603.961 into w140? Ever tried it? How hard? - PeachParts Mercedes-Benz Forum

bustedbenz · #1 05-30-2008, 08:45 PM

Thinking WAY ahead to the future when the body rusts away from my easily rebuildable (but still functional) 603.961 engine in the SDL. Don't think I'll ever buy another w126 because, barring something unforeseen, I think my engine is easily going to outlive my body - and when the engine needs rebuilding, I think the body will be too worn out to put a rebuilt engine back into (economically).

Here's what I'm hoping can be done... thinking of this in terms of 3-7 years down the road when my 603.961 is worn out and my w126 doors fall off from the rust... I would like to buy a w140 diesel with a rod-bender and drive it until the 3.5 dies and then... abandon the 3.5. While I'm getting those last few miles out of the 3.5, I will rebuild my 603.961 in the basement at leisure and have it ready to go back.

I would like to hear from anybody who has put a 603.961 into a w140 body that was originally powered by a 603.971. I'd also love to hear from anybody who knows a really good reason why such a swap would be impossible.

Thanks. This is years down the road but I might go on and start looking around (and saving up) for that perfect garage-kept rod-bending w140 in anticipation of rebuilding my .961 and dropping it in when the time comes.

I tried a few different search terms and couldn't find a previous thread that was somewhere along this subject...

TMAllison · #2 05-30-2008, 09:42 PM

Search SIXTO's posts.

He has already done the same basic swap reusing the the head(?) and IP(?) to create a hybrid 3L.

bustedbenz · #3 05-30-2008, 10:46 PM

Quote:

Originally Posted by TMAllison

Search SIXTO's posts.

He has already done the same basic swap reusing the the head(?) and IP(?) to create a hybrid 3L.

Meaning a 603.971 "top end" sitting on top of a 603.971 "bottom end"?

TMAllison · #4 05-30-2008, 11:21 PM

Ask or search.

I think he used a .961 with some of the .971 on top.

babymog · #5 05-30-2008, 11:26 PM

I'd keep the .971 head complete sans camshaft, and turbo, nothing else. Well, mounts, oil filter housing, oil pan, ... some other parts.

bustedbenz · #6 05-31-2008, 09:04 AM

What's the advantage of not just putting the entire 603.961 into the recipient car, using only the rod-bender's parts that are essential to make things physically fit?

Also... I assumed this was a fairly common thing to do. What are people re-powering w140 cars with when the 971 gives up the ghost?

babymog · #7 05-31-2008, 10:03 AM

The .961 will pretty much fit IIRC, the .960 will need parts from the .971 to make it fit.

The ..96x will probably have an older head, newer is better, I'd keep the newer (probably the .971) head and the .971 turbo is trimmed for more boost.

The .971 IP is not designed for the hp (and thus fuel flow) nor the RPM of the .96x, so the .96x IP is IMO better.

Just a matter of "cherry picking" to make an engine that is the best of both. I'm in the middle of taking two good running engines, a 603.960 and a 603.971 and making one very good 3.0. It doesn't have a home yet, but if it's finished before something catastrophic happens to the '87 or I find a 140 diesel that needs an engine, it'll be my super-turbo '87 300D engine. Might as well optimize the "gene pool" of the engine you're building.

Hatterasguy · #8 05-31-2008, 01:26 PM

Screw the 603 drop in a turbo charged 606 like another member did. Than you will have the amazing S300D that MB never imported to this country.

I think he said the whole conversion cost him like $4k.

All you need is an S350D than find a wrecked E300D to get the engine out of, I think he made a custom intercooler because he 210's wouldn't fit behind the 140's bumper.