standard pistons assistance

standard pistons assistance

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Discussion

sagalout

Original Poster:

18,906 posts

289 months

Thursday 1st July 2004
quotequote all
Can anyone confirm please, the pistons in my 1275 block are stramped 21963 G7(?) 06(?). The block has the letter "B" on the top face and the pistons are also stamped with "B", Indicating to me that they are the original standard size pistons matched in the factory, rather than an overbore. Can anyone confirm please?

Cooperman

4,428 posts

257 months

Thursday 1st July 2004
quotequote all
Sound like standard factory fitted pistons.
If you are going to re-bore, then the optimum pistons now available are Hepolite 21253. These are available at +.020", +.040" and +.060" at about £150 per set.
If you just want a nice road engine, then 21251's are OK. The only thing the 21253 has that's better is a set of holes behind the oil control ring, rather than the slot which the 21251 has. Both are good pistons.
If you do fit the 21251's, you will need to deck the block a bit more to make the piston crowns come right up to the top and thus get the correct higher C.R. see my earlier post on Comp Ratios.

sagalout

Original Poster:

18,906 posts

289 months

Thursday 1st July 2004
quotequote all
Thank you Peter, the bores are fine so wasn't thinking of an overbore (actually I was, but budget constraints....). More thinking about replacing the rings as suggested. Thats when I can get back into the garage, if Alison had seen me in there last night,the way my back is, I'd have had more than pulled muscles, trapped nerves & back strain!
Regards
Tony H

Cooperman

4,428 posts

257 months

Thursday 1st July 2004
quotequote all
That sounds fine, Tony, just make sure you give the old bores a decent honing.
If you want some really good rings, I use 'Total Seal'which have a 'gapless' 2nd ring. You get them from Lowman-Jones in dagenham, who import them from Phoenix, Arizona. My buddy in the States says they aer the same rings as the F1 Air racing people use. the only problem is that a set are about £130. Fantastic rings, though.