harmonic balancer

[tealindy]

I have an 85 and an 86 Tercel 4x4 wagon. I am always looking for the best deal on parts when I need them and they seem to be getting harder to find as many of you well know. The Harmonic Balancer broke on one of the cars (it ran great just no power to get up a hill )and the only one I could find anywhere was from a salvage yard for $180+.
I finally found a place that would rebuild them, like new, and I highly recommend this place to anyone. It was less than $135 (shipping included), fast turn around time, and the car is running great. (now I need a clutch, oh well, its still a great little car)
Dale Manufacturing in Salem, OR 503-364-8685 Harmonic balancer rebuild

[TURTCEL]

Hey tealindy, how did your harmonic balancer break? Was is just a freak deal or did it occur while it was being removed or installed? I am curious because I have not heard any other members mention that these balancers tend to have any problems with them.

Any chance you have any pics of the before and after repair of the balancer that you could post?

Peace

[Petros]

the harmonic balancer is pretty durable, but the rubber does separate occasionally. There have been a few list members that have had to replace theirs. I think if they get oil soaked from a leak or something, the rubber will break down. I think I have several spares, I have also sent them to list members that needed them. I have saved all of the ones I have, but I have not had them go bad. Tealindy, you should have check here first! but they are used ones of course, no warranty.

Good to know of a place that rebuilds them. Thanks for posting the info.

[tealindy]

This car would crank right up, idle like a top and generally drive fine on the flat, BUT we noticed the car would act as if it had no power when trying to go up the smallest hill, we were told several things like no compression, bad cylinders,etc. We kept searching for other answers.
We did a complete tuneup and a valve cover gasket replacement (as it did have a lot of oil all over the engine). This did not help the lack of power problem.
We were then told to check the harmonic balancer and found that the rubber had broken down allowing the pullies to slip apart.
Sorry, I dont have pictures before and after. We were able to purchase the "key" from a Toyota dealer, (the ones from the parts stores dont fit right even if they tell you they do) to put it all back together with a new timing belt, and that fixed the problem. I hope this can help someone else.

[dlb]

i've heard the name lots but actually had no idea what a harmonic balancer was or did, so i just looked it up.

http://en.wikipedia.org/wiki/Harmonic_balancer

can it be seen with all the belts on? is it just part of the crank pulley? what is the "key" that is needed to remove/replace it?

[larry mcgrath]

The corect name for the key is (Woodruf Key) looks kinda like a nickle cut in half it si comonly used to index -or allign parts on shafts, key stock is some times used also it's generaly square. Larry

[tealindy]

Yes, a woodruf key, I could not think of the name of it.
thank you

[Petros]

when you look at the front pulley you are looking at the harmoic balancer. Ours are not very large, they can be for large engines. It is like a little flywheel that is connected to the hub or shaft through a "fluid" coupling, in most cases that means a bonded rubber layer between the weight on the outter rim and the hub of the pulley. In the case of our cars it also includes a pulley to drive the accessories, but this is not always the case.

The function of it is very critical, the larger the engine the more so. What happens when each piston drives the crank around there is an impulse of power the winds up the crank against the inertia of that darn heavy flywheel. As the energy pulse goes out the flywheel and through the clutch to drive the car, the crank will unwind like a spring, sending the pulse back up the crank. Think of the crank like a torsional spring, it will wind up, and than unwinds as each piston puts another power stroke into it. These energy pulses that are now traveling up and down the crank will overlap at various harmonic rpms, and can become so large they can damage the crankshaft. The harmonic balancer will take those energy pulses and dampen them through that bonded rubber layer, it decouples the energy pulses from the crankshaft, stopping them from reflecting back up the crankshaft. all rotating machinery suffers this problem and must have some way of stopping the harmonics from building up at certain rpms. there were many spectacular failures in the early days of the industrial revolution until they studied the phenomenon of harmonics in rotating shafts. Harmonic balancers are so common now we hardly even notice them.

It was part of my engineering education, with very complicated mathematics involved. I have studied it with interest when I was considering building a homebuilt experimental aircraft with a pusher prop. Almost all of the home built aircraft with drive shafts have harmonic failures of either the crank or the driveshaft, so I wanted to know how to fix the problem in the one I may eventually build. Although the math is complex, solving the problem is not so hard. Just have various places in the drive train with rubber couplings (which can also be rubber belts), friction couplings can also work, to stop the energy pulses from winding up any torsional shaft if the system. With an engine you either have to have a massively heavy crankshaft (very stiff and strong so the harmonic rpm is above the operating rpm), or put on the harmonic balancer at the front of the crank. all manufacturers now use from harmonic blancers.

NEVER drive your car without a functional harmonic balancer! I am surprised you can actually feel the difference, I guess it takes a noticeable amount of power out of the crank to overcome the harmonic vibrations at certain RPMs.

[dlb]

that was an excellent explanation. thanks, pete.

[emilyrobin]

Better late than never, I'm jumping into this conversation! I'm so glad you guys are here.

There's a crazy rattle coming from underneath the engine of my '86 SR5, and lo - I've just heard from my mechanic that the rubber is coming apart on my harmonic balancer. She's grumbling that they are very hard to find, and warned that if I were to find one in a parts yard I might have to just buy the whole engine to get one.

I don't have any pictures, but that wikipedia page is helpful.

Petros, any chance you still have a spare harmonic balancer lying around? I might be able to put it to good use!

I'm about to post a query in the Used Parts section, too... Thanks for all the great information (again) and the dude in Salem looks SO LEGIT.

[Petros]

I might have one kicking around in a box somewhere, I am not even sure where to look. there are other members that have them too. when I junk a car or engine I always save the front harmonic blancer because sooner or later you will need to replace it. I have sold a few already, so not sure if I have any left.

You might consider getting yours rebuilt in the place listed at the beginning of this thread, not too far from you as I recall.