Crankshaft/Harmonic Balancer problem

HuskieMobileMan · April 27, 2006

On my '89 GMC G3500 van (5.7 TBI) I noticed that my crankshaft/harmonic balancer pulley was wobbling a bit, so I took off the pulley and balancer to find a big gouge out of the crankshaft where the balancer fit on it.

What are my options here? Can the end of the crankshaft be replaced where the balancer fits onto it, or does the whole crank need to be replaced? If the whole thing needs to be replaced, can it be done w/o removing the engine from the vehicle? Any help is appreciated!!!

ChevyTech007 · April 27, 2006

I hate to bring bad news but, I would just replace the engine with a GM reman. I don't think it can be rigged. Replacing the crank in-chassis might be possible but more trouble than its worth. If the engine has to come out, its an 89 module. How many miles??? It might be time to bight the bullet.

Cheekster96 · April 27, 2006

Are you leaking any oil from your front or rear main seals? Any seapage coming from the timing cover area?

Does the engine wobble or vibrate harshly at idle or is it smooth?

I used a a Harmonic Fluid Dampner with good results on my Z28. Doesnt cure all vibrations, but helps.

With an older engine like that, might be time for a trade or crate motor.

Good luck.

Lee

HuskieMobileMan · April 27, 2006

Are you leaking any oil from your front or rear main seals? Any seapage coming from the timing cover area?

Does the engine wobble or vibrate harshly at idle or is it smooth?

I used a a Harmonic Fluid Dampner with good results on my Z28. Doesnt cure all vibrations, but helps.

With an older engine like that, might be time for a trade or crate motor.

Good luck.

Lee

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It's pretty darn smooth for the age. I bought it a few years back with like 120K on the engine, but supposedly it had been rebuilt right before I purchased it. I have only put 10K on it at the most since then and made a lot of repairs.

I was talking to a buddy of mine and he told me that I could probably drop the oil pan and get access to the crank to replace it w/o removing the engine. Could anyone verify this. The only thing in the way would be a cross member from the suspension.

One more question, with the limited access to the engine being a van, how would the engine need to be removed from the vehicle? Would you need to drop it out of the van? Thanks.

redvett · April 27, 2006

Can you take a picture of the crank snout so we can see it? You may be able to use a Locktite product to make the fix.

HuskieMobileMan · April 28, 2006

Can you take a picture of the crank snout so we can see it? You may be able to use a Locktite product to make the fix.

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I would but it is a lost cause now. The crank needs to be replaced. Any info on how to replace the crank? Can it be done by just removing the oil pan? Would I need to remove the cross member of the suspension? Is it drivable with no balancer and pulley for a short distance? I have 2 batteries that I could get a full charge into before driving it.

redvett · April 28, 2006

You can drive it a short distance until it gets hot. Changing a crank in the van is harder than pulling the engine. The whole front suspension has to come down. How much of the crank snout is missing?

HuskieMobileMan · April 28, 2006

You can drive it a short distance until it gets hot. Changing a crank in the van is harder than pulling the engine. The whole front suspension has to come down. How much of the crank snout is missing?

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It is all there, but I was trying to drill into the center today so I could rethread the inside so I could attach the installer. That didn't work too well. A chunk around the outside of the crank is missing, I would say that there is a dime sized chunk missing.

redvett · April 28, 2006

A dime sized chunk wont matter. I would use Locktite "Quick Metal" and it wont come off. You wont need the center bolt but if you can use it do. Follow the instructions on the product you will need a special cleaner to clean the crank end & balancer surfaces. I have used this product on powersteering pulleys and never have had aproblem with them coming off. You can use a hardwood block & 3 lb hammer and drive balancer back on. Dont hit the outer ring just the center. Take the fan shroud, radiator and fan off so you have room. Done it many times.

HuskieMobileMan · April 28, 2006

A dime sized chunk wont matter. I would use Locktite "Quick Metal" and it wont come off. You wont need the center bolt but if you can use it do. Follow the instructions on the product you will need a special cleaner to clean the crank end & balancer surfaces. I have used this product on powersteering pulleys and never have had aproblem with them coming off. You can use a hardwood block & 3 lb hammer and drive balancer back on. Dont hit the outer ring just the center. Take the fan shroud, radiator and fan off so you have room. Done it many times.

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Thanks, I will see what I can do. If I hammer the pulley on too far would it be bad to use some grade 8 washers as spacers between the balancer and the pulley?

redvett · April 28, 2006

You cannot install the damper too far on it stops at the timing gear.

HuskieMobileMan · April 28, 2006

You cannot install the damper too far on it stops at the timing gear.

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Thanks for the help man. I took your advice, but used JB Weld for the adhesive/sealant. I cleaned both parts real good with sandpaper and used acetone to finish the cleanup. I filled in the gouge on the crank and coated both the inside of the balancer and the crank with JBW. Took a 1.5" pipe plug to distribute the load on the balancer and took a 4lb. sledge to bang it on. It went on and lined up perfectly with the other pulleys under the hood and it was straight.

I don't think it will matter, but I rotated the balancer 180 degrees to get the worn parts on the opposite sides of the setup. I know my timing mark will be off but I will make a mark in the compartment to where it should be.

redvett · April 28, 2006

Why didnt you align with the keyway? Now the torque of the engine will twist the damper around. The Quick Metal is far better than JB.

ken1mod · April 29, 2006

Gentlemen,

I compl;etely agree that the keyway must be used.

Ken

HuskieMobileMan · April 29, 2006

Why didnt you align with the keyway? Now the torque of the engine will twist the damper around. The Quick Metal is far better than JB.

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Basically I turned it 180 degrees becuase the damper fit pretty much all the way on when the key was aligned without appling any pressure. That is also where the wear is on the crank. At this point I don't see this working for me with the conditon the crank is in. Looks like I am stuck replacing the crank.

I did pull the dampner off and got all the JBW off as well.

Now my question is a steel shaft a lot better than a cast shaft when buying a crank?