Harmonic balancer or bad water pump cause of engine vibration?

[64\/54Cadillacking]

My fellow Cadillackers,

I have had this problem ever since I've owned my 64 but it's getting even worse now. While the engine is running if I rev up the engine in park, the interior starts vibrating pretty badly. I've always had this slight rough idle too even with the timing being adjusted properly including the carburetor.

I feel engine vibration inside the cabin at a steady idle as well, and while driving I can't go above 45 mph without the engine really vibrating the cabin violently. Motor mounts could be an issue, but the vibration feels more mechanical and is constant.

The transmission shifts perfectly fine, but I decided to call a local transmission shop and ask if a bad flywheel could cause the vibration in park, and the technician told me that it's not likely. He told me that severe engine vibration is usually caused by a worn out harmonic balancer and or a bad bearing in the water pump while being revved up.

How does one determine if the balancer is bad on the engine? I do hear a slight bearing noise from the water pump, but I don't see any fan wobble or balancer wobble.

As a note, my engine block is from a 67, so it uses a 67 water pump, but it has a 64 valve train, and a 64 intake. But it has a 65 transmission, so it's a little Frankensteined. But it all works.

One issue that makes it worse is that I can't get the engine to idle smoothly at 400 rpm's in Drive like the shop manual states, this includes my 54 Cadillac engine, both engines run rough when the idle speed is set that low. Both engines seem happy around 550 rpm in Drive, what could cause this?

Last but not least, the harmonic balancer has slipped because the timing marks are are slightly off when I reinstalled my distributor awhile ago. Trying to find TDC was a real PITA because of that.

[signart]

There are other ways to find TDC, but as far as eliminating the water pump as culprit, just remove the belt from the pump pulley for a trial.

[wheikkila]

Yes, removing all the belts will eliminate it being anything driven by the belts. My first thought is the harmonic balancer or the flywheel.
               Thanks Wayne

[64\/54Cadillacking]

Ok thanks guys, will a bad harmonic balancer have play in it if I remove the belts and wiggle it?

[The Tassie Devil(le)]

Shouldn't move, unless it is actually falling off.

The only way they can move is with a degrading Vulcanised rubber sleeve.

Bruce.

[Big Fins]

Getting true TDC will tell you if the balancer is slipping around because the timing mark will be way off IF it's on the balancer itself, but I think it's on the pulley and that shouldn't change. The pulley is bolted to the inner hub of the balancer.

Ok thanks guys, will a bad harmonic balancer have play in it if I remove the belts and wiggle it?

It may or may not. It could just be rotationally slipping.

[signart]

After the belts are removed take a close visual to see if the rubber has deteriated to the point that you may actually see some damgaged remnants of the rubber. Do this of course wih engine off. If there is obvious deteriation, you are done wih your diagnosis, and quite possibly you will already have engine damage.
If not any visual damage with engine off, run the engine and observe to see if you can detect any abnormal movement there, at idle and on acceleration.
These tests are not conclusive unless you actually see any abnormal movement or deteriorization of the rubber.
Further test for HB failure would include finding true TDC as mentioned above.

These are just suggestions, asI have never experience a harmonic balancer failure to the point that caused the engine to vibrate so violently as you describe. I can see how a balancer in such bad condition could cause this. I have experienced slippage to the point of moving the timing marks.

The only time I have exprienced the vibration you have descibed (i.e. vibration condition that progressively gets worse to the point that shakes the interior of the car while not in motion.) This condition was caused by steel crankshaft in a sbc that was warped. Don't know if the Cadillac engine you own has cast crank or steel crank.

[fishnjim]

The rubber body mounts most probably are fossilized as well and that's what transmits the vibration to the passenger compartment.   So you're in for a bit of a "surgery" if you want that big caddy ride to re-appear.
What's the mileage on that beast?   Mechanical overhaul time?   
At a certain point, there's so much wear that you can't reasonably approach from a one by one solution.   The internet is not going to reduce this to a single issue.

[walt chomosh #23510]

One thought added to the mix is my 1955CDV had a vibration that I struggled to find. In my case it ended up being the bolt holes securing my motor mount to the block were worn! To fix, I reamed the block holes one size bigger....from 1/2 to 9/16 if I remember correctly.....no more vibration....walt...tulsa,ok

[64\/54Cadillacking]

All great information guys. Thank you for the input. I'll remove the belts and check for wear at the balancer. If I can't find anything wrong, I might just take the car in to a shop so they can diagnose the problem for me.

[V63]

My thought is it's probably the harmonic balancer. A friend rebuilt his 429 and then removed it again only to find it was the balancer the whole time 🤦🏻‍♂️

[George D. Mukalian CLC # 10047]

I had a similar issue for a long time and it ended up being the fan clutch.

George

[79 Eldorado]

As I was reading through the other replies I was wondering if it could be a bad plug wire(s) or fouled plug(s). A vehicle will run on less than all cylinders but it will vibrate. I've mentioned it on the forum before but I've diagnosed a bad wire using a timing light with a built-in tach. Instead of putting the pick-up only on the number one wire you check each wire and compare the RPM. I had a vibration case where one wire was reading about half the RPM of the other wires. If something like that is the issue the great thing is you don't need to remove anything to check it.

Scott

[64\/54Cadillacking]

I noticed last night while the engine was running, I didn't see any serious wobble from the fan or pulley.

Scott, I'll try what you suggested. I do have a timing gun with a built in tach so that will help eliminate a fouled plug or wire.

After doing that, I will remove the belts and check for play at the fan clutch, and balancer itself. There is a bad oil leak around the front crankshaft seal where the balancer mounts onto. I'm going to also jack up the car a little to check for worn rubber on the dampener. I just need a buddy to sit in the car and revv it up so I can feel where exactly the vibration is coming from. Either the flywheel or HB.

Walt, I took a look at the motor mounts and the passenger side mount bolt doesn't look fully seated, it's as if it backed out which could mean the bolt hole has stripped loose. I'll take pictures so you guys will see what I'm talking about. Hopefully I can figure this out soon because I already miss taking her out to cruise, and this vibration has to be fixed before anything. Safety first.

Also have any of you been able to get your Caddy's to idle smoothly at 400 rpm's at idle in Drive? For Cadillacs that mention it in the shop manual.

[Big Fins]

You may have your own answer with the front seal leak. Look at the balancer and the rubber insert for oil rot. You could have it right there.

I'm not that schooled on how much a partial ounce may throw off the crank balance and the balancers were drilled to the hundredth of an ounce for balancing.