OM617 problem in gear - Page 3 - PeachParts Mercedes-Benz Forum

Ltpro · #31 01-10-2018, 08:09 PM

Quote:

Originally Posted by Diseasel300

How are you measuring boost? If you're actually making 12PSI of boost under load, the engine is doing all it can and the injection pump is delivering adequate fuel to spool the turbo to maximum output. If you had a fuel starvation issue, the turbo would NOT be spooling.

I have a boost gauge installed . And actually if you have a bit of load ( which the motor does it will build boost ) , if I drive it and give it throttle it will build boost but the temperature will rise much faster than normal which tells me its leaning out - 10-12 lbs is easy to build when everything is working good (most everything ) .

Ltpro · #32 01-10-2018, 08:11 PM

Quote:

Originally Posted by NZScott

FWIW the turbo will spool to full boost with the ALDA line venting to atmosphere (experienced that on the one road trip I did with my wagon)
(Edit: Not to imply OP's ALDA isn't, just saying it doesn't need that much fuel to spool the turbo)

I agree , it doesn't take much fuel to spool a turbo that size. This is for sure and odd issue , its been kicking my butt for days now .

Diseasel300 · #33 01-10-2018, 08:42 PM

Quote:

Originally Posted by Ltpro

I have a boost gauge installed . And actually if you have a bit of load ( which the motor does it will build boost ) , if I drive it and give it throttle it will build boost but the temperature will rise much faster than normal which tells me its leaning out - 10-12 lbs is easy to build when everything is working good (most everything ) .

Diesels run hot when they run rich, not lean. Gas engines run hotter when lean vs rich. If you're seeing the temperature rising and you're building boost, it sounds more like you're lugging the engine.

ROLLGUY · #34 01-10-2018, 09:50 PM

Quote:

Originally Posted by Diseasel300

Diesels run hot when they run rich, not lean. Gas engines run hotter when lean vs rich. If you're seeing the temperature rising and you're building boost, it sounds more like you're lugging the engine.

I agree, and as I said before, I think he is running too tall a gear. This engine was mated to a 4 speed trans in a car with 14"tires and 3 something gears. The Wagoneer has much larger tires and only a 3 speed trans. Instead of adapting the engine to the 3 spd trans, i suggest adapting the 722.X trans to the transfer case so it will have a lower first gear. Just my .02

Diseasel300 · #35 01-10-2018, 10:14 PM

Quote:

Originally Posted by ROLLGUY

I agree, and as I said before, I think he is running too tall a gear. This engine was mated to a 4 speed trans in a car with 14"tires and 3 something gears. The Wagoneer has much larger tires and only a 3 speed trans. Instead of adapting the engine to the 3 spd trans, i suggest adapting the 722.X trans to the transfer case so it will have a lower first gear. Just my .02

For giggles, I looked up an '84 300D OM617 turbo compared to an '83 Wagoneer 360 V8 on the Automobile Catalog and you may be onto something. I tried to give links to the pages, but the way that site is set up, it's all PHP, so the links don't work, the attached screenshot will have to suffice.

At lower RPM's the horsepower and torque delivery from the 617 is a fraction of what the 360 chunks out. Throw in high gearing and big tires and the 617 probably isn't gonna produce a lot of giddyup in that vehicle. To make sense of the chart, the green lines are the 617, blue are 360. Hard to believe a 360 V8 was only rated 140HP in 1983...

BillGrissom · #36 01-11-2018, 12:35 AM

Sounds like the best theory. A 360 in^3 = 5.9L, and what Chrysler called the later engine named "Magnum" (same block). Compared to the 3.0L OM617, it is no wonder the lower torque is noticeable, despite diesels being know for that. Even in our little cars, M-B installed gearing with a very low 1st gear. Indeed, so low that after shifting to 4th on the highway at 65 mph you keep waiting for the last shift which never comes, and listen to the engine whine at 3000 rpm (worst in my 1984). The Chrysler 727 has only 3 gears and spins maybe <2500 rpm at 65 mph in my 1965 Newport (no tach), so 1st gear must be pretty tall. That doesn't hinder my 383 (6.7 L) V-8. As an aside, many 50-60's GM auto trannys had only 2 gears. Today's cars have mostly 8 to 10 gears.

As an aside, I was stunned by a "no power" issue in my 1985 300D after an engine swap. It wouldn't go faster than 5 mph in a test drive. Strange since I had ran the engine on the ground OK. I connected a boost gage and saw it drop to a low vacuum as I pushed the pedal. I pulled the inlet duct off the turbo and took out the paper towels I had stuffed there to keep out stuff (shouldn't assemble at night) and it ran great after that. But the OP has a boost gage.

NZScott · #37 01-11-2018, 12:46 AM

Quote:

Originally Posted by Diseasel300

Diesels run hot when they run rich, not lean. Gas engines run hotter when lean vs rich. If you're seeing the temperature rising and you're building boost, it sounds more like you're lugging the engine.

Yea, have to agree on that for sure.

Time to twincharge it!

