Wobbling Vibration Damper

[Col Webb]

Hey all. My 64 230 SL developed an engine vibration.  I found that the crankshaft bolt had worked loose and the damper was wobbling in and out. I did not remove but torqued to spec. Still have a slight vibration that gets worse as rpm goes up. Not nearly as bad as before. I think that I machined out the damper or the crank shaft end. Any comments on this? Any suggestions on where to get a replacement damper. Should I upgrade to the crank shaft bolt kit with the spring washers and oversize pins? If so do I need to use the special drill bit as stated in the BBB instructions? Any help will be greatly appreciated. Thanks Chuck

[franjo_66]

Hi Col

I have gone through this drama (look at this thread http://www.sl113.org/forums/index.php?topic=21217.0 )

You can purchase the new dampner, upgraded stretch bolt and dowel pins from MB. I bought mine from the MB Classic Centre
This has helped (together with new engine mounts). Vibration is noticeably less but I still have the wobble.

In my case, the assessment is that the front snout of the crankshaft has been worn down so that the dampner can't fit snuggly as it was intended to.
I don't have any knocking or other issues, so for the moment I will leave as is.

My mechanic believes that the crankshaft can be removed without disassembling the entire engine. So in the new year we will remove crankshaft, repair front snout and rebalance and fit back in with new bearings and see how that works out

Regards
Franjo

[Col Webb]

Thanks Franjo: I saw your thread earlier. Thanks for posting that information. After reading it I was afraid that that was the conclusion. In my case the car was driven only a short while with the vibration. Now, after retighting, I cant see or feel (screw driver resting on spinning damper) a vibration at the damper/pully so I hope the damage was not great. Thanks again for the response. Yours Chuck

[Col Webb]

Update: Drove the 230 today. Vibration barely noticable at idle. as rpms go up vibration gets more sever. Franjo, is that what you experanced? When said you are redoing the snout of the crankshaft what are you doing? also are the bearing you are talking about the main crank bearings? Sounds like a bottom end rebuild. Thanks again for your input. Chuck

[franjo_66]

Hi Chuck

Yes similar symptoms to what you have stated.
No vibration at idle, becomes somewhat noticeable above 4000rpm

However it was far more severe until I installed new dampner, stretch bolt and engine mounts. Much smoother now.

Dampner still has a slight wobble due to wear on the snout which prevents the proper (snug) fit.
The snout needs to have repair undertaken to compensate for the wear/damage. Then machined to bring it back to original diameter/specifications followed by a full polish & balance. So essentially it is a bottom end rebuild when you factor in the installation of new bottom end, bearings, etc

Given that my motor has excellent compression, leak down values, no oil consumption, leaks or noises, I will go with the repair procedure as above.
All up quote is $1,800 including labour

[Col Webb]

Thanks for the info. Boy, the problems that a loose bolt causes.  On the rebuild of the snout, is metal added and then machined to tollerance? My engine is not in get shape. burning oil and exhaust blow by. Looks like Im heading to the machine shop. Are you driving yours with the vibration? Thanks again.

[franjo_66]

That's right Chuck - metal is added to the snout and then machined so that the priginal dimensions are achieved

If my engine was at the stage where a rebuild was looming then I'd go the whole hog, but at this point I can't justify $15,000 - $20,000 on what is a basically sound engine.

Still driving it, as normal daily duties don't produce vibrations. So I avoid any high-reving activities !

[Col Webb]

Thanks for the advice. Yours Chuck

[Col Webb]

Franjo: I’ve emailed Jon at the classic center and he gave me a quote on an invoice. Of course now I have more questions. The invoice is showing "counterweight" for the vibration damper. From the other treads, I thought the damper and weights were separate parts. Does the new damper come with new weights attached that then have to be removed? Also I asked for the kit described in the BBB. The Invoice is showing a bolt and a washer with separate part numbers. Is the bolt kit different and if so do you have a part number so I can give it to Jon. Finally the job in the BBB says to use a special drill bit. Is this necessary and is it included in the kit? Again I greatly appreciate your help. Yours Chuck

[Col Webb]

Franjo: Sorry to be a pest but have another question. The BBB says to use locktite type fugeteile. I cant find this. Also the BBB talks about removing the counter balance not just the vibration damper. What proceedure did you use? Are the Damper and Counterweights seperate assemblies? Thanks Chuck

[franjo_66]

Hi Chuck

Sorry for the delayed response

The dampner I bought had the counterweights attached (i think it is an upgraded part that does not require counterbalancing with the crankshaft assembly)
Attaching the upgraded stretch bolt etc did not require any drilling

Fairly straightforward

Hope this helps

Rgds
Franjo

[Col Webb]

Franjo: Greatly appreciate the response. What’s going on is I’m getting different information from different sources and am getting confused. The BBB makes it appear that the damper and weights are separate parts. The Classic center thinks they are one part. EPCnet shows the damper as a separate part. Also, I’m trying just to replace the damper for a couple of reasons. I'm reading that to replace the weights the crank assembly would have to be balanced. Also, the wobbling appears to be at the damper and the counterweights seem steady. The classic center gave me a number to call. I'd appreciate it if you would keep an eye on this thread so I can compare what I find out with you. Thanks Again Chuck

[franjo_66]

No prob Chuck
I think that what's happened is that MB have released an upgarded version of the dampner (with counterweights attached) that has come out well after the last BBB release?

