M103 turbo....done to death?

[duxthe1]

Of course not, but it could be time for a new thread Less than a year ago I picked up a 92 300TE 4-Matic with the Mosselman twin turbo kit installed. Detonation had trashed the pistons and the head. So the challenge that lies before me isn't "how can I turbocharge it?" but how do I build a shortblock that will allow me to turbocharge the F*** out of it?
Since there is a lot of similarity between the M103, M104, M60x engines, Ive come up with a few tricks.
1) piston oiling: The M603 piston oilers installed on the M103 block will provide oil dedicated to cooling the underside of the piston crown. With increased temperature stability in the piston, detonation is less likely. (note:M104 oilers will fit but spray a lot closer to the side than the M603 part does)
2) oil pump gear: Again from the diesel bin, the M603 oil pump gear is a turbo motor must-have. It's smaller size results in more oil pump rpm's. This mod helps ensure that there is enough oil for 2 turbos, 6 piston oilers, AND your engine bearings.
3) flywheel: There is room for improvement here too. The center section of the flywheel is only a single sheet of metal. (it has an M102 part #) The turbodiesel engines actually double up on the sheets of metal in the center section of the flywheel and omit the spacer between the flywheel and crankshaft. When adding a lot of power to a M103 it makes sense to use the same flywheel setup as the high torque turbodiesels.

Hopefully these mods will give my turbo gasser the legendary reliability of MB's turbodiesels. Aside from the aforementioned mods I've still got to make a decision on stroke, rods, and pistons.
The decision on stroke is really asking which crankshaft to use. I'm leaning towards the stock crank simply b/c it deosn't involve the outlay of any more cash. A 50$ M104 2.8L crank on ebay has had me drooling over the idea of a de-stroked high RPM screamer. Of course a 3.6L stroked M103 can be done with a diesel crank (350SDL, not the 300 SDL). I'm sure that it would have plenty of torque Unfortuantely that is a rare crank to get your hands on.
As for rods I think that the factory rods are some of the toughest rods around but I still don't trust them in my high dollar shortblock. A local custom shop recently quoted me $3500 USD for a set of 6 titanium rods. That is a LOT for a set of rods but would take all the worry out of ever breaking one. Not to mention the weight savings in the reciprocating mass
Pistons present a lot of choices. Fancy cast alloys or forgings? The high RPM screamer would likely get the lighter alloys. With an engine that is apart b/c of detonation the forgings seem the better route. On the downside though, the forged slugs require more running clearance increasing the likelyhood of a rebuild on an engine I never want to see inside of again.

So what do you guys think? How would you build your twin turbo dream mercedes?

[am3037]

......Id stick with the standard M103 internals.

weak points are the pistons. Replace with forged items.
rods. start getting ****ty at 400hp. Either linish/shot peen/arp caps or go with forged ARGO customs (H beam)
Valve springs need to be changed. Custom or find something that fits.

Oiling system is adequate. Its the tuning that is ****. CIS-E is just crap if you really want to turbo the **** outta your 6. custom fuel rail, injectors, seats, bosses, regulator, pump, lines and a MOTEC.

The bottom end is not typical of engine build designs and is not suitable to being set up with 'V8' thinking in mind, i.e. dont set it up with more crankshaft end float, dont cam it, dont underdrive anything. Go for black metal bearings with extra tight clearences.

Id say with two gt28RS turbos shes good for just a tad under 400rwkws with US compression, minimal lag, and daily driver cruising.

I think your engine only died for two reasons. Someone turned up the boost and the CIS-E went lean, or the mosselman piggyback thing ****ed up and went lean.

The motec is a $3500 unit in Aus (with all options) but is worth every penny with the amount of warnings it can give you.

I see the thai boys are fitting 2jz-gtes in with relative ease, Cost wise, this might be your better option, but id stick with the m103.

titanium rods arent neccessary. a good set of forged I beams will do perfectly, more than youll ever pump outta the m103.

Stroke it to 3.6, and then you can fit a pair of HKS GT30's! and go for some serious rwkw!!!! how does 700hp atw??

Like you said you wanted to turbo the **** outta it.

[Rahulio1989300E]

Wow, that sounds fun!

But what would the total bill be?

[dkveuro]

$20k



Just in case you thought of bringing it to me ...




.

[am3037]

the price of perfomance.


he said he wanted to TURBO THE **** OUTTA IT.

ask 300evil how his EFI M103 is going...think you'll find he has done it for a lot less than 20k.

[duxthe1]

Heard today from a co-worker who had built a twin turbo C-36. Guy that bought it blew it up. Apparantly he was tweaking the boost past the 12 PSI it was tuned to run at. Said it bent two rods! At 12 PSI it was dyno'ed at 440hp, probably was over 500hp when it blew. Really has me thinking hard about those titanium rods. That's one expensive insurance policy