PeachParts Mercedes-Benz Forum - View Single Post - Favor for a friend 82' 240d to 300 turbo swap

junqueyardjim · #6 12-25-2011, 02:47 PM

I finished mine swap this summer. There is a lot of work to do, but basically it is engine out, a few changes, (some new parts like engine mounts,ect) and engine in. The standard pilot bearing (from the 240D - but a new one) works in all the 617's except for the 85 model year. It should gently tap in. If you have an 85 engine, I found it will still go in on a hot day if you put the bearing in a deep freeze overnight and quickly drive it all the way in with a good HD deep socket pushing it in. Your shift rods will need to be shortened by 4" inch. Since the factory thread is a rolled on thread, I would attempt to cut the four inch section out of any straight piece. It takes two cuts with a hack saw and one weld and is very easy. Finding the correct cross member can be a problem, though I found one the first time I looked for one at the P & P. It is the cross member from the 240D automatic which you need. It makes it much easier to do the job if you have two complete cars to work from, a 240D four speed and a 300D automatic. I parts my 300D out at the same time I pulled the engine from the 240D. I still threw away a little more then I should. I used the radiator and oil cooler from the 300D and put on new oil hoses. You can "usually" get the oil line out of the cooler if you are very careful. The front section of the drive shaft will have to be "expertly shortened". A good shop will cut out the four inches, machine a very tight fitting short piece of tubing to insert inside, press the piece together and re-weld. If the job is neat and very clean and consistent with the welding I see no need to balance it. But it could be a problem! The same with the 240D flywheel. I had no reference as to how the flywheel was mounted on the 240D, I could find no marks on the flywheel, and I just remounted it using all new and expensive stretch bolts. They are designed for one use only! But we put the flywheel and clutch on and we have no balance issue. Again, it could be a very nasty problem! Very important to use a torque wrench on many of these critical bolts. It is a must! If you don't have one, buy one. If you plan to use the heater on the 240, you have to get a new heater hose from the engine to the firewall. The 240D uses a very short almost S shaped hose from the back of the engine. However, with the added length of the engine, that hose and fitting would be right against the firewall. So I took the fitting from the back of the 240D head and placed it in the the threaded hole in or toward the front of the head on the drivers side where the temp sender went to the exhaust manifold side. The 2nd or rear temp sender is for the gauge. The hose feeds through the injection lines, makes a 90 degree turn and goes back to the heater. It is a great time to clean up the engine compartment, the PO on mine had painted it all black with some type of undercoat, whew what a mess, but I got rid of all of that. Also, check under the battery tray, make sure you have no corrosion started there, also a great time to check the bushings in that control arm that run across the back of the engine compartment. You will have to use the exhaust from the 300D of course. If it is all rusted out, better look at replacing it. I found one like new from a forum member and traded him my transmission from the 300D. Sometimes luck is the best thing we have going for us. If you are going to use the 300D cooling system, then you will have to install the recovery tank and brackets to the right side inner fender. I junked mine and had to buy one from a forum member. The change of rear diffferential is an absolute must. If you left that 240D RA in there with the 617Turbo, you would feel like you are driving a Mack Truck tractor. It would be all wind up and no go, a real stump puller! At the same time you get or pull the differential, save the axles even if they need repair. If you have to open the diff to get the axles out, make sure you save the " C clips" , and immediately put the cover back on and tape the axles openings closed to keep that baby clean. Dirt in that diff is a disaster.
Then of course you would want a speedometer that would match the RA and get that or save it also. And I would think it should go without saying, but if that clutch and pressure plate don't have the look of real new to it, it better be replaced because the 617 turbo is all that the clutch can handle, probably is more than it can really handle.