Knocking Noise

T

taterjacksam

Junior Member
Started my 30 Fordor and there is a knocking sound from the what sounds like the rear of the engine or bell housing. After 30 seconds noise stopped. Shut engine down and restarted and no noise. Shut engine down and waited for 15 minutes and restarted and the knock was there again, 30 seconds later no knock. I guess I need to find a Model A mechanic.
 
Removing the belt is a good idea. I suggest trying to exactly locate the noise. There are quite a few things that can make noise at the rear of the engine/bellhousing area.
 
Just thinking, but it could be a bad valve or worn bearings. Try putting it in gear and letting out the clutch a little to put a load on the crankshaft. If the noise changes it could be a bearing. If not then it might be a valve. If a noise disappears after 30 seconds it indicates that oil drained away from a worn area when the engine stopped and then worked back into the worn area after 30 seconds of engine running.
 
I just restarted and got outside and the noise is at the rear of the engine best I can tell. The noise went away shortly after starting it took 20 - 30 seconds and it was gone.
 
I had a knock once and it was the ring gear that had slipped on the flywheel a bit, and was hitting the casing. Hammered it back into place gently and it's stayed put ever since...no more knock.
 
It could be piston slap. My Town Sedan would knock (Cluck) on startup and the noise would just melt away after 30 seconds after the oil got up into the cylinder. I was careful to keep the rpms low on startup. I drove the car 5000 miles and never had to fix it! Ed
 
I did try a couple of things that were asked. I started the engine after a while and the knock noise started, pressed the clutch and no difference in sound, let out on clutch in gear and no sound difference. Knock noise stopped after about 20 - 30 seconds as usual. Hopefully it will be what you had Ed. I will get in touch with local Model A Club and see where to take the care to be looked at. Thank you for the responses.
 
Sounds like a center main to me. Try shorting out the center plugs while it is knocking. If it reduces it or it goes away you found it. It wont be that loose, just needs adjusting.
 
George I did what you suggested and the knock almost completely disappeared. I have sent an email to the local club but haven't heard from anyone yet. The noise still goes away on its own after 30 seconds or so.
 
Glade you found it. It goes away because the oil gets in there and cushions it. It will keep getting worse the more you drive it. You should be able to remove some shims and get the right clearance.
 
Ed in Maine said:
It could be piston slap. My Town Sedan would knock (Cluck) on startup and the noise would just melt away after 30 seconds after the oil got up into the cylinder. I was careful to keep the rpms low on startup. I drove the car 5000 miles and never had to fix it! Ed
Click to expand...
Ditto!
 
Piston slap or center main are the main things I can think of. My 29 engine had the center main babbit completely gone, and it made a very loud rattle at any speed over idle.

My 28 engine has piston slap, and it's a lighter ticking noise that never goes away due to the amount of slop.
 
Follow-up

After weeks of searching for a mechanic that could and would work on my engine its in the shop. The mechanic called yesterday and asked me to stop by. When he dropped the pan there were aluminum pieces in the pan. They were not shavings but small pieces. There were no shims on any of the main caps. Since it was Friday he didn't want to take the caps off until Monday morning the see were the pieces came from. Any ideas I can fret over for the weekend??:confused:
 
You must log in or register to reply here.
Back
Top