1300 block question

WildWilly

True Classic
Hi guys, advice needed again. Finally have someone lined up to help me put the motor back together. Wondering what is the maximum bore I can go on the 1300 block. I think stock is 86mm and I think I'm already bored to 86.2mm. Just wondering what the max would be. Not wanting to go to the max but wanting to know that I am safe. The plan is to go to 86.4mm. I'm hoping that's a safe place to be. Thanks.
 
Only 87mm?

If you go 87mm, are you using 1500 pistons at that point? If so, could you bore a 1300 block to accept 87.4mm pistons?
 
Fire ring I.D. on the head gasket is usually around 87.2mm... so regular max overbore size is 87.0mm, unless you source a special head gasket... and 87.0 seems to be the max size regardless of original bore size from most of the better piston manufacturers (Mahle / Kolben Schmidt / Mondial / Borgo) although some vendors stock 87.2, 87.4 and even 87.5... but these are definitely not the aforementioned brands.

SteveC
 
good info as always!

Makes me think sticking with 87 max is also the way to go. So when it comes time to build I should plan on making a 1320cc block :)
 
I have 88 MM bore

on 2 different engines and have had no trouble. I used forged Cosworth and forged Aries pistons. I did o-ring the block and use stock head gaskets. The gaskets can hang over slightly into the bore but I have found that different gaskets vary somewhat so choose carefully. I have been using this set up with 11.2 to 1 compression since 1979 and have never blown a head gasket. I see that Midwest Bayless has a head gasket made for this purpose and I would use that one next time. It can be done but you better be sure things are put together correctly. As others have said 87 MM is a safer way to go.

Charlie
 
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