Worn camshaft?

[jiri_j]

Hello guys, I started a thread on scraping noise coming from the engine when accelerating.
http://www.aulro.com/afvb/discovery-2/120051-scraping-noise-when-accelerating.html

This noise, however, dramatically developed into a loud knocking/banging noise. I have found out that driving the car at idle speed and introducing an engine load (by braking) I can get a noise at low frequency. You can actually hear pretty loud banging :-( This is the reason why I started a new thread on camshaft. Hope that some of you have an experince with v8 and give me some advice. Thank you!

I took a sample of the noise comming from below the engine, first at idle and then at 1000rpm:

http://muj.optol.cz/janousek/LR/cam-idle_plus_1000.wav

I measured the frequency of the noise and it is exactly at half the frequency of the crankshaft. This means camshaft seems to be a problem.
Why camshaft??? I had an engine rebuild 1.5 years ago (40t km), which involved a camshaft replacement. The reason was a cracked timing cover, which allowed an oil pressure drop in the engine. As a result the camshaft was worn out and had to be replaced.

For this reason I put an oil pressure gauge and monitor the engine oil pressure. No problem at all here. Changed oil every 7500km. So why a worn camshaft???

Or is there anything else that could make noise at half the frequency of crankshaft? worn hydraulic lifters? These were changed as well by the way. Looks to me I am facing a big and expensive job :-( Any thoughts how to test for a worn camshaft further???

Thank you again!
Regards Jiri

[Pedro_The_Swift]

Thats one horrible noise--:eek:

LR V8 camshafts are not the hardest things in the world,, but it wont be that,, it might be things rotating ON the camshaft, maybe a lifter?

what was replaced with the cam?
followers?

[jiri_j]

Camshaft was replaced together with hydraulic tappets (is this synonym to followers :confused:), timing chain and gears.

[PhilipA]

IMHO camshaft noise will not change with the load on the engine,BUT an exhaust leak noise certainly will.
before you do any dismantling check your exhaust manifold gasket to head bolts and the flanges between the exhaust manifold and exhaust pipe. From the noise I think it is the latter.ie a blown gasket.

Regards Philip A

[jiri_j]

I checked for exhaust leaks already. At the manifold and also y-pipe gaskets. This is more serious. Something is banging loud in the engine at half the frequency of crankshaft. Metal to metal.

I think that camshaft has to work harder under load - there is more pressure inside the combustion chamber, hence more work to open/close valves. Anyway, the maint point here is that noise which I recorded was taken under load and with idling engine, this means there is not so much lubrication of the camshaft and lifters than at high rpm. Hence, this noise is more pronaunced.

[Geedublya]

Not likely to be camshaft and followers/lifters if they were replaced so recently but could possibly be valve gear related. Maybe a rocker or damaged push rod. Remove inlet manifold and rocker covers to check.

[mike 90 RR]

I checked for exhaust leaks already. At the manifold and also y-pipe gaskets.

Yes .. I listened to your "Death rattle" sound file

Before you even think of dismantling ...

Half of those noises can be attributed to failed exhaust gaskets ... check the bolts of the "manifold to head" .... Chances are that you have been tightening them up prior on a regular basis, or they are loose (Don't discount blown gasket either)

Also .... That Rattle .... use a 700mm length of garden hose and stick 1 end in your ear ... Use the other end to track the noise (Stethoscope) .... You will be able to "pin point" the noise and the part ....

..... Tell us where you track it to

Cheers
Mike

[LOVEMYRANGIE]

The rocker arm pushrod seat in the 4.0L had an issue with coming loose from it's casting. Resultant noise was similar to a bigend rattling and would reverberate thru the engine making it hard to determine what it was.
I would remove the rocker gear first and check all the seats in the rockers. Get some new rocker bolts before you put them back on.
If you have damaged one, you may well want to check the pushrod and pop in a new one also. Generally pretty cheap.
Just a word of warning when removing rocker gear, loosen all the bolts and then individually by hand hold the pushrod down and press the rocker to "unstick" it from the rod. Nothing worse than dropping a pushrod down inside the valley... Makes lots more work to retrieve it.

Cheers


Andrew


Sent from my mobile tellingbone using rock carvings.

