Engine Transplant Recommendation

I bought my first non-GM car in more than twenty years yesterday. It is a

1985 Mercedes 230 CE which is a gray market car here in the US. The body and interior are in very nice shape but the engine is shot due to a timing chain problem that bent valves and probably damaged the pistons.

Instead of the expense of rebuilding this engine, I am thinking of putting in a GM V-6.

It looks like that there is plenty of room to it mount in place of the original straight four.

What engine, transmission combination from what vehicle would you recommend? Keep in mind that this is a rear wheel drive car. I'll be looking at auctions to find a wrecked car so that I can get all the electronics too.

Thanks, Scott

------------------------------------------------------------------------------------------------------ Check out the website . They provide aftermaket engine mounts (among other things) and "how-to" information for dropping GM V8s into various vehicles. I haven't specifically checked, but there's the possibility that some of their stuff is applicable to GM V6s as well.

Not affiliated, Mark

I second sdlspamo's choice. The 4.3 is a good motor and should be easy to find, plus I believe it has the same bolt pattern as a small block. If you get board with the six a 350 should bolt right up to the 700r4.

On Mon, 26 Mar 2007 09:38:20 -0800, a rock fell the sky, hitting Scott Buchanan on the head, and inspiring the following:

As others have mentioned, the Vortec 4.3L V6 was a great engine. I had a '95 Jimmy which I drove for 150K miles in seven years. Just watch out for the early ('95-'96) injectors as they are FUBAR.

Again, it is basically a 5.7 minus two cylinders with the same bolt pattern and can hook up to the same tranny.

The jagsthatrun site is pretty useful for a swap. I haven't looked in a few years, but I knew a few guys who did a V8 swap into blazers using their advice.

If you're really itching for some fun, try a 6.2 or a 6.5L diesel. Again, same bolt pattern as the 5.7 AFAIK.

"Mark Sparge"

Lot of things to line up and/or interfere. Unless you have CAD models of both, or are real handy with a torch (I'm not), I'd want to know the combination was going to work.

My experience is limited to dropping in a different option available from the factory. That was enough work.

If I was going to go through the work in your case, though, I'd go Chev 350. I'd get the baddest, fastest, smoothest engine I could afford and stuff it in there. It would have to have lots of machined and powdercoat stuff, and lots of modern Tuned Port electrical crap that I could tweak myself. I think that would provide the most fun for all the same efforts involved.

- D

You're taking the trans that goes with the V6 or one that can handle even more, you'll certainly need a custom driveshaft anyway... Just the rear axle is all you'll have left that it could possibly break. I don't think a MB would have one so weak as not to be able to deal with it in more or less normal driving. Maybe if you're doing burnouts you could break it.

Thanks for the responses. I read up on the Vortec. It looks like a good engine but I think that it may be too much power for this application. I don't want to break anything. Did they use the 3800 in any rear wheel drive car?

The Vortec is indeed a better engine, but you're not talking insane horsepower here. You won't be breaking anything - at least not because of the Vortec.

Some Camaro's and Trans Am's had the 3800.

What vintage engine/trans are you considering? Modern distributorless/EFI/fully electronic, or older distributor ignition and/or carbureted?

If you're going for an older simpler approach, then since *EVERYONE* is going to recommend a Chevy 350 I'll be contrarian and recommend either an older Buick v6 or v8 and associated trans, OR a Ford 5.0 and associated trans. A turbo 3.8L out of an 80s Regal would be a very cool swap in a Benz. Both Buicks and Fords have front-mount distributors and will likely have less firewall clearance issues than a Chevy. If it were

*me* doing this swap it would be Mopar all the way. :-)

The Buick 3800 has gone in rear-drives from its inception in the 70s (Regal, Grand National, etc.) to the last of the v6 F-bodies (Firebirds and Camaros), so there are RWD transmission choices factory paired with both Gen-1 and Gen-II 3800s.

