Hydraulic Valve Lifter Additives - Recommendations?

[v8s4me]

I've got a slight rattle as the revs slow to idle (3.9 V8). There's no noise when the engine revs or when it idles, just an annoying little rattle from the left bank as the revs drop. I'm wondering if it might be down to a couple of the hydraulic valve lifters getting lazy and if so would an additive help.

Any suggestions? (Apart from don't slow down )

[v8s4me]

Perhaps "on the over-run" was a poor way of describing it. The noise occurs not when the engine is under braking load but simply when the revs are dropping back to idle eg rolling up to a set of lights and lifting off, or after blipping the throttle when stationary. Also it only happens when the engine is hot.

I'd have thought, as you do, that if there was a rocker pad missing then the noise would be there all the time. The engine was rebuilt by Powers less than 10k ago and gets an oil and filter change every year so I'd like to think it wan't little ends.

I think there is a small air leak at the manifold but that is quite different (a higher note) and does sound more like a tappet.

[v8s4me]

ChimpOnGas said:

....If you haven't done so already surely the next step should be to take the car to your engine builder, go for a drive together so he can hear the noise for himself, and then see what he says?....

That's a 200 mile round trip and a tank of petrol. Food for thought though.

[v8s4me]

Looking back at my paperwork I too have the TVR885 cam. On the invoice I have new liners, rings and hydraulic lifters but no mention of little ends. I seem to recall Dom telling me he'd throw in a set of pistons which might explain why there's no entry for these items on the invoice. Anyway, it's 16,000 miles old now not 10,000. Don't the miles fly by when you're having fun?

After a run back from Spa at a sustained 3,000rpm to 3,500rpm for several hours more or less non stop the rattle was still there but no worse than before. After the car has been standing during the winter it certainly rattles a bit until the lifters pump up so that's why I was thinking this little rattle is lifter related.

I'm sure you're right about the intermittent use our engines get and leaving them standing during the winter can't help.

I'm going to try this stuff at the weekend and see what happens....

[v8s4me]

macdeb said:

.....why would you think an additive would cure a mechanical noise?

Because the diesel additive I bought from them did exactly what it claimed to do.

macdeb said:

.....Is it a rattle when slowing and or revs declining after a push of the throttle at standstill?....

Revs declining after a push of the throttle at standstill.

[v8s4me]

carsy said:

.....Does it sound like this....

No. Definitely not. I'd be really worried if it sounded like that. I'll try and do a little video and post it to YouTube if it records the sound accurately.

[v8s4me]

Classic Chim said:

...I personally wouldn't put anything other than the correct grade oil in it.

What do you put in yours? I've been using Valvoline VR1 20/50 for a few years now and it seems fine...





On Auto-routes the gauges read like this hour after hour, mile on mile until the car needs petrol or I need a pee so I'm not going to lose any sleep over this. The only gauge that changes is the fuel one

[v8s4me]

I'm going to try an additive and if that doesn't work then I'll forget about it until the next oil change and try something different to the VR1. Or maybe I'll try and ignore it altogether. I'll post up what happens.

BTW, what oil do you use?

[v8s4me]

I went to a TVR specialist open day today and got their well respected mechanic to have a listen. When the bloody thing eventually decided to do its little rattle his immediate diagnosis was timing chain. Two options:-

1. Replace; 4 hours labour plus parts.
2. Ignore it.

Guess which one I'm going to do?

Thanks to all for your suggestions. It just proves how difficult it is to come up with a diagnosis from a written description.