On my 2001 VDP with 92K miles, 3rd owner, have a metallic knock at start like someone taping a pipe with a hammer - goes for 3-5 seconds then calms down for a while. If I put it in reverse the metallic tap comes back. Also reappears at 2000 rpm. Just had the transmission rebuilt about 800 miles ago. Could it be bad oil pump, timing chain tensioner, something related to the transmission, or worse? We will start here …. Thanks, Vance

 

If the tensioners have not been changed they are at risk, even if they are not the source of the knock. Remove the cam covers and check the condition of the secondary tensioners, upgrade if they haven't been changed. Chain rattle could be described as a knock.

The knock could be something as simple as a loose exhaust hanger or heat shield, hard to diagnose without being next to the car.

 

+1 to RJ's response...do the simple thing and remove the cam covers and check the 2ndaries. If you have a bore scope, it'd be a good time to use it to check the primaries.

 

Thanks guys for the suggestions. This is one of those circumstances where I need to draw the line on the cost of repairing the car (its the white one in the pic). So the best I can do is diagnose as much as I can and with a little help from fellow Jaguar enthusiasts, narrow the culprit. The noise sounds like 3 hits of a wrench handle on a piece of metal - then it goes away for awhile - hence my initial thought of oil not getting up into the upper part of the engine. I will look inside over the weekend.

 

My old E-type used to rattle like hell while starting up waiting till oil pressure built up ....

T.