Can cam gears be noisy?

Mart

Mart

Well-known member
Has anyone experienced noisy cam gears? Steel crank gear/Aluminium cam gear, 59A style, thrusting towards the block.

Fresh build.

I have a noise like a whirring noise. It isn't the generator or water pumps as it is the same with the belt off. Has anyone experienced noisy cam gears?

I can't think of anything that would make a whirring noise. Probing around the motor with a listening stick has so far failed to pinpoint the source.

Any ideas?

Mart.
 
All I can tell you is that I installed aluminum cam gears in my last two builds. I can't hear them (much to my chagrin).
 
Could the throw-out bearing be skimming a clutch finger?
Anything suspicious at the back of the cam, like oil pump or drive gear?
 
Mart, when I built the 260" Merc engine for my '41 I used 59A style gears, new steel on crank and new aluminum on the cam. It did same as you are hearing...especially when the engine was cold. Lessened as it warmed up, but was there for almost 6000 miles before it became completely quiet. Thrust was correct, gear mesh correct, everything in order. It had to be the gears bedding together as the cam gear matched the crank gear as it slowly bedded in.



Terry
 
My 8BA has what I think is cam gear noise. It started making noise with about 40,000 miles on the engine. it makes noise between 1700-2500 RPM under light load. noise goes away when letting off the throttle.
 
Mart, I had that from the helmet distributor some years ago on my '36, from the vacuum brake, when the worn leather tip got dislodged. Took out the vacuum brake piston and it disappeared. I'm not sure if a crab distributor uses the same system.


Adam
 
I had the same noise that Cadillac512 described and it went away after break-in. I also returned the oil filter to the top of the timing cover by tapping it 1/8th NPT.
 
Thanks for the input, fellas.
Based on Cadillac512's reply and my own gut instinct I changed the cam gear today. It quitened right down.
So thanks very much. I can confirm that cam gears can generate a whine.
I pulled two motors and I can imagine two scenarios.
1, I fitted the gear from the other motor and if I refit it to it's original motor it might be quiet.
2, I did fit the gear from this motor but it must have been noisy before.

So I don't know which is correct but I am happy that the motor runs ok now.

Quite the learning experience.

Thanks again all.

Mart.
 
I haven't heard mention of anyone checking cam gear lash.
Over and under size cam drive gears are available for adjustment.
A block that has been align bored and had a standard gear installed will almost certainly have gear noise.
 
Pete said:
I haven't heard mention of anyone checking cam gear lash.
Over and under size cam drive gears are available for adjustment.
A block that has been align bored and had a standard gear installed will almost certainly have gear noise.
Click to expand...


Hi, Pete
In my case the backlash was .004" with the new gears. Within .001" all the way 'round so I ran it but the noise was there and took that 6000 miles to go away. The odd thing to me was the loudest time was with a cold engine-as it warmed to operating temp the noise lowered to about 50% of when it was cold. One would think the aluminum gear would grow when hot, decrease clearance and get louder, especially as oil thinned. The noise was an unmistakable gear whine. After 9 months and 6K miles it was gone and now at 12K miles it's still nice and quiet.


Well done, Mart...glad she's sorted!
 
Last edited:
Exactly what I found today on startup of a rebuilt 8ba. So nice to be able to go back on the search button and find what others have experienced. After about 45 minutes of run time it lessened considerably. But I guess I should be prepared for noiser cold starts for a while. Used crank gear and a new aluminum cam gear of unknown origin. Stethescope brought me directly to the middle of the timing cover. Thanks Mart!
 
A good ol' Henry Ford fiber cam gear is 70+ years old and a new one might or might not be made to the same tolerances. But just think what could be done today with modern materials. Carbon fiber comes to mind, or some type of nylon like delrin? But alas, our hobby appears to be in decline and I doubt anyone will step up to the task commercially. And don't get me started on a 100,000 mile timing belt set....
 
Last edited:
You must log in or register to reply here.
Back
Top