Harmonic Balancer - PeachParts Mercedes-Benz Forum

retmil46 · #1 01-05-2013, 01:06 AM

Been spending much of the past two weeks going over my mother's 92 Mustang 5.0 convertible, for delivery to my friends that live south of Austin.

This afternoon, I was running it at idle to warm it up, so I could run the EEC-IV system thru the different tests to resolve why the CEL keeps flashing on and off while accelerating or going uphill after it's warmed up.

I'd just recently installed a new Hayden fan clutch and fan blade, plus changed out the serpentine belt. I was looking down at these, to make sure everything was running correctly, when something else caught my eye...

I could visibly see the harmonic balancer (or vibration damper) behind the crank pulley wobbling, both radially and axially, with the engine just running at idle speed.

From what I've heard over the years, harmonic balancers where the rubber insert is still in good shape are NOT supposed to behave in this manner - and behavior of this type is supposedly a dead giveaway that it's well on it's way to failure.

Car is 20 years old with 90K miles on it - my mother has owned it for the past 15 years and 40K miles of that - and this is the original factory balancer on it, unless it was changed somewhere in the first 50K miles.

Original balancer with 90K miles and 20 year old rubber insert.... doesn't give me a warm fuzzy... especially when wobbling like a cheap toy gyroscope...

Local mechanic I called said "well, how much wobble is it, 1/16", 1/8", 1/4"? If it isn't that much, I wouldn't worry about it". But he did offer to look at it first hand come Monday.

My initial instinct is to call BS - no rotating part attached to the external output of an engine crankshaft should be making THAT kind of motion unless something is getting ready to head south.

New replacement balancer is only about $60. My gut feel is to simply cut thru the crap and just get the balancer replaced straight out - not that difficult a job on this vehicle - especially since the vehicle is going to a new owner who is also a close friend.

Never dealt with this type of problem on a vehicle before. Is my assessment correct, that this is something that needs to be addressed ASAP?

Aquaticedge · #2 01-05-2013, 02:56 AM

Cheap insurance to stave off a possible catastrophic failure. I'd replace it. with it wobbling on all Axi's it's on it's way out.

Can't Know · #3 01-05-2013, 03:29 AM

I'm with aquatic edge...change it. Particularly since it's going to someone you know.

t walgamuth · #4 01-05-2013, 06:39 AM

I have been in this position or similar ones before. I would call the buyer and tell them of the situation. It is something you did not know about before selling them the car. I would offer to knock something off the price and let them fix it or give them the choice of sharing the bill with you. They will have a choice and if they choose the first, they can have their own mechanic do the work, if they choose the second, you were up front with them and they benefit from a brand new hb.

Of course they could choose neither and then you are simply back where you are now and you could choose to go ahead and fix it.

Either way I believe they will appreciate your honesty and having a choice.

jplinville · #5 01-05-2013, 09:24 AM

The cost to fix it on your own is minimal...what's the cost of your time when dealing with things for your mom so she doesn't have to?

Replace it and have peace of mind that it's done. It's not a difficult job, and doesn't require many, if any, special tools to do.

Brian Carlton · #6 01-05-2013, 09:32 AM

Quote:

Originally Posted by retmil46

Local mechanic I called said "well, how much wobble is it, 1/16", 1/8", 1/4"? If it isn't that much, I wouldn't worry about it". But he did offer to look at it first hand come Monday.

Sorry, you don't go and waste time and money to change it based upon some internet opinions from people that have never seen the specific part.

What you and I both do not know is the acceptable runout from the factory on the component. Since it's assembled with a rubber piece in the middle, the runout, by definition, isn't going to be anywhere close to a machined steel piece.

My personal opinion is that their manufacturing tolerance would allow a runout of 1/16" on that piece and they wouldn't be concerned about it. They might even accept 1/8" but that would be really poor workmanship at assembly. But, again, I don't know the specific piece.

The recommendation is to have the local mechanic, or anyone else familiar with the component (Ford dealer?) take a look at the piece and render an opinion. Alternately, you could find a similar vehicle at the dealer and ask to see if said vehicle also exhibits the same condition.

Why waste time and money if the replacement does the same thing?

Mike D · #7 01-05-2013, 09:36 AM

Kinda hard to take advice from a guy who's making a career outta changing a couple of spark plugs, ehhh?

Just kidding Brian, BTDT.

Brian Carlton · #8 01-05-2013, 09:43 AM

Quote:

Originally Posted by Mike D

Kinda hard to take advice from a guy who's making a career outta changing a couple of spark plugs, ehhh?

Just kidding Brian, BTDT.

Oh........you got me there...........the word "career" is definitely applicable.

I am so fortunate that the van is not the DD. I'd be out $1500. by now.

retmil46 · #9 01-06-2013, 10:59 AM

OK, crawled up under the front end of the car and took a close look at the balancer.

In short - it's JUNK - no two ways about it, it needs to be replaced.

Rubber on one side is mashed out over 1/8". Last short test run, the thing is being thrown out so far to one side from the center of rotation, that if it isn't replaced soon I have a real concern it's going to take out the timing adjustment pointer.

