S54 Odd Camshaft Wear

[Pklauser]

I definitely hear you in pricing, but getting another used head could put you in the same position. Unless you have a source for rebuilt heads that are cheaper than followers, if you do, please share 😁

I'm thinking one day I'll upgrade my cams, and at that point I'll get new followers.

[sapote]

and I'd find all the varnish rubbed off the backside of the lobes with too little clearance

Why this is the evident for having too much valve clearance (or you were thinking of too little clearance)?

[Arith2]

Don't switch to the worst oil you can buy specifically for this problem. Liquimoly has the most detergents by a long shot and the worst protection. Most oil already have MOS2 in them whereas Liquimoly makes you spend $15 extra for it.

I doubt oil choice caused this but rather a long oil change interval or excessive gas in the oil. I had an engine that let go because of a lack of oil changes. The cams had those marks. You mentioned having the engine cleaned?

[cobra]

I really don't think this has anything to do with clearances, or oil, or additives, or anything else. I think it's a materials and/or design issue. I also think OP could leave it untouched for another 100k miles and it will more or less look the same.

[sapote]

I really don't think this has anything to do with clearances,.

Too much valve clearance caused valve ticking, and loud ticking is like hammering between cam lobes and rockers, no? Hammering surfaces will not stay smooth for long.

[jet_dogg]

This may come as a shock but metal engine components do experience wear.

[cobra]

Too much valve clearance caused valve ticking, and loud ticking is like hammering between cam lobes and rockers, no? Hammering surfaces will not stay smooth for long.

Using that reasoning think about where the hammering (clearance going to 0) would occur. Not at the tip, but on the side of the cam as it begins to ramp up. .
The wear marks are on the tip where there is the highest valve spring force and smallest contact area (highest pressures). Oil film becoming too thin is possible root cause.

Thing is I've never seen this on any other motor I've taken apart. The cams always look perfectly brand new. But on the S54 I've seen these marks on my own car and others on the internet

[cobra]

This may come as a shock but metal engine components do experience wear.

In theory the cam should have "infinite" life as long as it is running on oil. Then again so should our rod bearings LOL

[sapote]

Using that reasoning think about where the hammering (clearance going to 0) would occur. Not at the tip, but on the side of the cam as it begins to ramp up.

Very good point. I guess I could say the ramp side hammering caused the rocker to have a little rough surface, then this accelerated by the lobe tip at high pressure point. I have 4 sets of used stock cams and they all look normal, but I think it depends on the history of the engine and how it was used, as the M3 has relatively high cam lift. Never heard of this issue on M54 or M52TU engines, some have over 250K miles, with almost zero valve clearance with hydraulic lifters.

[Arith2]

In theory the cam should have "infinite" life as long as it is running on oil. Then again so should our rod bearings LOL

If there's friction, there's wear. Infinite life means nothing will touch it. Even air would wear them down given thousands of years. Oil is not frictionless, it's just a lot lower than metal on metal contact. The oil was probably contaminated at one point past the filter.

[T.J.]

If there's friction, there's wear. Infinite life means nothing will touch it. Even air would wear them down given thousands of years. Oil is not frictionless, it's just a lot lower than metal on metal contact. The oil was probably contaminated at one point past the filter.

He said theory and put infinite in quotes. Cams certainly exhibit wear under normal use, but we agree this isn’t normal wear - as you’ve mentioned contamination is a potential culprit.

[Arith2]

He said theory and put infinite in quotes. Cams certainly exhibit wear under normal use, but we agree this isn’t normal wear - as you’ve mentioned contamination is a potential culprit.

In theory, it should have normal wear. That is my point.

[saint_m3]

My cam is pitted like this as well. Doesnt make a tick though and I am just sending it. Any update one what you have done?

[pynacl]

My cam is pitted like this as well. Doesnt make a tick though and I am just sending it. Any update one what you have done?

I'm doing the same, just sending it. I've just done more frequent oil changes and installed a Dimple magnetic drain plug to catch any accelerated wear. Mine also doesn't tick so I'm not super worried about it and my plan is to run it until it ticks/flat spotting occurs.