Ltpro · #38 01-11-2018, 07:39 AM

Well , you got me thinking and at 5am this morning I had to go double check something . I originally was going with a bigger engine and I had ordered an 1500 stall converter , and after switching to the om617 I ordered a 2500 stall converter - both in the same box both the same color . SOOOO , I decided to go out and open the box I was about to ship back and there sits my 2500 converter looking back at me and smiling - had to confirm it with the part number . The low stall converter is loading up my engine well before it can make any power , took me a whole 5 seconds to realize my mistake . First time in 15 years this has happen to me but theres always a first time , and i'm sure not my last ..

Diseasel300 · #39 01-11-2018, 09:27 AM

Oops! Yeah a T/C with a 1500RPM stall can cause problems - the OEM stall rating was around 2000 RPM. If you swap the T/C out with the 2500RPM stall unit, please follow back up. I'd still change out the lift pump primer handle on principle to prevent future problems though.

Quote:

Originally Posted by NZScott

Time to twincharge it!

ROLLGUY · #40 01-11-2018, 10:47 AM

Quote:

Originally Posted by NZScott

Yea, have to agree on that for sure.

Time to twincharge it!

Better yet- "Twintake" it!

Ltpro · #41 01-11-2018, 01:14 PM

Quote:

Originally Posted by ROLLGUY

Better yet- "Twintake" it!

What I know is building custom turbo systems , keep an eye on me you should see some new things soon . Learning this old system first but I should start building new parts soon .

Ltpro · #42 01-11-2018, 01:17 PM

Quote:

Originally Posted by Diseasel300

Oops! Yeah a T/C with a 1500RPM stall can cause problems - the OEM stall rating was around 2000 RPM. If you swap the T/C out with the 2500RPM stall unit, please follow back up. I'd still change out the lift pump primer handle on principle to prevent future problems though.

The lift pump handle was to get here on Tuesday but its getting here today instead . I may have time this weekend to change out the TC , I still cannot believe that wasn't even in my mind - what a waste of time .

Frank Reiner · #43 01-11-2018, 04:11 PM

Lt:

For purposes of comparing the overall 1st gear ratios, as corrected for tire size,
the following calculations can be used:

final drive ratio x 1st gear internal ratio / tire rolling radius

For the Benz: 3.07 x 3.68 / 12.65 = .89

For the Jeep: 3.07 x 2.45 / 14.44 = .52

A gear correction of 1.71 would be required to equalize them; hence the Jeep would need a 5.25:1 final drive to achieve a corrected overall 1st gear of .89!!
Substituting a 180 cu.in. engine for a 360 cu.in. engine makes things tough.
If the Jeep has a 2.76:1 final drive ratio, as some did, it makes the correction even more extreme.

We should note that the stall speed of any given TC is a function of the torque applied; a TC that stalls at 2500 when driven by a 360 in. engine,
will stall at a rather lower speed when driven by an engine of half that displacement.

Ltpro · #44 01-11-2018, 09:06 PM

Quote:

Originally Posted by Frank Reiner

Lt:

For purposes of comparing the overall 1st gear ratios, as corrected for tire size,
the following calculations can be used:

final drive ratio x 1st gear internal ratio / tire rolling radius

For the Benz: 3.07 x 3.68 / 12.65 = .89

For the Jeep: 3.07 x 2.45 / 14.44 = .52

A gear correction of 1.71 would be required to equalize them; hence the Jeep would need a 5.25:1 final drive to achieve a corrected overall 1st gear of .89!!
Substituting a 180 cu.in. engine for a 360 cu.in. engine makes things tough.
If the Jeep has a 2.76:1 final drive ratio, as some did, it makes the correction even more extreme.

We should note that the stall speed of any given TC is a function of the torque applied; a TC that stalls at 2500 when driven by a 360 in. engine,
will stall at a rather lower speed when driven by an engine of half that displacement.

I will start off with a clear disclaimer : I have never owned a domestic car and don't know more than the average joe about transmissions . For a living I have been building custom turbo systems for all sorts of applications and doing engine builds . I'm not at all afraid or too proud to ask for help when I have no idea what I'm talking about . Now with that out the way ....
As far as picking out a stall all I've been ever told is that you have to match the ENGINES torque peak to the stall rpm range . Gearing is a secondary attribute of the mechanics which relies on torque and HP to determine its end result which is the moving of the mass . So if you have an engine producing peak Tq @ 1400rpms then depending on your desired outcome you'd get a TC which ranges about 500rpms pass that point so somewhere from 1400 to 1900 will work . Any respectable TC shop will give you that range because that also helps account for some gearing and other add-ons such as mid cams or headers . In the case of the om617 it appears it makes its peak around 2500 , so a TC ranged from 2500 to 3000 should work just fine for my application which is daily driving . I'm not a rock climbing guy or muding guy , if I want speed and head-banging lowend torque I can just build me some twin turbo V8 or import inline 6 and call it a day . Gearing is another issue for another day , installing this wrong TC was my mistake . I was "sure" I had grabbed the correct one which is why I didn't even think about it . I do appreciate your post and thanks for taking the time out to reply .

Ltpro · #45 01-11-2018, 09:11 PM

....and what's your name little fella?