorrow I'm ringing a fellow in this country who does, or so I been told Nicasil coatings. So what might develop is a Custom JEs and a nicasil block running genuine Porsche rings. N.B no problem with sulphur fuels here. Maybe he has a piston coating process also. For anybody reading this post that is not familiar with nicasil it is used in BMWs and many 911s it is a type of chrome. Now the original piston coating that came on the alusil type motors was iron, the coating from memory was called Feron.
The coating from my knowledge does not have to be iron it just has to be not aluminium to prevent the galling. The process I am familiar with is chroming. Remember that the rings in an alusil block are chrome. In a nicasil block they are not. Can't run chrome on chrome, otherwise more galling. There seems to be no easy solution, because if I got the JEs chromed which costs about $250 then I have to use the really expensive rings that run on the alusil the're about $800 as apposed to $400 for rings that run on nicasil, the other end of the spectrum is rings that run on a steel bore they cost $150 but you need a steel bore, aaaaahhhhhh.
So I will know more tommorow. How much are titanium conrods in the States does anybody know?
Brad I would have thought that given the stroker crank is made from scratch why not use a standard chevy journal so that custom rods aren't required.
Incidently I had thought of making my own custom stroker crank, I had a quote and it would be made from en26 so I'm sure you know what that is and it is cheaper than any of the big three by a margin of 25%. It would be probably lighter also due to less material being needed but I'm not trying to reinvent the wheel here and I think that we should support them when we can, and pay for their knowledge as long as it is worth paying for that is.
<img src="graemlins/c.gif" border="0" alt="[ouch]" /> <img src="graemlins/drink.gif" border="0" alt="[cherrsagai]" /> <img src="graemlins/beerchug.gif" border="0" alt="[cheers]" />
08-04-2002, 05:21 PM
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Greg, good point about the piston skirt loading with "short" rods.
Here's a link to a cylinder-coating company that has the contract for Jaguar's
new 4.0 liter V8 :
<a href="http://www.usnicom.com/flash.html" target="_blank">http://www.usnicom.com/flash.html</a>
There might be some useful info in there for you.
For titanium connecting rod shopping/info, take a look at :
<a href="http://www.grpconrods.com/" target="_blank">http://www.grpconrods.com/</a>
<a href="http://www.performancemarket.com/conrods.htm" target="_blank">http://www.performancemarket.com/conrods.htm</a>
(this site has a list of manufacturers with links to them)
<a href="http://www.paeco.com/conrods.html" target="_blank">http://www.paeco.com/conrods.html</a>
(prices are SCARY!)
<a href="http://www.malvernracing.com/showcase.html" target="_blank">http://www.malvernracing.com/showcase.html</a>
<a href="http://raceseek.com/connecting_rods.htm" target="_blank">http://raceseek.com/connecting_rods.htm</a>
(another webpage with a list of manufacturers with links to them)
That should get you started anyway.... lots of stuff out there!
Brad
'78 euro 5 speed
928 Owners Club
Rennlist #020804-2937
Here's a link to a cylinder-coating company that has the contract for Jaguar's
new 4.0 liter V8 :
<a href="http://www.usnicom.com/flash.html" target="_blank">http://www.usnicom.com/flash.html</a>
There might be some useful info in there for you.
For titanium connecting rod shopping/info, take a look at :
<a href="http://www.grpconrods.com/" target="_blank">http://www.grpconrods.com/</a>
<a href="http://www.performancemarket.com/conrods.htm" target="_blank">http://www.performancemarket.com/conrods.htm</a>
(this site has a list of manufacturers with links to them)
<a href="http://www.paeco.com/conrods.html" target="_blank">http://www.paeco.com/conrods.html</a>
(prices are SCARY!)
<a href="http://www.malvernracing.com/showcase.html" target="_blank">http://www.malvernracing.com/showcase.html</a>
<a href="http://raceseek.com/connecting_rods.htm" target="_blank">http://raceseek.com/connecting_rods.htm</a>
(another webpage with a list of manufacturers with links to them)
That should get you started anyway.... lots of stuff out there!
Brad
'78 euro 5 speed
928 Owners Club
Rennlist #020804-2937
08-04-2002, 05:43 PM
#12
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The connecting rod ends are also offset. On the 16V engines the piston pins bore is offset 1.5MM, on 32V engines M28/ 43,44 the pin bore is offset 1M, to prevent piston noise (slap)
In the early years mahle pistons were chrome plated, KS piston were iron coated, mahle has sense developed a graphite coating (ferrostan) to coat the piston
<img src="graemlins/beerchug.gif" border="0" alt="[cheers]" />
In the early years mahle pistons were chrome plated, KS piston were iron coated, mahle has sense developed a graphite coating (ferrostan) to coat the piston
<img src="graemlins/beerchug.gif" border="0" alt="[cheers]" />
08-04-2002, 06:46 PM
#13
Thanks Steve for the info on the offset, here is an article about rod ratios for those interested. 6 inch rod seems quite attractive.
<a href="http://www.grapeaperacing.com/GrapeApeRacing/tech/rodslength.cfm" target="_blank">http://www.grapeaperacing.com/GrapeApeRacing/tech/rodslength.cfm</a>
<a href="http://www.grapeaperacing.com/GrapeApeRacing/tech/rodslength.cfm" target="_blank">http://www.grapeaperacing.com/GrapeApeRacing/tech/rodslength.cfm</a>
08-05-2002, 03:34 AM
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Very informative read on connecting rods.
Thanks <img src="graemlins/bigok.gif" border="0" alt="[thumbsup]" />
Brad
'78 euro 5 speed
928 Owners Club
Rennlist #020804-2937
Thanks <img src="graemlins/bigok.gif" border="0" alt="[thumbsup]" />
Brad
'78 euro 5 speed
928 Owners Club
Rennlist #020804-2937
