Date registered: Apr 2006
Vehicle: W111 Coupe
Location: Washington DC
Mentioned: 1 Post(s)
Quoted: 11 Post(s)
All these engines have the same mounting points. You need 3.5/4.5 engine arm brackets and engine mounts out of a W108/109/111. The arms will be a straight fit on the engine block and then the engine and mounts will be a straight fit on the front axle carrier. You will need a W108/109/110/111/112/113 fan clutch and fan propeller.
for the 3.5/4.5 engines (iron blocks), I think the exhaust manifolds will clear the engine bay, whatever the donor car.
For the 3.8/4.2 engines (alloy blocks), If the donor car is a W126 I think the exhaust manifold won't clear the engine bay. Then it's easy to source manifolds from an r107. 3.5 and 4.5 manifolds will also fit. You will need an oil filter housing out of a W126 if the donor car is an r107 to clear the front axle carrier.
For the 5.0 and 5.6 engines (alloy blocks) the best manifolds are out of an r107 560SL. Here again, you will need an oil filter housing out of a W126 if the donor car is an r107.
A four speed manual trans out of a 3.5 (rare) will be a straight fit on the 3.5 and 4.5 iron blocks, and will also fit the (very rare) early 5.0 alloy block only found on the 450SLC 5.0 with little modification.
For the 3.8/4.2/5.6 and later 5.0 engines, the bolt pattern is different and your best bet is to modify a cut-off auto trans bellhousing and adpapt it to your manual trans with an hydraulic release bearing. You can cut the back of your current bellhousing and mate it to the cut-off auto trans. You will have to make your flywheel. You will also need to fit stronger bearings in the trans for it to handle the torque. If you go that far I will give you the bearing reference you need.
If you go for an auto trans, you most likely will have to shorten the driveshaft.
You can source a 3.27 rear end out of a W108 4.5.
The early 3.5 and 4.5 are the easiest to convert to Megasquirt because they are already EFI. Later engines went K-jet, sot the easiest is to retrofit the early 3.5/4.5 EFI hardware and plumbing.