231 oddfire aftermarket clutch options

I've got a '75-'77 231 oddfire that I'm collecting parts to rebuild. Some time back, I put a new stock clutch in it and resurfaced the flywheel. With 36 inch tires and a SM465 with the low 1st gear, it's slipped pretty bad from day one. Now that I've got it pulled apart again it's time for something better, but there's not much out there in the way of support for the 231 with it's 9.125" clutch disc.

Summit has a clutch that claims better than stock grip, but I doubt much better:
http://www.summitracing.com/parts/zzz-mu1860-1b/overview/make/buick

I found a centerforce dual friction clutch with both the 9.125" disc diameter and 1.125" 10 spline hole that I need, but it's listed for '79-83 American motors / Jeep, so I'm doubtful of the pressure plate bolt pattern being correct.
http://www.jegs.com/i/Centerforce/183/DF824878/10002/-1?parentProductId=#moreDetails

I also found a Centerforce I clutch plate for the same application which would probably be better for low rpm use, but haven't found the disc to go with it yet, if it would even work anyways.
http://www.jegs.com/i/Centerforce/183/CF361878/10002/-1?parentProductId=2181964#moreDetails

Has anyone with a 231 found a solution for this? Would I be better off swapping to a 225 flywheel and using a common centerforce I clutch? My 231 flywheel already weighs 46 pounds, so I'm not sure there would be a weight advantage to switching, but going from a 9.125" clutch disc to a 10.5" disc has to make a difference in performance. Maybe that difference in diameter is what I need to be pursuing anyways.

Anyone have a spare 225 flywheel laying around that could be for sale?

 

aren't the 231 engines and their flywheels balanced together?

 

My understanding is that both the 225 and the oddfire 231 are externally balanced, and the flywheels are interchangeable. The even fire 231 is an internally balanced engine, and to swap odd fire to even fire flywheels you have to get them rebalanced.

I could be wrong, I'm just going off what I've read online.

 

not having the flywheel you have . but couldn't you just remachined for a 10 1/2 pressure plate
just a example of other holes
http://www.advanceadapters.com/prod...ly-ballanced-buick--oldsmobile-38l-v6-motors/

 

i'll have to measure but i think i'm running a 10" disc on my 231 with the heavy flywheel. i have a few in my shop and will take a measurement for you if you need me to.

 

I have 14 of them on the shelf but shipping would probably be a crazy number.

 

The best solution would be a flywheel with a larger diameter disc and pressure plate assembly then use the Centerforce type assembly. Especially with the tire diameter you list. You can use the 225 flywheel on the oddfire 231 as the balance is close enough where it should not be an issue. Not so with 225 on an evenfire 231/252.
No matter what you do as far as clutch assembly goes I don't think the 9.125" clutch will ever hold up to the use you are putting it to.

 

That's what I needed to hear. I like the idea of machining my current flywheel, but the pressure plate is mounted in a 1/4 inch deep recess. By the time I got that machined bigger and the holes re drilled, I think costs would exceed what I could find a 225 flywheel for.

 

I'm with Nick on this. You need a larger disc and I would also be looking at getting the flywheel redrilled for a 10.5". Just about any of the major aftermarket clutch manufactures have decent pressure plates. I have had very good results with Hays' clutch products, including their steel flywheels. I remain more than a bit dubious about Centerforce's dual friction discs. Having two different types of facing on the same disc seems to me to be just blowing smoke. The least desirable facing is going to fail. FYI, the AMC link isn't going to have anything that will directly fit. This is all GM.

 

I'm just now getting back on this project. I picked up a 10.5 inch Centerforce clutch that fits a 225 v6. I've got a machinist who is going to machine my 231 flywheel to accept the bigger clutch. I'm looking to confirm that the face on a 225 flywheel is completely flat? As in the pressure plate and clutch disc both sit on the same plane? It looks that way in the pictures I've seen, but I want to make sure before I have the machine work done.

The 231 flywheel has a 1/4 inch deep recess that the pressure plate sits in, so I'm planning on having the outer raised portion machined off so everything's flat.

 

I have the 225 flywheel and center force clutch on my of 231

 

Foster, I did exactly what you are planning when I put the 231 in my JEEP. I don't know if the following problem was a result of machining the flywheel down or not but here it is:

When I mated the trans to the engine, my clutch fork would not move the throw out bearing far enough to disengage the clutch. It would actually bind a bit on it's shaft, or rather the front bearing retainer on which the bearing slides. I was quite perplexed by this. I ended up having a new, longer pivot ball stud made for the clutch fork to pivot on which, in effect, moved the fork closer to the pressure plate. I did not know it at the time but, you can buy the ball stud in different lengths from places like summit.

It was no big deal once I figured it out. Again, I am unsure if the flywheel machining was the cause of the issue or not but, nothing else seems to make any sense to me as I didn't really change anything else. Maybe someone else can chime in on this. Just something to maybe be aware of. Wouldn't be enough to keep me from doing it again. My first choice would be to use a 225 flywheel, though.

 

Interesting. I was hoping the 1/4 inch difference wouldn't be enough to cause problems. Sounds like I should just address the problem now while everything's apart and not take the chance.