300SD engine transplant prep
 

okay, so I'm finally at the point of dropping a good junkyard engine in a soon to be acquired 85 300sd. I think I'm going to be okay, as I'm getting the car for free and the engine for $300. plus $115 to rent the trailer to get the car the 200 miles home. fortunately the engine is halfway between the two.

the car has 250K and a thrown rod, the donor engine has 270K and runs like a top according to the guys at the junkyard and comes with the 90 day catastrophic failure warranty.

the question is: what should I be doing to this engine before I put it in? ( as I want to make sure the engine and transmission are OK before spending $500 on parts.)

should I be worried about the transmission? I've heard that the 126 trannies were tougher than the 123 series, at least behind the turbo'd 617.

since the rod went on the original engine, I'd worry about oil starvation to the IP and turbo, but as the new engine is complete, and I have an 83 300d parts car, I think I'll be OK.

according to the PO, when the rod went the engine locked up and locked the rear tires and sent the carskidding down the road, and I'm a litttle worried about what that shock loading might have done to the transmission.
I have a set of flex discs to go in.

so in short, I'm planning on putting in front and rear oil seals, new crank to flywheel bolts and putting in the engine. if it's ok, then I'm going to put in a new primer pump, rebuilt injectors, water pump, thermostat, timing chain, tensioner and rails, valve seals, and a couple other odds and ends.

are any of those things something that I'm going to regret not doing while the engine is out of the car? things that I just can't do while the engine's in the car?

how about the transmission? according to the PO the car ran fine and drove fine till it broke down.

thanks all
karl

The 123 and 126 turbo cars used the same tranny except for the little attachment at the end for the speedo (mechanical vs electronic) the naturally aspirated 300d's had a different tranny.

if it were me i wouldnt worry about the tranny or the flywheel bolts.

but someone else might have a different opinion.

tom w

I would replace the oil filter housing gaskets and oil cooler hoses now, and the injection pump mounting gasket if there is the slightest leakage. Take a good look at the throttle linkage return spring at the injection pump - mine almost wore through at the upper attachment point, which is surprisingly difficult to access. Good luck with the swap. Mack

See a previous thread....
 

....where I commented on this issue almost exactly. I've done the opposite, so I know some of the pitfalls :( .

http://www.peachparts.com/shopforum/showthread.php?t=147394

thanks guys. I'll have a good look at those oil cooler lines when the engine's out.

are the timing chain tensioner rails and whatnot much easier to do with the engine out?
I'm 500 miles from home with no mercedes to look at.

karl

much, much easier. Make sure you get the best sealant between block and upper oil pan, whatever that is. Also, you might as well plastigage the bearings if you have the crank out (to replace rear oil seal, the crank comes out). Plus, if it does not have a block heater, now's the time. The factory threaded plug is usually on wicked tight.

does the crank have to come out to do the tensionser and such?

I'm going to do the guides and such when the engine's out, and do the chain after it's in and running. $120's a fair part of the budget for the project.