[jiri_j]

Half of those noises can be attributed to failed exhaust gaskets ... check the bolts of the "manifold to head" .... Chances are that you have been tightening them up prior on a regular basis, or they are loose (Don't discount blown gasket either)

Also .... That Rattle .... use a 700mm length of garden hose and stick 1 end in your ear ... Use the other end to track the noise (Stethoscope) .... You will be able to "pin point" the noise and the part ....



Hi Mike, I did a compression test on all 8 cylinders and got 170+/-5 psi. I checked each exhaust manifold individually by running the engine on 7 cylinders. I haven't found any difference in the rattling noise when I disabled cylinders one by one.

I bought a stethoscope to track the noise, however it is very difficult to track it. I am pretty sure that the noise is not comming directly from the rocker covers. When I listen to the engine from top (upper inlet manifold), I can hear the noise, and also when I listen below the engine (sump pan). I have the feeling that the noise comming from below the engine is louder than from top. On the other hand the noise is at half frequency of crankshaft, so my mind turned immediatelly to camshaft.

[PhilipA]

Hi Mike, I did a compression test on all 8 cylinders and got 170+/-5 psi. I checked each exhaust manifold individually by running the engine on 7 cylinders. I haven't found any difference in the rattling noise when I disabled cylinders one by one.



Well the cam lobes sound OK at 170PSI all.
The MOST COMMON thing that happens to these engines is a stuck exhaust valve, but 170PSI suggests no.
Gudgeon pin slipped and scraping bore?
Piston skirt breaking up?
as above broken rocker? ( but 170 says no)
Regard sPhilip A

[Pedro_The_Swift]

as Phillip says,
it wont be connected to compression,

it IS idling/running on all 8?
(wheres that sound file--)

[PhilipA]

I just had a thought.
have you looked at the flex plate being cracked?
That would make clang clang noises and vary with load , and be worst at idle.
Regards Philip A

[jiri_j]

Thanks PhilipA. Seems that only removing the inlet manifold will give an answer. As a next step I will try to run the engine without the serpentine belt and try to track the noise from the front of the engine.

[jiri_j]

as Phillip says,
it wont be connected to compression,

it IS idling/running on all 8?
(wheres that sound file--)


The sound file is here (first at idle with no load (no noise), then idle under load (rattling noise) and at the end 1000rpm with load):

http://muj.optol.cz/janousek/LR/cam-idle_plus_1000.wav (http://muj.optol.cz/janousek/LR/cam-idle_plus_1000.wav)

I can hear clicking noise (probably lifters) and more loud rattling noise which is half the frequency of engine rpm.

[jiri_j]

I just had a thought.
have you looked at the flex plate being cracked?
That would make clang clang noises and vary with load , and be worst at idle.
Regards Philip A

Do you mean the plate used to fit the camshaft? I think it is called thrust plate in RAVE, is this the plate you mean? Please could you specify?

[Blknight.aus]

Id be shutting down each cylinder one at a time by pulling the injector plug lead as well as backing the timing of a touch.

to me it sounds halfway between pinging and big end knock if its a combustion related problem on one pot its only going to turn up at 1/2 crank speed because it only fires every second turn of the crank.

Id also look for a blown out exhaust manifold and if you have a spot thermometer check each port of the exhaust manifold for temp, if everything is good then all should hit the same temp at the same time. if ones getting there quicker than the rest or its not getting to the same temp then thats the pot with the problem.

best of luck.

the flex plat is the bit that connects the torque converter to the crank. think lightweight flywheel.

[jiri_j]

the flex plat is the bit that connects the torque converter to the crank. think lightweight flywheel.

OK, first of all I have a manual transmission. There is a drive plate which is probably something similar. Anyway it seems to me that the noise is not comming from clutch, rather from engine, and if it would, I would expect noise at engine rpm and not half rpm.

[Blknight.aus]

crank shaft noises can occour at lots of different multiples of crank RPM due to the harmonics thing.

I still think a cylinder by cylinder shut down to identify which part of the engine is causing the problem is a good idea as is running the engine with the rocker covers off.

if its valve train related 90% of the time you can spot it in the movement of ther rocker arms or by scoping them with a metal rod/touching them.

