so how do you crank up the fuel on an OM617?

[Forrest Nearing]

hey gang, I just registered...

I'm a turbo diesel lover. I'm into the 5.9 B series Cummins. my daily driver is a 1997 2500 5sp with some mild injectors, pump tweaks, a bigger turbo, clutch, etc. currently making 42psi of boost and loving every minute of it!

my 2nd and 3rd vehicles are gassers, but I've got them up for sale, and I'm looking to buy a turbo diesel powered car as my second/backup car.

the VW TDI's are too rich for my blood, and I've never been a fan of FWD vehicles, and I've heard the old 5cyl Mercedes are bulletproof... I've found an '82 300D with a 4sp manual tranny that I'm looking at. I like the quirky old 70's styling of it.

but my biggest fear is that it'll be too sluggish and slow...

on the first and 2nd generation Dodge/Cummins, there are a lot of external adjustments that you can do to the injection pumps that REALLY bump the performance considerably.

all I've seen on the OM617 is turning up the off-boost fueling to get the turbo spooled up quicker. that's always a good thing, but there's GOTTA be a full fuel adjustment too, right?

on the Cummins you can adjust full fueling, which increases fueling across the board and requires lowering the idle speed when you turn it up... then there's the off-boost fueling to help spool the turbo up... and then you can adjust the delivery curve based on RPM.

I know the earlier mechanically injected VW diesels used the bosch VE pump as found on the 1st gen Cummins...

what pump is used on the MB 5cyl's?

GOTTA figure out how to crank these babies up... even if it means sending a set of injectors to be extrute honed!!! I don't think I can deal with 90hp in a 3000+lb car!

Forrest

[Wasuchi]

The only external adjustment that I've ever heard of on the 617 is the ALDA and it just adjusts according to boost levels. It's a Bosch pump but there aren't any other adjustments that can be made on it really unless you take it out and can find a rebuild shop that knows how to tweak them.... I don't know how much can be done then either. The pump on the 603 engine is a little more adjustable I believe. If you get the 617 running good and the ALDA adjusted right they aren't too sluggish or slow.... they aren't a rocket by any means but they can get out of their own way at least.

[Wasuchi]

Oh, a turbo 617 should be 123hp from 82-84 and 125hp for 85 and I think 175ft/lbs. Forgot to mention that the pump is an inline pump too.

[Forrest Nearing]

ahh, 123hp and its corresponding torque numbers should be quite livable... figure a few more pounds of boost, and free flowing air filter and exhaust... maybe bump that up 20-30hp?

I don't know where I got the 90hp from... these cars/engines are kinda hard to find information on!

what's the approx curb weight on an '82 w123?

I don't need a rocket, just something that can merge onto the highway halfway decent and get through that 70-80mph Dallas traffic! LOL!

Forrest

[coachgeo]

Do a search on "ALDA" you enrichen that. Also turning up the Booste somewhat. So search on that topic too. Make sure you know what PSI is considered "overbooste" .

Also check linkage of the 617A vehicle you get. The can get loose and not be activating the IP to full throttle even though you got your foot all the way in it.

Still though they are quick slugs on acceleration. Cruise is where they are happy.

I’ve also heard that valve adjustment and pump timing do wonders with the ALDA adjustment. I’ve done the ALDA adjustment and it made a noticeable difference. Here are a few links that can help.
http://engine.mbzarticles.org/diesel/ Read the turbo adjust it good reading. The ALDA adjust is like sliding the plate forward on the P7100 on the Cummins. The other thing I found is (might have gotten that info here), there is a banjo bolt at the back of the intake manifold that takes the boost signal to the ALDA valve. Take it off and be sure it is clean they get clogged up with junk and the engine goes into a default mode because the ALDA valve can’t see the boost. It made a difference on mine.
Another site by one of the guys here http://207.210.95.34/~boostd/ this guy knows his Benz.
Ditto on the Cummins I had a 96 and loved it and now have a 2000 and really like it. Got the Suncoast tranny, EDM Mach 1.5s high flow banjos and EZ and a few other goodies.

[Forrest Nearing]

awesome, lovin' the info...

still up in the air between a 617 or an old VW turbo diesel... I realize the mercedes is a more well refined and more powerful vehicle, but the VW will be cheaper and should haul down 40+mpg w/ ease... plus the pump is the old VE found on the 1st gen Cummins.

if this little '82 runs/drives well, I may be a 300D owner before too long though!

Forrest

[Maki]

'82 300d turbo with 4-speed manual?

