Banger tapping noise at idle...

I have an intermittant loud metallic type tapping noise from my B model banger mill, tap, tap, tap,......tap,.......tap.
The noise only appears to happen at idle and is not always there, seems to be coming from the timing gear area of the motor. I've taken the timing cover off and run the banger for a short time, the noise is definately coming from the front of the mill, although the aluminium timing gears looks okay. Anyone got any ideas of what it could be?

Gomez.

 

How's your oil pressure A BONED? Getting oil in through the Banger okay?

Hopefully nothing serious dude.

HC.

 

Piston slap is most noticeable at idle, cold. Could be a scored piston, too. Does the engine smell scorched? That is usually a score. I would pull the head and check the bores, especially the front one. No big deal to remove the head on a flathead, anyway!

 

Oil pressure's great. The banger runs hard, no effect on performance at all. I might remove the timing cover again and drop the pan to have a better look. Sounds like something is loose somewhere?

Gomez.

 

R Pope, the mill has no unusual smell to it.
Looks like it needs to come apart, damn, the good weather is almost here too.

Gomez.

 

Just a thought.....is the oil pan tray snapped in tight?

 

Maybe you worry too much.
Thats my conclusion after driving my 31 coupe for 14 years. These engines are just plain noisy. I've worried the whole time but nothing bad has happened. OK that one time on the way home from the store it got real noisy and I found out that an exhaust valve seat disappeared. Never did find it in the exhaust system.

 

I had a horrible knocking once, sounded like a really bad big end. turned out to be a blown head gasket, it's funny how sounds can be so decieving. it got worse with revs.

 

This noise is louder at idle and quieter with RPM and is a rattling, metallic noise.

Like A Boned stated, all things led us to believe it was an aluminium cam gear gone loose and the sound was coming from the front cover/crank snout area. This sound only started in the last few days and has been getting louder but it does'nt sound like a big end gone bad. More like a flywheel gone loose and rattling. Engine still runs very well though.

I know the cam gear needs 100 ft/lbs of TQ and loc***e to keep it there. Can the spring tensioned cam gear ****on on the inside of the timing cover be causing this noise if the spring tensions on it has gone bad thereby allowing it to "hit" the front of the cam gear at idle ?

Might have to clean it up some and pull the pan for a look see - maybe pull the starter and check the flywheel is'nt loose even that thats at the rear of the engine.

Rat

 

I had a set of br***/bronze timing gears do this, rattle and bang at idle. It sounded like the gear had come loose on the cam.
It turned out the cam ****on spring was too soft for the cam grind.
The helical gears try to push the cam forward.
This is why the racers replace the spring/plunger with a set bolt and locknut.

 

Cam ****on was my first thought also. Is it greased well and not frozen in its bore? I'd probably try replacing the spring first before tearing the engine apart.

 

Crank pulley coming apart? Watch for movement while its making the 'noise'.

 

Bump. Anymore ideas anyone?

HC.

 

Don't feel alone on this one Chris, the old 21 studder in the tub is banging away now, developed the noise on the way home


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I was listening to it at bens, I would also check the dist drive shafts, good luck.

 

Thommo, sorry to hear that man.
Hope it turns out to be something simple like loose bolts on your flywheel...?

sideshowrob, thanks for the tip. I'll check the dizzy drive shaft as well as the timing gears, and flywheel hopefully it's something easy to fix.

Thanks for all the lads with your useful suggestions.

Gomez.

 

A quick update: It looks like the aluminium cam gear has a little clearance (as it should) with the helical teeth of the crank gear. But the movement of the cam gear can be moved with just one finger meaning that it does not turn the camshaft as well. I would imagine to move the cam gear that is bolted tightly to the camshaft would require more effort.


I still haven't removed the cam gear yet, but am now expecting the cam to flop around a bit on the camshaft even though the cam gear nut is tight. There is however no horivontal movement of the gear (left to right). Is this a common issue? I have no real experience, but would this mean the two locating pins that locate the cam gear on the camshaft be worn? Or the cam gear locating pin holes be worn?