TheSamba.com :: View topic

Mon Sep 01, 2025 2:33 am

Just noticed the wear in the cam slot from oil pump on a reground cam. Is this normal and is it ok to use?

g][/img]

Mon Sep 01, 2025 3:39 am

Since the engine only turns one way and it looks like it's already together I'd grudgingly run it.

.
.

Mon Sep 01, 2025 6:16 am

Press the drive shaft in the oil pump gear out farther. You can do it in a vice with a couple of sockets. I usually have to push them out about .050+” so they get full engagement in the cam. It’s barely riding in the cam now, and it will just keep wearing.

No need to split the case or anything, just check it doesn’t stick out past the pump body when you are done.

Brian

Mon Sep 01, 2025 9:49 am

I would worry more about the oil pump tang that did that damage. But that was probably in a previous installation if the cam is reground. Whoever did the regrind must have considered it OK.

It will probably wear a new oil pump tang unevenly to match its uneven contact surface as that wear probably does not go as deep as the tang of a new pump.

Mon Sep 01, 2025 11:28 am

Engine is at mock up stage only. Is it worth running this cam or am i best to look at another? Is this wear going to cause any long term issues?

Mon Sep 01, 2025 11:57 am

dl1970 wrote: Engine is at mock up stage only. Is it worth running this cam or am i best to look at another? Is this wear going to cause any long term issues?
As long as you have the oil pump gear tang fully engaged (per Brian's comment) with the camshaft slot. It shouldn't be a problem running it as is.

That said, if you don't correct the pump gear tang engagement, you may end up with this happening,

I found this when my oil pressure was Zero psi at startup one afternoon years ago.
The PO/Engine builder didn't check the tang engagement when he built the engine.
The camshaft slot looked like the OP's did. I ran it with a new 26mm oil pump until I replaced the cam during a recent build.

Mon Sep 01, 2025 12:16 pm

I've usually seen the wear on the pump shaft and not the cam gear.

Mon Sep 01, 2025 6:31 pm

As Brian said, this is an important step that some builders do not check. I have had to adjust on almost every engine I’ve built. Besides chewing up the tang, it causes low oil pressure at idle.

Mon Sep 01, 2025 11:28 pm

txoval wrote: As Brian said, this is an important step that some builders do not check. I have had to adjust on almost every engine I’ve built. Besides chewing up the tang, it causes low oil pressure at idle.
^^^^^^^^
Agreed

Mon Sep 01, 2025 11:46 pm

I so appreciate all this advice! I have measured the engagement and adjusted the drive shaft depth. I couldnt find an exact how to but used the following method. Fitted oil pump housing and nuts to hand tight. Offset the drive shaft tang so not in the cam slot. I then measured the distance the drive shaft cog sat out of the oil pump housing (4.2mm). I am assuming it therefore engages 4.2mm when rotated into the cam slot. I then punched the cam drive a further 1.7mm into the cog to give a final measurement of 5.9mm of engagement. Hoping this is the correct method!! Without your advice it would have been well off and adding to the issue! We work in metric in New Zealand so I believe this is initial engagement .165inch. shaft punched in .067inch to give final engagement of .232 inches.

Tue Sep 02, 2025 5:24 am

There should be some end play, tang shouldn't bottom out in cam slot.

Tue Sep 02, 2025 7:59 am

This might help:

https://www.thesamba.com/vw/forum/viewtopic.php?t=340626&highlight=oil+pump+drive

Tue Sep 02, 2025 8:31 am

dl1970 wrote: Engine is at mock up stage only. Is it worth running this cam or am i best to look at another? Is this wear going to cause any long term issues?

If it sheds chips the metal will go somewhere. The filter will catch it if you're running full flow. Otherwise the main bearings will catch it. I reckon one tiny steel chip equals one groovy main bearing.

.
.

Wed Sep 03, 2025 6:38 pm

The old cam here is the victim, the oil pump and case is the perpetrator.
So sure you can use the cam again, but the oil pump alignment in the case is what you might want to re-check.

Get the alignment and engagement depth correct, there will be no more problems.

The problem was because the oil pump was not aligned right before, and not engaged enough either.