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Midget Rod Question

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racingenglishcars said:
The later 3 ring pistons are really much better. I hope you didn't actually <span style="font-style: italic">buy</span> these pistons.
My 1275 has the old 4 ring pistons. I'm using them because it's cheaper to just get a set of rings, rather than a new set of pistons.
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That is what I did. Everything was in good shape I just re ringed it because I was in there and figured it needed it with 48k on it. Is there some info showing where/why the three ring pistons are better?
 
racingenglishcars said:
As long as it holds compression and keeps the oil in the bottom end, it's ok. The 3 ring pistons just have less friction against the cylinder, giving the engine more power. Deves rings improve even more on that point by having less friction.
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Ah, that makes sense. Heck, I remember Omega pistons. Since the A series was made for so long, I imagine that there is every conceivable type piston out there for any purpose on these engines. I never got to see the A+ motor but I imagine it still looks somewhat the same.
 
Jack - they're 8.9:1 pistons

Yep, I bought 'em! I don't really see any difference in 3 & 4-ring pistons...however, I can see the benefit to 5-ring (even though there's more friction).
 
Yep, as Tony and I discussed on Firday, all A-series rod are offset, in the factory and Bentley manual there's a nice drawing showing rods offset and which way they should face, it you installed the piston backwards and then followed the front on the piston stamped on the piston top, it wouldn't go in the bore all the way because the offset of the rod would backwards and the rod would hit the crank going in, in Tony's case this happen about the time the 5th ring in the ring compressor started to go in the bore, and when it was forced, and could not go no any further, guess what was the waekest link in the chain, you got it, the cast iron ring. With 1275 this problem never comes up much because not many 1275 piston are labled front, so if you just follow the rod offset drawing in the manual, you're less likely to do this. Don't feel bad Tony, you could have put your 16 to 1 compressio ratio race pistons in your racing 948 with the valve reliefs on the wrong side like my buddy did, that broke alot more than some rings, it could defintely be worse.
 
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