View single post by DStein
 Posted: 04-29-2007 05:47 pm
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DStein

 

Joined: 04-28-2007
Location: Grand Rapids, Michigan USA
Posts: 2
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 Hey guys!  Be careful!   The fatory service manual specifies that the "A" and "B" designations are for piston diameter.  There is also a corresponding "A" and "B" liner to go with that piston.  This must be noted when working on a stock motor.  Of course, if you have had a machine shop re-hone the liners.....Stock A pistons are 3.7467"-7.7472" B pistons are 3.7472"-3.7477".  A liners are 3.7510"-3.7515". B liners are 3.7515"-3.7520".  Thus a large "A" piston can be matched with a small "B" liner sucessfully.  Use discretion and check piston-cylinder clearances and keep the lot within spec and you'll be fine.  or buy matched sets.  This is why good mechanics/rebuilders/machinists get good money to perform these services.  If you are doing a DIY, you are best to order the parts you need as a set so that you are assured that the things you didn't think to check have been addressed by someone who knows to check.  This may make me an unpopular voice, but as a former tech, I have found a great deal of misinformation in this area.  I have sucessfully rebuilt several 907's as well as v-12 Jags, etc.  and am aware of many of the pitfalls.  Even at that, there are, I'm quite sure, snags I have not hit.  I have been a Jensen owner since 1988. '74 healey, 104 cams, dellortos, etc.  

Dan