Super Long Rod 2.4

[Miasma]

Hey,

I just wanted to gather some opinions on my planned engine assembly.

Carrillo finally got back to me on a set of rods that I've been trying to get custom made for my 2.4 engine. They are 159mm h beams with carr bolts, expensive but are light weight and super strong. I'm using my OEM 100mm crankshaft as well.

To run these rods with my crank I need to use a shorter piston - Manley 87mm 9.5:1 pistons with a 1.012 compression height.

I'm wondering what the risks would be to run a piston this size? The reason I want to run a longer rod than just a 156mm is for the increased piston/rod ratio. I'm matching this block with a fully built head to try and max out my rpm as much as possible while still maintaining a nice torque curve for the street.

Aaron D

 

[Miasma]

Has anyone ever used a 1.012" piston?

 

[ThunderChild]

found this link, donno if its gonna help but theres alot of focus around a 4g63 block with that compression height.

 

[Miasma]

Ya that's the thread I read awhile back when I started to rethink the design of my engine setup. Was just wondering if anyone here had personal experience with this piston height.

I think I'm gonna go ahead with them though, because I can maximize my piston/rod ratio while still maintaining a 2.4.

 

[ThunderChild]

i dont have personal experience, but my instructor drag races a 60s vw bug on nitrous (setting up to run 8s or bust, then go turbo ). asked him what his compression height is and its .975, so he says. 2.6l displacement based on a vw bus block. heres his site

id say that compression height from any reputable and quality piston manufacturer would be just fine

 

[JacksonAuto]

Hard to compare a 4G63 piston to a VW. There are too many other variables to consider.

 

[ThunderChild]

Hard to compare a 4G63 piston to a VW. There are too many other variables to consider.

True, I didn't mean to oversimplify. He actually uses a lot of Chevy parts as well, can't recall exactly but I believe he based his current piston specs off BBC.My thought would be with a smaller piston bore, you could maintain strength throughout with a shorter compression height and less material. The only concern I would have would be the oiling ring and proper lubrication to the wrist pin.

But I have seen far shorter compression heights on turbo pistons, just none of my own yet.