M

marcinbrighton

New Member
Hi all.

Looking for some advise on a new noise :)

Couple of months ago my rangie (MY2000 4.6 Thor with multipoint LPG) started making noises which I first thought to be a sticky tappet.

As it was due a service I didn't worry too much and waited to see what it would be like after an oil change.

Sadly no change. I tried putting some hydraulic tappet additive stuff (Wynns) which I've used before in other engines with success, but still no change.

As it hadn't gone away easily, I started thinking about it a bit harder, and noticed that it was only noisy under acceleration, once I'd got to speed and backed off the throttle, it was silent (even when no significant drop in revs).

I wondered if it might be HT circuit arcing, but I've checked in the dark and can't see anything.

No difference between LPG and jungle juice either.

She drives ok, a bit juddery now and then which may be connected, but not too bad.

I did record the noise, but I can't seem to upload an mp4?

So, any ideas - I'm a bit stuck now.

Cheers

Marc
 
Thanks guys,

Will try running her on petrol for work tomorrow (so around 90 miles).

I'd wondered manifold, but I can't see any evidence (EAS hasn't gone wrong yet!!!).

Should've said in my first post too, I've put a screwdriver up to the rocker cover, and can hear the cam spinning, but no louder on the noise.
 
martynv8 said:
Is it worse cold or when warmed up?
Click to expand...

It doesn't seem to make a great deal of difference to be honest, which is why I'm leaning away from tappets.

It does sound quite metallic though, so not sure on the manifold idea, but if no improvement running on petrol for the next couple of days I will try to get the heatshield off at the weekend to have a better look
 
Could be the camshaft and lifters in the process of eating themselves - not uncommon with a Rover V8 and disastrous for the rest of the engine which will be picking up swarf in all the major bearing surfaces. A Rover V8 with a broken rocker also runs surprisingly well.

Do a compression test.
 
StuckAgainSteve said:
Could be the camshaft and lifters in the process of eating themselves - not uncommon with a Rover V8 and disastrous for the rest of the engine which will be picking up swarf in all the major bearing surfaces. A Rover V8 with a broken rocker also runs surprisingly well.

Do a compression test.
Click to expand...


That was my first thought (tappets / lifters). But, no increase in noise when listening thru a screwdriver and the oil that came out at service (mebbe 1500miles after the noise started) was completely clean, nothing on the sump plug at all.

How does a compression test show up worn camshaft or lifters though? I thought it was only for HG or rings?
 
Valvetrain issues usually show up as a variation in compression, it won't be as obvious as a blown head gasket kind of difference, but a difference will be seen none-the-less any disruption to the airflow during the compression test will reduce the "flow-charge" effect of cylinder filling reducing pressure figures, do a test with the throttle closed and open to see how much this can affect readings - you'll be surprised. I've seen Rover V8s with a slight misfire turn out to have next to no cam lobe left on some cylinders, so the cylinder(s) in question were mere passengers! The valves were hardly opening and compression readings were poor.

If the valvetrain is fine then don't overlook exhaust gaskets, some blows can sound like a tap, drive somewhere remote and pour a little brake fluid in the inlet. Brake fluid smokes like buggery and will show up any exhaust manifold leaks. Don't do it in town or the neighbours won't be pleased! When I was young and stupid I fitted a washer bottle system filled with brake fluid to the inlet of my SAAB 900, a quick press of the button would create a James Bondesque smoke-screen behind me - I thought it was funny - the consequences could have been fatal - silly boy. On the plus side when I stripped it down to port the head - the ports, pistons crowns and ring lands were like new, it transpires brake fluid has a powerful decoking effect on a running engine!
 
Thanks Steve.

Presumably the only way to fully rule out the cam is to strip it down. Is that a mare of a job, that ends up being one of those jobs that 'while I've got it this far apart I might as well replace............' ending up costing £000's :D

I'll give the brake fluid a try though, where do I drop it into the inlet? I guess after the MAF, but can I run it OK without the MAF and drop it into the end of the inlet manifold?

