Does Anyone have a formula to calculate
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...I was just thinking and getting ready to start this stroker build and realized that I have never seen such a formula, but in fact rod size does directly affect stroke. Right? That started me thinking about the different combo's etc.... What is affected is frictional loss of power due to the thrust loads put on the thrust side of the cylinder walls. This is more prone when short rods are used with long stroke. Maybe that will help.
Cstraub
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So basically a longer rod is going to affect piston speed in the cylinder and would affect compression, as well as put more stress on the piston and cylinder walls as a result. Which might tell me that a 4.125 stroke crank and a 6.125 rod combo might not be a good idea assuming I could have custom pistons made to accomodate it?
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Piston speed is very critical, once you exceed 5280 in piston velocity the engine will going into a pumping harmonic that. . .well simple terms. .will destroy the engine at some point.
CStraub
CStraub
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Originally Posted by Cstraub
Piston speed is very critical, once you exceed 5280 in piston velocity the engine will going into a pumping harmonic that. . .well simple terms. .will destroy the engine at some point.
CStraub
CStraub
Rod length doesn't enter into displacement or avg. piston speed calcs. The possible rod length you can stuff into a 3.75 stroke SBC only varies about 10% with 6.125 being about the practical upper limit and 5.565 being about the lower limit.
Choose your rod and piston combination based on use (blown or NA) and cost. IMO, there's not a whole lot of difference in 6.0 or 5.7 rods, but I'd chose the 6.0s for my stroker if my rod of choice was offered in that length as standard.
My $.02
No, not in SBC or SBF stuff. I do run into it in the big inch stuff, 540 CID and bigger. It is a critical calculation for those engines.
Nextel Cup. . .jeezeee I'm not going to be able to deal with it. Now our oil pans will be paid for with phone cards!!!!!!
Cstraub
Stef's Oil Pans
Nextel Cup. . .jeezeee I'm not going to be able to deal with it. Now our oil pans will be paid for with phone cards!!!!!!
Cstraub
Stef's Oil Pans
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Yeah its going to be N/A, but later I may run a relatively small shot for insurance
. I'm planning the 4.00 stroke with a 6.125 rod. I was toying with the 4.125/6.125 combo, but I think with an iron 6.0L block I'll be ok with the 4.00/6.125 combo. Not to mention the block prep work to get the 4.125 stroke and long rods in there. I don't want to get quite that crazy for a daily driver. Now i'm just going to work on finding some AFFORDABLE pistons for this LS1 ....
. I'm planning the 4.00 stroke with a 6.125 rod. I was toying with the 4.125/6.125 combo, but I think with an iron 6.0L block I'll be ok with the 4.00/6.125 combo. Not to mention the block prep work to get the 4.125 stroke and long rods in there. I don't want to get quite that crazy for a daily driver. Now i'm just going to work on finding some AFFORDABLE pistons for this LS1 .... 
Dang... pistons and rods are pretty affordable(about the same as an sbc).. try pricing a ls1 stroker crank 
Something that you should be careful of if you go with a 4.125/6.125 is the pin height in the piston.. it will likely be up in the rings, which isn't ideal
Something that you should be careful of if you go with a 4.125/6.125 is the pin height in the piston.. it will likely be up in the rings, which isn't ideal Thread Starter
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Yeah...that is my concern. I want to keep it as driveable as possible. I've heard we have some LS1 stroker cranks available cheaper than the $1600 
Lunati job, but I can't seem to find a link or phone #. Can anyone point me in the right direction? Thanks
Lunati job, but I can't seem to find a link or phone #. Can anyone point me in the right direction? Thanks