Technical Harmonic damper ring slippage.

Firstly, they are not balancers, even if they have a balance weight function.

I have had more people than I can count tell me that the outer ring on certain harmonic dampers is prone to slipping.

Now, I have also worked on more engines than I can count, and, while I have seen a few rings spun clean off, I have yet to see one that simply moved, and everything else was just fine.

Given how many people have repeated the tale, how about some hard evidence?

Post some pictures. Make sure that the are not just ones with the wrong timing tab.

 

When I worked at a Buick dealership in the early 80s the Buick 350 was notorious for slipping or spitting off the rings. If driven for long enough it would wipe out the bearings in the bottom end. Rod and main. Sorry no pictures. I did not keep a camera and film at work.

 

In 1973, I was the second owner of a 67 Impala with a 283. It could not be timed with a light. It was obvious the damper had moved on the rubber. The only way I could time it was by ear.

 

I have not had a harmonic balancer slip, but have had a fibre timing gear do so. I fought a persistent distributor issue for months in a '62 GM Holden ute. Car would chew the distributor rotors out. Bought multiple NOS rotors, even replaced the distributor with a rebuilt one. Car came home multiple times on a tilt-tray truck, often several hundred kilometres from home.

It turned out that the steel hub had begun to spin on the fibre part of the timing gear. Must have got worse over time, but ended up spinning 120 degrees before I hunted it down (the last failure was substantive, and car would not run). Suspect it slipped a few degrees, then a few more each incident then finally jumped maybe 100 degrees in the last one.

Replaced the timing gear, and all good. The old gear was still (at least finger) tight between the hub and fibre part of the gear when removed (i.e. not spinning madly).

Photos, including degree measurements of the spun vs new gears here: http://www.fbekholden.com/forum/viewtopic.php?t=22653&start=165

Cheers,
Harv

 

bought a truck with a slipped one on a Ford 240

 

A ring that has slipped and is otherwise fine? Perhaps a one time event such as sudden engine stoppage or a bath in one of the engine fluids. Hasn't happened to me that I'm aware of.

 

I would have to dig through the s**** bin at work but just in the last couple months .

One on a gm 4.3 V6 it spun and stuck again, only saw it as we where doing an engine swap .

the other was on a Chevy 3.0 4 banger . It had separated , same thing doing a engine swap and noticed it .


To be honest have not seen it before these two instances in a loooooooooong time , but two in very short order . So yeah it does happen .

 

had one get loose and slip on a 250 chevy. And just because I knew you'd be asking this question, I took a picture of the bad one and the new one, so you can see the timing mark in the wrong place (both timing marks are at the bottom, the crank key is in a different position). Rather clever of me to anticipate this, 15 years ago, eh?

 

And, you know, if you hadn't saved those images, you would have been savaged! In a kind sort of way...

 

Many years ago,,,I had one on a 440,,,,,it didn’t really slip,,,,but it was literally coming apart front to back .
The ring was slipping off,,,,,boy,,,,I’m glad I caught it in time,,,LoL .

Tommy

 

My YBlock moved. I was able to get another one. Sent it to the Damper Dr in central California., had it rebuilt and sent back in 2 days. The original is one is I n a box to be done if needed.

 

I had one my grandsons Mazda the car was getting hot. but the damper had belt groves in it and drove the water pump. It was slipping co bad that the pump was not turning. I have seen alot of dampers that looked like Jims.

 

Consider the rubber is at least 40 years old in anything we're working on and the crank dampener goes thru a heat cycle every time the engine is run.

It ****s paying for a new one, or one of the damper restoration companies, but I trust the rubber ring less and less as time goes by.

If the rubber is cracked at all, I find a different one - but, I'm usually working on SBC and replacements are easy to find.

 

I had a real nice '68 Corvette with the 300 HP engine and automatic. I could only get it to run decently if I ran it at 40 degrees advanced. It had obviously slipped. I sent it to a guy in Oregon who specializes in rebuilding these and it came back perfect. Set the timing to the factory marks and it ran great.

 

No pics here either. But a long long time ago (mid-60s), I put a 383RB into a 58 Dodge. Really nice ride BTW. After using it for a few weeks I decided it needed a tune-up. Checked timing and the mark was now where to be found. Well, I finally found it, about 90 deg away. Used spares were hard to find for that engine, and I couldn't afford a new one. So, drilled and tapped a couple of set screw holes, made a new tdc mark and ran it. Yeah, I know the set screws killed the whole dampener role but it worked, sorta.

