Lower balance shaft binding/tight

marko · 10:52 AM

Lower balance shaft very hard to turn. Removed bearing cap, replaced spacer, seal, O-ring, noticed the engine mating surface is not even. In the picture there is a ridge where the two halves meet. The lower half sticks out about 1mm further than the upper half. There is now way the bearing cap can be mounted flush on the mating surface. You can see on the bearing cap mating surface that half is brown and the other half is clean. I'm thinking this is making the bearing cap a little cockeyed.
Installed bearing cap. shaft turns smoothly, start tightening down the bolts and the shaft binds and is hard to turn. Placed a thin cooper washer between the engine and bearing mating surface on the upper bolt hole. Varied the torque on the three bolts when tightening and I can get the shaft to spin a little easier but it's still too stiff.

Received another bearing cap from Tbone425 (thanks Chris!). Installed it, shaft spins freely, start tightening bolts and it binds. Placed the cooper washer between the mating surfaces on the upper bolt again, start tightening bolts and shaft is now spinning freely. Installed key, gear, tin plate, start tightening the bolt and the shaft starts to bind, but not nearly as much as with the original cap.
Put it all back together, take it for a drive, now I have an slight engine vibration.

Back to the binding when tightening the gear bolt. I placed two washers on the end of the balance shaft to keep the gear from sliding inward. If the washers are too thick, the gear would have in/out play, too thin and the gear would go too far inward and the shaft will bind. Had to grind one of the washers to get the right thickness. Now when tightening the gear bolt, the balance shaft spins very freely with no in/out play from the gear.

Put it back together, go for a drive, engine is much better, but still a very very slight vibration. I suppose my next step is to swap the bearing cap race with the original race. I dreaded doing that initially as I didn't want to fudder up the cap as it is aluminum. Anyone have any advice on swapping the race's?

Bradical · 08-22-2015, 11:01 AM

They have to be pressed out with a special tool. With the uneven face like that I would suspect the issue you are having is with cover alignment- the front race is going to true-up the balance shaft and while the shaft will spend freely without the front race, it will shift the position of the shaft so the rear bearing isnt set right anymore.

I didnt even know it was possible to remove the front bearing race section without loosening the hardware for the balance shaft cover- i would totally remove the cover, clean it, install everything back and follow the tightening sequence with the front race/seal in place and everything should line up true and not bind. I had the same issues until I did it this way myself.

marko · 08-22-2015, 11:39 AM

Quote:

follow the tightening sequence with the front race/seal in place and everything should line up true and not bind

This is my problem. Neither bearing cover (I was calling it a bearing cap) will work when installing it normally. The mating surface on the engine is uneven causing the shaft not to line up true (I believe).
I tried all different sequences of bolt tightening on both covers but the shaft will still bind. Only when I add the washer to the upper half of the engine mating surface can I get the shaft to spin freely using the new bearing cap. Doesn't help when using the original.
You're in Lake county, I'm in Tampa, come on over and help me out.

Bradical · 08-22-2015, 11:57 AM

Are you 100% positive that the upper and lower balance shaft covers werent mixed up? That will definitely cause this issue because the covers were machined for bearings when the block was made. You can't swap them and replacing them with a cover from a different engine will NOT fit right!

Tampa is like 2hrs away, but we could work something out maybe? That would be fun!

marko · 08-22-2015, 12:36 PM

The upper and lower covers are totally different. The lower cover is also the power steering pump mount. Would be impossible to mix those up.
Yes, I've read in few posts that the bearing races or sleeves are matched, but the bearing housing is interchangeable. That's why I wanted to try and swap the bearing races or sleeves. I knew that before I started, but I read in someone's post that they just swapped the whole thing and it worked out. They got lucky I guess.
I'm not real optimistic that even changing the bearing race will help. I'm thinking the original races have probably worn cockeye because of the engine mating surface, but then again it didn't cause a vibration, just caused the shaft to be stiff.

kdjones2000 · kdjones2000's Garage

The later blocks have the rear bearing cap machined into the cover. It is align-bored to your block. That's why there is a number stamped on it. The front larger opening where the front bearing comes in is also align-bored at the same time.

