Sweptline.ORG

I'm looking for the proverbial needle in the haystack. 2 years ago, I purchased a set of NOS, Poly 318 forged TRW Pistons # L2097F in +.030" oversize. I'm just now beginning to get going on my block and rough bore was just about to begin when it was discovered that one piston of the set of 8 is actually a +.040" piston. I know at the time I bought mine that they also had a +.040" over set which sold. So, I'm hoping that a member here may have been that person and he may have my +.030" piston in his set. Doubtful but worth a shot.

I've been doing some checking in the last 30 minutes and ironically found an NOS single piston on eBay, also L2097F but in +.020" over! Amazing. The search goes on.....

- EM

Weigh the .030 and .040 pistons, supposedly they should be the same. If you balance this engine, I doubt if you would have any ill side effects. I bought a dart sport once that had a .030 over piston with the rest being stock bore. Could not tell. Not ideal, but might come down to this.

No. There is a difference in the bore AND the ring grooves. I can machine the piston as a last resort but I want to try to see what I can find first. Setting up to machine the O.D. requires a special (and extremely accurate) holding jig.

- EM

marklein wrote:Weigh the .030 and .040 pistons, supposedly they should be the same. If you balance this engine, I doubt if you would have any ill side effects. I bought a dart sport once that had a .030 over piston with the rest being stock bore. Could not tell. Not ideal, but might come down to this.

Sorry. I mis-read your reply in my haste. Yes, I can do that and already thought of that. It certainly would work but I don't like doing things that way.

- EM

I don't like the idea of it either, but it may come to that. Must be one somewhere, does TRW still exist or is it called something different now? Perhaps contact them?

If you got them from a speed shop out Lansing, MI off ebay. I got 0.040 set. Just went through my set I haven't installed yet. All are0.040.

Thanks for your reply Viking. Yes that is the shop. I appreciate that you checked your set. I have a set of later model TRW pistons (also +.030") on the way to keep me going on the build but I'll continue to look for the replacement to my set.

- EM