What is the wear limit for the camlobes on a 1979 300D. The nominal measured maximum thickness accross each of the lobes is 1.520" to 1.525" on all of the lobes except cylinder number 1 intake and exhaust, and number 2 intake (the first three from the front of the engine). They measure 1.498", 1.490", and 1.504" respectively. There is obvious signs of wear on these and little or no wear on the remaining lobes. The car runs fine but does this wear mean we should replace the camshaft or is the wear acceptable for continued engine life. The mileage is 120,000.

Thanks
Jeff Stepek

That does seem strange. Did the car go for long periods without adjustment leading to overly tight valves and premature wear? Most cams are surface hardened and once you wear through the surface they wear down quickly. What concerns me is the particles and debris this would create. I would keep a very close eye on the cam, maybe check it every 3K and compare your measurements? That or just swap it out. Grab a used cam at a boneyard. Don't forget to take the followers too and keep them in order so they end up on the correct cam lobe. They wear in patterns so keeping them in the same relative position should maintain this. RT

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When all else fails, vote from the rooftops!
84' Mercedes Benz 300D Anthracite/black, 171K
03' Volkswagen Jetta TDI blue/black, 93K
93' Chevrolet C2500HD ExCab 6.5TD, Two-tone blue, 252K

I think you should start planning for a new camshaft. There is a 1979 camshaft on www.pgauto.com for $70.33, just to give you an idea of the cost. In dealing with them, you get a right to return the part. You might see one on EBay, but inspecting and rejecting it is a problem without some kind of agreement.

I'll bet someone here could locate a camshaft for you too.

My 1982 300D must have fortunately had the oil changed very regularly during its 335K miles. No observable wear on the camshaft and essentially no timing chain slack. (Oh, you should be checking your timing chain slack too.)

Have you done a valve adjustment, and were they tight?

Ken300D

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1982 300D at 351K miles
1984 300SD at 217K miles
1987 300D at 370K miles

We have put about 10,000 miles on the car. The oil has been changed every 3000 miles since new (have records). The valves were adjusted right after our purchase. Several of them were tight but I cannot remember which ones. As noted the car seems to run okay, but am still wondering if the .020" wear does have an effect on performance or as suggested accelerate additional wear.

Thanks for the replies.

Jeff Stepek