From:Ken Lee
Subject:RE: Ace pistons Date:Sat Apr 19 04:50:09 2014
Response to:5131
Hello Chris ,
I have the old pistons frrom my Ace which are cast iron and they
measure 3-1/4 inches O/A height , 1.4 inches compression height
I would give 8thou clearance (saves some running in) or 6thou and
run in for 500miles , although take it easy for a few hundred anyway
the weight is 7.85 ounces .
I used Harley (sorry) 45 pistons which are nearly 3 ounces heavier
standard but had to take 0.90thou of the crown to get compression
right and make bronze bushes for the gudgeon pins . I used the 45
pistons that take the inner circlip not the ones where the gudgeon pin
takes the circlip . Although the 45 pistons are only 2-7/8ths high , I
haven't had any problems in about 7,000miles . I believe Egge M/Co
used to supply Pistons for Indian Fours and possibly ACE but not sure
if they still do , part number 1307 see -
Hope this is a bit helpful , best of luck , keep us informed and don't
forget to keep -
informed too , also might get more help there !!

Could anybody help with the following please

We have a 1922 ace undergoing an engine rebuild require the following information if possible

The piston diameter is 2.714 which is 1922 oversize

Overall height of piston from skirt to crown
Target weight of piston without rings and pin
Compression height ( centre of pin to crown )
Piston to bore clearance

Many thanks