Expensive?

Recently she's developed a bit of a clattering when fully warmed up. Only does it when revved in neutral - seems fine at tickover and under load. Changed oil 20/50 / slick 50 and its made no difference. Pressure might be a bit low - about 30 in gear - down to bugger all on tickover (when hot).

I've posted a video on you tube - cant see much but more for the noise!!

http://www.youtube.com/watch?v=FNecbfu4rQA
 
Hello TP,

That does sound rather nasty... :shock:

Have you been able to narrow down the area from which the noise appears to be coming? Can you hear the noise throught the gear lever? Can you feel the knocking from anywhere?

I have heard a noise like that before, and it turned out to be a connecting rod bearing... :shock:

Ron.
 
:roll:

Can't feel it or really hear where it's coming from. No vibration. Can't really hear it from inside when moving.
 
Hmmm,...I would suggest taking the rocker covers off and running the engine and see if that helps to narrow down the location of the noise.

A heavy tapping noise is usually caused by something which undergoes an up-down type of motion as opposed to a constant circular motion. Lifter noise tends to be much softer than what can be heard in the video.

If a main bearing cap has come loose, you should be able to both hear and feel it through the gear lever when the engine is at idle. Given that the noise is audible when the engine is being revved would therefore suggest a different cause.

How many miles / kilometers has car travelled, and how often do you change the engine oil and filter?

Ron.
 
Not sure. It's a replacement engine from an sd1. Can't find any history on that. Well looked after by previous keeper and regularly serviced. I've done about 2000 miles since buying in jan and this is first time i've heard a squeak! Only does it after 15 mile trip, been fine on short runs. I'll have to do some digging i suppose
 
Given that the engine exhibits next to no oil pressure when hot, that would suggest considerable wear in the rocker shafts, lifters, camshaft bearings and of course big end and main bearings.

Without a retaining plate, the camshaft can move back and forth and knock against the inside surface of the timing cover, especially if it along with the bearings are seeing considerable wear.

Another area that can cause a noise such as that is if the exhaust manifold develops a leak where it meets the cylinder head. Can you see any blackened lines radiating out from around the exhaust manifolds?

There are many things it could be....

Ron.
 
That's a very odd noise indeed! If I listened correctly it seems to be almost entirely on the overun after blipping the throttle? I have to say it sounds more like a bit of loose tin getting mixed up in the fan belt/pulleys than anything. Couldn't be the pressed tin fan on the front of the alternator by any chance? Or even the pressed tin "thrower" that's bolted into the crank pulley?

Chris
 
I'm liking your possible causes better chris! It's only doing it when fully warmed up for half hour tho. Dead right on the overrun. Thought it mite be chain tensioner.
 
tantus pedis wrote,..
Thought it mite be chain tensioner

It won't be that one as the V8 engine has no chain tensioner.

It would appear that once up to proper temperature, something is able to move freely....hmmm

Ron.
 
Have you removed each spark plug and had a look? Are they roughly all equal in appearance?

I have been having another listen, and although initially only occuring on the overrun, towards the end of the video the noise continues with the engine revs. Something loose or broken.. :?

Ron.
 
I'd say that it sounds to be at engine speed rather than camshaft speed, but not being able to see the engine running speed makes this a harder call. Initially I'd disconnect the belts to eliminate those, then pull the plugleads off one at a time to see if the noise disappears when any particular lead comes off. It could be the top of a valve guide adrift, which then slides up and down on the stem as the valve opens and closes. It doesn't sound heavy enough for a big end, but could be a small end, although they rarely give problems, and pulling the pluglead on that cyl should tell you. Remove the plugs and see if you can see evidence down on the top of the piston that something has been bouncing about down in there, and see if a small magnet brings anything out. (Now you know where that missing washer from the last job you did is........... :oops: ) Look at the plugs while they're out, as the bottom end of the porcelain can crack and fall off.
The ends of the piston rings can break off, and then wear a path upwards to end up with the broken part above the piston. You can normally fish the bits out with a magnet, however the piston (and the bore as well) get damaged.

Listen to roughly where the noise comes from, then put a screwdriver on the engine, with your ear on the end of the handle and move it about until you pinpoint it. (Keep it away from the plugleads...... :LOL: )

Then if you locate it to a bank, or even if not, run it with the rocker covers off.
 