Just so you know, that's not a combination that the factory put together as far as I'm aware. There are some gray market 300Ds out there with manual transmissions and no turbos, and plenty of 300D turbos with automatics. No cross-pollenation, though. This car is likely a Frankenberry -- not that there's anything wrong with that...

Russ M
'82 300td
'82 300cd

[gsxr]

I skimmed the posts above and didn't see the correct answer, so I apologize if I missed it. Anyway:

The ALDA adjustment will turn up fuel delivery "off idle", which is what MOST older Mercedes diesels sorely need. The calibration goes leaner over time as internal springs weaken, or something like that. But, the ALDA is still limited by the internal full-load adjustment.

Yes, you can turn up the full-load fuel deivery. But on a 617 is a royal PITA. You need to pull the oil filter housing (!!) so you can remove the rear IP governor cover plate. The adjustments are in there. You can increase the max RPM as well, but I wouldn't get too crazy with that. Problem is, if you turn up the fuel without more air, you just get black smoke and possibly *less* power. If you turn up the boost past factory spec, you risk too-high EGT's which mean melted pistons. The best method is to install an intercooler, then turn up the full load screw, which should result in a safe ~20% power gain (probably ~150hp, up from stock ~125hp). I honestly don't know what gain if any is possible with just setting boost to the top of factory spec (0.85 bar, or 12.5psi) and tweaking the full load screw to maximize fuel for that boost level. So far, nobody has done this and reported the results.

I plan to attempt this on my OM603 engine this summer, and will post on this forum with the results. I've already proved that turning up the boost alone (no IP adjustments) did NOTHING for power gain - same power at 12psi and 18psi.

Here is a document that shows how to turn up the OM603 pump, which is vaguely similar to the 617 pump:
http://www.meimann.com/docs/mercedes/Bosch_full_load.pdf

Search this forum for info on the intercooler, a guy did a *beautiful* installation on a W123, but refused to turn up the fuel delivery....!

[R Leo]

Originally posted by Maki
'82 300d turbo with 4-speed manual?

It may not have been available from the factory but, I can tell you without a doubt, that an '83 300TD (turbo) with a 4-speed manual is some fun in a package!!!.

[Maki]

Hey, I believe it! I also recall a guy on another list dropping a turbo into a W114 chassis. I've always preferred the handling of that chassis, although I'm not sure if he beefed up the front springs. I think I'd want to.

I just wanted to make sure that the prospective buyer knew what he was getting into, seeing as how he is new to MB diesels.

Russ M.
'82 300cd
'82 300td.

[gsxr]

Originally posted by TheVirginiaDude
High EGT on a diesel is a result of too little air not too much.

Actually it's from too much air+fuel combined, and/or high intake air temps (no intercooler and/or excessive boost pressure). Restrict the airflow alone and you lose power, the excess fuel cools the charge, you get smoke and EGT's shouldn't be high.

[Forrest Nearing]

agreed to a point... (a very good/important point BTW!)

high EGT's on a diesel can be caused by too little oxygen...

but there are LOTS of factors involved... on our (relatively) low compression 16:1 Cummins engines, we've got LOTS of room for air and fuel... we crank the fuel, and we need to push more air in there to help properly burn the fuel... too little boost = too high EGT.

BUT, with high compression, lack of intercooler, and running the turbo on the high side of the map, you run into causing high EGT's by increasing the heat of the charge temps.

so there's a balance point where adding more boost won't lower EGT's and will actually start raising them, but it's a fairly wide plateau and should be easy to find with a little testing.

I can't imagine 17psi being out of range of the turbo, but I could see how 22:1 compression could heat things up quickly... looks like water injection and or an air/water intercooler could REALLY help push the power/torque limits without getting nuts w/ the EGT's.

speaking of... what kind of EGT are these engines safe to? the Cummins can be run at ~*1300 non stop, but they've got piston cooling oil nozzles... I run my truck up into the *1400-1500 range often, but only for a brief moment

[Forrest Nearing]

good to know. so I'm guessing/assuming that the safe EGT guidelines are similar between the 617's and the Cummins?

man, I'm getting excited now... this is the kind of info I was searching for despirately, and now I'm finally finding it!

hope this car turns out to be a decent one... otherwise I'm probably gonna end up with a VW... I CAN'T STAND automatic transmissions, and 99.9999% of the Mercedes I'm finding are autos!

Forrest

[R Leo]

Originally posted by Forrest Nearing
I CAN'T STAND automatic transmissions, and 99.9999% of the Mercedes I'm finding are autos!

Forrest

It's easy enough to change trannies.