DDP

I am planning on using an N/A block for my turbo build. Just swapping the pieces from my turbo engine into an N/A block. They are the same correct? If it is an early block, would that matter? I will be using the turbo balance shaft housings. What are the differences in the blocks...early and late.... if I use all the turbo parts? Thanks

theedge

The bridge for the upper balance shaft is different, it has the feed port for the turbo oiling. You cant swap them between blocks. Thats the only big difference IIRC. Theres also the oil pan.

fast951

The oil holes feeding the bearings are smaller on the early blocks.

Jfrahm

If you are putting the turbo pistons into the NA block do you need to match the tolerance group?

lart951

I have a good block, If you are interested I will let it go very cheap.

944CS

you always must match tolerance groups

DDP

meaning....?

Pauerman

Tolerance group 1 pistons in tolerance group 1 cylinders.

Pistons and cylinders are broken down into 3 different tolerance groups for standard size and 1st oversize.

I've run into this exact situation with my 3.0L shortblock. I have tolerance "0" pistons for a tolerance "1" bore. The factory recommended piston to cylinder wall clearance is VERY tight - .020mm or .0008"

You can get away with running this combo if you want to be close to the max piston to cylinder wear limit - approximately .003"

I'm swapping my 104mm turbo pistons over to the first oversize.

HTH

Chris White

Do a search -this has been covered in great detail....several times!

M758

Also the balance shaft housings are match setted to each block. This means that to get proper sealing of the housings you need to only install the set that came on that block. There is a stamping on the housing and the block to identify this.