That's in addition to the swashplate-type motion it's making.

Google search on the Mustang forums, for cars of this era, seems to be a common complaint - not so much mileage but age - the rubber just gives out. And of course, the way it's sleeved and keyed onto the crank, you have to replace the front main oil seal as well.

Doesn't say much for Ford's engine design, when the stock balancer needs a 50 ounce counterweight to make the engine run correctly. Entire balancer weighs over 9 lbs just by it's lonesome.

This, and all the other crap I'm running into going over this beast, is vividly reminding me why I haven't personally owned a Ford since 1987.

kmaysob · #10 01-06-2013, 04:16 PM

Quote:

Originally Posted by retmil46

OK, crawled up under the front end of the car and took a close look at the balancer.

In short - it's JUNK - no two ways about it, it needs to be replaced.

Rubber on one side is mashed out over 1/8". Last short test run, the thing is being thrown out so far to one side from the center of rotation, that if it isn't replaced soon I have a real concern it's going to take out the timing adjustment pointer.

That's in addition to the swashplate-type motion it's making.

Google search on the Mustang forums, for cars of this era, seems to be a common complaint - not so much mileage but age - the rubber just gives out. And of course, the way it's sleeved and keyed onto the crank, you have to replace the front main oil seal as well.

Doesn't say much for Ford's engine design, when the stock balancer needs a 50 ounce counterweight to make the engine run correctly. Entire balancer weighs over 9 lbs just by it's lonesome.

This, and all the other crap I'm running into going over this beast, is vividly reminding me why I haven't personally owned a Ford since 1987.

i would replace the front seal weather or not it needed it if i had the balancer off. its actually a good design, prevents you from having to replace the crank if the seal wears a grove into it.

MS Fowler · #11 01-06-2013, 05:19 PM

Quote:

Originally Posted by retmil46

OK, crawled up under the front end of the car and took a close look at the balancer.

In short - it's JUNK - no two ways about it, it needs to be replaced.

Rubber on one side is mashed out over 1/8". Last short test run, the thing is being thrown out so far to one side from the center of rotation, that if it isn't replaced soon I have a real concern it's going to take out the timing adjustment pointer.

That's in addition to the swashplate-type motion it's making.

Google search on the Mustang forums, for cars of this era, seems to be a common complaint - not so much mileage but age - the rubber just gives out. And of course, the way it's sleeved and keyed onto the crank, you have to replace the front main oil seal as well.

Doesn't say much for Ford's engine design, when the stock balancer needs a 50 ounce counterweight to make the engine run correctly. Entire balancer weighs over 9 lbs just by it's lonesome.

This, and all the other crap I'm running into going over this beast, is vividly reminding me why I haven't personally owned a Ford since 1987.

Ford was able to keep the overall engine size by installing the harmonic balancer and splitting the balance duties between the crank counterweights, the balancer, and the flywheel. Putting all the balance on the counterweights would have required a larger crank, a larger oil pan and a wider engine.

rscurtis · #12 01-06-2013, 05:42 PM

Correct. Many V8 engines are externally balanced. Old IH V8's were timed on #8 cylinder so the timing mark on the weighted portion of the balancer would line up correctly.

retmil46 · #13 01-06-2013, 08:31 PM

I'm going to let the shop deal with the balancer and front seal - once I've got it back together enough to drive over there.

Right now, I'm having loads of fun troubleshooting, cutting out, and replacing all that cheap a$$ brittle heat baked and cracked plastic tubing, that Ford laughingly called a vacuum system. The tubing in both 87 MB's put together didn't give me anywhere near as much trouble as this Walmart-quality crap that Ford put in this single vehicle.

The only good portions of the original tubing left that will hold vacuum are where it disappears into the passenger side fender well and goes to the vacuum reservoir. Thank gawd for at least that - I was having nightmares of having to try and remove the wheel well liner to get at it.

But all of it inside the engine bay - heat baked and as brittle as dry spaghetti.

Not to mention that the 3 solenoids for the EGR and two air pump valves were toast as well.

And don't get me started on that POS EGR valve and it's associated position sensor.

Or 75 amp alternator with a SINGLE 14 GAUGE WIRE for an output cable - on a car with power windows, power door locks, power convertible roof, and A/C.

MS Fowler · #14 01-07-2013, 07:41 AM

I'd prefer to replace the balancer and let someone else deal with the emissions crap. Different strokes for different folks.

jplinville · #15 01-07-2013, 08:57 AM

This car has the same engine that my Mk VII had, and the same as which is in my wife's 89 F-250. Everything on this engine is easy to swap out or clean. The 302 H.O is one of the easiest engines to work on...if you have the right tools. I swapped out the harmonic balancer on my MK VII in under 3 hours, and the EGR valve in about an hour, and that included replacing a decent amount of the vacuum line...and that engine had over 240k on it before I sold it to my daughter! She's still driving it, and it still runs like a top!

It's all in how you approach the job at hand...I loved working on the Lincoln.

The truck is a bit of a chore, because it's so high off the ground. I had to use a step ladder to reach the two back plugs when I did the last tune-up.