Carpokes Porsche Forum

Hello carpokers,

When I removed the camshaft from the housing I needed to tap the end with a piece of wood (fairly forcefully) to achieve removal. It was the end bearing surface on the cam which was catching during the process. Is this normal?

Should I take it to a machine shop to remove a couple of thousandth of an inch from the surface? The cam seemed free to rotate before removal though. Should I simply heat the housing when I come to reassemble?

Can I ask the erudite carpoking community for the benefit of their collective experience on this one please?

Hi MarkP - I had a couple of issues like this in my recent rebuild with balance shaft ends.

I found that cleaning up the end by using some 400 grit sand paper held tightly around the end while rotating cleaned up the ends enough to remove the friction. It didn't take many passes.

Certainly not as precise as having a machine shop do it on a lathe, but was enough for me to solve minor friction issues.

Others may have better suggestions, of course.

Normal for the cam to stick in its bearings since they are a formed fit. I do not recommend removing any material or doing anything other than reinstalling, especially if the cam is rotating freely.

You should also inspect the bearings and journals for any severe wear or scoring that can be caught with a fingernail.

If you desire you can try running a plastigage between the cam journal and bearing to see the clearance. I am not sure if there are recommended cam journal to bearing clearances/tolerances listed in the FSM, but you can check. FSM is available for free in PDF format.

http://p914-6info.net/944%20Manuals.html

Excellent walfreyydo - that's exactly what I needed to know!

walfreyydo wrote: Mon Mar 03, 2025 10:27 am Normal for the cam to stick in its bearings since they are a formed fit. I do not recommend removing any material or doing anything other than reinstalling, especially if the cam is rotating freely.

You should also inspect the bearings and journals for any severe wear or scoring that can be caught with a fingernail.

If you desire you can try running a plastigage between the cam journal and bearing to see the clearance. I am not sure if there are recommended cam journal to bearing clearances/tolerances listed in the FSM, but you can check. FSM is available for free in PDF format.

http://p914-6info.net/944%20Manuals.html

Agreed on all counts. Great post and link!

MarkP wrote: Mon Mar 03, 2025 8:36 am Hello carpokers,

When I removed the camshaft from the housing I needed to tap the end with a piece of wood (fairly forcefully) to achieve removal. It was the end bearing surface on the cam which was catching during the process. Is this normal?

Should I take it to a machine shop to remove a couple of thousandth of an inch from the surface? The cam seemed free to rotate before removal though. Should I simply heat the housing when I come to reassemble?

Can I ask the erudite carpoking community for the benefit of their collective experience on this one please?

MarkP,
Since you reported that your camshaft rotated easily prior to removal, and you determined the difficulty was with the end surface of the camshaft, you only need to address that end surface. ScotchBrite is your friend. Use it to clean up the rear journal on your cam where it apparently has collected a skin of dirt/stain/swarth. Wrap the ScotchBrite around the journal and buff. The ScotchBrite won't remove any metal, but will clean the journal easily and quickly. I'm confident this will allow the cam to be installed easily and spin freely. This is a common issue. Be sure to oil the journals before reinstalling.