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Old 02-24-2017, 10:40 PM   #1
SAJ
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Default Noisy metal timing gear cured by torsional damper

My roadster had a noisy fibre timing gear at idle. See earlier thread https://www.fordbarn.com/forum/showthread.php?t=157518[URL="https://www.fordbarn.com/forum/showthread.php?t=157518"]].
I replaced it with an aluminium gear with no detectable backlash (too tight but all I had at the time). I then got a noise rather like piston slap, but my pistons have .0035 clearance and I only recently rechecked them. Then I realised that the slapping rattles were only as I passed through 1000 rpm 1500 rpm and 2100 rpm (approx, since my rev counter may not be spot on).
This coincides with the "roar" at these revs that many other Model A engines have. So I surmised that the crankshaft harmonic vibration that caused the roar might be shaking the aluminium timing gear and producing the horrible rattle, that makes the normally subdued harmonic roar sound like piston slap from helll
We had a rubber damped front pulley that another member produces, so fitted this.
Suffice to say the rattle is gone, the old torsional wind up noise is undetectable and the motor runs more smoothly up through the gears.
My theory may be wrong but the end result is a great relief. The torsional damper really works well on this engine. I think I will fit one to my wife's Tudor which has a quiet timing gear but a vibration at 2100 rpm too.
I still have a timing gear rhythmic clack at idle, which is not too bad. And changing the fan belt is impossible without removing the front apron and then the spring U bolts and crank handle bush. This is because the rubber mounted damper weight on the front of the pulley is about 3/8 inch thicker than a standard pulley.
SAJ in NZ

Last edited by SAJ; 02-25-2017 at 12:22 AM.
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Old 02-25-2017, 10:18 AM   #2
Special Coupe Frank
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Default Re: Noisy metal timing gear cured by torsional damper

What is the condition of cam plunger and spring in the timing cover ?

If it is weak or broken, that can cause a "clack" or knock at idle...

Interesting to hear about the torsional damper.
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Old 02-25-2017, 01:02 PM   #3
SAJ
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Default Re: Noisy metal timing gear cured by torsional damper

Frank. The timing cover spring was replaced with an adjustable threaded stop early on in the saga. No effect on the gear clacking noise. A polythene bolt threaded into the timing pin hole against the fibre gear immediately stopped the noise as an experiment to prove it was timing gear noise.
The post is about the beneficial result of a simple torsional damper on crankshaft harmonics really. As T Bird points out in a PM, putting in an aluminium gear with no backlash in not a good idea. But I ordered new crank and cam gears and when they arrived, that is what I got for backlash when fitted. They were free and not binding and I covered them with moly paste to ease the run in.
I had to get the car going for an event, so fitted them and I guess they wore in badly to give the noises and I got what I deserved. I will take the front cover off one day and see what backlash there now is.
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Old 03-19-2017, 02:59 PM   #4
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Default Re: Noisy metal timing gear cured by torsional damper

Hi SAJ
As a result of PMing you and learning the source of your New Zealand made torsional damper I was able to purchase one from Errol McAlpine.
Fortunately the motor in my speedster is set back 4" in the chassis which simplifies replacing the pulley, although I did have to lift the motor to clear the front cross member.
My motor had similar characteristics to yours, quiet at idle but with a very loud clatter from the timing gears under load and vibration periods through the rev range.
The torsional damper was a revelation and the car is now a pleasure to drive.
We have just completed a 300 mile trip cruising around the 60mph range and thundering up the steeper hills (Kaimais and Bombays) in either the 41% overdrive or occasionally having to drop down into top gear for tight bends or steeper inclines.
The change is a simply fantastic!
Keith
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Old 03-19-2017, 05:11 PM   #5
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Default Re: Noisy metal timing gear cured by torsional damper

That's great Keith. I just put another of Murray Horne's Dampers in Diane's Tudor which had a resonance at 55 mph. The harmonic has vanished too and the engine sounds more pleasant throughout the Rev range.
Both cars have counterbalance weights welded on the crankshaft and were dynamically balanced.
Since I don't hear a lot from others on the Barn about these vibrations (perceived more by sound than feel in my experience) I wonder if the welded-on weights shift the rev range lower into the range we drive at.
My Schwalms crank has harmonics at 1000, 1500 and 2100 rpm on my gauge, so as I traverse upwards through the gears the clatter from the timing gear was almost constant. And I had to avoid cruising at 2100 rpm which is about 57 mph.
Now It will sit there quite silently with no other changes but the rubber damper pulley.
SAJ in Nz

Last edited by SAJ; 03-19-2017 at 05:15 PM. Reason: Spell chequer errurs
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Old 03-19-2017, 07:56 PM   #6
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Default Re: Noisy metal timing gear cured by torsional damper

Could you please post the full details for this source of the harmonic dampers?? Thanks in advance.
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Old 03-20-2017, 03:22 AM   #7
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Default Re: Noisy metal timing gear cured by torsional damper

Hi Waxhead. These dampers are made by Murray Horn in Levin N.Z. His Company is Engine Restorations Ltd. His email is horn@xtra.co.nz
Murray says this is the best way to contact him.
The dampers are a straight fit to replace the standard Model A pulley. An added benefit is a shallow reverse scroll in the rope seal area to help contain oil.
SAJ in NZ

Last edited by SAJ; 03-20-2017 at 06:59 PM. Reason: removed extra dot at the end of email address
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Old 03-20-2017, 06:28 AM   #8
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Default Re: Noisy metal timing gear cured by torsional damper

SAJ,
Are you able to take a photo of this damper installed in your car and post it here in this thread?
Thanks for reporting your results.
Good Day!

