Harmonic Balancer....?

I just recently rebuilt my engine and im not sure what the problem is, but whenever my sc is ideling, there is a vibration. Could this be the harmonic balancer? My car is a 94 super coupe. I am new to this site and to my car for that matter, is this a common problem among other super coupe owners? Anyone with any input, please reply....!

Have you noticed if your dampener is wobbling? If your dampener is on its way out it can graze (or destroy) the crank sensor and the engine won't run so the dampener might not be the problem.

Is your car an automatic or 5spd?

welcome to the SCCoA,

'bird

Something I noticed

I have yet to drive my car since getting it going again, but I was lookin at my balancer and had noticed that at low rpms - under 900, the balancer looked almost like it had a wobble, but under revs, it spins perfectly. I was gunna replace mine, but I was curious to know how a stock balancer w/less than 30k on it could have gone bad when sitting.

if you end up needing one, i have a harmonic balancer and pulley for sale off of a 94 SC for $75 + shipping if you end up needing one.

jmpsu@yahoo.com with "harmonic balancer" as the subject

Jeff

Is the harmonic balancer going bad a common problem with Super Coupes? I also have an 87 Turbo Coupe and have never had any problems with it.

yes, they are known to break. do a search for harmonic balancer and you'll see how common it is.

Jeff

yep

you dont have to do a search, I just had that replaced, You can replace it before it gets your crank position sensor one it takes it out, you are stranded the car will try to turn over but it cant.

If you see it wobbling at a low RPM get a new balancer, i'm sure guys on there have them or you can buy one @Fordpartscheap.com. It's actually a or any of the sponsored places on sccoa.com

Just because the engine vibrates at idle doesn't mean there is anything wrong with the dampner. It could be bad motor mounts, vacuum leak, dirty injectors, worn plugs and on and on.

David

Yep. Ignore the balancer issue for now as there are more basic things to check. Though if during the rebuild you removed the balancer, you're more likely to have problems with it down the road. Due to it's design, the balancer tends to fail soon if it has been removed and reinstalled.

Start with determining if the vibration is due to the quality of the idle, or not. If you feel the idle is smooth and just question the vibration, start looking for places where the engine might simply be rubbing up against something.

The driver's side motor mount has a slot and tang that if the mount is twisted during installation can rub up against each other.

Also if the mounts have failed and you didn't replace them, they can be resting on steel, causing the vibration.

Like Dave said. Lots of reasons.

Well, the only stock thing left is the bottom end. Everything has been replaced during the buildup over the last year. New motor mounts, headwork, cam, bolts, all kindsa stuff. I think the fact that I have an aftermarket cam has something to do with this slight wobble at lower idle. Almost sounds like a v8, sure smells like a beefed up 8, then again, the fuel pressure is still up high.

Anyways, the other thing I had noticed was that on the stock crank pulley, there appeared to be a rubber blotch, almost similair to maybe a wheel weight. I was wondering if there is anything such as the crank pulley being balanced in conjunction with the balancer. I know, this probaly sounds strange, heck, even to me it sounds strange. If I took a pic, I could better explain it. I was just wondering if in some strange way, this blotch of rubber could be affecting the balancer, maybe infact throwing it off balance at lower rpm? I dunno, gunna replace with a bhj soon anyway. I prefer safer to sorry.

The SC block is Zero Balanced at the factory. The Balancer is static balanced seperately and then the assembly is balanced together.

There has been a big discussion on this though so check this thread. George and a few others noodled on this quite a bit.


http://www.sccoa.com/forums/showthread.php?s=&threadid=18407&highlight=zero+balanced

i read the posted link

alright i'm still having one hole in my understanding and it may stem from the fact that

my car is broke 300 miles away and i haven't seen it for 3 months, also i have a BHJ waiting to be installed.

What pin, are you talking about?? it sounds like it should be on the actual hub and not the pulley, but i don't recall seeing any pin on the hub itself, not that i've really looked at them closely.

George, i know you have a picture (hopefully).

My plan when i go to install over christmas break, was to measure the crank snout and balancer, then proceed to a shop to possibly hone the BHJ balanced to my pulley.

Is there anything wrong with this procedure???

Thanks
james

If you need to install the balancer in short order then get a set of underdrive pulleys. Those are zero balanced and you will only need to hone the balancer and bolt everything back together.

Aaron

The pins are like small metal dowels that go in the thick hub part of the stock damper.



Kind of hard to see in the pic from the back of the early damper. You could see them better from the front. The stated purpose was to final balance the engine assembly in conjuction with rivets in a flexplate or more pins in a flywheel. If you were replacing a stock damper these pins (if any are there) should be moved to their corresponding locations on the new damper.

The BHJ part has no provisions for these pins. If you reuse your stock pulley, the pulley and the BHJ damper should be balanced as a unit. That rubber blotch is actually a steel balance weight spot welded to the stock pulley when the pulley and damper were balanced as a unit from Ford. You can only buy a damper/pulley combo from Ford.

Like the other poster said, if you use the alumium underdrive pulleys, they are essentially zero balanced like the BHJ part, so you could just bolt them together and run with it.

Hmmm...

So more than likely, my balancer is alright for the time being and the cam is causing the slight wobble at low idle? With the christmas season approaching, money needs to be directed in other areas. I just don't want to dump money I don't yet need to, but I also don't want to destroy my bottom end either. I'm not driving the car yet, so it isn't that big of a thing anyway.