bummed.... engine running but accessories not turning. 1982 300CD Turbo - Page 4 - PeachParts Mercedes-Benz Forum

lutzTD · #46 10-20-2009, 08:28 AM

Quote:

Originally Posted by tangofox007

If lutzTD doesn't know the range of his torque wrench, how is anyone else supposed to know?

I used a torque wrench which had an upper limit of 250 ft/lbs. I did not find reaching the specified torque to be much of a challenge, but I am probably stronger than the average old guy.

I got it to 225 without too much trouble

, should I go to the upper limit or leave it at the mean?

Johnt49 · #47 10-20-2009, 11:27 AM

If you haven't loctited it, I'd remove the bolt, clean the threads & apply some loctite. Since the bolt has been stretched a couple times already and you're not sure about the balance (could have a little more vibration than it originally did) I'd probably go to the high limit.

lutzTD · #48 10-21-2009, 09:20 AM

more info on the failure.

I noticed in my pictures the bottom of the crank bolt hole didnt look right. upon investigation I noticed the bottom was full of a hard black plstic like substance. I also found this on the base of the bolt and in between the big spring washers. I used a drill and broke out all of the black stuff in the bottom of the hole. my thoughts are someone had taken this apart before and used some kind of black substance as a thread locking device. it looks like maybe they put so much in it hydrolocked the bolt and maybe gave a bad torque reading? Also it looked like they did not install the spring washer correctly as they were all stacked in the same orientaion and high in the middle against the crank.

I drove the car in today, 32 miles, and it seems much smoother than before. definitely my clacking noise is gone. I will hit it with a torque wrench tonight and take it to 240 ftlbs. then as a PM I will set my torque wrench at 220 and click it to verfiy it is staying put. I will plan to do this once a week and then maybe longer as I gain confidence.

for those who plan to do this, one thing I would do different is to use an under size reamer. I used a .3125 reamer and the 5/16 stainless dowel I used was just snug. I would have liked it to be a better press fit. next time I would use a .3100 reamer.

tangofox007 · #49 10-21-2009, 10:21 AM

Quote:

Originally Posted by lutzTD

Also it looked like they did not install the spring washer correctly as they were all stacked in the same orientaion and high in the middle against the crank.

"Same orientation" is correct, but the concave side should be against the balancer.

Quote:

Originally Posted by lutzTD

I will hit it with a torque wrench tonight and take it to 240 ftlbs. then as a PM I will set my torque wrench at 220 and click it to verfiy it is staying put.

Small increases in torque don't work, especially when using a "clicker" torque wrench. You need to back the bolt off, then set the desired torque while the bolt is actually rotating.

lutzTD · #50 10-21-2009, 10:41 AM

Quote:

Originally Posted by tangofox007

"Same orientation" is correct, but the concave side should be against the balancer.

OK, I stacked them like I used to use them in molding. 1st one concave to crank, second one concave to bolt, thrird one concave to crank. this make a spring, all the same way also makes a spring but the force is really, really high. is all three the same way from the FSM? I dont have access to one so I used them the way I used to in plastic molds

Quote:

Originally Posted by tangofox007

Small increases in torque don't work, especially when using a "clicker" torque wrench. You need to back the bolt off, then set the desired torque while the bolt is actually rotating.

Ok, I will loosen it to check the dowels. Is it OK to remove the bolt with belt tension on the pulleys?

tangofox007 · #51 10-21-2009, 10:51 AM

Quote:

Originally Posted by lutzTD

Ok, I will loosen it to check the dowels. Is it OK to remove the bolt with belt tension on the pulleys?

You will have to find an alternate way to hold the crankshaft; you can't access the slots in the balancer with the damper and pulley installed. And, how are you going to check the dowels with the pulley installed?

jt20 · #52 10-21-2009, 11:01 AM

Quote:

Originally Posted by lutzTD

OK, I stacked them like I used to use them in molding. 1st one concave to crank, second one concave to bolt, thrird one concave to crank. this make a spring, all the same way also makes a spring but the force is really, really high. is all three the same way from the FSM? I dont have access to one so I used them the way I used to in plastic molds

all three are concave to the crank, convex to the bolt head by FSM

lutzTD · #53 10-21-2009, 11:06 AM

Quote:

Originally Posted by jt20

all three are concave to the crank, convex to the bolt head by FSM

Ok thanx, is it ok to remove the bolt with the belts on?

lutzTD · #54 10-21-2009, 11:09 AM

Quote:

Originally Posted by tangofox007

You will have to find an alternate way to hold the crankshaft; you can't access the slots in the balancer with the damper and pulley installed. And, how are you going to check the dowels with the pulley installed?

I used the slots in the side of the balancer, I think I can stick my pry bar in from the side, the same as I did when I tightened it.

the washers that hold the balancer and dowels is smaller than the holes on the pulley, so with teh bolt removed you can see the entire crank end and about 1/4 inch of the balancer

I think I will just back off the tension on the belts rather than remove them

jt20 · #55 10-21-2009, 11:12 AM

tango may have a better opinion, but I don't see the issue with doing so. As long as the crank is not spinning fast, there is no vibration occurring b/w the crank nose and balancer that could lead to any deformation.

lutzTD · #56 10-22-2009, 09:57 AM

in earlier post I commented that I would use a smaller reamer to get a better press fit. you can get them here:

http://www.mcmaster.com/#8803a46/=464n62

8803A598
(Same as 8803A46)High-Speed Steel Decimal Chucking Reamer .3100" Dia, 1-1/2" L Flute, 6" L O'all, 6 FluteIn stock at $20.63 Each

I had to cut the shank to 1" and use a small hand drill to get in between the grill metal and the crank end.

for dowels I used stainless steel from McMaster also and cut them to .312 length

I taped stops on the drill and reamer to get the depth similar to the original dowels. I couldnt find a way to get a dial indicator in there for a depth stop, maybe a tube over the drill would work if I had to do it again

t walgamuth · #57 10-22-2009, 06:45 PM

Every time the bolt is taken out and in is risking damage to the fragile pins. Improper installatin of the pins is what did the damage in the first place. I question removing the bolt unless you are pretty sure there is a problem.

lutzTD · #58 10-23-2009, 10:05 AM

Quote:

Originally Posted by t walgamuth

Every time the bolt is taken out and in is risking damage to the fragile pins. Improper installatin of the pins is what did the damage in the first place. I question removing the bolt unless you are pretty sure there is a problem.

yeah im on the fence too. Its running soooo smooth right now. I think I am going to hit it with the torque wrench to see if it will click up to 240 and call it done. I will keep an eye on it for a while to make sure it stays tight, but since my manual vibration went away with my grenaded 4 spd it runs smooth as silk now. I lived with a lot of vibrations on this car for a while, I am beginning to think the dowels were bad for a long time before the final catastrophic failure.

stimpy451 · #59 10-23-2009, 01:10 PM

This thread is awesome.

t walgamuth · #60 10-23-2009, 04:33 PM

Quote:

Originally Posted by lutzTD

yeah im on the fence too. Its running soooo smooth right now. I think I am going to hit it with the torque wrench to see if it will click up to 240 and call it done. I will keep an eye on it for a while to make sure it stays tight, but since my manual vibration went away with my grenaded 4 spd it runs smooth as silk now. I lived with a lot of vibrations on this car for a while, I am beginning to think the dowels were bad for a long time before the final catastrophic failure.

Makes sense.