Cam wear question…

[A930Rocket]

Installing new lifters in my 05 BMW 330ci and I see some wear on the exhaust cam bearings and some small pitting on two lobes.

Trying to save some money and this being a weekend/some track car, what do you think?

The cam box and bearing caps are good, except one slight scoring.

Replace or go with it.

Edit: should I try to fill the lifter before install or turn the engine over without starting to build up oil pressure in the lifters (and engine)?

[hcoles]

Interesting - the pits on the dwell area.

[beepbeep]

Nothing to worry about. Engine probably sat for a long time at some point and you had some localized corrosion where oil film was lost.

[asphaltgambler]

Is this a re-grind performance cam from an OE core?

[Zeke]

I'm not an engine builder by trade but I sure wouldn't do that. A regrind on the cam and reconditioning of the lifters can't be that much. Buy the insurance. Just $0.02.

[Scott R]

Originally Posted by Zeke

I'm not an engine builder by trade but I sure wouldn't do that. A regrind on the cam and reconditioning of the lifters can't be that much. Buy the insurance. Just $0.02.

I’m with Zeke on this, and that wear is bad.

[A930Rocket]

Originally Posted by asphaltgambler

Is this a re-grind performance cam from an OE core?

I don’t know the history, but they are BMW cams. 178k on the clock.

Everything has been clean with no debris anywhere, including the oil pan I dropped to pull the timing chain cover.

I’m replacing all the lifters with OEM.

Chances are I’ll be replacing the cams this winter or spring with Schrick cams ($1500) and I can replace or recondition the cam bearing ledges then. New are ~$550 each or so.

[unclebilly]

Pits don’t cause wear, they are low spots and will be full of oil when the engine is running.

Run it.

[1990C4S]

Originally Posted by unclebilly

Pits don’t cause wear, they are low spots and will be full of oil when the engine is running.

Run it.

If the lift is still in spec, and it looks like it will will be, then I agree 100%l

[Dantilla]

Interesting.
I saw this when first posted, and have been waiting to see the responses.

In aviation circles, that cam is junk. No question.
Because the hardened surface is very thin, any pitting will soon lead to more damage exponentially.

Of course, airplanes are regulated tightly, and either airworthy, or unairworthy. There is no category for weekend/track toy airplanes.

[A930Rocket]

Originally Posted by Dantilla

Interesting.
I saw this when first posted, and have been waiting to see the responses.

In aviation circles, that cam is junk. No question.
Because the hardened surface is very thin, any pitting will soon lead to more damage exponentially.

Of course, airplanes are regulated tightly, and either airworthy, or unairworthy. There is no category for weekend/track toy airplanes.

It’s easy to pull the valve cover to monitor the cams and caps for wear. I don’t know if buying a used cam ledger is worth it until I buy a new set of cams. Also, I would think you would want the cam ledger and cam to be new for break-in purposes and longevity.

Being new to this car, I don’t know if the cam ledger and cam itself can be reconditioned. There are no bearings to replace now.

Edit: The pictures zoomed in to show more detail. When I get back in town next weekend, I need to check exactly how much pitting there is. From the picture, it looks more like a stain of some kind.

[Dantilla]

Originally Posted by A930Rocket

It’s easy to pull the valve cover to monitor the cams and caps for wear.

This is why I didn't post for quite a while.
I'm not giving you advice, I'm using your thread to learn.

The most highly stressed part of the typical Continental/Lycoming air-cooled airplane engine is the surface between cam and lifter.
The only way to look at the cam is to pull a cylinder or three.
The only way to replace a worn cam is to split the crankcase open. Pretty much complete engine disassembly.

I like hearing the responses from car guys that can ignore aviation requirements.