I can definitely tell you that the dampner I bought had the weights attached, and there is no need to counterbalance the assembly

Rgds
Franjo

[ja17]

I believe we have a terminology problem here. The front crankshaft balancer or (counterweight) is massive, thick, round,  steel disc attached to the front of the crankshaft by the large single bolt and two round pins. The vibration dampner is a separate part which is attached to the front of the crankshaft balancer by three or six bolts (depending on version W113). Early version 230SL engines used the vibration dampner made from two halves with springs and rubber discs in-between. All the latter vibration dampners were made as one unit steel and rubber. With all versions the vibration dampner is a separate part and attaches to the crankshaft balancer. Early W113 engines used a front crankshaft balancer which is actually a counter-balance.  Looking on the back side of it you will see a large masss of steel in one portion. This is the "counterbalance" which actually balances the throws of the crankshaft in the 230SL engines.  With the 250 SL and the 280SL engines, the front crankshaft balancer is balanced. There is no mass in one area. It is equally distributed.

Naturally when the crankshaft balancer or counterbalance becomes loose, the whole assembly including the attached vibration dampner wobble.

Your problem is with the front crankshaft balancer (or counter-balancer). This is the part which is damaged. The vibration dampner or also called harmonic balancer simply unbolts from the crankshaft balancer and is a balanced part in all instances.

[Col Webb]

Franjo: thanks for the help. I'm going to try to determine what is actually moving around. What you and Joe are describing does not seem to be what I am seeing, i.e. the damper and pully are moving and the counterweight does not seem to be moving. Thanks Again Chuck.

[Col Webb]

Joe; Thanks for jumping in on this thread. Im going to reexam for the only movement seems to be damper, not the counterweight (disk with timing marks). Is it possible that the damper has failed?  On another issue I saw in earlier threads that you and Crees (sp?) were going to do a video and manual on rebuilding the engine. Were you able to finish this project? It would be a great resource. I've rebuilt Chevy 350s but realize that the M127 is a different animal. I'm trying to determine if an engine rebuild is in my skill level. Do you know of step by step instructions for rebuilding. Thanks again, Chuck

[ja17]

Hello Col Webb,

Yes it would be a much easier fix if just the vibration dampner was moving. The crankshaft counter weight, (disc with timing marks) usually damages itself and the crankshaft end when it comes loose. Is your vibration dampner the type with two halves and springs and rubber discs , or is it the one piece composite rubber and steel ? No step by step instructional on engine rebuilding has been put together at this point.  I have lots of step by step photos during the rebuild of Alfred's engine a while back. Cees has some video footage of his rebuild also.

Your biggest hurtle would be sourcing the scarce and expensive piston assemblies for the W127 engine at this point.

[Col Webb]

JJoe: Thanks for your input.  From about 1500 - 2200 rpm, I can feel a vibration. I used a socket extension to touch the pulley, damper and counter weight. I let the extension ride on each.  Seems to be no vibration at the counterweight which is turning smoothly at this rpm.  The pulley and damper are vibrating/oscillating.  This weekend I will test at higher rpms and check to see what type of damper I have.  Thanks for the help. Yours Chuck

[Col Webb]

Dear Joe: This weekend I ran higher rpms. Used a socket extension to ride on the counter weight. No vibration or oscellation at counterweight. Vibration is at vibration damper and pulley. Both up and down and in an out. does not seem to be random movement.  Is this a damper problem or has it worked loose?  How do I tell which type of damper? are there photos somewhere? Is the damper a press fit? thanks Chuck

[ja17]

The three small bolts hold the engine vibration dampner to the counterweight. It is a tight fit but can be separated. The large bolt in the center holds only the counterweight on the crankshaft endl

[Col Webb]

Joe thanks for the response. Thats what I thought. I'm going to pull it apart again this weekend. Probably will have more questions. Thanks for your help. Chuck

[Col Webb]

Dear Joe and all: Ok, to recap. I have a vibration in the engine. I found that the center stretch bolt going into the crank shaft was loose. Retightened but could not get it to full torque (but very close). Vibration got less but still there.  Then I removed all belts and drove the car. Vibration was gone.  Examined the pully, vibration damper and counter weight. Counter weight has no movement up or down or in and out. Measured the pully and vibration damper without belts attached. Both moving forward and back about .01 inch. Pully moving up and down about .015 inch. Don't know if damper and pully work more with belts attached.Three bolts are torqued to spec.  I have not removed the damper and pully to examine.  Damper looks like a disk with rubber vulcanized to it. the center bolt is the old model with a solid washer and not the 3 spring washers. Any suggestions? Do i need a new damper? Looking at diagrams in the BBB it looks like the damper is a tight sleeve fit inside the counter balance.
Do you think the damper has slipped out? Thanks Chuck

[ja17]

You may want to perform the upgrade using the new bolt, washers and pins. The procedure is covered in the early BBB (P 03-10/3).  Sounds like the problem is the counter balance. You might also consider shims and locktite bearing mount, as last resort, if the crankshaft/counter balance is worn.

[Col Webb]

Joe: Thanks for the reply. i'll get the new bolt, washers and pins. Could you describe the loctight use and shims? Im not really understanding that. Yours Chuck

[Col Webb]

Joe: The BBB says to use a 3 lipped drill bit. I cant seem to find one. Is this critical?  I read your comments on the other post. Thanks for that. What type of loctite is used? What size of shims are used? Do you lay the shim on the side of the crank nose and then install the balancer? Thanks Chuck