Flywheel Question - PeachParts Mercedes-Benz Forum

diesel don · #1 08-16-2003, 04:55 PM

I'm in the middle of a job putting a flywheel & ringgear from a manual tranny onto a former 300 turbo engine that was equipped with an automatic transmission.

My question involves how to get the torque convertor off the automatic transmission. I can see the bolts underneath but cannot get to them. It looks like a straightforward re-installation of the manual flywheel if I can get this off.

If you need a picture, I can snap a digital but someone needs to shrink it for the forum. If you have this capability, let me know.

Any ideas?

Thanks

Don

kerry · #2 08-16-2003, 05:54 PM

I'm not familar with the MB torque converter but your question seems a bit odd to me. The torque converter is usually attached to the flywheel and it must be unbolted from the flywheel in order to remove the auto flywheel and install the manual. Perhaps things are different on the MB, but that is how I have always found them on other vehicles. So I don't understand why you would need to remove the converter from the transmission.

psfred · #3 08-16-2003, 08:29 PM

The torque converter bolts to the flex plate from the front. Access if through a hole in the flywheel cover behind the steering damper if the engine/tranny is still in the car. Bottom front of the bell housing.

Six bolts in three pairs, rotate engine to access them all.

After that the flex plate and flywheel can be removed after you separate the engine and tranny.

Peter

diesel don · #4 08-16-2003, 08:34 PM

Thanks Kerry & Peter:

The reason my question sounded confusing is because this is my first time through this. In talking with a friend on the phone, I found the access panel to the torque conv bolts. Thanks Peter for the excellent and timely help.

One more question....is there really a mark on the crank and on the flywheel that have to be aligned or is 'Ridge' funning with me. I've searched both of them and can't find any alignment marks.

Anyway, we're making great progress thanks to the forum.

Don

psfred · #5 08-16-2003, 08:55 PM

I've heard several things about that. I was told by someone who ought to know that pre W123 chassis, the crank, flywheel, and harmonic balancer are balanced together as a single unit, and must have parts replaced matched to the old part or the whole thing has to be rebalanced, requiring engine disassembly.

Later models, according to this source, have individual parts balance so that they can be replaced without reguard to imbalance.

I've also heard that all MB engines are still balanced with the crank, flywheel, and harmonic balancer assembled.

You should mark the flywheel and flange before removing the original flywheel, then have the balance checked. If it isn't balanced, the other flywheel will have to be matched to it, so that it is out of balance in exactly the same way and amount, and have the shop matchmark it while doing this.

The bolts on the flywheel may or may not be symetric -- if they are asymetric, one bolt is further out from the center than the others, check.

Peter

diesel don · #6 08-16-2003, 09:15 PM

Peter:

Now you have me worried. I've checked and rechecked for marks. All I can find is out the outside of the flywheel. As you would face the rear of the engine and look directly at the flywheel, there are holes drilled into the outside edge. These are not symetrical. There are four holes drilled on one side and two on the other (drilled straight into the outside perimiter of the flywheel). But as to how it relates to a symetrical crank, I have no idea.
I've checked the bolt pattern and all twelve are perfectly symetrical. In addition, the old flywheel is lying on the garage floor without it being marked. But even if I had marked it prior to removal, it would still offer no guidance for the new one.
Should I just reinstall the flywheel and pray? What other option remains at this point?

One last question:

How do I center the clutch disc between the cover and the flywheel as there is a bit of play? I would assume that it has to be perfectly centered so that it mates to the clutch shaft upon reinstallation.

Thanks

Don

JimSmith · #7 08-16-2003, 10:23 PM

Diesel Don,

I think psfred was suggesting you match mark the old flywheel and crank, then have the old flywheel checked for balance. If the old flywheel is not balanced to a minimum out of balance condition, you then transcribe the match mark to the new flywheel. Once marked have the location and magnitude of imbalance reproduced on the new flywheel. This way the original balance is retained with the new flywheel. I would try to see if there are any markings or stains or tool marks you made while getting the pieces off to re-establish alignment.

I would then take the old and new flywheels and have them checked for balance. If the old one is balance to a low residual imbalance, then I would assume the parts are individually balanced and you can go ahead and have the new one balanced to the same or better standard, then install it to suit your fancy.

If it has a significant imbalance you will have to rely on your ability to re-establish the alignment or orientation of the old flywheel, and go through the steps suggest by psfred - repeat the condition of the old flywheel on the new one and install it in the same orientation as the original one. If you cannot find any marks, stains, etc., then you may be in for a trial and error effort. I guess you have 12 choices if there are 12 bolt holes.

Good luck, Jim

diesel don · #8 08-16-2003, 10:40 PM

Jim:

Thanks for the thot of finding marks that I made. Indeed, one of my bolts stripped and I had a heck of a time drilling it out, etc. Plenty of marks there and I think I can get within a bolt or two of the original mark. It is the best I can do.
Why would the balance be so significant when the torque convertor was bolted to the flywheel and itself has a set screw in it to retain fluid?
Where does a guy get flywheels tested for balance?

Thanks

Don

psfred · #9 08-18-2003, 08:02 PM

Any good engine shop will be able to balance the flywheel. The drillings on the outer edge are where it was drilled to balance it, by the way.

A racing shop would be the best, or a good diesel repair shop.

If you have a flywheel seriously out of balance, the engine will "dribble" to the point the car will bounce on the springs -- this isn't funny. Get them checked, and make SURE they understand that if the first one (that you are replacing) has an imbalance, it must be DUPLICATED on the second -- if you explain the flywheel, crank, and balancer were balanced as a single unit, they will understand.

Peter

diesel don · #10 08-18-2003, 08:13 PM

One last question before I do this.

How much do I reattach to the flywheel before they balance it?

Torque Convertor?
Clutch Disc?
Disc Cover?

It seems to me that all of that stuff would affect its balance?

Don

psfred · #11 08-18-2003, 08:22 PM

Bare flywheel, the rest is balanced separately.

Peter

R Leo · #12 08-18-2003, 08:22 PM

Don,
If you are replacing an automatic with a manual, you won't be using the torque converter (which shouldn't be able to be attached to the manual transmission's flywheel unless something terrible has gone wrong. The other components are balanced by their respective manufacturers.

R Leo

diesel don · #13 08-18-2003, 09:35 PM

R Leo:

I understand that but we're checking for former balance and I wondered if it had to be checked with it attached.

Thanks Peter. I'll have them checked soon by themselves.

Don