I'm trying to figure out if I can put a cam, bearing caps and rockers I got from an early 1990s 300sel 3.0 into my 1990 190e 2.6L. I ran out of oil driving up i80 on my way to Reno. Luckily I pulled over quickly before any major damage was done. When I got it home I put oil in and started it up, the engine nock went away, after taking the pan off and plastigauge the crank shaft clearances found it is still in tolerance, its overall in good condition.

It's obvious that someone had worked on the engine in the past it looks like the exhaust side of the head was machined so the S stamped in the side of the head is missing, I can't tell if it has a hardened cam or not.
I found that the bearing caps had been installed in an incorrect order the worst being #1 was on #6. #6 had a huge chunk of metal missing from right beneath the exhaust side rocker. The aluminum pieces where found in the oil. The cam is scored at the bearings . I need some advice , thanks

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1969 230 inline 6 dual carb 60,000 Miles 2nd Owner doesn't run right
1982 300 SD 455K - my reliable commuter car
1990 190E needs new crank shaft ran it out of oil
1996 C220 bad wiring harness

Cam caps are not really interchangeable. They are rough machined , bolted to the head then line bored.

However you can hand fit a used cap to get you going again.

The cam journal will need polished but don't be too worried about removing scratches that go around the journal. Removing all the scratches so will only make it smaller, just get rid of anything that looks like it will tear metal as it rotates.

Get another cap, bolt it to the head, use a straight edge across 2 good bearing caps, ( with the replaced one in the middle ) . If the cap isn't too far above or below, precede to the next steps.

Install the install the cam ( but not the chain or rockers ) and use plasti gauge on the bearings to get an idea of clearance. If the replacement cap is too large / small of a clearance, try another cap. Once you have settled on a cap, remove the cam, replace the cap then look at the parting line to see if there is a ledge. If so , try another cap. Once you have found the best compromise, file the legs to reduce clearance, shim to increase, chamfer the parting line edge if there is a ledge.

When finished, don't run the car at high speeds for say 500 miles any high sport have a chance to flatten out. Oil pressure at idle might be slightly lower of the clearance is large.


The only other way to fix this is to replace the head or have a machine shop bore that cap for a bearing insert. ( looks like a connecting rod bearing ) . Doing the patch up is worth the risk.

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1969 230 inline 6 dual carb 60,000 Miles 2nd Owner doesn't run right
1982 300 SD 455K - my reliable commuter car
1990 190E needs new crank shaft ran it out of oil
1996 C220 bad wiring harness

The problem is I have no good bearing caps they were all installed in an incorrect order so the best I can do now is install new caps and a matching cam from the junkyard and hope it works

__________________
1969 230 inline 6 dual carb 60,000 Miles 2nd Owner doesn't run right
1982 300 SD 455K - my reliable commuter car
1990 190E needs new crank shaft ran it out of oil
1996 C220 bad wiring harness

Be sure to check roundness of the used caps and bearing clearance when bolted to the head.