Which engine should I swap in? - PeachParts Mercedes-Benz Forum

Johnhef · #1 01-29-2008, 10:23 PM

To start, vehicle is a 1983 380SEC 194K.

I have two available engines, one still in the car a 1984 500SEC (M117), 120K and a lone engine, a Euro 380 (M116), unknown mileage, unknown car, rebuild sometime in the past.

Now, not worring about the unknown of the 380 motor, based just on specs what should I put in the car? It's not a daily driver and is going to be just for fun, a rice hunter and even possibly some autocrossing.

What I know (or think I know) about these two engines so far

Current 3.8 US M116: 155HP?

5.0 M117: 184HP?
3.8 M116 Euro: 212HP?

I forget where I saw these numbers at the moment but they're exactly as I saw them.

I'm getting a different set of specs from wikipedia- which is a little confusing because it lists the 5.0 M117 anywhere from 220-269HP and the 380 engine as 201HP. It doesnt say what years or versions these numbers are from (4 different ones for the 5.0 alone). Does anyone have known correct specs for these engines?

So....what would you do?

Roncallo · #2 01-29-2008, 10:40 PM

Those numbers are about right for the best Euro 3.8 and the worst US 5.0. You may however find the 5.0 to perform similar to the 3.8 only due to a wider power band. You can find that data on the 107 CD under the engine section.

What would I do??

I would sell both engines and get a nice low milage 5.6L M117.

John Roncallo

Johnhef · #3 01-29-2008, 11:01 PM

I'm already getting one

but not for that car. While yes a 560 swap would be the optimal decision, I want to use what I've got with either the 500 or Euro 380.

I did find some more specs that seem to be more accurate and descriptive:

380SE/SEL/ SEC 3,839cc, 88 x 78.9mm, V8-cyl OHC, type M116, Bosch fuel injection, 204bhp at 5,250rpm; 225lb.ft at 3,250rpm. US models 155bhp at 4,750rmp; 196lb.ft at 2,750rpm (from october 1980 for US models; from spring 1981 for other markets)

500SE/SEL/SEC 4,973cc, 96.5 x 85mm, V8-cyl OHC, type M117, Bosch fuel injection, 240bhp at 4,750rpm; 296.6lb.ft at 3,200 rpm (to spring 1981). 231bhp at 4,750rpm; 298lb.ft at 3,000rpm (from spring 1981 to October 1985). 245bhp at 4,750rpm; 286lb.ft at 3,750rpm (from October 1985). 184bhp at 4,500rpm; 247lb.ft at 2,000 rpm (US models).

Question now, how much of a difference does the torque make with 225lb/ft compared to 247lb/ft at a lower RPM?

Also- Whichever engine I decide on, I will probably use euro manifolds with a custom exhaust, I already have the ones for a 116, and ones for a 117 will be on the way shortly. How much of an effect will this have on those numbers as well?

Dee8go · #4 02-01-2008, 10:34 AM

I thought the engine was the main reason you bought the 500. Are you having second thoughts about that? Can you put a turbo on it, you think? Didn't someone here put a twin turbo on either a 500 or a 560?

Johnhef · #5 02-02-2008, 01:20 AM

I bought the car for the grille. The engine and interior were afterthoughts.

cost of entire car < cost of used grille

t walgamuth · #6 02-03-2008, 09:59 AM

I would recommend the us spec 500 over the 380 euro for two reasons....the extra torque will be helpful on the autocross course. A nice fat flat torque curve is what you want there to get you going after a tight turn. Also the us spec 500 runs on regular which is a lot cheaper to buy. A factory original 500 motor with 120k is barely broken in if it has had decent care. Slap in some new chain guides and go. Any rebuilt motor is only as good as whomever built it and you probably don't know who or what they did to it.

I autocrossed my 84 500sec summer before last. It was nice. Not comptetitive against the newer smaller cars, but we surprised some folks and had a great time.

I used the b(?) setting of low the little gate at the bottom of the shift pattern where you push the lever to the right. It will hold whatever gear you are in until you reach a speed while slowing down that will allow first gear at the redline to operate and then it automatically downshifts for you, this is handy when approaching a turn. You will be pretty busy and not wanting to think about shifting down.

Tom W

Johnhef · #7 02-11-2008, 09:14 PM

Well I think I've found my answer. I bought a Euro 500SEC last night, so now I'm thinking about selling the 380SEC, problem solved....right?

Chad300tdt · #8 02-11-2008, 09:21 PM

Wow. How do you come across so many deals?

truckinik · #9 02-11-2008, 09:52 PM

Quote:

Originally Posted by Johnhef

To start, vehicle is a 1983 380SEC 194K.

I have two available engines, one still in the car a 1984 500SEC (M117), 120K and a lone engine, a Euro 380 (M116), unknown mileage, unknown car, rebuild sometime in the past.

Now, not worring about the unknown of the 380 motor, based just on specs what should I put in the car? It's not a daily driver and is going to be just for fun, a rice hunter and even possibly some autocrossing.

What I know (or think I know) about these two engines so far

Current 3.8 US M116: 155HP?

5.0 M117: 184HP?

3.8 M116 Euro: 212HP?

I forget where I saw these numbers at the moment but they're exactly as I saw them.

I'm getting a different set of specs from wikipedia- which is a little confusing because it lists the 5.0 M117 anywhere from 220-269HP and the 380 engine as 201HP. It doesnt say what years or versions these numbers are from (4 different ones for the 5.0 alone). Does anyone have known correct specs for these engines?

So....what would you do?

Scrap them all and shoe-horn in, a Chevy Big Block, 502, Fuel injected, Crate Engine..?

Nick

Johnhef · #10 02-12-2008, 07:15 AM

Thats the answer to everything isn't it!