Transaxle alignment

[kram350kram]

So... I line bore a block, move the crank centerline some, get another transaxle, etc...

With a removable bell housing I can dial in the centerline of the crank to the transmission input shaft and make necessary corrections. I have no ability to do same with a transaxle with an integrated bell housing.  How would one go about checking concentricity with a non removable bell housing?  Any input appreciated.   

[jbcollier]

When you line-bore a block, you trim the main bearing caps and then bore do that an absolute minimum is removed from the block itself.  The crank centre line should end up in virtually the same place.

[kram350kram]

Thanks yes but using a new block, block to transaxle adapter, adapter to a Porsche transaxle I am concerned with stacking error upon error to out of specification. This transaxle has a tapered roller bearing input so no play whatsoever. If it was a standard ball bearing input at least there would be some play at the pilot bushing/bearing.

[Chuck Nukem]

Have you already made the adapter? That is the part where the alignment comes in. I am currently working on one for a customer to adapt a hewland box to a big block chevy. What we have to do next is make sure that the centerline of the crank, and the centerline of the inputshaft are in the same axis. The best way to do this is to design the adapter plate to have a round hole that is concentric to that axis. To check this I would mount the adapter plate to the block and make a test shaft which fits in the crank pilot bearing. Then you would use a dial indicator to sweep the round bore of the adapter plate. Do the same for the transaxle. If they both read zero then you are ok! If they do not read zero then the bolt holes and dowel holes need to be adjusted relative to that large circle in the center of the adapter plate.

[jbcollier]

Bolt it all up to a bare block with the bearing caps torqued on.  Use a long straight edge on the main bearing surface and see how it lines up.  Even more exact make up a mandrel exactly the right size with a centre point.

[kram350kram]

Bingo, the light just came on! Just zero plate to block, then plate to transaxle. With adjustment dowels on one side or the other, good to go. Thanks to all.