Cam wear on a 4.5 V8
 

How common would some wear be on the cam lobes of a 4.5 V8 with 105,000 miles?

The mechanic of someone I sold the engine to seems to think there shouldn't be any.

MDN

An MB mechanic I know in Corpus Christi told me that he has seem 4.5 lts. go as much as 400k miles w/o serious wear. We were talking about replacing the timing chain at 100k. He said that he had seen chains at 350k+ but that the slides should be replaced at 100k intervals. Any engine that can take that king of wear should not have a cam failure at 105k unless there has been lack of oil to the cam.

Clarification
 

I'm not asking about the best of what's possible - just real world.

If you bought a 4.5 out of a '72 SL and the ONLY thing you knew about it was that it had 105,000 miles, what would you expect to see when you pulled the cam covers off? Scratches and wear on some lobes, or like new from one end to the other?

Are 90% of the 31-year-old engines with that mileage still pristine, or 50%, or 10% . . . ?

Are you LUCKY if one shows no wear (because of previous owner maintenance or whatever), or should you EXPECT it to have no wear because lack of proper maintenance is so rare as to be almost unheard of.

MDN

if the car has been well maintained and frequent oil changes with top quality oil, i would NOT expect to see rhs cam lode wear.

Mark, Kip:

Please - you've avoided my question.

Leave out the conditionals (e.g., "if the car has been well maintained . . .").

Imagine instead that you bought a 4.5 engine from an ad for $400 without being able to inspect it or hear it run from an individual you don't know who told you it had 105,000 miles on it, it ran strong, didn't burn or drip oil, and had no known problems - and that's all true.

Assume you know NOTHING ELSE about the history of the '72 SL it came from - in particular, you have no idea how it was maintained over its 31 year life at the hands of who knows how many previous owners.

You get it home and take the cam covers off - what do you really expect you'll find in this engine - some lobes with scratches and wear, or all cam surfaces looking like new?

No coulda, shoulda, please. Hell, I could have Bill Gates' wealth and Tom Selleck's looks (with a lot of luck, drive, and proper maintenance), but would you expect that I do?

MDN

Assume you know NOTHING ELSE about the history of the '72 SL
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It should have very minimal wear. That being said, again that is the "average" because most owners do at least minimum oil changes, etc. But if you got an engine that was abused or had little if any routine care then you certainly could have a cam with that kind of wear.

If I bought an engine sight unseen and felt that the seller was up front when I talked to him I would expect to get a running engine that had had reasonable oil pressure with no major signs of abuse. The fact that the cam lobes are slightly? scratch is part of the risk. As long as I did not feel that I had been grossly misled by the seller then I would take what I got. At 105k not many owners would have taken off the valve covers just to pass the time on a Saturday afternoon. The buyer should have NO reasonable expectation that the owner would know that the cam is scratched. All the buyer, in good fath, can do is present a product as described and 'caveat emptor'.

Cam wear is likely on an M117 -- there are know problems with the oiler tube plastic clips, so that the cam can be oil starved.

I'd expect about half of used engines to have a perfect cam -- there was a reason, after all, that the car ended up in the yard. Owners, particularly third and later ones, don't usually keep older cars up very well, tend to drive them till they drop. The result on an M117 will be cam wear from inadequate lubrication.

Peter