OM602 modifications - 190D turbo - PeachParts Mercedes-Benz Forum

Mitch H · #1 10-22-2005, 12:22 PM

I've got a W201 project that's still in the early planning phase. I'd like to see 40-50mpg on the hwy, and if the car could keep up with a 2.3-16V that would be nice too. Thus far I have purchased a wrecked '87 190D 2.5 turbo with auto trans and 2.65 diff. There's a halfway decent '92 2.6 5sp for sale in a neighboring state, and a fellow across the border in Ontario is replacing his entire 2.3-16V suspension so I can probably get his old parts cheaply. My engine is showing some signs of probable head gasket seepage, and has about 220k mi on it, so I'll be rebuilding it when I have it out of the car.

How much power is available if I stick with the current turbo and IP? I intend to have the head ported, and put a ceramic barrier coating on the piston crowns, combustion chambers, valves, and exhaust ports. Also put in a set of perfect circle rings and replace any worn parts in the engine. I will be installing an EGT gauge. If I can get 150-200hp from adjusting the wastegate, full load screw and governor, I'll be satisfied with that, at least for now.

I'm thinking I can just put the 2.6 flywheel on the diesel and drop it in the 190e chassis with the 2.65 diff, underhood wiring, radiator, etc from the 190D. Then I'd want to rig up an electric hydraulic pump (or get the Vickers pump from a S124 300TD) and get the SLS installed and working, and shim the front springs until the car sits level with the heavier engine. Am I missing anything?

t walgamuth · #2 10-22-2005, 02:04 PM

start with swapping the trannies between the two cars and selling off the 2.6. at that point you should almost break even not considering your time. beyond that you are treading where i wouldn't go. i wouldn't rebuild a motor that is running fine for a little seepage. and i wouldn't modify it unless i knew that someone else had tried it and had good results. the factory setup is compromised for safety, durability, power and economy. when you emphasize one element more you will give up somewhere else. it is easy to bury yourself in a modified car that no one else wants to buy for fear of the compromises made.

i like to tinker too. but too much usually will waste money in the long run. if you look at as entertainment in leu of drinking beer and bowling, well ok. but dont think of it as an investment.

tom w

sixto · #3 10-22-2005, 02:51 PM

I'm not sure what porting will accomplish. Fuel is injected into the prechamber, not into the air charge so swirl and turbulence have different importance in this engine.

Are you sure Perfect Circle rings are rated for 22:1 static compression ratio? Are they available in the extra thickness of Diesel rings? MB might have counted on some leakage to keep the head gasket intact.

You might have to drill a hole in the crankshaft for a pilot bearing.

A 190D 2.2 5-speed just breaks into 40mpg with judicious driving. I can't imagine a souped up 2.5 doing any better.

Sixto
87 300SDL

t walgamuth · #4 10-22-2005, 05:12 PM

with 123s they are all drilled for pilot bearings.

tom w

Mitch H · #5 10-22-2005, 07:16 PM

Quote:

Originally Posted by sixto

I'm not sure what porting will accomplish.

I was hoping for more air w/o increasing boost (or without increasing it as much) to get more torque at higher rpm without adding more backpressure & intake temp than necessary.

This project came about because I was on the verge of buying a new econobox, and the daughter of a friend wrecked the 2.5t. When I got to thinking about it, I decided I'd much rather spend $4-5k putting a W201 in better than new condition than spend $7k on a brand new Korean tin can. I might get real tired of that Aveo in 200,000 miles or so.

I know that there are Perfect Circle rings for OM617, I haven't inquired as to rings for 602/603.

I did a little reading on the finn forum and in the archives here, it seems that Mauri thinks the 602/603 IP tops out around 30hp per cylinder unless you go to bigger barrels and plungers. I'd like to think that cleaning up the ports and insulating the pistons would get me there without intercooling.

If Mauri can claim 6-7 liters/100km with a 3.0/automatic in a 124, I figure I can try for 5 liters on the hwy with a 3.0/5sp in a 201. I might not get it, but it'll be fun to try.

I'd like to build the engine because:
1. I want it to be in tip-top shape for another 20-30 years. I could fix the fuel system and just drop it in a fresh body if it wants to run evenly on all five cylinders, but I'd likely be inside the engine within five years anyway.

2. This car changed hands for $1000 two years ago, and shows signs that some previous owners treated it like a $1000 car.

3. It has to come out of the wrecked body anyway, so now's a good time.

sixto · #6 10-22-2005, 08:28 PM

I'm not trying to dissuade you. On the contrary I'm very interested in your project. Vicariously, I'm egging you towards dropping the mpg goals in favor of more power

Sixto
87 300SDL

Mitch H · #7 10-22-2005, 09:08 PM

Quote:

Originally Posted by sixto

I'm not trying to dissuade you. On the contrary I'm very interested in your project. Vicariously, I'm egging you towards dropping the mpg goals in favor of more power

I don't think they are mutually exclusive in a diesel, unless you drop the compression ratio to run higher boost, or cool the engine with excess fuel. Most of the Finnish superturbos disappear in a black cloud at the drag strip, but I'm not sure that is necessary. Mauri claims 34-39mpg from his old S124 with a 400hp engine. He also claims it didn't smoke. One reason he gave for the high mpg was the large bore IP elements squirt the fuel into the cylinders faster, making the timing more precise. I won't have that unless I decide to send an IP to Finland for the full superturbo treatment in a couple of years. (or get really crazy and try a DIY pump rebuild)

I wish I knew of an easy way to get more fuel in the cylinders, like maybe replacing injector nozzles or delivery valves, the 12v Cummins crowd does both to good effect with a very similar inline IP. Does anybody know a part number for an injector nozzle that will put more fuel in the cylinder and less in the return line? I contacted a couple of Cummins pump tuners and neither one of them wanted to look up the injector specs for a Mercedes, they only work with Dodges. My local Bosch guy won't help with anything that increases fueling, says it would be illegal for him to get involved with out of spec road vehicles.

