Not so good results from 4spd swap - Page 5 - PeachParts Mercedes-Benz Forum

JDmills · #61 04-09-2008, 06:29 PM

Quote:

Originally Posted by Bajaman

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.

If this car was trouble free, I would be bored and not learning anything.. so I am not "glad" to have this vibration, but curious never the less, as to where it originates.. and I am also comforted not to be alone in that particular forest...

this weekend I will dig in and start exploring some driveshaft solutions.. and thinking about the engine miss.. in greater detail..

JDmills · #62 04-11-2008, 04:49 PM

Quote:

Originally Posted by Bajaman

I also have a nasty vibration like you from 800-1600 RPM that I believe is a combustion related event.

Bajaman,

I was just driving the wagon today and the low speed miss has disappeared. the only thing I have done in the last week, was to put a fuel additive in the tank, made by CRC I believe that is for controlling/removing water. I was planning on changing the fuel filter as soon as this tank of fuel is used up, so I will be starting the summer with a new filter, and no water in the tank. not that I have any reason to believe there was water/alge in the tank, But I was gonna start there.. the engine now runs as it did back in december.. I have not answers here.. but figured I would pass it along.

lutzTD · #63 04-16-2008, 01:32 PM

I now have the same vibe, under load in 3rd and 4th. I put in the 240D auto crossmember and I used the 300D auto mount which seemed to be much softer than the 240D auto or manual mounts.

my question is: can someone with access to european part number books look up the number for the transmount on the '77 300D 4speed?

also there was a post and I looked forever today and cant find it showing the different mounts tried and which tested out the best. The 240 Auto crossmember fits perfect and did reduce the over all noise of the motor but it has now concentrated all that noise at the specific bands of rpm and gear that everyone else seems to be experiencing.

I put in 1/8 of washers and it was better, I going to try another set of washers making me about 1/4 down. Im also going to try an angle finder and see if I can determine if there is a difference on the tranny angle and DS stub angle. that will let me hone in on the spacer requirement

#64 04-16-2008, 01:40 PM

Quote:

Originally Posted by lutzTD

my question is: can someone with access to european part number books look up the number for the transmount on the '77 300D 4speed?

There isn't a part number on my 300D 4-m crossmember.

lutzTD · #65 04-16-2008, 01:44 PM

Quote:

Originally Posted by ForcedInduction

There isn't a part number on my 300D 4-m crossmember.

what about the trans mount?

Bajaman · #66 09-25-2008, 07:17 AM

After trying everything I can think of, I have a new theory. But first I'll list everything that I have done to remedy the vibration.
New stuff:
trans mount -auto version
cross member 240 auto version
flex discs (2)
centering bushing (2)
center support and bearing

The only thing that I have not done is replace the u-joint, and the driveshaft has not been balanced, but it has zero vibration when there is no torque on the shaft, so I don't see how it could be out of balance (again the vibration is the worst under light to moderate torque from 1600-1900 rpm).

New theory: The springs in the clutch are too weak for the larger 5 cylinder motor/lighter flywheel. One thing that led me to think about this is that the springs really do seem too light because sometimes I get a nasty surging when I slow to say 1200 rpm then hit the accelerator. A critically damped system would not oscilate like this. The clutch springs seem like the biggest contributor here. The only other thing that would be a big factor would be overall drivetrain slop. There is some for sure, but it doesn't seem excessive.
Bottom line, is there a clutch available with heavier springs?? Or am I reading this completely wrong? Where are our vibrations guys?

#67 09-25-2008, 07:27 AM

Quote:

Originally Posted by Bajaman

New theory: The springs in the clutch are too weak for the larger 5 cylinder motor/lighter flywheel.

Nope. If that were the case then a few dozen converters and almost half the 300D's in europe would be having the same problem.

I don't have any vibration problems worth complaining about. I'm very happy with my conversion.

Stevo · #68 09-25-2008, 10:02 AM

Your sure you got the drive shaft back together just the way it came apart?

Bajaman · #69 09-25-2008, 11:47 AM

Almost everyone who does the swap complains about vibrations. I don't think its a coincidence.

No, the driveshaft is custom, but if it were the culprit, it would not just show up under load.

Stevo · #70 09-25-2008, 04:01 PM

Maybe its just a consequence of the 616 F/W being seven pounds lighter than the 617 flywheel, least thats the number that I remember from somewhere.

bgkast · #71 09-30-2008, 11:11 AM

I don't mean to sound like a tree hugging hippy (joking

) but I filled up with biodiesel yesterday, giving me about a B50 blend in the tank, and my vibrations have noticeably decreased. I used to be able to rattle my sunroof if I lugged it too much, but now I can't. Maybe it has something to do with biodiesel's less "violent" combustion?

Bajaman · #72 09-30-2008, 11:44 AM

BG your comment about biodiesel combusting slower than diesel would fit nicely with the hypothesis that the flywheel is the culprit. A heavier flywheel would tend to dampen the vibration caused by quick combustion.
On a similar note, I have noticed a dramatic increase of what I will call 'lurching' since I "upgraded" to 265 nozzles. What I mean by lurching, is when I am driving slowly in 1st or 2nd and accelerate gradually, the car will lurch violently (like they do in movies when a kid is learning to drive a stick shift). This only occurs under light to moderate acceleration. Heavy acceleration does not yield the same results.
This lurching is what initially got me thinking about clutch springs being too light. I suppose that I have somewhat more torque than stock. Significantly more at lower rpms do to the VNT swap.
I just wish it drove more like my Scout. You can lug that thing right down to idle and get NO vibration whatsoever. Not that I seriously lug my engines, I just like to shift to a higher gear when cruising around under low torque conditions... saves fuel.

bgkast · #73 09-30-2008, 05:53 PM

I get that too. I believe it is play from a few hundred thousand miles on the diff and transmission. I have had the same thing happened in other manual cars I have owned.

Bajaman · #74 10-01-2008, 08:27 AM

gears certainly wear over time. I wonder if the backlash in the diff. can be adjusted by adding shims behind the pinion.

SW · #75 10-01-2008, 01:10 PM

Quote:

Originally Posted by Bajaman

gears certainly wear over time. I wonder if the backlash in the diff. can be adjusted by adding shims behind the pinion.

Adding shims to the pinion will change the depth of the pinion relative to the ring gear. If backlash is too sloppy, what you want to do is tighten up the pre load on the carrier bearings. On the benz diff you will have to add shims to the carrier bearings or maybe even change them out. Not hard, but very tedius.