Cheers

Marc
 
marcinbrighton said:
Thanks Steve.

Presumably the only way to fully rule out the cam is to strip it down. Is that a mare of a job, that ends up being one of those jobs that 'while I've got it this far apart I might as well replace............' ending up costing £000's :D

I'll give the brake fluid a try though, where do I drop it into the inlet? I guess after the MAF, but can I run it OK without the MAF and drop it into the end of the inlet manifold?

Cheers

Marc
Click to expand...

I'd just squirt some in downstream of the MAF with the engine off - it'll find its way! :)
 
Hi again.

Right, nice day so I've been looking into this more. Took the heatshield off and ran it, no noticeable leaks from the manifold.

Did a compression test, 178-180 across all 8 cylinders, with the exception of No.2 which was at 170. I'm quite pleased with the result from a head gasket point of view, but does this point to valvetrain at all?

While she had wheels and inner arches off I had a good listen around, and it does seem to be coming from the center of the engine, which suggests cam/pushrods.

How big a job is it to change? I've looked in rave and it looks a bit of a mare, looks like it goes something like:

LPG disconnected, Inlet off, rockers off, front of engine peripheries off, sump off.

I guess it goes without saying to replace the timing chain (and gears?) but what else would it make sense to do at the same time?

I'm not too worried about doing it, but shes my daily drive and I don't get a lot of time to work on her during the week!

I remember seeing a thread a while back about types of cams, I'll go searching.......

Cheers

Marc
 
marcinbrighton said:
Hi again.

Right, nice day so I've been looking into this more. Took the heatshield off and ran it, no noticeable leaks from the manifold.

Did a compression test, 178-180 across all 8 cylinders, with the exception of No.2 which was at 170. I'm quite pleased with the result from a head gasket point of view, but does this point to valvetrain at all?

While she had wheels and inner arches off I had a good listen around, and it does seem to be coming from the center of the engine, which suggests cam/pushrods.

How big a job is it to change? I've looked in rave and it looks a bit of a mare, looks like it goes something like:

LPG disconnected, Inlet off, rockers off, front of engine peripheries off, sump off.

I guess it goes without saying to replace the timing chain (and gears?) but what else would it make sense to do at the same time?

I'm not too worried about doing it, but shes my daily drive and I don't get a lot of time to work on her during the week!

I remember seeing a thread a while back about types of cams, I'll go searching.......

Cheers

Marc
Click to expand...

Oil pump while you're in there. If the cam turns out to be worn then it would be an idea to replace rockers and rocker shafts as they would have picked up swarf. Big end shells are cheap - as you have the sump off - you get the gist! :D
 
I've seen a few metions of the pipercross cam, is it really worth it? the missus is gonna do her nut when I tell her £425 for the kit :D

Obviously I don't want to go anywhere near britpart for it, but is there anything in between?
 
StuckAgainSteve said:
Could be the camshaft and lifters in the process of eating themselves - not uncommon with a Rover V8 and disastrous for the rest of the engine which will be picking up swarf in all the major bearing surfaces. A Rover V8 with a broken rocker also runs surprisingly well.

Do a compression test.
Click to expand...

I agree here you should at least take the cam cover off and check the cam lobes for wear
 
marcinbrighton said:
she's done just over 100K, no idea if its the original, but if I've got it apart enough to look at the lobes, it's not that much more to take apart to replace from what I can see!!
Click to expand...

True, most can live with a loud tappet but a cam that's a different story it cost nothing to check it :)
 
get it sorted quick! i had same problem on my 2000 vogue. One day whilst driving along i lhad a missfire and gradually slowed to a halt. after eventually digging deeper an deeper it turned out to be the oil pump had failed!!! hence why tappets were noisy, thet wernt getting enough oil up. Font mean to scare you but i would be checking it out mate
 
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