The V8 Owners Forum -

I have a rover v8 fitted in a ford f100 that is a recent purchase which has an intermittent tappet noise. I checked the angle that it sits in the chassis which is 3 degrease downward tilt at the gearbox tail shaft
On the over run when braking it develops a noisy tappet ( very loud ) that slowly gets quieter if left to tick over or accelerate away. Not measured the oil pressure but the oil light doesn't flicker at idle and goes out straight away after start-up.
I can't understand why this would happen and wonder if what the problem could be.
Any ideas?

Leaking exhaust manifold
Sounds just like a noisy tappet

Just a couple of other off the wall ideas.

Has it got an automatic gearbox?
If it has then it could be a cracked flexplate.

If it's a high mileage unit it could be cam walk which is causing a cam lobe to act on the dished part of a badly worn follower thus giving temporarily more clearance.
(Large crank end float will allow the timing chain and cam to walk)

Also, oil pressure drops on overrun/ breaking with an auto gearbox.

It does have an auto box so I can see I'm going to be busy checking that lot.
Thank you for the suggestions, I'll report back.

Well as promised, a reply. I found the solution to be adding engine oil over the correct level as indicated on the dipstick. Problem sorted, though I'm not sure why.

I had that with an early V6 Essex engine, found rockers were dry and squeaking all the time, mismatch of sump and dipstick, just remarked them for the correct amount in the sump

truckdoctor wrote:Well as promised, a reply. I found the solution to be adding engine oil over the correct level as indicated on the dipstick. Problem sorted, though I'm not sure why.

The oil pick up in the sump has a gasket where it bolts to the block. If this gasket is leaking, air will be sucked in and you will get a loss of pressure. If you flood the sump with more oil the leaking gasket may suck oil instead of air. Just a theory!!!