i have a 30 coupe and when the engine is at idle it has a clatter/knock when i pull the spark advance down it gets louder , i have shorted out the plugs one at at time and no change in noise at all? engine is responsive as it's revved up noise increases with it. any suggestions to fix or problem? what to check?
engine knock -clatter help
- Thread starter mll1446
- Start date
Jim Brierley
Well-known member
Could be any of several things. If it is quieter when hot, suspect piston slap, nothing to worry about. Could be timing gears, pull the little cover and inspect for wear & looseness. Use a stethoscope to try and narrow down the location of the noise. If it is serious, it will get worse, if not, drive and enjoy it.
Rock Hornbuckle
Well-known member
It is difficult to say, without being able to hear it. Try your local Club. You'll find someone that's heard the same noise before.
Special Coupe Frank
Well-known member
Rod bearings generally have a "lighter", "hollow" sound when they knock, main bearings usually do not knock at idle, but make a dull thud when pulling under load.
Take the side-cover off the timing case, and observe the timing gear as the engine idles (do NOT rev the engine - this will spew oil over the RF fende r! ).
If you see the timing-gear "walking" fore & aft, in rhythm with the knocking sound, the cam plunger / spring are stuck or broken, and the sound is the cam / timing gear slamming back and forth. Common problem.
SC Frank
Take the side-cover off the timing case, and observe the timing gear as the engine idles (do NOT rev the engine - this will spew oil over the RF fende r! ).
If you see the timing-gear "walking" fore & aft, in rhythm with the knocking sound, the cam plunger / spring are stuck or broken, and the sound is the cam / timing gear slamming back and forth. Common problem.
SC Frank
steve s
Well-known member
I've never done it but I've heard that a simpler test is to take out the timing pin, reverse it, and press it against the timing gear as though you were going to set the timing except with the motor idling. It is said that you can apply enough pressure to stop the wandering/slamming gear noise.
I would wait until someone else seconds this motion before trying it--worried about scratching the gear.
Steve
BILL WILLIAMSON
Well-known member
A friend had loose flywheel bolts. Take starter off & see if flywheel will rotate back & forth about 1/8" Bill W.
(If a loose center main is suspected, shorting out #2 & #3 at the same time will "kill" the noise)
(If a loose center main is suspected, shorting out #2 & #3 at the same time will "kill" the noise)
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Tom Wesenberg
Well-known member
This never made sense to me either, because the pin would drop into the cam gear dimple and simply vibrate in and out of the hole. A lot of guys claimed it worked for them, so one day I tried it on a pickup with a loose two pice timing gear. By the noise I pretty well knew the gear was the problem and when I inserted the timing pin about all I got was a vibrating pin from the timing dimple.
1931 flamingo
Well-known member
Could it possibly be a loose c/shaft pulley hitting the frame or spring mount?? Might ck before pulling any thing apart.
Paul in CT
Paul in CT
steve s
Well-known member
This never made sense to me either, because the pin would drop into the cam gear dimple and simply vibrate in and out of the hole. A lot of guys claimed it worked for them, so one day I tried it on a pickup with a loose two pice timing gear. By the noise I pretty well knew the gear was the problem and when I inserted the timing pin about all I got was a vibrating pin from the timing dimple.
Not sure, but I'm sort of remembering that you were supposed to grind the point off of the pin so it rides over the indentation.
David Martin
Member
Last week I did a study of Model T engine knocks on the MTFCA forum site. Lo and behold, I discovered 12 distinctly different causes of engine knocks. Check it out. I'm sure most of them apply to the Model A engine as well.