compression ratios

[Prevolution]

I've run a destroked 2.6L using a 2.0L crank with stock rods.

Bore the block to 92mm, use Mahle flat top pistons for air cooled VW's and they zerodec in the block.

The pistons are forged (at least that's what Mahle claims), are relatively inexpensive but difficult to find without the VW sleeves. The only problem is that they're not available in an overbore so when it's time to rebuild you either need a new block or resleeve the existing one.

[cheaterparts]

i have heard of 3mm being shaved of the magna heads with no problems at all
so work out what comp you want then do a couple of calcs

I'm running 3.5 mm from a magna head with flat top pistons 11.2 :1

whats the effect on cam timing with 3mm off the head ?
and can the cam tensioner still keep the chain tight ?

pete - each mm you remove from the head or deck ( or combo of each ) retards the cam by about 1 deg

as for the cam tension I fit a spacer behind the tensioner which is a 9/16-14mm bore ,washers work as well
just measure how far the plunger is out of the pump with the head dummy fitted ( with a head gasket )
remove the pump and fit ether a made up spacer or washers over the plunger to space it
after the pump is refitted you can still remove the head and sit the top cam sprocket on the seat
just like std
the spacer stops the cam chain being to loose before oil presure comes up
the tensioner works like std when oil presure is working on it