Loose harmonic balancer pulleys
 

'89 C4 with about 500 miles post rebuild. Engine runs great. However...

When checking valve clearances I noticed that the pully was freewheeling on the crankshaft. Apparently, the main bolt partially backed out. Everything is still intact, and, thankfully, the thing didn't come flying off at 5K rpm.

I am feeling very lucky (no damage) and at the same time puzzled (wondering if I have to drop the engine to fix).

Has anyone run into this? I suspect that I didn't get full 175 ft-lbs of torque on assembly. Is there any way to remount the pully assembly with the engine in the car? If so, how do I ensure that the timining marks are aligned properly? Also, I can't remember, but is that bolt left-hand threads?

Any advice would be very appreciated. The warm weather is even coming to New England and I want to get on the road!

Thanks.

The pulley should be similar to the pre-1989 ones, if memory serves me correct. There is a very high torque value for this pulley - it should not come off. I don't think it's a left-hand thread.

To retighten, I believe you need to remove all of the rearward parts of the engine (incl mount - support the engine with jack stands). You should be able to gain access within the engine compartment.

Use some red Loctite on the bolt just for added assurance. I believe there is a lock washer too on that one...

-Wayne

if it's spinning, the locating dowel is sheared off. that's what positions the pulley on the crank, so the timing marks are in the right place. so the pulley needs to come off, and you will need to figure out how to get that dowel out. hopefully the crank and pulley are ok. they may well be damaged from all that spinning around. you're done driving it until it's fixed, right?

Not driving it until this is solved...

I got the pulley assy off the crankshaft and this is what I saw:

1. The dowel pin is intact and undamaged.

2. The end of the crank has a small arc of damage, about 1/4 inch long running from the locating hole. It looks like it just spun the pulley and gouged the end of the shaft and then tapered off.

I disassembled the pulley assembly by marking and removing the allen headed machine screws so that I would get enough knuckle room to remount the hub. My plan is to torque the hub to proper torque (173 ft-lbs) and then reattach the pulley. If it works, then I would not have to break the engine mounts...

I'm not sure why this happened, but I have two theories.

First, I simply did not torque the both sufficiently when I mounted it, and the rotation of the engine simply caused the hub to spin.

Second, I torqued it right but mounted it in the wrong place so that the dowel pin didn't align. Again, the rotation of the engine
caused the hub to spin and when the dowel pin landed in the hole, it just got loose.

What a mess, either way.

The book says to clean the tapered mounting surfaces with solvent, and to use a little oil on the threads and face of the bolt. No mention of locktite. Any suggestions?

Thanks.

the second theory sounds likely, being the dowel is intact. amazing. use a new bolt with the locking flange. inspect the mating surfaces well for irregulatities. with that special bolt, properly torqued, loctite is redundant.

Redundant, but then again, we have an anomaly here. I would use the red Loctite for insurance...

-Wayne

Well, it now seems clear that I can't reassemble the pulleys in place because there isn't enough room to get the third pulley (A/C) in place. Couple questions:

1. How much space should there be between the back face of the main oil seal and the front edge of the pulley hub? Is 1/4 inch too much?

2. Would there be any problem with mounting only two of the pulleys and leaving the A/C disconnected for now? (Will doing so impact the proper balance of the engine?)

3. How much wiggle room is there to remove the engine mounts when retorquing the crankshaft bolt without misaligning the engine and tranny? I certainly don't want to bust anything.

Thanks.

Wayne, I like Loctite as much as the next guy (good with salads or steak) but I'm curious why you recommend Red Loctite instead of Blue. I only use Red on fasteners I won't mind heating the area up in order to remove them. It is because of the size of the bolt?
-Chris