Last edited by Dave in MN; 03-20-2017 at 06:41 PM.
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Old 03-20-2017, 05:26 PM   #9
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Default Re: Noisy metal timing gear cured by torsional damper

Thanks SAJ
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Old 03-20-2017, 08:26 PM   #10
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Default Re: Noisy metal timing gear cured by torsional damper

Quote:
Originally Posted by Dave in MN View Post
SAJ,
Are you able to take a photo of this damper installed in your car and post it here in this thread?
Thanks for reporting your results.
Good Day!
Hi Dave. I have attached photos. The roadster has rubber front engine mounts and rear float a motors. The engine sits about 10mm further forward than it should (or the chassis is 10 mm shorter at the front!) and I have not found out why. There are signs of accident damage and when I got the car the right front wishbone leg was shorter than the left one, cocking the engine to one side, so that whoever installed the rubber front mounts offset them by almost 3/4 inch to compensate for some reason. I replaced the front wishbone with an even-legged one and, now I recall, I also realigned the front chassis by about 3/4 inch too. The wishbone ball misses its socket by about 3/8 inch at the rear and forces up into it. I mention all this because you can see the distance between damper and spring U bolts is less than on the Tudor, which has about 1/2 inch. But I doubt whether one could change the fan belt on the Tudor without removing the U bolts first.
I carry synthetic linked fan belts in both cars anyway to make an emergency change easy.
A long reply to a simple question I know.
One day I will fix the roadster clearances but not until I retire probably!
Regards
SAJ in NZ
Attached Images
File Type: jpg harmonic balancer in Tudor.jpg (36.2 KB, 346 views)
File Type: jpg harmonic balancer in roadster2 (Custom).jpg (65.0 KB, 331 views)
File Type: jpg harmonic balancer in Roadster (Custom).jpg (67.5 KB, 321 views)
File Type: jpg linked belt2.jpg (68.8 KB, 333 views)
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Old 03-21-2017, 11:01 AM   #11
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Default Re: Noisy metal timing gear cured by torsional damper

Those RPM's are the natural vibration points for these engines, some are more noticeable than others. They are usually more noticeable when driving, and mostly in high gear. It figures that a damper would quiet them.
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Old 03-21-2017, 07:33 PM   #12
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Default Re: Noisy metal timing gear cured by torsional damper

Quote:
Originally Posted by waxhead View Post
Could you please post the full details for this source of the harmonic dampers?? Thanks in advance.
Seems that LOT of guys here want to know what you have asked.
I've contacted Murray Horn. He will join us (new member) shortly and give you/us whatever information is wanted.
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Old 03-21-2017, 07:56 PM   #13
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Default Re: Noisy metal timing gear cured by torsional damper

That's great! I look forward to hearing about them!
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Old 03-21-2017, 08:18 PM   #14
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Default Re: Noisy metal timing gear cured by torsional damper

I'm not surprised that there is a lot of interest here. Vibration in the car really detracts from the driving experience.
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Old 03-21-2017, 10:08 PM   #15
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Default Re: Noisy metal timing gear cured by torsional damper

hi guys, I am the culprit who makes these Harmonic Dampers. I have been making them for the engines I build which have weights on the cranks and a lightened flywheel and when fitted removes the harmonic shudder that the As suffer. I recently sold a few to customers to try on there engines to see if they would improve a basic engine and buy the feedback they may be of some benefit. however there are a lot of variables that can affect an engine and I doubt a damper will cure all vibrations as it is there to absorb harmonic vibrations and a badly out of balance engine will vibrate at all revs.
I have fitted about 30 of these to my engines and had an early failure with the rubber bonding but made a modification and have had no other fail.
I guess what im saying is I can supply them to you but cant guarantee the result you will get. perhaps when a few more are fitted and reports come in we will get a better idea of success/failure!
I can supply them for $300 US including postage to most countries.
my email is horn@xtra.co.nz
regards Murray Horn.
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Old 03-22-2017, 12:39 AM   #16
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Default Re: Noisy metal timing gear cured by torsional damper

Thanks for the info Murray
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Old 03-22-2017, 01:49 AM   #17
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Default Re: Noisy metal timing gear cured by torsional damper

Quote:
Originally Posted by erl View Post
hi guys, I am the culprit who makes these Harmonic Dampers. I have been making them for the engines I build which have weights on the cranks and a lightened flywheel and when fitted removes the harmonic shudder that the As suffer. I recently sold a few to customers to try on there engines to see if they would improve a basic engine and buy the feedback they may be of some benefit. however there are a lot of variables that can affect an engine and I doubt a damper will cure all vibrations as it is there to absorb harmonic vibrations and a badly out of balance engine will vibrate at all revs.
I have fitted about 30 of these to my engines and had an early failure with the rubber bonding but made a modification and have had no other fail.
I guess what im saying is I can supply them to you but cant guarantee the result you will get. perhaps when a few more are fitted and reports come in we will get a better idea of success/failure!
I can supply them for $300 US including postage to most countries.
my email is horn@xtra.co.nz
regards Murray Horn.
Hey Murray,
WELCOME aboard !
One question....is the 'rubber' material that you are now using in latest models...vulcanized in between center and outer ring or pressed together ?

Last edited by hardtimes; 03-22-2017 at 01:50 AM. Reason: ........
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Old 03-22-2017, 02:22 AM   #18
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Default Re: Noisy metal timing gear cured by torsional damper

valcanized under pressure
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Old 03-22-2017, 11:34 AM   #19
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Default Re: Noisy metal timing gear cured by torsional damper

Quote:
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valcanized under pressure
Very good, thanks for your efforts to help the hobby !
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Old 08-10-2017, 09:47 PM   #20
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Default Re: Noisy metal timing gear cured by torsional damper

Well, let's open another can of worms.

What effect, if any, would having one of Murray's dampeners on an engine already fitted with one of the dampers that Ron Kelley puts on the front face of the flywheel?
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