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Clatter! Clatter!

Posted: Wed Jul 31, 2019 8:15 am
by Jem
I have had this annoying loud clatter on a light throttle - open or close the throttle and it shuts up. The large cam gear is a new aluminium item. Checking backlash, I can get a .007" feeler between the teeth. Is this my noise? Would a nylon gear quieten things down? Does anyone sell an oversize gear?

Someone is going to tell me to take the block back to the guy who poured and bored the mains. Tricky, it was FoMoCo themselves - the block is a NOS item originally sold for replacement purposes. It is my experience with some factory replacement parts that stuff rejected on the assembly line was considered acceptable for the parts market.

If this isn't likely to be the noise, then the other candidate is the problem I have had with tight piston pins. The engine started getting stiff to crank when hot and I have just had to hone and lap #4 & #1 pins as they were stiff. If it shuts up when I put them back, all well & good, otherwise I have to live with the ally gear for a while - at least I know it's not dangerous!

Re: Clatter! Clatter!

Posted: Wed Jul 31, 2019 8:24 am
by Les Schubert
I’ve found a noise like you describe is usually centre main bearing

Re: Clatter! Clatter!

Posted: Wed Jul 31, 2019 8:44 am
by Jem
I'll check that as I have it all apart.

Re: Clatter! Clatter!

Posted: Wed Jul 31, 2019 10:29 am
by Steve Jelf
I would rather have a little noise than a timing gear failure. If that turns out to be the source of the clatter I wouldn't resort to a nylon gear, especially if there's a generator. Yes, I know lots of people have used them with no trouble, but I haven't. Having experienced failure of both fiber and nylon gears, I will go with bronze or aluminum every time.

Re: Clatter! Clatter!

Posted: Wed Jul 31, 2019 10:51 am
by Norman Kling
A loose rod bearing can cause a knock on light throttle and no noise on heavy of no throttle. First thing I would check if it were my car would be the rod bearings.

If it is the camshaft gear, you can get one oversize. which should fix that problem.
Norm

Re: Clatter! Clatter!

Posted: Thu Aug 01, 2019 5:57 am
by Jem
Generator!? I have a perfectly good Armstrong starter, don't need no lektricitie.

Bearings are all within tolerance. The clatter is a very light noise, like rattling a stone in a tin-can. I can replicate it quite well by grasping the front pulley and waggling it, so I'm sure it's the gear. I don't think anyone in the UK stocks anything other than stock ally or used steel gears, so I'll live with it.

Re: Clatter! Clatter!

Posted: Thu Aug 01, 2019 10:01 am
by Philip
when i first got my car it had a noise like that i found a 3\8 nut in the number 1 cylinder. philip