The Ford Barn - View Single Post - Noisy metal timing gear cured by torsional damper

Dave in MN · 08-11-2017, 03:24 PM

Carl, I think it could only help absorb a bit more of the torsional pulse change (torsional vibration) at ignition and compression. It is my opinion that Ron Kelly's flywheel mounted absorber takes a small amount of the torsional stress/pulse from the rotating assembly. The added weight of the dampener/damper also changes the rpm range the pulse or vibration is felt.

I know this due to some experimentation I did between 2012 and 2013. I was trying to tame a vibration in an engine with a very light flywheel, V-8 pressure plate and a counter weighted Burlington crankshaft. The vibration was very bad at a road speed between 52 and 55 mph in high gear. By adding the Ron Kelly like damper to the light flywheel the range of vibration changed to a road speed of 43 to 44 mph. It narrowed the range and decreased the perceived intensity to about half. I machined two more flywheels for a V-8 pressure plate varying from the least amount possible to lighten the flywheel and then prepared one that was half way between the extremes. All three flywheels were drilled to mount a customized Chev. harmonic damper on the front side of the flywheel.

Changing to the heaviest flywheel with the damper mounted, the perceived vibration was barely noticeable. The same heaviest flywheel was installed without the damper and the vibration was more noticeable and what I would say typical of a Model A. I went on to check all combinations of flywheel weight with and without the damper installed.

These tests required lots of work as the varying weight flywheels and damper were first tested on a dyno and then mounted in the same car (mine) and driven.

I believe the addition of weight to the assembly did the most to dampen the felt torsional pulse and harmonic vibration. The addition of the damper to any of the flywheels added weight so it helped reduce the pulse but when the damper was added to a very light flywheel, it dampened the felt vibrations more than the next heavier flywheel without damper. The weight of the damper was close to the weight steps of the prepared flywheels.

So my summary: The addition of a damper to the assembly does more than just the addition of weight to the assembly and the result is that the damper improves the felt vibration. So I think Ron Kelly is on to something here.
All this is just my opinion from tests I completed a few years ago.

If we want to debate something further, let's consider the concept of the "Rattler" torsional damper. There is a company in the UK that builds a light weight Model A/B compatible flywheel with "Sterling Rattlers" installed. They claim the addition of the puck weights to the flywheel helps to reduce the torsional stress on crankshafts.

Check out the Sterling Rattlers: http://vibrationfree.co.uk/our-servi...sport/rattler/

Rattler Model A/B flywheel assembly: http://vibrationfree.co.uk/sterling-...egory=16322086

Good Day!

08-11-2017, 03:24 PM	#21
Dave in MN Senior Member Join Date: May 2010 Location: Jordan, MN Posts: 1,411	Re: Noisy metal timing gear cured by torsional damper Carl, I think it could only help absorb a bit more of the torsional pulse change (torsional vibration) at ignition and compression. It is my opinion that Ron Kelly's flywheel mounted absorber takes a small amount of the torsional stress/pulse from the rotating assembly. The added weight of the dampener/damper also changes the rpm range the pulse or vibration is felt. I know this due to some experimentation I did between 2012 and 2013. I was trying to tame a vibration in an engine with a very light flywheel, V-8 pressure plate and a counter weighted Burlington crankshaft. The vibration was very bad at a road speed between 52 and 55 mph in high gear. By adding the Ron Kelly like damper to the light flywheel the range of vibration changed to a road speed of 43 to 44 mph. It narrowed the range and decreased the perceived intensity to about half. I machined two more flywheels for a V-8 pressure plate varying from the least amount possible to lighten the flywheel and then prepared one that was half way between the extremes. All three flywheels were drilled to mount a customized Chev. harmonic damper on the front side of the flywheel. Changing to the heaviest flywheel with the damper mounted, the perceived vibration was barely noticeable. The same heaviest flywheel was installed without the damper and the vibration was more noticeable and what I would say typical of a Model A. I went on to check all combinations of flywheel weight with and without the damper installed. These tests required lots of work as the varying weight flywheels and damper were first tested on a dyno and then mounted in the same car (mine) and driven. I believe the addition of weight to the assembly did the most to dampen the felt torsional pulse and harmonic vibration. The addition of the damper to any of the flywheels added weight so it helped reduce the pulse but when the damper was added to a very light flywheel, it dampened the felt vibrations more than the next heavier flywheel without damper. The weight of the damper was close to the weight steps of the prepared flywheels. So my summary: The addition of a damper to the assembly does more than just the addition of weight to the assembly and the result is that the damper improves the felt vibration. So I think Ron Kelly is on to something here. All this is just my opinion from tests I completed a few years ago. If we want to debate something further, let's consider the concept of the "Rattler" torsional damper. There is a company in the UK that builds a light weight Model A/B compatible flywheel with "Sterling Rattlers" installed. They claim the addition of the puck weights to the flywheel helps to reduce the torsional stress on crankshafts. Check out the Sterling Rattlers: http://vibrationfree.co.uk/our-servi...sport/rattler/ Rattler Model A/B flywheel assembly: http://vibrationfree.co.uk/sterling-...egory=16322086 Good Day! Last edited by Dave in MN; 08-11-2017 at 03:47 PM.