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[JamesV6CDX]

My V6 is making a horrible noise, and aside of a short period where it was much better, it always has!

https://www.youtube.com/watch?v=gErkVUU93yM

The story behind it is that the car was once a 2.6. I transplanted a 3.2 block, and then fitted late 3.0 heads (which are the same as 3.2 heads) with 3.2 G and J Cams.

When you start the car from cold, it's silent. Beautifully silent, no tapping or knocking.

As it starts to warm up after a few minutes of idling, (maybe 2-3 minutes) a "tap tap tap" noise starts to creep in... and before long at all it's just like it is in this video.

If you then drive the car for a good distance, say ten miles, it goes quiet(ish) again, but is still detectible.

I don't think it's anything terminal. It's done about 700 miles like it.

New oil went in at the time of the top end rebuild. After 200 miles and this problem still being there, some wynnes lifter treatment went in. No difference.

A further 500 miles later, (today) I dropped the original (I think 5/30 fully synth) oil and let it drain. I then refilled with 10/40, and ran the engine for an hour. I then drained this new oil (which came out looking as good as it went in) and put ANOTHER load of clean 10/40 in.

During this the sump has been off and the strainer is clear.

Does anyone have any views on this noise? Keep plugging on with more short oil changes?

Sometimes I think it sounds like a lifter, and other times I do not!

The car pulls like a train and there are no nasty noises when driving and no oil pressure lights etc.

I'd be v grateful for your views, please

[JamesV6CDX]

Just because I know I will be asked:

1) Cambelt kit is brand new, 700 miles ago. (I know this doesn't always mean it's foolproof)

2) Cam bearing caps are the correct ones originally from the heads, are in the correct order and rotation, and are torqued properly

3) Water pump etc etc pulleys are tight. (noise is still present if you run it briefly with the aux belt off, so it's not aux related)

[andyc]

Would it be worth fitting an external oil pressure gauge, start the motor from cold and watch the pressure as it warms up and starts to tap, at least you can rule out oil pressure
Andy

[Steve B]

 Hi James  You said some months ago now that you had a tapping lifter on this car,And that it goes silent once warmed up.
Well i have too,And as time goes on they do get louder and get to the point where they dont go silent when the engine is fully warmed up.

But on saying that:- yours is not really a constant tap,tap,tap. Meaning on the vid it seems to miss a beat every few taps,And it does seem very loud if it is a lifter.....Is it a lifter that has failed suddenly.  Just a thought.

[05omegav6]

That sounds more sinister than sticky lifters... Piston or crank related

[JamesV6CDX]

That sounds more sinister than sticky lifters... Piston or crank related

Crossed my mind mate I must say!!!

[JamesV6CDX]

On the other hand. It's lovely and quiet after it's run for a bit. I did 100 really, really harsh miles the other day and it went like stink, which I guess means it might not be? :/

[tidla]

hydraulic tappets.
Anything else is there for good once the oil is hot and thin.

[JamesV6CDX]

It sounds like it's coming from the passenger side...

[Steve B]

Will take someone like you james not long to rule out lifters...See post #1  http://www.omegaowners.com/forum/index.php?topic=131643.0

[78bex]

From about +14 to 16 seconds I can hear a dull knocking that then gets masked by the more mettalic noise. Is the compression on each pot within limits
   

[Kevin Wood]

Does sound a duller knocking than you'd get out of a lifter but trying to diagnose engine noises from a recording is a bit futile.

I have heard quite a few V6s making similar noises when idling. I think Andy's suggestion of checking the oil pressure is a good starting point.

Does it remain at higher revs or disappear above idle?

Does it get any better or worse under load?

Performance isn't really an indicator, IMHO.  Performance won't be affected unless the piston rings or valves aren't sealing.

[Marks DTM Calib]

You did use the T-vents from the original engine?

[JamesV6CDX]

You did use the T-vents from the original engine?

No, but I compared them, and they were exactly the same

[JamesV6CDX]

In reply to your questions kevin, you don't really hear it much above idle speed, if you were to hold the revs at 2k rpm, it would not be heard.. Likewise it cannot be heard when driving