4.125 stroke question
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4.125 stroke question thinking of doing a erl 4.125 bore and 4.125 stroke. this is a race car build, n/a carb and race fuel. Not wanting to turn over 7600 to7800. other option 4.155x 4 inch anyone have any experience pros or cons?
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From: Studewood/Acres-Homes TX.
Would be good only with any ERL/RED 5.8 resleeved block. 6.2 block R good 4 4.100 stroke.7.0ls7 block can that a 4.250 crank. Lq9 block can take a 4.1- 4.125 stroke but a custom piston R needed $1100.oo. your choice ....even a LSX block.
4.185" x 4.0" is an option too, it'll get you 440ci. I built a couple and the last one made over 600whp on a Mustang dyno through an unported FAST manifold. Got close to 900whp with nitrous.
I've heard that stock sleeve engines with over 4.00" stroke often have oil consumption issues and can be a little more difficult to clearance. Not sure if this is true or not, but I recently bought a 4" stroke rotating assembly on this assumption.
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From: Studewood/Acres-Homes TX.
Well 4.125 or 4.100 crank will work with LQ9/ LS2-3 BLOCK BUT WILL OR MUST HAVE A
CUSTOM PISTON / HKE- LME BUILD THE ENGINE OTHER WISE OIL BURNER
O YEAH GZ VAC. PUMP WILL HELP KILL OIL consumption.
CUSTOM PISTON / HKE- LME BUILD THE ENGINE OTHER WISE OIL BURNER
O YEAH GZ VAC. PUMP WILL HELP KILL OIL consumption.
I've heard that stock sleeve engines with over 4.00" stroke often have oil consumption issues and can be a little more difficult to clearance.
ther option 4.155x 4 inch anyone have any experience pros or cons?
If it was a street motor, I would probably go with the longer stroke since that usually produces more low end torque and not worry about trying to make it scream to 7600rpm.
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A 360 CID (4.185"x3.27") at 7600 would have a piston speed of 34.52 ft./sec.
I'm not saying that a 360 incher would ever make the power of a 468" monster but since roughly 60% on an
engine's rotating friction is piston rings.....a 23% reduction in distance traveled is huge !!!!! The engine would most
certainly make more power per cube by virtue of efficiency.
Last edited by A.R. Shale Targa; Feb 9, 2014 at 10:49 AM.
Piston speed would be 44.86 feet per second per piston....Geeesh....
A 360 CID (4.185"x3.27") at 7600 would have a piston speed of 34.52 ft./sec.
I'm not saying that a 360 incher would ever make the power of a 468" monster but since roughly 60% on an
engine's rotating friction is piston rings.....a 23% reduction in distance traveled is huge !!!!! The engine would most
certainly make more power per cube by virtue of efficiency.
A 360 CID (4.185"x3.27") at 7600 would have a piston speed of 34.52 ft./sec.
I'm not saying that a 360 incher would ever make the power of a 468" monster but since roughly 60% on an
engine's rotating friction is piston rings.....a 23% reduction in distance traveled is huge !!!!! The engine would most
certainly make more power per cube by virtue of efficiency.
I think it depends on the RPM range you want to operate in, but without a displacement limit, I'll take the biggest bore and longest stroke I can have within reason for the most cubic inches.
Agreed. Though it is kind of cool to hear it at 7500rpms. 
It also depends on budget. It's cheaper to go to add stroke with a new crank that it is to add lots of bore with a sleeved block.
It also depends on budget. It's cheaper to go to add stroke with a new crank that it is to add lots of bore with a sleeved block.