Hi guys, sorry to bump this one but uploaded a new video that shows the noise much better than the previous one - to recap, this noise happens whenever the cars been off for more than a few minutes - it makes this noise which, with a few revs, seems to be a ticking tappet/lifter type noise, but i've not heard a lifter noise like this. After a few blocks driving its all but gone; if you concentrate you can hear its there but alot quieter. Power is unaffected, doesn't run hot, doesn't use oil. I am at a total loss on this - HELP!!

http://www.youtube.com/watch?v=YSVTczdhu7w

Could be any number of things...maybe your fuel pump pivot is f**k?

sounds like its at cam speed, do you have a mech fuel pump installed?
otherwise pull a lead off each cylinder when its idling and see if it changes

yep, I agree with it being at cam speed - I've already tried pulling plug leads, no difference. Interesting that 2 of you say fuel pump - yes, it has a mech pump - but its on lpg - fuel lines aren't even connected...which doesn't necessarily mean it can't be the pump ... another thing worth adding, though, when i had the rocker cover off, I felt the top of each rocker - they all felt smooth in operation - but the front one on passenger side bank had a slight roughness which corresponded with the noise - the other rocker on the same cylinder had a similar feel but not as much which had me scratching my head - maybe if the fuel pump is causing the prob I'm feeling that thru the cam and rocker??

one way to find out, take the pump off, and either put a block off plate on, or cut the lever off the pump
you can run it for a few secs without the pump fitted to check

my thoughts exactly, just run out of time last nite. will do this evening...but it makes sense - the noise is at cam speed, and the thing that has got me is that its a rubbing sound more than anything, and lifters and rockers don't really move that way - but a fuel pump arm does...I'll check it out tonite.

ok.....no, its not the effing fuel pump.....AAAARGH!

what rocker covers does it have? I've seen rockers touch the inside of some covers.
Get a long screw driver and use it like a stethoscope and have listen all around the motor.

it has tallish Moroso covers - they've been on it for 2 years and this is a very recent thing...thanks for the suggestion though... Oh, and when I had the cover off the other day I cleaned it very thoroughly inside and out (after getting rid of old gasket residue ) - no marks or anything...

OK, now going to other ideas.. thinking of changing filter and putting in some different oil..maybe Shell Helix for older engines or Nulon - I know everyone will now suggest their fave oil and I'm not sure its going to make a hellova lot of difference anyway.

I am seriously thinking of chucking a different engine in, thats how nuts this is driving me...

Valve guide? I had a Clevo with one dead guide & it sounded like a collapsed lifter.

sounds like lobe gone of the cam or lifters stuffed
what grade oil u running?

have you over revved as it may be a bent push rod ! had similer prob with 1 of my old clevo's a few years back . only suggesting that you pop the rockers off and check the push rods to if there true !

Um, OK, all is now good....God, how do I admit to this??....I feel soooo stupid - I'll blame my age...

Yesterday I was pretty well resigned to the motor being stuffed so I thought ah, what the hell, drive it until the motor dies, then get another motor. So, as an insurance policy, I thought I'd get a Nulon `worn engine' type additive and chuck it in there. So, car's idling, going `donk donk donk' and (maybe cos the noisy lifter is directly under the cap) as soon as I started pouring in the goop, I mean, I've poured in the first inch out of the bottle, and the noise just stopped. Immediately. So, went for a drive, no lifter noise, no nothing. So today I figured I'll change the oil to be on the safe side, put a sumpful of Nulon high kilometer 20W-50 in it, but when I've gone to change the filter I always, out of habit, write the oil change date on the new filter - the OLD filter had a date of november 2009.....sooooo, the basic problem all along was the oil's worn out, I'm an idiot, and the moral of the story is....don't trust your feeble old memory as to how long ago you did your oil change

Oh, and it drives really nicely, really quietly now.....

Time to pull it apart then.

should service it regularly on the same date each time like 1st of july and 1st of january. so this wont happen again.