Hi, I have an issue which is worrying me at the moment concerning my build with the following major items.

Wiseco pistons, eagle rods. cometic HG, Z1 GT675 turbo kit.

 

Had a reputable machine shop do some machining for me and took delivery yesterday for starting the assembly.

I asked for the block to rebored to suit my 88mm Wisecos as well as the decking of the block to be trued and finished (AR50) for Cometic (.045"/1.2mm) mls head gaskets.

All looked good until I checked to see that I got my original block back by checking the engine numbers and ...well the engine numbers are very feint to gone and worried that too much has been taken off. Any suggestions here? Barring that I have no numbers on the block which will raise law enforcement eye brows.

My main concern is with the possible excessive decking, I thought first step would be a trial fit of the bearings, crank, rod and piston to see if piston is in or out of the bore as I know that the VG30 is a flush/zero piston to deck. This I have done and I have a situation where the piston is out of the bore by .152mm or .006".

Is this going to pose a problem with respect to any mechanical interference etc.

I value any feed back, thanks

when decking the block and havng the Head skimmed you need thicker gaskets .045 are stock size

 

now the Machine shop should be only taking around 5>8th each from the Deck and the Heads .. so u will end up with 10>16th less over all

this has to be reflected with the gasket u buy ( 051>053 / 1.4>1.5mm ) this is one of the main reasons u buy your gaskets last

 

now if you do use the gaskets u have u need to make sure that there is no piston>valve contact but will give u a slightly high comp ratio

 

i'm not saying dont use them or to .. but what i have said is the Normal rule for building

 

its your choice if u use ... on other engines that i have built Non VG30dett .. its been ok to use the sock size gasket

with machined ... and the engines are still going strong today

 

Mark

when decking the block and havng the Head skimmed you need thicker gaskets .045 are stock size

 

now the Machine shop should be only taking around 5>8th each from the Deck and the Heads .. so u will end up with 10>16th less over all

this has to be reflected with the gasket u buy ( 051>053 / 1.4>1.5mm ) this is one of the main reasons u buy your gaskets last

 

now if you do use the gaskets u have u need to make sure that there is no piston>valve contact but will give u a slightly high comp ratio

 

i'm not saying dont use them or to .. but what i have said is the Normal rule for building

 

its your choice if u use ... on other engines that i have built Non VG30dett .. its been ok to use the sock size gasket

with machined ... and the engines are still going strong today

 

Mark

 

Hi Mark, thanks for the info...contacted my engineer and he confirmed that he took off 0.004" off the heads and also 0.004" off the block, 0.008" in total. I think I will go with the 0.045" cometic HG. Wiseco also confirm that their pockets are deeper than stock so that helps aswell. I will check piston to valve clearances as a matter of course.

How is that motor of yours going? watched your build thread closely.

Cheers

Ant

Well some feed back...measured the combustion chamber and came up to 48.5cc as this was the only unknown value and so entered all the known data into the compression ratio calculator and it spat out a comp ratio of 8.9033 :1

This will be acceptable and now can continue the rest of the assembly, not sure how its going to affect the cam timing but will have to see.