Dreaming of a V8 swap, can anybody tell me if my stock 4 speed manual has a chance behind a m117 5.0 or 5.6 motor? If not, do I have any other options besides the automatic gearbox?
chris505 - 9/28/2004 2:56 AM
...can anybody tell me if my stock 4 speed manual has a chance behind a m117 5.0 or 5.6 motor?....
Do you mean will it handle the torque? Not on a regular basis, but you could baby it and maybe get it to last with some good synthetic oil in it. There's also teh matter of teh clutch. The pressure plate would probably need to be beefed up to handle the V8 torque. But the main problem is that the gear ratios will be all wrong for the power band of that engine. My 4-speed has me cruising at highway speeds at 4,000 RPM. (and that's running 4.9 gears and 32" tires) It won't be any fun at all driving that V8 around spun up to 4 grand all the time.
Best bet is to do an engine/trans combo swap, but if you want a manual with the V8, you need somebody more familiar with MB products than me to tell you what combo they ever sold like that.
Hipine - 9/29/2004 10:25 AM
Best bet is to do an engine/trans combo swap, but if you want a manual with the V8, you need somebody more familiar with MB products than me to tell you what combo they ever sold like that.
I read once over at the 126 forum that some 500se police cars were sent to the UAE with Getrag 5 speed manuals. So I figured I could use one from a G in my case, but recient reading about these things failing in high tourque aplications (behind turbodiesels)has me looking into other manual gearboxes.
Im curious, what exactly fails in these trannys, is it just the syncroes loosing teeth?
Would that gearbox be the G1/18-5/4.7 ??
If so, I have one lying around in my garage....
It originates from a mercedes van but is essentially the same...
It is for sale but I am located in the UK, along long away!
Thats the one, do you know what motor that van had?
Very tempting, send me a PM with your price.
I know this type of swap has been done in Europe several times. The few that Ive seen (3)had autos but I bet some had manuals, has anybody ever herd of this????
I just dont want to be stuck in the desert with a broken gearbox.
The 5-speed Getrag is a very good gearbox, but put behind a turbodiesel it will sooner or later fail, depending on the driving style.
The symptoms are worn synchros, and even worse, failing bearings. My box is due for replacement, and the late stage symptoms are poor synchronization on all gears exept 4th (goes straight through). I also have bearing noises on all gears besides 4th. Also, the physical wear shows itself as a huge amount of fluff on the oil-change plug. Oil black and grainy after 1000km!
I would definately go for an auto box if I should stick a V8 in my G. The 4-speed is supposed to be more robust, but I suspect the torque is too much.
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If I ever do a swap like that it will be with an auto trans. The torque convertor really improves your crawl ratio. It also absorbs much of the abuse the drivetrain is subject to. Sure they suck up some power in the process but with a big V8 that shouldn't be an issue. I think Harald P mentioned that the auto boxes didn't last very well in his Rubicon trucks. I suspect that additional cooling capacity of the tranny fluid may have helped.
Going with an auto would make sourcing the parts soooo much easier. Have the salvage yard pull the engine and tranny complete from an S-class. It would seem much easier than trying to find a manual trans V8 flywheel and clutch.
I would still be a little concerned about road drivability as Dave mentions. All of those old auto trannies have a direct 4th gear (1:1 ratio) and are going to be spinning pretty fast on the highway. MB always used taller rear end ratios with that direct top gear instead of the American way of using deeper rears and an overdrive top gear. So with 4.9 gears, or heaven forbid the 6.17's its going to be loud and thirsty on the road.
After what I've been reading on the german mb-g.de the clutch on the fourspeed manual is too weak paired with a OM617A. An OM617A is supposed to deliever 250 Nm, not sure about a M117 but they should defineatly be stronger. That being said, I wouldn't have any concerns putting an OM617A in front of my 4speed manual. On a 5speed Getrag GL275, that's another question!
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