Anyone using over 4.00" stroke cranks???
10-24-2005, 07:12 AM
#1
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Anyone using over 4.00" stroke cranks??? Are any of you guys using anything over a 4.00" stroke? Any thoughts on the 4.100" or 4.125" cranks? I know piston side loading becomes an issue as does the wrist pin height. I assume the piston skirt also runs out of cylinder at the bottom (which is needed to support the piston) at some point, correct? What rods are used, std. 6.125"?
This is for a FI application and I'm looking to keep the RPM's under 7100, power levels could exceed 800 rwhp. Some big turbos are going to be used so more stroke will help spooling.
I know >4" cranks have been done many times, I'm looking for feedback and opinions (people with real experience please). I tried doing a search, but just about every thread has the word stroke in it... LOL!.
Thanks!
This is for a FI application and I'm looking to keep the RPM's under 7100, power levels could exceed 800 rwhp. Some big turbos are going to be used so more stroke will help spooling.
I know >4" cranks have been done many times, I'm looking for feedback and opinions (people with real experience please). I tried doing a search, but just about every thread has the word stroke in it... LOL!.
Thanks!
10-24-2005, 08:54 AM
#4
I think Fastech built a pretty good stroker motor with a 4.125 and spun it close to 7k. I believe that it was a 395" (stock bore). Contact them or PM Reckless for more info.
I'd be less inclined to go to 4.125 for a motor using 7000 or higher shift points.
I'd be less inclined to go to 4.125 for a motor using 7000 or higher shift points.
10-24-2005, 10:52 AM
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Your best bet would be to call around to some of the sponsors. HPE is very knowledgeable about this subject as I have a 38 cc head that I'm trying to get 11.7 to 1 compression with with a 4.155" bore and 4" stroke. We discussed larger strokes too and Erik was very helpful in indicating why the larger stroke will not work with my pistons, one of the reasons being them comming too far down out of the bottom (he went in the much detail but I did not follow all of it via a phone conversation). Good luck. I think with a standard combustion chamber head (55 and up) you will be just fine with over a 4" stroke but would be best to consult with the experts who build these motors on a regular basis with very few "come backers".
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10-24-2005, 05:37 PM
#8
Using the longer stroke is fine if you have a good bore/stroke ratio. Lots of people have used the 4.125 succesfully without any trouble. Personally I wouldn't do it in such a high HP scenario, with a stock bore that is. If the bore is excedding 4"+, then I'd probally do it. The longer stroke will be more prone to make amazing mid numbers and probablly wouldn't want to rev extremley high.
Erik is currently building my motor, which is an extremley long 4.185 stroke. The long stroke is fine, espeacially when you are using as large bore as I am at 4.150". The thing is, is that all the parts need to be built around what you are doing. Almost everything but my rods are custom ordered parts. You just need to know what you want when you start the project. Everything down to the proper sleeves has to be taken into consideration. Erik deffinatlly knows what he is doing, and that was the main reason I chose him to build mine.
Originally Posted by DAPSUPRSLO
Your best bet would be to call around to some of the sponsors. HPE is very knowledgeable about this subject as I have a 38 cc head that I'm trying to get 11.7 to 1 compression with with a 4.155" bore and 4" stroke. We discussed larger strokes too and Erik was very helpful in indicating why the larger stroke will not work with my pistons, one of the reasons being them comming too far down out of the bottom (he went in the much detail but I did not follow all of it via a phone conversation). Good luck. I think with a standard combustion chamber head (55 and up) you will be just fine with over a 4" stroke but would be best to consult with the experts who build these motors on a regular basis with very few "come backers".
10-24-2005, 07:54 PM
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I am also building a large displacement LS1.
4.125 s X 4.190 b , 455 cu.in. I am at the early stages. Car is coming off engine, ( engine removal this week).
Block will go to R.E.D. for resleeve.
Please keep me posted the your engine progress.
Have you choosen a cam yet?
I don't know which cam yet.
I have ordered the AFR 225 heads.
Bob
4.125 s X 4.190 b , 455 cu.in. I am at the early stages. Car is coming off engine, ( engine removal this week).
Block will go to R.E.D. for resleeve.
Please keep me posted the your engine progress.
Have you choosen a cam yet?
I don't know which cam yet.
I have ordered the AFR 225 heads.
Bob
10-24-2005, 09:06 PM
#10
Originally Posted by Dutchesscamaro
I am also building a large displacement LS1.
4.125 s X 4.190 b , 455 cu.in. I am at the early stages. Car is coming off engine, ( engine removal this week).
Block will go to R.E.D. for resleeve.
Please keep me posted the your engine progress.
Have you choosen a cam yet?
I don't know which cam yet.
I have ordered the AFR 225 heads.
Bob
4.125 s X 4.190 b , 455 cu.in. I am at the early stages. Car is coming off engine, ( engine removal this week).
Block will go to R.E.D. for resleeve.
Please keep me posted the your engine progress.
Have you choosen a cam yet?
I don't know which cam yet.
I have ordered the AFR 225 heads.
Bob
10-25-2005, 06:35 AM
#11
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Talk to TPIS a sponsor----------------------->
They have done a number of 427's that are 4.060 bore x 4.125 stroke
I personally know of 2 that are at about 530rwhp and 515rwtq
They have done a number of 427's that are 4.060 bore x 4.125 stroke
I personally know of 2 that are at about 530rwhp and 515rwtq
10-25-2005, 07:05 AM
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Originally Posted by Beast96Z
Using the longer stroke is fine if you have a good bore/stroke ratio. Lots of people have used the 4.125 succesfully without any trouble. Personally I wouldn't do it in such a high HP scenario, with a stock bore that is. If the bore is excedding 4"+, then I'd probally do it. The longer stroke will be more prone to make amazing mid numbers and probablly wouldn't want to rev extremley high.
Erik is currently building my motor, which is an extremley long 4.185 stroke. The long stroke is fine, espeacially when you are using as large bore as I am at 4.150". The thing is, is that all the parts need to be built around what you are doing. Almost everything but my rods are custom ordered parts. You just need to know what you want when you start the project. Everything down to the proper sleeves has to be taken into consideration. Erik deffinatlly knows what he is doing, and that was the main reason I chose him to build mine.
Erik is currently building my motor, which is an extremley long 4.185 stroke. The long stroke is fine, espeacially when you are using as large bore as I am at 4.150". The thing is, is that all the parts need to be built around what you are doing. Almost everything but my rods are custom ordered parts. You just need to know what you want when you start the project. Everything down to the proper sleeves has to be taken into consideration. Erik deffinatlly knows what he is doing, and that was the main reason I chose him to build mine.
Erik is deffinately a top notch guy. I think the reasons the longer stroke would not work in my situation is cause of my custom pistons with a 37 ish cc dish to get the compression down relocating the pin which would pull the piston past the "comfort zone" in the bottom of the sleeve, but once again, I'm not sure about that.
10-26-2005, 07:07 AM
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Originally Posted by Fandango
What cranks are you 4.125" stoke guys using?
Callies a pretty popular in this size. Also, I think Lunati offers some as well but not sure about that one.
10-26-2005, 05:33 PM
#17
Originally Posted by DAPSUPRSLO
Callies a pretty popular in this size. Also, I think Lunati offers some as well but not sure about that one.
