Merc transmission compatibility
Discussion
A mate of mine is looking for some information. He has an F-reg Mercedes, which he has extracted from a scrapyard, with sound mechanical components, and an Opel Commodore which is mechanically knackered. His plan is to stick the 4.2 litre V8 out of the Mercedes under the bonnet of the Commodore, and to cut out the rear section of the Commodore floorpan and replace it with the corresponding section of the Mercedes so he can use the Mercedes IRS in place of the existing beam axle. He then plans to supercharge the V8, increasing power in stages to a target of 500bhp.
He wants to make sure his transmission and diff are strong enough to take the extra power, and reckons the easiest way to do this would be to install Mercedes components from a suitably powerful model. Unfortunately information on Mercedes parts interchangeability seems to be somewhat scarcer than it is for Cortinas and Escorts
So if anyone here can advise on which model(s) would be suitable to extract the transmission and diff from, he would be grateful. Also useful would be names of Mercedes breakers, preferably around Bedfordshire.
TIA!
He wants to make sure his transmission and diff are strong enough to take the extra power, and reckons the easiest way to do this would be to install Mercedes components from a suitably powerful model. Unfortunately information on Mercedes parts interchangeability seems to be somewhat scarcer than it is for Cortinas and Escorts
So if anyone here can advise on which model(s) would be suitable to extract the transmission and diff from, he would be grateful. Also useful would be names of Mercedes breakers, preferably around Bedfordshire. TIA!
500 brake is a lot! Only comparitively recently have Mercedes models started having that sort (and beyond) of power, and even then the limiting factor has been the transmissions! The SL65 has a 7 speed auto...
The only Mercedes tranmissions worth having are autos, and I'm not sure the torque convertor would be up to the job if your mate was to take the supercharging route. Maybe with extra oil cooling? But its still a lot of power and torque...
What might be an option is the five speed auto out of a V8 Jaguar XJR which is actually a Mercedes unit. XJR has the best part of 400 bhp so the box may be up to the job. Failing that, something out of an E55 or V12 S Class.
What do other PHers think?
Andy
>> Edited by CheekyChap on Wednesday 8th September 23:35
The only Mercedes tranmissions worth having are autos, and I'm not sure the torque convertor would be up to the job if your mate was to take the supercharging route. Maybe with extra oil cooling? But its still a lot of power and torque...
What might be an option is the five speed auto out of a V8 Jaguar XJR which is actually a Mercedes unit. XJR has the best part of 400 bhp so the box may be up to the job. Failing that, something out of an E55 or V12 S Class.
What do other PHers think?
Andy
>> Edited by CheekyChap on Wednesday 8th September 23:35
So there's not a lot of margin in Mercedes transmissions? Right. Perhaps he would be better off sacrificing some "bolt-on" straightforwardness and looking at adapting American muscle-car transmissions. How about Mercedes diffs - are they similar in terms of margins?
I do wonder a bit about the 500bhp. He is planning to upgrade in stages, by using progressively smaller pulleys on the supercharger and seeing how things go at each stage, and it's not impossible that he'll be happy with something less stratospheric.
The XJR info is useful, thanks. That might be a way to go.
I do wonder a bit about the 500bhp. He is planning to upgrade in stages, by using progressively smaller pulleys on the supercharger and seeing how things go at each stage, and it's not impossible that he'll be happy with something less stratospheric.
The XJR info is useful, thanks. That might be a way to go.
The Merc transmissions aren't quite as beefy and solid as, say, a yank trucks.
He probably has a 722.x transmission in the 420 now. My 190's a 722.4 I think, which is good for anything up to the 2.8 M104 but not the 3.0.. I only know this as I was looking at putting the 3.0 into my car.
Unfortunately that's all I know and it's completely useless to you. Oh well.
It's torque that must be worried about rather than hp. Maybe a trans from a 560 would do the trick? Or you could try a Porsche 928's box for manual or auto. I think the auto is Mercedes' too.
Sounds like an interesting if bizzarre project but I love frankensteins like this. Keep us updated.
Russ
He probably has a 722.x transmission in the 420 now. My 190's a 722.4 I think, which is good for anything up to the 2.8 M104 but not the 3.0.. I only know this as I was looking at putting the 3.0 into my car.
Unfortunately that's all I know and it's completely useless to you. Oh well.
It's torque that must be worried about rather than hp. Maybe a trans from a 560 would do the trick? Or you could try a Porsche 928's box for manual or auto. I think the auto is Mercedes' too.
Sounds like an interesting if bizzarre project but I love frankensteins like this. Keep us updated
. Russ
The Porsche suggestion is interesting, thanks. I'll pass it on.
The reason he's ended up with this bizarre project is mainly due to chance. The Commodore's straight six is knackered, seems to have a broken crank from the clattering and banging that resulted from trying to start it and judging by the amount of black sludge in the rocker box anything fed by an oilway smaller than a sewer pipe is probably dead of oil starvation as well. The Mercedes was a lucky find while he was looking for somewhere to store the Commodore - before that he was thinking along the conventional Rover V8 lines, with some temptation in the Chevy 5.7 direction.
The reason he's ended up with this bizarre project is mainly due to chance. The Commodore's straight six is knackered, seems to have a broken crank from the clattering and banging that resulted from trying to start it and judging by the amount of black sludge in the rocker box anything fed by an oilway smaller than a sewer pipe is probably dead of oil starvation as well. The Mercedes was a lucky find while he was looking for somewhere to store the Commodore - before that he was thinking along the conventional Rover V8 lines, with some temptation in the Chevy 5.7 direction.
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