[mike 90 RR]

I did a compression test on all 8 cylinders and got 170+/-5 psi. I checked each exhaust manifold individually by running the engine on 7 cylinders. I haven't found any difference in the rattling noise when I disabled cylinders one by one.

That sort of covers Daves suggestion



I bought a stethoscope to track the noise, however it is very difficult to track it. I am pretty sure that the noise is not coming directly from the rocker covers. When I listen to the engine from top (upper inlet manifold), I can hear the noise, and also when I listen below the engine (sump pan). I have the feeling that the noise coming from below the engine is louder than from top. On the other hand the noise is at half frequency of crankshaft, so my mind turned immediately to camshaft.


.... I'm working from the noise off that sound file ....



... That "Death rattle" makes your engine sound like a Diesel ... :eek:

Is this statement correct ....
The rattle is not present on NO LOAD .... but is clearly heard on LOAD

In some respects it (Rattle) replicates a engine that has massive (too much) advance ... Can you check the timing on the D2 ...



When using the stethoscope .... It is an excellent tool ... You need to be patient with it, and place it in many spots, to get it to the heart of the noise


I doubt this next bit is the suspect ... But is possible
The other is a loose gudgeon pin (Piston) ... This can be checked for being suspect, without stripping the motor ... I can explain the method if required

[jiri_j]

Is this statement correct ....
The rattle is not present on NO LOAD .... but is clearly heard on LOAD


I doubt this next bit is the suspect ... But is possible
The other is a loose gudgeon pin (Piston) ... This can be checked for being suspect, without stripping the motor ... I can explain the method if required

Hi Mike, thank you for your help. Yes, the statement is correct: noise is ONLY present when the engine is under load. When no load, everything is fine at ALL rpm, idling well. When loaded, no matter what rpm, you can hear noise. At higher rpms (like 1500rpm and above) the noise is like continuous scraping noise - metal is slightly grinding another metal, remainds me like a chain slipping over something, noise can be heared only inside the car with closed doors; at lower rpms (idle and 1000rpm) the noise is loud knocking noise (at half frequency of engine rpm) and can be heared outside/inside. ALWAYS there has to be a load on the engine. If no load, no noise. I also observed that at idle you need only a little of load, at higher rpm higher load, to reproduce the noise.

Could this be timing chain? At higher rpm grinding eg. a timing gear cover, at lower rpm influencing an engine advance and hence the loud knocking noise? But my question is, why would this happen ONLY when the engine is under load?

I have an OBD2 tool and can measure timing advance at variuous conditions. I will do it. I will redo also the David's test with switching off cylinders, since I concentrated before on the high rpm noise (scraping noise). I will give it a try once more, this time for a loaded idling engine.

Yes please, post here the method. I am happy to check for a loose gudgeon pin! Thank you again and I greatly appreciate help from all of you guys!!!

[bee utey]

What varies between load/no load is the hydraulic pressure in the torque converter. When you select drive this pressure acts across the converter nose diameter and pushes your crankshaft forwards. You may have a failed thrust bearing face on the main bearing that deals with end thrust. Possibly the bearing is replaceable without stripping the engine but it may also be the crank shaft thrust face that is badly worn. Lever the crankshaft pulley fore/aft and check for the amount of movement.

There is also the possibility that you hear the flywheel hitting the starter motor. There is very little operating clearance between the starter cog and the flywheel. You may be able to put 1mm of packing under the starter to space it forwards.

[mike 90 RR]

Hi Jiri

I'm only commenting on the timing side .... Comments and suggestions via the others are all valid and should not be discounted




But my question is, why would this happen ONLY when the engine is under load?

I had a re-listen of the sound file

Ever owned a manual gearbox car ... and you slowed down to 20kph in top (4th) gear ... then put your foot down to go faster .... and then a rattle noise appears from the motor as a protest from too much load on too low-a revs

Well ... That is what yours sounds like to me ;)



I'll revise my thoughts on timing position and make a suggestion that it is set at TDC or just a bit before TDC

The reason for the motor to rattle, if this was the case, is that with NO LOAD ... There is little resistance, and the motor is able to keep turning in the correct direction ...
BUT ON LOAD ... the motor now has resistance, and then the Piston (Being set at prior to TDC) is in a state of instability and does not know (piston) whether to turn the crank, clockwise or anti clockwise

Hence .... A rattle



So I ask you to check the timing position of the spark and how it progresses on advancing through the revs .... You have the crank angle sensor and it is all advance & controlled via a ECU? .... But try to check it via a timing light if you can




Yes please, post here the method. I am happy to check for a loose gudgeon pin!

