Very early 2000 engine knock and rattle

partviking

partviking

Member
Well the engine is finally back in my '63 car all ready (or not as the case may be) for Coughton Court but I have an annoying knock/rattle so i would appreciate your opinions on the my engine and the possible cause.

It sounds like top end to me. I've had the cam cover off and checked the clearances, all spot on except No 4 exhaust which has only 7 thou clearance.

Both chains are new as are the tensioners though it does sound to me like some timing chain rattle when I first open it up (ignore the resonance its just a loose number plate) and the knock/rattle that is my concern can be clearly heard at high revs though it is quiet at tickover.

Chain guides are all tight and I can find no obvious problems under the cam cover. Could it be bottom end?

Subject to your comments my plan is to replace the cam bearings and reshim with head in situ...waste of time or worth a punt?

Your comments and opinions much appreciated ...as this car is chassis no 400-00316 I'm desperate to get it to Coughton but running our of time.

For the record the engine has not been rebuilt just cleaned and painted and chains/tensioners replaced so the head hasn't been off.

https://www.youtube.com/watch?v=fvzKdVc3b_k

Regards

Alan
 
Hi Alan

On the video its hard to make out; it does sound more like top end. I don't think the valve clearance you mentioned would be of any consequence; the car idles too well. You could always connect an oil pressure gauge to rule out the bottom end. Should idle at about 50psi.

You need to try and isolate the noise; Take it off idle and use your ear to a screwdriver placed at various points to locate the source of the noise.

Since its quiet on tickover and becomes noisy as revs rise I'd look at:-

1) Oil filter in oil line to top cam chain tensioner. Has the cam chain tensioned been released after cam chain swop ?
2) Cracked carb to manifold adapter.
3) Carb heatshield.
4) Noises from the distributor.
5) Cracked exhaust manifold.

Pat
 
The initial noise sounds like a chain, progressing into something more like a tappet noise. I'd say top end rather than bottom, and if you want to prove that point, pull the leads of one at a time while it's making the noise, and if it disappears, it will be piston downwards on that particular cylinder, if not it's top end. As for the chain noise it could be a tensioner not expanded, or problems with the oil supply to it.
 
Many thanks for your replies.

Pat the top chain was nice and tight so the tensioner is clearly locked in correctly but, although I think it unlikely I assume if its not getting a good oil feed it may well slacken in operation when running?
I will check this and also check the other possibilities mentioned.

I'd say top end rather than bottom, and if you want to prove that point, pull the leads of one at a time while it's making the noise, and if it disappears, it will be piston downwards on that particular cylinder, if not it's top end
Click to expand...

Thanks for the tip Harvey, I assume this should rule out big ends?

My only other thought is cam bearing shells but find it hard to believe a worn shell could make such a clatter.

I will let you know how I get on.

Regards

Alan
 
Pulling the plug lead should eliminate big end, small end, and piston as the cause.

I can't ever remember seeing worn cam bearings, I have seen cracked caps though, so that's worth checking.
 
Hmm. I think I'd check -

oil feed to chain tensioner - look at the small nylon filter gauze tucked inside the oil feed banjo where it joins the head.

insulator block between carb and manifold - has it shed the steel collar that protrudes into the manifold?

little ends :(

Chris
 
Further to previous posting I have now followed the advice given. I'm confident it isn't bottom end after trying Harvey's plug lead trick. I've checked upstairs and again followed the advice given but to no avail. The rattle still exists though I think it is getting quieter....or I'm getting used to it!
However, I've now noticed No 3 exhaust cam has a nasty graze on the heel of it (see pic) and that portion is very rough to the touch. Not sure what could of caused it..sticky tappet/valve maybe? Preumably this could account for the 'rattle'. I'm unable to see if there is any equivalent damage to the top of the tappet but guessing its quite likely. I did a compression test and all four pots are within a whisker of 120 psi.
Any ideas and comments appreciated. No room on the server for the pic hence link below.

Alan

image.jpg
[/url][/img]
 
Alan

Your car is early enough to have still got the original chain tensioner set up. This was notorious for "tinkling" noises. I'm pretty sure you'd distinguish this sort of noise readily from something that could be a cam issue, little ends etc. What do you think? Could it be timing chain? It doesn't have to be slack if you have the original tensioners.

After that, then Michael Allen is probably the expert in little end problems having just changed the con rods in his to overcome the issue.

Chris
 
Chris,
The annoying thing is both chains and tensioners are new but happy to accept the tinkling its the knock/rattle that annoys me.

Harvey,
I've tried to make the picture bigger, link below.

Forgot to mention the noise is only when the engines under load, lift off at 4000 rpm and it disappears instantly.

Will try and upload another video as much of the background noise has been eliminated.

Regards

Alan

 
partviking said:
Forgot to mention the noise is only when the engines under load, lift off at 4000 rpm and it disappears instantly.
Click to expand...

This does indeed point to an exhaust manifold leak.
 
You must log in or register to reply here.
Back
Top