On early blocks the rear bearing cap is separate, making it more possible to swap covers and get away with it, but you still can have issues on the front opening.

I would never try to swap covers on late blocks with the integral rear bearing cap, like you have.

marko · 08-22-2015, 01:18 PM

So what would you do then....

Bradical · 01:24 PM

No no, the front covers where the seals are wont get mixed up because of the PS bracket. I am talking about the balance shaft covers themselves. Those CANNOT be swapped and if they were removed and not marked and put back incorrectly it would cause all of the issues you are describing because of the alignment boring as described.

marko · 08-22-2015, 01:27 PM

Oh, yes I see. No, those are the original covers. Those have never been removed.

marko · 08-22-2015, 01:33 PM

Well, I should say they have never been removed while I was the owner. I bought the car 20 years ago with 29k miles on it.

Bradical · 02:49 PM

There is no reason why they wouldnt align right on the front of the block like that unless they were flipped. Its worth trying to swap them.

kdjones2000 · kdjones2000's Garage

The important bit on the parts in the picture you have with arrows is that the INNER faces of the block and balance cover are aligned. It looks like they are.

The faces of the block and cover should also be aligned, and if you haven't done anything to it then I am sure that they are.

Sounds to me like you have some interference elsewhere that is preventing your lower balance shaft front bearing/PS pump mount from seating properly.

Was there a spacer installed behind that mount when you took things apart? If it were stock there shouldn't be.

I would also loosen up the "L" shaped support and allow it to move forward/backward before tightening the mount down - it has enough adjustment for that.

marko · 08-22-2015, 03:42 PM

Everything is stock, there wasn't a spacer back there. I'll take everything apart tomorrow and try that with the original bearing cap, thanks.

Bradical · 08-22-2015, 05:15 PM

Kd is right about the L bracket... If its not loose when you torque the balance cover down it will sit uneven and bind. The face of the balance shaft cover should be flush

marko · 08-23-2015, 03:53 PM

Ok fellas, yet another joyous weekend under the car.
Took everything back apart, started from scratch with the original bearing cap. Loosened the L bracket bolts, put the bearing cap on and the rest of it and no help, gear is very tight, can barely move it with one hand.
If I tighten the two lower bolts on the cap and not touch the one upper bolt, the shaft will spin freely. The upper bolt corresponds to the engine mating surface that is lower then the other half. Again I put a copper washer in between the bearing surface and engine surface at that bolt hole and no help, still tight. I thought maybe it is too thick as it worked for the other bearing cap so I pounded it a bit to make it thinner. That worked. Shaft spins very freely at this point with all the cap bolts tightened. Now the shaft is tight again after tightening the gear bolt. As before, I put various thickness washers at the end of the shaft, tighten the gear down and now the shaft spins freely with no play in the gear. Put it all back together, took it for a spin and all is good, no vibrations at all.
I don't know how the mating surfaces became uneven like that, unless it came from the factory like that or the original owner had a serious problem down there with less then 29k miles on the car. In any case, the engine isn't being dragged down so much anymore, maybe I'll get better gas mileage.

marko · 08-23-2015, 04:00 PM

Better pic of the mating surface ridge, other side is about the same.

Bradical · 08-24-2015, 04:26 AM

Im telling you Marko, the only way its going to sit like that is if the two balance shaft covers were mixed up during an overhaul or the balance shaft cover is not original to the motor. They shouldnt sit like that

marko · 08-24-2015, 10:22 AM

Well, like I say Bradical, it must have been done before I owned the car 20 years ago with less then 29k miles on it.

Bradical · 01:26 PM

Its possible! How did you get to this point?

Re-reading the first post, its possible your slight vibration is unrelated, say if your motor mounts are worn.

kdjones2000 · kdjones2000's Garage

A way to tell definitively is to look at the block number stamped onto the balance shaft cover, and there should be an identical number stamped onto your block. It's a 3 digit number.

If those numbers are different, then the cover has been replaced. If not, something else is going on. Since that cover is pinned into position on the block, I don't see a way for it to just "become" misaligned.