Harmonic balancer trouble - PeachParts Mercedes-Benz Forum

offalot · #1 05-03-2009, 11:50 PM

Hey all, Im new hear and to the MB world. I posted this on another board with almost no help, then the local Mercedes guy pointed m to here. And in doing searches on here compared to elsewhere this looks like the place to get answers. I read a bunch of old posts on this subject and got alot of good info, but still couldnt answer my quetion. Heres what I posted. Im mainly asking about the lip as the other questions were covered. ( lohttp://en.allexperts.com/q/Mercedes-Benz-repair-822/Belts-pulleys-etc.htmtsa info here )

Hello all, noob here. I just bought an 82 300SD, I got it for a steal because the harmonic balancer fell off on the previous owner. The engine starts and runs fine so I think it is a really easy fix. Just a coule questions. Has this ever happened to anyone, why would it? Also there is a lip around the outer edge of the area the goes into the oil seal area. it is beveled out and sharp. I don't know whether this is suposed to be there or if it is there as a result of some kind of wallowing action that occured when the pulley came off. Here is a pic to be a little clearer. Sorry for the quality, my cam lacks a macro feature.

moon161 · #2 05-04-2009, 01:00 AM

There should be dowel pins held in the balancer that locate it in relation to the crankshaft. You can put it in the right way and the wrong way (180 degrees off), both are possible. The two positions would be TDC w/ both valves closed, and TDC w/ exhaust closing and intake opening. Not sure which is correct, I'd have to pop my valve cover.

It may have come off if at some point the big ass bolt with the 27mm head that holds on the balancer and main pulley loosened or came out. Perhaps it was installed w/o the dowels and permitted to slip on the crankshaft. Since the main pulley that drives the water pump is mounted to the balancer, this ain't so ideal. Don't know how this pickle arrived, please explain in more detail and picture the balancer & shaft from both ends if yer able.

Putting it back on (after dowels are replaced if missing- see a machinist) means identifying the proper position, pulling radiator, shroud & fan, water pump pulley & sticking a mirror down there to see the crankshaft end. Heat the balancer to an honest 250 F, slide on w/ hot mitts, rotate till the dowels slide in & check work w/ a mirror. Work quick but not in a hurry, be prepared to repeat till correct. Don't muscle it in. Torque for the bolt is 240-260 ft lb but check to be sure.

moon161 · #3 05-04-2009, 01:02 AM

That ridge looks pretty deep on the balancer. Don't think mine had much more than some shine where the seal rode, maybe as much as .010" off the diameter, but it looks to me like you got maybe .080" off the dia. You got a mike or caliper?

mplafleur · #4 05-04-2009, 06:49 AM

Quote:

Originally Posted by offalot

Hey all, Im new hear and to the MB world. I posted this on another board with almost no help, then the local Mercedes guy pointed m to here.

How did he point you here; Mercedesshop.com, or Peachparts.com?

offalot · #5 05-04-2009, 06:59 AM

Moon, I have all neccessary parts removed and got the pins from the dealer. I heard it was a bear to get lined up, I will be patient. I have calipers and mics but what do I reference the measurement to.
The guy told me about both, he explained the switchover to peachparts.

moon161 · #6 05-04-2009, 10:07 AM

More frustrating than hard. Soak it to 250F (1-2 hours, convection oven, more in a regular oven) and you've got a 1, maybe 2 seconds of sliding fit to seat the pins and at least know that it's lined up right. First time I did it, followed the recipe, got it on the first try. Second time I did it it was more the the 7th or 8th.

That collar that sticks out the back looks unusually worn to me. The ID of the front lip of the crankshaft seal (an almost new one) is about 1.88". It's probably a slight stretch fit, so I'd look for that OD of that collar to be around 1.93-1.95" (just guessing here) where the front lip rides. If you put it back to together and it gushes oil you may need a new one match balanced to the old one.

Does it look like lots of leakage around the seal?

offalot · #7 05-04-2009, 05:44 PM

Ok So heat it up, really 2.5 hours?? Then slide it on, Im assuming the 2 seconds is because the heat conducts into the crank, expanding it. So if it is not lined up do I need a puller to get it off? And lined up jest means the half moons are perfectly lined up and the woodruffs will slide in, Correct? I will see if I can get a better pic of that collar because the part that concerns me is there is a slightly flared out adge at the butt end of it, it seems as though it would cut into something. I didnt notice where there could have been alot of oil, but the oil was low and it had been sitting for some time.

moon161 · #8 05-04-2009, 07:05 PM

It's a interference fit, so you need the puller if it sticks. I tried like an hour at 250F in a convection oven, licked my finger, touched the balancer and got vapor, so I was like 'that'll do', but I just frustrated myself. Even if the surface temp is 250, the inside can be cooler. 'Soaked' means no internal temperature gradient. Could go hotter, but 250 is toasty in your mitts as it is. 250 is not some magic number that Fritz in stuttgart came up with, its from the recipe that came with my crank seal. If adhered to it works well.

The crank and ID of the balancer should be cylindrical surfaces except for the pin cutouts, and maybe a chamfer at the end. The ID should be maybe .005 less than the OD of the shaft. The rear lip of the crankshaft seal rides on a wear ring which is a light press fit on the shaft. If you want to change the seal while you're in there, I have a puller which may get it off if it's stubborn.

Any burrs on the ID or OD will make your life not very easy. Try knocking them down with a stone and some oil.

offalot · #9 05-05-2009, 10:42 PM

Okay, got some better pictures of this flaired edge I speak of, and upon closer inspection I fear the inevitable, I just need someone else to confirm it. Does anyone have any ideas how it might have flaired like this? would there be anything else it may have taken with it?

lietuviai · #10 05-06-2009, 12:28 AM

Quote:

Originally Posted by moon161

It's a interference fit, so you need the puller if it sticks. I tried like an hour at 250F in a convection oven..

Maybe it would be better to try this in a propane grill so you wouldn't be in "hot water" with the wife, spouse, room mate, etc..

jt20 · #11 05-06-2009, 12:43 AM

Quote:

Originally Posted by offalot

wtf...?

were there any dowels on your crank?.. how hard was it to remove the balancer?

wtf happened to that thing.

offalot · #12 05-06-2009, 06:56 AM

Wish I could tell ya. The previous owner did it. As far as I know the dowels were on it, and it just came off. He had all the belts, the bolt and said he lost the dowels so it seems he was able to get it before it totally came off.

moon161 · #13 05-06-2009, 09:36 AM

Looks rough. I don't know what raised that lip. If the ID is flared as well, I'd say get one off of a parts engine and match balance it. If just the OD is messed up. have a machinist turn the lip down and get OD to spec. It doesn't look like the OD is real worn, but I can't figure where that material on the lip came from.

Mark DiSilvestro · #14 05-06-2009, 09:59 AM

Suggest a new, or good used, replacement balancer as that collar looks like it's certainly shorter now from spinning against whatever shoulder or gear lies behind what's left of the front oil seal. Hope the crank is OK.

Happy Motoring, Mark

jt20 · #15 05-06-2009, 11:26 AM

its almost like someone put the wrong sealing collar behind it. It was too wide and too thin, therefore it spun.

if you could remove the balance by hand.. it needs to go. As well as the elements that provide pressure / friction to it