Local mechanic had i listen today. He's done some v8 stuff. He thinks a lifter. It didnt do it when i got to him as the run in was easy and not much traffic. It gave a single click on a blip but that was it. I let it idle for a bit and it started again properly. Can't be debris if only when hot - or oil thinner? Never does it when cold. Working 7 day stretch at mo so not got time to look properly :-/
 
I can't think of a reason why a lifter should sound distressed on the overun and not under power - the loads on it are the same whether the engine is powered or not. Harvey's suggestion of a little end (ie the bearing between the connecting rod and the piston) is more sensible, but to prove you'd have to have the plug out rather than disconnected. This to eliminate the load on the little end from the compression stroke. That's a pretty time consuming operation to remove each plug in turn, running the engine briefly between each!

I am personally still in favour of the external bit of tin theory. As you blip the throtle the engine tries to move about a lot and is restrained to a reasonably small movement by the tie rod on the right front of the engine looking into the bonnet. The tie rod goes to the nearside inner wing. Is that loose at all? Or has damaged rubbers? On the other side of the engine the exhaust comes very close to a tin heat shield protecting the brake and clutch master cylinders. If the engine is moving more than it should, or if the exhaust is misaligned, that would be a good candidate on the overrun. Moving back, have a look underneath at the security and alignment of the exhaust pipes coming off the manifolds back to where they join up to the rest of the system. Is something able to touch under extreme engine movement there? Another possibility might be the throttle linkage. Is the rubber bearing mounted onto the front bulkhead in which the horizontal shaft to the carbs terminates intact? If not you might get the shaft rattling against the bracket in certain circumstances. There's also a win here in that you won't get full throttle movement at the carbs with a damaged or missing rubber!

And don't forget my original suggestion - check there is no end float in the alternator shaft which would allow the fan to contact the alternator body!

Chris
 
That sounds identical to the noise I get on start up sometimes,it goes away once the oil pressure builds.
I would think it is a hydraulic lifter failing!
They can knock on cold start up as they wont hold pressure well,or they can knock when warm as thinner oil and pressure blows by the seal in them!!
If you can get it to do the noise for a few seconds- 1 min, listen to the rocker cover with a screwdriver placed by your ear or piece of tube like a stethascope. if its just the one thats failed/failing it can be replaced but better overall to replace the lot once you strip it down that far.
Its a relatively easy diy job if you have basic mechanical know how.
As for cost,MMM??
When I was going to do mine I reckoned about £200 max for all the parts that would be needed,lifters,gaskets,sealant,antifreeze,cleaners,etc
And barring problems,a casual saturdays tinkering to do it!
 
Pilkie wrote,..
When I was going to do mine I reckoned about £200 max for all the parts that would be needed,lifters,gaskets,sealant,antifreeze,cleaners,etc

Hello Pilkie,

Don't forget the camshaft too. Fitting new lifters while keeping a used camshaft is the perfect way to ruin the not only the camshaft but the new lifters too. You would need to do it all again in just a few months time.

Ron.
 
One thing further to my earlier posting, and that's regarding the possibility of it being a lifter, and that is that I would expect that a non working lifter would have an effect on the running if it wasn't pumping up at all, and it sounds as though the engine is still on all 8 when the noise is there, I'd expect at least some effect on the running, possibly even the loss of that cyl altogether. Holding your hand next to the exhaust will give you a good indication if the engine goes off song at the same time as the noise appears at its worst.
 
if you catch it early enough the wear on the cam will be minimal,so wont need replacing,and the new lifter will automatically compensate for it!
Would be interested to hear harveys view on this?
 
pilkie said:
if you catch it early enough the wear on the cam will be minimal,so wont need replacing,and the new lifter will automatically compensate for it!
Would be interested to hear harveys view on this?

TBH if it was my car and I dismantled it and found 1 lifter faulty for whatever reason, providing the cam wasn't marked, and I didn't want to go for a new cam and followers at that time, I'd fit 1 lifter, see if it cured the problem, and then wait and see what happened over time. The worst that can happen is it needs a new cam and followers, which is no worse than it would have been if done earlier.
Recommmending others to do it is not quite the same thing though, they'd have to make their own minds up........

I'd certainly be keen to have the rocker covers off to have a look and listen...
 
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