Intermittent rattle under cam cover

[JMW2310]

I have a 1967 Series1 4.2l. On a recent run from Sussex to the West Country I got a load rattle which sounded like it was coming from under one of the cam covers. It could only be heard at low revs. When I reved the engine it appeared to go away. It appears to have cleared up now but I am keen to establish the cause in case it is serious. Any suggestions welcome.

[Tom W]

What frequency was the noise? Does it change with RPM? The guides the tappets run it can come loose, then they get clouted by the cam. Several people sell hold down kits.

[abowie]

Firstly I would tighten the timing chain and see if the rattle recurs.

[pmansson]

Agreed. I had a rattle between 1600-2200. Tightening the upper chain sorted that problem.

[PeterCrespin]

I have a 1967 Series1 4.2l. On a recent run from Sussex to the West Country I got a load rattle which sounded like it was coming from under one of the cam covers.

Which cover?

[JMW2310]

What frequency was the noise? Does it change with RPM? The guides the tappets run it can come loose, then they get clouted by the cam. Several people sell hold down kits.

Hi Tom, sorry for the slow response! The noise is a consistent rattle. It is more noticeable when idling that when at higher revs. It really only seams to happen when I go on a long journey.

[JMW2310]

Firstly I would tighten the timing chain and see if the rattle recurs.

Thanks Andrew, I’ll try this first.

[Tom W]

If it’s a constant rattling that doesn’t change frequency as the revs change, then it’s unlikely to be something rotating in the engine. I’d look for something loose in the engine bay that only resonates at certain speeds.