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Harmonic Damper Noise?

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M

MarkA

Jedi Trainee
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Hey All,

I have a new noise comming from the front of the engine. I hear it loudest at the timming cover and with slow engine speeds, less than 500 PM. It start to be heard at ~1000 RPM and gets louder as the engine slows down. I am thinking (hoping) that it is the harmonic damper. It is a heavy metal thunking, has sounds similar to the pulley and timming cover combined when tapped with a small hammer. You can feel the noise all of the way back to the stick shift, but is definitely loudest at the front of the engine.

I just finished replacing the timing cover seal and gaskets. The engine had been running for a hour when I started hearing this noise. The damper/pulley are original and the rubber material is a little old and cracked.

What do you think?

Thanks,
Mark

67 BJ8
 
Re: Harmonic Dampner Noise?

Danger Will Robinson!!!

If that dampener delaminates, it has been known to take the snout of the crankshaft with it (Layne Perkins BJ8, circa 1987).

I wouldn't mess around with it, just pony up and buy the modern replacement (pictures later, dinner just hit the table...).

Edit: pictures added...

dampener.JPG


dampener_socket.JPG
 
Re: Harmonic Dampner Noise?

Hi Randy,

I don't mind riding the pony, just didn't think about replacing it when I was ordering parts. I am going to pull the timing cover off again tomorrow or the next day and take a look inside for anything else going wrong.

I have never had a damper go bad on me before, so I don't know what the symptoms are. Do they normally make some sort of noise or do they just let go. If I don't see any thing wrong inside of the timing cover, I just don't want to assume it is the dampner (even though I am going to change it now). What is the part number on the ProRace Damper? I did not see an application listing for a Healey.

Thanks,
Mark
 
Re: Harmonic Dampner Noise?

I don't know why, but it is listed on the Moss site as an internal engine part. Go figure, anyway, the part # is 031-206. Here is the link. Moss
 
Re: Harmonic Dampner Noise?

Hi Greg,

I saw that damper on the Moss site. Do you know who makes it?

Mark
 
Re: Harmonic Dampner Noise?

Hi Mark,
It's Pro-race . Australian originally, but they have a US address now also. Nice unit, but you have to boil it in water for something like 15 minutes to have any hope of getting it on. John Loftus had his original damper rebuilt, not sure who did it though. Probably a lot cheaper.
 
Re: Harmonic Dampner Noise?

For a slightly different approach, I used the ATI "Super Damper". Instead of the rubber being bonded, it uses Elastomer O-rings which can be replaced if needed. The number & hardness of the rings are selected to match the engine vibration characteristics. The hub & outer ring are one piece with the inner weight ring being rubber mounted. No danger of the outer ring slipping & changing timing marks or breaking the bond & coming loose. As a bonus, the outer ring has 360 degree engraved timing marks.
https://www.atiperformanceproducts.com/products/dampers/101/index.htm

Denis Welch obtains the outer damper & rings from ATI & makes inner hubs to fit the Healey Fours & Sixes.
https://www.bighealey.co.uk/search.php?keyword=damper&Search=Search&cat=1
See the attached pic.

I find that I can turn the long stroke Four, which is originally redlined at 4,800 rpm, easily to over 6,000 rpm with this damper & a good crankshaft. A great investment for engine life/longevity, though not cheap.
D
 

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Re: Harmonic Dampner Noise?

Yes, I had my Harmonic Balancer rebuilt. The rubber was cracked on mine after 45 years but had not delaminated. It usually costs around $100 but there was a special going on when I ordered mine and got it for $54 including tax and shipping (from Damper Dudes).

My motor is not high performance and keeping things original has been the mantra on my rebuild. If you have a high rpm motor like Dave, Greg and Randy go for the upgrade. I agree you should check behind the timing cover since the noise might be with the tensioner or something else that is loose. Here's some link of folks who rebuild the balancers.

https://www.damperdudes.net/

https://members.aol.com/damperdoc/

https://www.dalemfg.com/daley_001.htm
 
Re: Harmonic Dampner Noise?

I had the same noise with a new damper (Australian). It turned out that the Woodruf key way was imperial on the crank (naturally), but metric on the new damper. The noise was the slap at low revs. I got a special key machined to fit.
 
Re: Harmonic Dampner Noise?

Well,

After pulling off the timing cover last night and taking a look, there was a small string of metal trapped between the camshaft sprocket and the locating plate behind it. It looks like it wore down the locating plate brass enough to change the where the sprocket rode and allow chain to slap the damper mounting bracket at low RPMs. The wear area on the damper mounting bracket grew during the 1 hour run of the engine.

The camshaft sprocket has an indentation in it where the metal string/shaving was embedded as it rubbed against the locating plate. The chaing looks OK and the sprocket could be cleaned up, but I think it looks like it's time for a new chain and sprocket set.

After looking at the assembly a little closer, I now realize that the locating plate should be tightened down after placing the sprocket on the camshaft for alignment of the plate. Those two holes in the sprocket line up quite nicely with the locating plate bolt holes! The metal string/shaving came from the camshaft being mounted against a non-centered locating plate.

I continue to live and learn...

Mark
 
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