I suppose I could trade mpg for driveability and acceleration by using a 3.92 diff, the 2.6 should come with one.

JDmills · #8 10-22-2005, 10:55 PM

I think this is an interesting project. I would try and get it running first, then start to tweak it. Yeah, it involves doing things twice, but it also allows one to attack particular aspects of performance, or economy issues with real data and experience. Also it is my experience that having something to drive while planning a upgrade is more fun than trying to motovate myself to get out to the barn and chip away at a project that had a lot more involved in it than I expected... of course we each have our own way of doing things and your way is best for you. Go for it!!

JDmills · #9 10-22-2005, 11:02 PM

Oh, forgot to mention that the dodge boys seem to gain fuel efficency with a bump in the injection timing as well, that may give you a bit, Just so long as the pressure in the combustion chamber does not spike beyone the head gasket's ability to hold together...

I bet there is some diesel injection shop in this country that would work on the IP for you. How about a shop that works for the tractor pulling crowd?

Mitch H · #10 10-23-2005, 09:54 AM

Quote:

Originally Posted by JDmills

How about a shop that works for the tractor pulling crowd?

Good point. The big boys use CAT, Cummins, Detroit, but some of those lawn mowers have turbo OM616s in them. The 616/617 pumps aren't that much different from the 601/602/603 pumps.

I have an extra 617 turbo pump. I hate to mess up a good pump, but I got it cheap and I might pull it apart and see how hard it would be for me to change out the plunger/barrel assemblies. I think 7mm barrels would be a good idea. With 62% more pump displacement, I'd probably be shortening the rack travel instead of lengthening it. One thing I wonder about: If 330 hp is possible with 62% bigger pump barrels, why isn't 200 hp possible with the stock 5.5mm barrels?

I also posted on the Finn forum yesterday, already got answers from a couple of the "been there, done that" crowd over there. Not bad for a foreign language (english) topic.
http://www.mersuforum.net/forum/viewtopic.php?p=241804

If you want to register there, the first four boxes on the registration page are screen name, email addy, password, and repeat password. Paikkakunta is hometown. That was enough to get me registered for posting.
Register here:
http://www.mersuforum.net/forum/profile.php?mode=register

Jetmugg · #11 10-23-2005, 10:44 AM

Eariler this year, I completed my "5-speed manual into 190D 2.5T" project. I used a 2.5 diesel flywheel, I'm not sure if the 2.6 flywheel that you listed in your original post will work. It might, but I have no idea.

I kept the original 2.65 rearend, which should work great if you are not trying to build a race car. The 2.65 seems more suited for relaxed commuting or highway driving. On my last 2 tanks of fuel, on 2 subsequent highway road trips, I got 39.11 and 40.2 mpg, respectively. That was mostly cruising at 2000 rpm and approximately 70mph.

My car has 240K miles on it, and may not be as "fresh" as a newly rebuilt hot-rodded engine. I hope you do go for the project, as I'm sure I could learn quite a bit from it. I don't have the guts or money to tread into uncharted territory with my car. More boost and possibly an intercooler might make a pretty big difference without the need for ceramic coatings, special piston rings, or a custom IP.

That said, I would like to see you become a pioneer in W201 diesel performance, so that I might be able to follow in your footsteps.

Later,

Steve M.

t walgamuth · #12 10-23-2005, 12:12 PM

is successful, right?

tom w

Mitch H · #13 10-23-2005, 12:18 PM

Quote:

Originally Posted by Jetmugg

I kept the original 2.65 rearend, which should work great if you are not trying to build a race car.

Hi Steve.
I plan on using the 2.65 too, especially if I end up with a non-overdrive Getrag from a 16v. You don't mention any problems with your setup, does that mean your first gear is plenty low enough for normal driving? It should be 25% taller than first gear in a factory 5 speed non-turbo 2.5. (2.65 final drive vs 3.07, 3.91 1st gear vs 4.23).

I was about ready to buy a '92 2.6L, then I found a 16V that I might get cheaply. I'd love to have the 16V suspension, steering gearbox, seats, and limited slip diff, if I can use the 2.65 ring and pinion with the LSD. 16V cars and 2.6 5sp are supposed to be rare, but I've seen about 10 16V and two 2.6 5sp for sale in the last month. What's hard to find now is 190 diesels that the owners want to part with. That might change if diesel stays over $3 for a while.

JDmills · #14 10-23-2005, 12:21 PM

More thoughts on putting it on the road as it is, then tweeking it: I bet the stock IP has the ability to push more fuel than the Intake side can support. If you were to combine adjustments to the injection pump's full fuel adjustment circut, and then added in the fuel enrichment ALDA changes, I would bet you can get darn close to 200HP with out spending any extra $$.. But the stock turbo would not be able to support that level of fuel enrichment With out modification.. A intercooler would also be helpful, long before needing to upgrade the IP plungers...

Also you may find that as a result you have a motor that produces a bunch of torque and is fun to drive with out posting huge Horse power #s

t walgamuth · #15 10-23-2005, 01:10 PM

are ways to increase boost that arent too expensive. one fellow on this site has a much modified 116 300sd. using impellers from buick turbos and such. he did all the work himself and didnt spend a lot of $. cant remember his name but you might do a search.

tom w