2.2 case half alignment problem
 

I have a 2.2 that i'm rebuilding, and had the case line bored as the bores were oval along the parting line. They were done by a shop i trust - one of the PP supporters and prolific engine builder/machinist. I have been inspecting all dims prior to assembly and find the main bores with bearings installed, on size perp to parting line, but way over (.009" measured or about .006 over) near the parting line. I have a very nice Mitutoyo dial bore gauge that allows me to measure within .0005".

I have only measured with bearings (supplied with line bore work) installed, and the only thing i can figure is that the alignment dowels and holes have slop or a bugger that is causing a case half offset. When measuring near the parting line, i am measuring directly across from one half to the other.


My next step is to split cases again, remove bearings, and remeasure bores, and also feel with my finger if the case halves feel offset.

Has anyone experienced this? Any suggestions on solutions?

Thanks in advance

CC

I have a bore gauge and it's no easy task to use ESPECIALLY at 1/1000ths. Have you thought about trying plastigage to verify. It's simple enough to install the bearings and crank, then torque it down. I'd put a bit of green plastigage every 90° on each main. It'll also give you a chance to check for burrs/crumbs.

Then, take your findings to the machinist and see if he agrees and develop a course of action.

thx Tharbert,

I figured out the problem - the flywheel end of the cases are aligned by the two sleeves around the studs, while the pulley end of the cases are aligned by the #8 main o.d. The main o.d. is a line to line (or very slight - on order of a thou or so) interference fit with the bore so it aligns the case halves perfectly. I was going to install the no 8 main and re-mic the bores, but the bore gauge wont fit thru the small bearing id, so i took your suggestion and plastigauged the bearings. All checked good, so i'm a happy camper.

I have a 2.2 that i'm rebuilding, and had the case line bored as the bores were oval along the parting line.

There's lots of old junk #8 bearing housings floating around so next time you can have one of those bored out to allow your measuring of the bores. Or cgarr has pointed out that there's a VW air cooled case bearing sleeve that can be used as well, since it has the same OD as the Porsche #8 bearing insert