I've sent you a PM concerning this ....



Cheers
Mike

[Lucus]

Mike I agree with you.

I ment too post a reply a couple of days ago but got side tracked.

Too my ears it sounds like retarded timing under load.

Being a D2 I would start with inspecting the crank angle sensor, and flywheel pickup

[jiri_j]

Thank you so much guys!!!


There is also the possibility that you hear the flywheel hitting the starter motor. There is very little operating clearance between the starter cog and the flywheel. You may be able to put 1mm of packing under the starter to space it forwards.

I would start with checking the clutch - flywheel, drive plate etc then. This could really be the source of the scraping noise on acceleration. This is very difficult to pinpoint, since the engine has to be under load and high rpm to hear it properly. The flywheel could be also the source of timing issues at lower rpm, which I have, since it carries the crankshaft position sensor reluctor ring.

Is there any other way to inspect the clutch assembly without removing the gear box? Probably not :-| Note again that my v8 is manual.


So I ask you to check the timing position of the spark and how it progresses on advancing through the revs .... You have the crank angle sensor and it is all advance & controlled via a ECU?

Yes exactly Mike. I can check it real time on my obd2 tool. I will measure advance versus rpm at load/no load conditions. btw I will give you a call if I run out of ideas and will start inspecting the pistons. I appreciate your help!

Cheers Jiri

[jiri_j]

Hello there, I am back from holidays and ready again for a 'rattle noise' investigation. Just to remind all of you it was a rattle sound at low rpm when the engine is loaded, D2 V8 2001.

I measued the spark advance as a function of rpm. I made three measurements: 1-no load on the engine, 2-going up-hill, 3-when the engine is loaded (going up-hill and braking the same time). There is a pdf attached. The rattling noise came only at the situation #3 at low rpm (600-900rpm). Can I learn anything from this, Mike?

Not sure if it is related, but there was backfiring through an exhaust when reving the engine up to 3500rpm and suddenly releasing throttle. This would confirm a timing issue. When driving the car (no load, high load), there is no backfiring (at least I can't hear any). Backfiring appears only when reving the engine above 3500rpm and suddenly releasing throttle.

What I did so far: I changed spark plugs and wires. The same time I checked for a leaking injector - they work perfectly, no build-up on them. I changed the y-pipe exhaust gaskets. Checked for clogged cats using an inspection camera. Using obd2 I checked these sensors: MAF, intake air temperature, engine coolant temperature, throttle position sensor, 02 sensors. Long term fuel trims -1%. So far found nothing. Tomorrow I want to check the fuel pump for pressure and delivery. Any thoughs?

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[justinc]

I would get someone to lever the front pulley back and forth and measure the endfloat. Unfortunately if it is excessive, then the bottom end may be irrepairable if the crank thrust bearings are ground away. I have seen one where the crank was actually using the block as a thrust surface eventually:mad:
There was also a very loud knocking as every conrod was being thrust out of alignment by the crank end float.

Being a manual though, I would expect the noise to change as the foot is pressed on the clutch if the crank float is to blame, does this happen?

JC

[jiri_j]

Hi Justin, I checked the crankshaft and it is solid. Touch wood :) The noise is half the frequency of crankshaft, so I suspect something else - like camshaft or so. The noise appears only when engine is loaded and at very low rpm - this corresponds to low engine oil pressure (around 15 psi). So I was thinking: if there is unsufficient lubrication of lifters (possibly worn), could this produce this kind of noise? As I wrote already I have some backfiring issues as well - reving the engine to 3500rpm and lifting off the throttle suddenly, there is backfiring through exhaust. Could anyone help, please???

