Not so good results from 4spd swap - Page 4 - PeachParts Mercedes-Benz Forum

t walgamuth · #46 04-07-2008, 09:18 AM

That would be correct.

Tom W

Bajaman · #47 04-07-2008, 12:13 PM

Quote:

Originally Posted by JDmills

I have a drive line vibration on the wagon conversion I did as well.. it has to be the Ujoint.. OR that is my next attempt, just as soon as the ground dries out.. also i have had an engine vibration develop in the last thousand miles, which was not there last summer when the manual transmission was installed.. so I don't think it is an imbalance condition in the flywheel, but something else.. or that is what i Hope.

Could you describe this vibration? I would like to know what RPMs are affected most (and what gears).

JDmills · #48 04-07-2008, 05:28 PM

Quote:

Originally Posted by Bajaman

Could you describe this vibration? I would like to know what RPMs are affected most (and what gears).

It shows up at 35-50 MPH, in 4th, or 35-42 in 3rd.. always going away by 2200 RPM in each gear, and usually the worst at about 1900 RPM. Yet it is possible to get rid of it by holding the engine just between coasting and acceleration, then the drive line is smooth, and vibration free.. accelerate or deaccelerate and you get noise mostly on deacceleration, or noise and vibration on acceleration.

As for the engine vibration that is more of a 12-1500RPM thing.. which is new this winter.. almost as if a cylinder is missing, but I can not hear it miss..

winmutt · #49 04-07-2008, 05:43 PM

Quote:

Originally Posted by JDmills

Yet it is possible to get rid of it by holding the engine just between coasting and acceleration, then the drive line is smooth, and vibration free.. accelerate or deaccelerate and you get noise mostly on deacceleration, or noise and vibration on acceleration.

This totally lends credence to my point of it being related to the trans mount/angle of ds. Try lowering the trans crossmember and see if it goes away. Between that and using the thicker transmount my issues disappeared.

JDmills · #50 04-07-2008, 06:27 PM

Quote:

Originally Posted by winmutt

This totally lends credence to my point of it being related to the trans mount/angle of ds. Try lowering the trans crossmember and see if it goes away. Between that and using the thicker transmount my issues disappeared.

I think you are correct, although I have all ready lowered the transmission almost 1/2 an inch.... I may have to adjust it some more..

I used the automatic transmission rubber "A" mount, and the automatic transmission cross support bracket turned 180 degrees.. I will crawl back under the car this week to do some more investigating..

winmutt · #51 04-07-2008, 11:03 PM

Quote:

Originally Posted by JDmills

I think you are correct, although I have all ready lowered the transmission almost 1/2 an inch.... I may have to adjust it some more..

I used the automatic transmission rubber "A" mount, and the automatic transmission cross support bracket turned 180 degrees.. I will crawl back under the car this week to do some more investigating..

Oh wow. Thats way to far. Mine was 1/8th" or so. Turned 180 eh? Its centered? Pics?

JDmills · #52 04-08-2008, 07:21 AM

Quote:

Originally Posted by winmutt

Oh wow. Thats way to far. Mine was 1/8th" or so. Turned 180 eh? Its centered? Pics?

I dropped the tailshaft end 4 flat washer/spacers worth, because the flex disk bolts were not aligning to the driveshaft.. but you may be right, it might be too much.. although it seemed to be logical at the time, back before winter.. will try to look at it again this week, although the mud is kinda deep here right now.

As for the centered-ness of the transmission mount cross brace. It appeared to keep everything aligned, left to right. I don't have a digital so I am useless in that respect.. but it allowed me to use the automatic transmission mount, which was all but new.. and just a bit of welding some more steel on the now, front part of the mount, and it seemed to work fairly well..

Bajaman · #53 04-08-2008, 08:35 AM

So you used a 240 crossmember with an automatic mount? Or the automatic crossmember?

Bajaman · #54 04-08-2008, 08:42 AM

JD,
Your vibration at 1900 RPM seems to be a common denominator. That describes my vibration very well. I also have a nasty vibration like you from 800-1600 RPM that I believe is a combustion related event. I don't see how it could be otherwise, as everything is neutrally balanced. I have tested injectors, timed, set valve lash numerous times, but to no avail, I am down to delivery valves or the whole pump at this point.

JDmills · #55 04-08-2008, 03:37 PM

Quote:

Originally Posted by Bajaman

So you used a 240 crossmember with an automatic mount? Or the automatic crossmember?

I used the 300 TD tail shaft support brace, or what ever that thing is called..

Bajaman · #56 04-08-2008, 04:42 PM

sorry, somehow I missed that...

JDmills · #57 04-08-2008, 08:51 PM

Quote:

Originally Posted by Bajaman

JD,
Your vibration at 1900 RPM seems to be a common denominator. That describes my vibration very well. I also have a nasty vibration like you from 800-1600 RPM that I believe is a combustion related event. I don't see how it could be otherwise, as everything is neutrally balanced. I have tested injectors, timed, set valve lash numerous times, but to no avail, I am down to delivery valves or the whole pump at this point.

How about a compression test? I have done nothing in an attempt to repair my misfire.. although it kinda sounds like that at times, other times It is more easily felt than heard.. it is almost nonexistent at an idle, but shows up at 1200 rpm quite well as a slow speed vibration.. but it is sometimes worse than others.. go figure.. may start with a change of the fuel filter.. it is a hail mary, but a local trucker suggested it, as he has had that problem with his rig..

Bajaman · #58 04-09-2008, 07:06 AM

I rebuilt this engine two years ago. Compression is around 405-410 on all cylinders. Injectors were new last year, but I intend to check them again. The only thing thats left is the injection pump. This thing has never run right, and I suspect something may have been wrong with it when I bought it. Cleaning the delivery valves is next. If that does not solve the shake, then I will swap in another injection pump.

JDmills · #59 04-09-2008, 01:38 PM

Quote:

Originally Posted by Bajaman

I rebuilt this engine two years ago. Compression is around 405-410 on all cylinders. Injectors were new last year, but I intend to check them again. The only thing thats left is the injection pump. This thing has never run right, and I suspect something may have been wrong with it when I bought it. Cleaning the delivery valves is next. If that does not solve the shake, then I will swap in another injection pump.

What are the symptoms of a bad injection pump? and what wears out on them when they do go out the door? the 1300RPM shake on my car has just developed since january.. I would be curious to do a compression test on the car, but don't have a diesel compression tester, and have not made it a high enough priority to invest in one..

Bajaman · #60 04-09-2008, 02:47 PM

I don't know, I am targeting it because its the only thing left. I would assume that injection pump problems are going to be noticeable at low RPM just like a bad injector due to the low injection volumes and lower kinetic energy at the flywheel. Fundamentally they are all combustion related events that exhibit themselves as a vibration. These can be related to the following:
Compression
Injector spray pattern
pre-chamber problems (loss of ball)
delivery valve sticking/ improper seating
improper valve lash
Injection pump malfunction (wear/misadjustment)
Feel free to add to the list, I'm just listing the most obvious to me.
I am sorry to hear about your vibration, but at the same time I'm glad to hear that I am not the only one with these symptoms.