3.0L Cam in 2.6L M103? Will it work?
 

My 260E has some slight scoring on the cam and the rocker arms

I have read that the early 103's have a soft cam + rockers that were updated according to the FSM in mid 1989, but it requires matching cam + rockers.

So if I managed to find a good looking, low-mileage updated 3.0L cam + rockers at the junkyard would it fit?
Would there be any benefits/drawbacks to using it over a 2.6L?

Thanks,

I dunno the answer to your question, but without such a swap just make sure to use oil with zinc additive.

I just got the valve stem seals done, so assuming its still not burning a quart every 150mi then I will be getting Rotella-T 15-40 changed ASAP. I hope it will clean up the 'red' valvetrain a little better than the current 10-40 I am using.

So, based on that I know about the differing cams now, would it be safe to say that Dino oil should absolutely be used in any early 103 using the earlier tin-plated cam design? Is it still recommended on the updated design too? Just so I know for future reference and knowledge.

use 0w-30 for 500 miles, twice or maybe three times. heavier oils don't clean as well as light oils.

but it really doesn't matter, change your hot and often and you'll be fine

No difference in camshafts in 2.6 or 3.0 liter M103 engines.

Using a 10W-40 or 15W-40 doesn't matter in So Calif.

However the lighter weight oil will allow better lubrication in cool weather.

Thank you guys that answers my questions. I'll keep my eyes peeled.

I read somewhere that in 1989 MBz changed the camshaft profile for a smoother idling engine (M103), as the earlier cams were known to idle a little rougher than the new ones. That may be what the FSM is referring to in the mid-1989 production change that ps2cho mentioned. Does your response above mean that a 89+ cam (and rocker arms) can safely be used in a pre-89 M103 motor, or only that a 2.6 and a 3.0 use identical cams, provided they are of the same model year?

For all USA M103 (2.6L or 3.0L) engines.....the camshaft part number is 103-050-64-01.

OF course that number has "many" earlier versions & requires MANY additional parts on pre 1990 cars.

So a camshaft & rocker arms from any M103 will "fit" into any other M103.

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.

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 so I can't tell if it has a hardened cam or not. I also 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