[justinc]

Hi Justin, I checked the crankshaft and it is solid. Touch wood :) The noise is half the frequency of crankshaft, so I suspect something else - like camshaft or so. The noise appears only when engine is loaded and at very low rpm - this corresponds to low engine oil pressure (around 15 psi). So I was thinking: if there is unsufficient lubrication of lifters (possibly worn), could this produce this kind of noise? As I wrote already I have some backfiring issues as well - reving the engine to 3500rpm and lifting off the throttle suddenly, there is backfiring through exhaust. Could anyone help, please???

Ah, sorry I couldn't load the sound file, but if it is half the speed of the crank then yes, I would suspect maybe the cam thrust plate, excessive camshaft endfloat? This will cause a scraping noise as the chain is quite close to the case, AND upset engine timing as these engines run a cam position sensor and this can be geting some unpleasant signals by being struck by the cam sprocket.
The oil pump is also driven off the front of the crankshaft.

Removing the timing case is relatively easy, maybe a 'stethoscope' will help isolate the noise?

JC

[bee utey]

double post

[bee utey]

Your backfiring is probably due to an exhaust leak at or near the head. Nothing to do with timing. It will suck air in on trailing throttle. Probably the engine noise too, as it is consistent with one cylinder firing. Do the garden-hose-stethoscope trick and try to pinpoint the noise. Probably a cracked or damaged exhaust manifold.

A useful tool for finding exhaust leaks is a strip of paper about 1cm wide 5cm long, hold it in long nose pliers or tack it to a dowel, hold it all around the exhaust joints. It will flutter where there is escaping exhaust gas. Saves burning fingers.;)

[jiri_j]

Your backfiring is probably due to an exhaust leak at or near the head. Nothing to do with timing. It will suck air in on trailing throttle. Probably the engine noise too, as it is consistent with one cylinder firing. Do the garden-hose-stethoscope trick and try to pinpoint the noise. Probably a cracked or damaged exhaust manifold.

A useful tool for finding exhaust leaks is a strip of paper about 1cm wide 5cm long, hold it in long nose pliers or tack it to a dowel, hold it all around the exhaust joints. It will flutter where there is escaping exhaust gas. Saves burning fingers.;)

Hi there, thank you for your reply. I checked for an exhaust leak (between the manifolds and engine block) and found nothing! The trick with the paper is a good idea, however I wasn't able to find anything. Tried also the garden hose trick. I have replaced the y-pipe gaskets already and will try to replace the manifold gaskets to be 100% sure.

I checked also a fuel pump and it delivers 165 litres/hour when the tank is full. However, with 40% tank the fuel flow is only of about 65 litres/hour and the pump picks up air! This could explain the loss of power (when I use more and more fuel in the tank). Seems to me that the one-way valve is stuck or something like this. I will look at it. The thing which I learned from this is that at full tank the fuel pump works sort of ok, therefore it doesn't explain the backfiring in the exhaust. I checked also injectors and they work perfectly. I can exclude fuel delivery.

I found also one interesting thing: my ECU doesn't detect misfire!!! I unpluged a spark plug wire, the engine started to run on 7 cylinders which was very obvious. Even tried to rev up to 2000rpm, however there was no misfire code stored in the ECU. Why??? Isn't the CKP or CMP acting in a funny way? Maybe thats why I have the timing issues. Any thoughts???

Thank you for any help! Regards J

[jiri_j]

Does anyone have any advice where to start and what to check regarding the misfire (non)detection? Thank you J

[bee utey]

Does anyone have any advice where to start and what to check regarding the misfire (non)detection? Thank you J

I doubt the D2 ECU has misfire detection. Unless it's mandated for a particular market it isn't fitted. It takes quite a major fault for the D2 check engine light to show. Australia go the full requirement for OBD2 quite late in the piece, way after the D2.

[clubagreenie]

The D2 is OBD2, or I hope it is. Otherwise my scanner is working by art.

[jiri_j]

The D2 is OBD2, or I hope it is. Otherwise my scanner is working by art.


D2 is OBD2 that is for sure mate. Beeutey's comment was that maybe for Australian market they didn't enable misfire detection. Just wondering why. In my case whatever I do to get a misfire, it is not recorded by the ECU. Does anyone else have the same experience?

