V12 noise, please help!

[Marcusj1000]

Hello all,

I have a series 3 '74 e-type that was taken off the road about 4 years ago due to a timing chain failure and subsiquent doom for the top end. The repair work was carried out buy a private garage with a very good reputation however due to finances the owner took the car back with a few remainding jobs to do before it could be run. The owner then left the car in his garage for a few years until I took ownership of it.

I re-wired the engine electrics, reshimmed the valve gaps (still a bit tight though), rebuilt the water pump, rebuilt the carbs,replaced the radiator and various other minor jobs and she ran farily well with a bit of tweaking.

The problem is a metalic rattling noise that seems to be in time with the revolutions of the engine, I used a stethescope to pinpoint the area of the noise and it seemed to be at the top end on the left bank about two thirds back. I did some research and understand that these engines are suceptable to dropping a valve seat if overheated and with the state of the original rad I guessed this could be the case so started to strip the left bank down from the top until I found evidence of the problem. I now have the head removed and stripped down but the valve seats all look very well set and there is no sign of damage around them. During the initial rebuild the inlet valves have been replaced but the exhaust valves look to be the originals even though there are marks on the pistons from all valves hitting all pistons.

I have inspected the exhaust valves and to the eye they al look straight but I think I will replace with new anyway to eliminate them as a problem.

Is there anyhting else I can check while I have it in bits? I am worried that I will re-build it with new valves but I'm not convinced that I have fixed the problem!

The heads look good, the cam chain and ancilliary parts are new and I have no reason to think that the work done before my ownership is suspect.

Any advice is gratefully recieved.

Marcus.

[vipergts]

Well mine had a rattle from the front of the engine which turned out to be the pulley support hitting the chain

[Woolfi]

Maybe this noise is comming from the valve tappets because of to much wear of the "tappet-piston" and the "tappet-cylinder".
Regards Wolfgang Gatza

[Marcusj1000]

Hi,

Thanks for the responses. I am fairly certain the noise was coming from the top of the engine around the valve area. There is a suspect looking cam folloer that has a rough top and looks worn. I think I will replace this and the old (potentially bent) valves and re-build checking everything as I go.

The valve clearances were very tight but with the smallest "A" shims. I wonder if this could be a clue to the problem though they were all about the same and the noise didn't sound like it was coming from every valve. I'll put it back together and measure it up, is it possible to get undersized shims if I need them?

I'll re-assemble it all with the new bits and let you know if it has fixed itself while it has been dismantled!

Cheers, Marcus.