You might take a look at the marine 3.0 4 cyl that OMC and Mercruiser use.Same bell pattern as a 350 chev and make 120-140 hp even with the marine intake-exhaust manifold. Will

Scott Buchanan wrote:

Makes you think, doesn't it? :-)

Well, not knowing too much about the engine bay of that particular car, its hard to say. And in general Mopar swaps aren't always "easy" because of the rear distributor on the LA smallblocks, the size of the big-blocks, and the overall size of most of the v8-capable automatic trannies. Both the TH200r4 or 700R4 are quite a bit smaller than the A-500 and A-518 Mopar 4-speed ODs. For those reasons I'd probably abandon my "roots" and not even consider a B/RB big-block (383, 440) or an LA smallblock (318/340/360).

Without knowing too many details, here's what I would probably dig deeper into:

1) a turbo 4-cylinder Mopar from a FWD 80s Mopar, coupled to a RWD transmission from a late 80s Dakota (when the Dakota also used the 2.5 common-block engine that the FWDs used). The FWD Mopar guys get stupid-huge horsepower out of 2.2/2.5 turbo engines by putting on big intercoolers, big injectors, aftermarket turbos, etc. and the engines take the pounding very well (same bearing sizes as a 426 Hemi or 440). And they aggravate the bloody heck out of us muscle-car guys by getting 25+ mpg when they're not spooled up and running 12-second quarter miles. I never know whether to consider them buzzing little pests, or amazingly cool! :-p 2) A modern Hemi (5.7) which is sold as a crate engine complete with engine control computer (or carburetor and simplistic distributorless ignition controller if you go low-tech). Its nice and compact without a distributor sticking out anywhere, and narrower/lower (for the most part) than OHC v8s like the Ford Modular and Mopar 4.7. Actually size-wise its pretty similar to a GM Gen-III v8. It will mate up to any smallblock Mopar transmission bellhousing, so you can go old-school/bulletproof with an A-727, or you can go with a 90's A-518 OD transmission from a Ram, if it would fit under the floorpan. Or get creative and use a stick.

Either option would require a lot of fabrication, but the turbo

4-cylinder would almost certainly fit with room to spare. Something really out there like a fuel-injected slant-6 would be beyond cool, but I wonder whether there's enough room for a long American inline-6, and it certainly would be a DIY fuel injection setup and nothing that's OBD compliant.

A Jeep 4.0-liter straight out of a circa-2000 Cherokee would be a contender in the "low bucks/ use it exactly as it comes out of the donor" category if there is room. Those are extremely torquey and would make for a peppy driver.

I was thinking about an OBD II engine for fuel efficiently and cleaner emissions. I can handle the electronics. I had a '82 Cutlass with the 3.8 and thought it was a great motor. Turbo? Humm....

I am not a Morpar guy, but what would you recommend?

What are we talking about: 200 HP? The original engine is about 140 HP.

No burnouts here. The only doughnuts will be inside the car.

Since you want a newer engine and I expect you would like decent mileage I would probably look into using an adapter plate with the factory trans and use a 3800. The 4.3 is a great engine but gas mileage is not it's strong suit. Get a 3800 from a later vehicle and use an adapter plate to bolt it in. Just find a machine shop to make one.

Conversions, especially ones where there isn't prior development work already done for you, can be very costly and problematic. I don't know what the weight of the original engine is, but you would want to make sure that any replacement isn't significantly heavier or the handling and braking can be severely compromised.

If you really must do this, by all means I would stay away from the

2.9/3.1/3.4l family of engines. I don't know if they were ever made for rear wheel drive or not, so it might be a moot point. Packaging efficiency is very good, but problems like leaking intake manifold gaskets and other make for a less than ultra-long-life design.

The 3800 from a later model Camaro or Firebird donor would be the first thing I would look at if I just had to make the conversion. Other possibilities might be the V-6 Mustang motor and transmission from 1990s vintage stangs. Lots of fabrication and making do would be involved in such a swap.

Lots of folks have done GM swaps into Volvos, Jaguars and Jeeps, but I haven't seen much written about doing so into an MB product.

Personally I would tear down the original MB motor and make it right. The cost and headache will probably be lower in the end than using low cost GM parts as the basis for a swap.

John