Trying to get info on engine pistons

[Galaxybj]

I am trying to find out where to get rings for the pistons in my '71 240Z. This is what is on the top of the pistons: RA 2517 020H

TOP 0015 TJ

These are dished pistons. PO said he thought the original owner had it rebuilt about 50,000 miles ago.

Any ideas as to manufacturer and if they are oversized? Appreciate the help. I have not been able to find anything on the web searches I have done.

-Bill-

[DaveN]

Dished pistons prove it was rebuilt. All original 240 pistons had flat tops. For ring info your best bet is to start to start calling aftermarket piston manufacturers, & local rebuilders in the hope someone will recognize that marking code.

I'll risk a guess that you still have the original E3100 head and the OO put in dished pistons to lower the compression from 9.5:1 so he could use unleaded regular gas.

DaveN

HLS30-96167 now

#00013, #14489, and #66826 in the past

[240ZMan]

The bore of the L24 and L28 are different, and unless I'm mistaken, dished pistons were only used on L28s and are not available for L24s. I'll guess that when the previous owner had the engine rebuilt, they started with an L28.

You might want to measure the bore: is it 86 or 89 mm?

[Galaxybj]

I also guessed the OO put them in to run regular fuel. I was surprised and kinda disappointed when I saw the dish. I would have liked to have the flat tops because I would like a better performing cam, but don't really want the extra expense at this time to buy new pistons. The head is an E31. The bore measures 83mm - original size for the 240.

[240ZMan]

You might want to price out a set of ITM pistons. They came with rings (moly on top!) and the total price was a bit over $200 IIRC. A decent set of rings is over $100 by themselves. You're going to need to hone the cylinders anyway, so the extra cost to bore .10 over isn't much. Figure about $5 per piston to swap the rods. I'd guess that the extra cost of going to flat tops would be about $200.

I went down this path last year and am very happy with the results on my L28. Reground the cam with Delta Cams, kept the stock springs, and it pulls strong to 7k now. Regrind was only about $125 including shipping. In a few weeks I'll put it on the dyno for a tuning session and will find out how much power this netted me.

Just something for you to think about

[240ZGL]

I thought that dished pistons were used on the turbo 280 motors. Maybe you have a turbo short block. I know some mech shops will pull a short block out of the bone yards to do what they call a rebuilt engine.

[Galaxybj]

Not a turbo short block as this is a numbers matching car - original block. If I can't find out who the manufacturer is of these pistons (so I could get just the rings) I will most likely buy a new set of pistons. If I go new, I'll most likely go back to the flat tops too.

[XjakobX]

Well, thinking about this, you have L26 pistons in your L24. L26 pistons DID come in a dished form, so says the L26 i helped a buddy of mine rebuild. He's the original owner, and has never had that engine opened up before. Makes sense when you increase stroke, that you have to make adjustments to keep the CR down.