 

Yeah, had a 327 reaction ring rotate a few degrees on the hub, many, many years back, 1971 or 72.

Mike

 

Had one with cracks all around the edges and a half inch outside the groove, timing mark right on and no wobble.

 

Another 440 mopar here, this time it was mine and the last time I used a stock damper on a performance engine, haven’t had a problem since…

 

So far, this data set has one point (and I figured you would be the one to show evidence).

 

My stepdaughter had a 90-ish Buick with a traverse engine. She told me it was “clunking”

Sure enough, would “clunk” on accel the “clunk” on decel. I could rotate the outer ring about 30 degrees by hand, back and forth. Only time I ever came across a bad one.

 

My intuition speaking here, but wouldn't every "ring fell off the dampener" story begin as a "ring started slipping around the dampener" story if it had been caught in time?

For a high revving engine, there wouldn't be a lot of time between those two events. But grandma's old Impala might go a few years before anyone put a timing light on it to notice. Just a thought.

 

Buddy blew up a circle track motor and rotated the ring on a GM Performance damper. Which IIRC was a rebranded ATI Super Damper.

Way back in the day we'd at least verify the timing mark when putting together claimer circle track engines. So many of them were off or the rubber was in such bad shape it became standard practice to replace them with at least a new Chinese damper.

 

I oft hear the words "are prone to" or "are likely too" (both mean the same thing BTW).

Likely means probably. Probably means that the statistical odds of something happening are more in-favor, than against, which in this case would mean that at-least one more than one-half of all dampers have rings that spin.

It seems odd to me that after after millions of vehicles have been produced with a similar elastomer isolated ring, that there are only a few anecdotes, and a scant number of pictures.

It's almost like it is quite rare. I suspect what is happening here is the old "telephone game".

Kinda like how every SBC came from a Corvette, how to ID a 4-bolt main block from the outside, how to determine spline count on a 9-inch from the registers, and how 010 blocks have high Nickel content (they don't).

 

If you leave it leaking oil long enough, and it has belt grooves on the ring to give it some extra torque, and the car is in the road for several decades, then it's likely to slip. But that doesn't apply to most of them, does it?

Most of the anecdotes are from before we all had a free photo studio/processing lab in our pockets...and also before anyone had highly technical world wide discussions about parts failures. So I would expect there to be very little evidence, even if it's a common occurrence.

you're just lucky I was able to find the photo, so you'd have a point of evidence, at all!

 

My parents had a 76 Century with a 350 that slipped the ring a bit. The old man took it in for a tuneup and the "mechanic" that did the work said it's ready to pick up. The timing was so far off it sounded like a diesel going up the street. He asked the guy about it and he was told it's (the timing) right where the book says it should be.
16 year old me took it upon myself to just time it by ear to at least get it drivable again.

 

I never had one slip on me or come apart yet, but I did replace a couple that had cracked rubber coming out under the ring while I had an engine apart for a rebuild. Maybe I just caught them in time.If I remember correctly those were on 2 327s , 3 or 4 350 Chevys and 2 Ford 300-6s..
BTW, I recently rebuilt a 261 and found that a late 292 -6 damper will fit a 235/261 -6 perfectly and profide a second grove in case someone needs power steering or AC. And I also found out that all chevy 6s have the damper key at the 12 o´clock position with #1 at TDC and I tried this with a 327 damper, same seems to be true for Chevy V8s. Keyway at 12 o´clock means #1 is at TDC.


Yes, there are a couple mm´s of space between the damper and the timing cover.

 

Dorman #594031 is the one I used on my 261

 

Kinda common on those older high mileage 3.8s. I used to hear the clunk and check that first by just grabbing the belt on either side and rotating side to side watching the crank bolt. Even made a removal tool (since I didn't want to buy one).

Back to the OP, I've seen a few over the years and never took pics (at work in the 90s). Old crusty, oil soaked 350's when you try to check the timing for a smog check . I remember them looking like old factory original cars (working near a retirement community) and replacements were plentiful.

 

This was a not-unheard of problem for a couple of years on the Buick V6s. It was occasionally even hard to get a new damper from GM without having to jump through a few hoops.