[alien]

D2 is OBD2 that is for sure mate. Beeutey's comment was that maybe for Australian market they didn't enable misfire detection. Just wondering why. In my case whatever I do to get a misfire, it is not recorded by the ECU. Does anyone else have the same experience?
*This is only my thoughts so please read it as such*
I would have thought the ECU will only pick up faults in the injection system.
A plug or lead would only show as runing rich and then be compensated for.

Might have to go back to basics, plugs leads, cap, rotor, distributor base plate ect..
I know you said you you pulled each plug lead, can you do the same for the injectors with out doing damage?

[bee utey]

The D2 is OBD2, or I hope it is. Otherwise my scanner is working by art.
As I said, full OBD2. I meet many vehicles with OBD plugs that are not fully operational in Australia. Up to about MY 05 I meet plenty that don't do all the things MY 08 cars do. If a manufacturer can save $5 a vehicle by not including something they will. When first converting D2's I was surprised at how many things wouldn't trip the check engine light. Now I know its an industry wide thing.

Just did an '08 Triton, and it had the misfire sensor, because I tripped it. The MY 04 one I did earlier didn't.

[jiri_j]

Hello everyone,

I want to update on my progress regarding a diesel-like noise of my V8. This happens when the engine is at rather low RPM with loaded engine; I uploaded a sample of the noise in the first post of this thread.

Except the noise, which is particularly pronounced when the engine is hot (using HPR10 - 10W50 spec), the truck runs fine but I can feel that the power is not the same as used to be before. The engine is also slightly pinging when using 95; no pinging using 98 Vpower.

I checked a lot of things, beginning with the management system - checked ALL the sensors if they are within spec using an oscilloscope, checked exhaust leaks and vacuum leaks by presurising the exhaust and inlet, found nothing. During my last two oil changes I found metalic chips in the oil. These are non-magnetic chips of size 1mm x 0.1mm, there were of around 20 of them, and around 50 much smaller metalic particles. I cut the filter and after inspection I didn't find any chips in there.

I took the sump off and started from there. I checked the conrod bearings and they seem to be very solid. I inspected the camshaft - couldn't see all the lobes - but still found two lobes with some wear. I took a few pictures of the lobes; it is also obvious that there is some wear on the lifters. Sorry for the poor quality of the images :-)

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36891

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I guess that the wear will be only worse resulting in a lot of particles possibly demaging bearings and other staff. Is it a time for a cam job???

Also the timing chain looks stretched, allowing of around 1-2cm movement towards the centre axis of the gears. I could turn the crankshaft a few degrees without turning the cam, so I guess a proper timing is affected. The chain set was changed 50t km back. What is the service lifetime of the timing chain and gears??? Also couldn't find specs what is an acceptable tolerance for a chain tension. Anyone could provide this information?

Thank you all! regards Jiri

[davrac]

Holy crap Jiri,,,, it seems that this has become an epic mission for you.

You mentioned that you had non magnetic flakes in the oil. Bearing material is non magnetic.

I know that you said that you had the sump off. Did you removed the big end caps(conrod caps) and inspect them? I know that you said it is in the same timing at the camshaft but you have to consider that the a conrod is only loaded up on the firing stroke (once per revolution of the camshaft) which means that a conrod bearing with minor wear might only knock on the power stroke under load (one revolotion of the camshaft).

If it is only minor wear of a conrod bearing you would probably not have been able to feel it with your fingers on the bottom of the conrod cap.

Were the big end (conrod) bearings replaced 40-50000klm ago after you had you oil pres probs? Premature wear may have started at that stage and got worse over time. Conrod bearing wear is very common and occures quickly with low oil pres.

Valve train noises are usually there all the time and are not affected by drivetrain load. Drivetrain load is only on the crankshaft.

You noticed excesive play in the timing chain. Is there any marks on the timing cover were the chain may have been slapping on it. Although would expect this noise to change with engine RPM and not drivetrain load.

Did you replace the spark plug leads before or after your knocking noise began. Leads in the wrong order / place on a V8 can cause all sorts of grief. Loss of power,,,backfiring,,,,,and detonation under load (pinging/eng knock).

If that sump is still off I would visually check the bottom end bearings while its all apart.

Happy hunting and good luck:)

[clubagreenie]

D2 is OBD2 that is for sure mate. Beeutey's comment was that maybe for Australian market they didn't enable misfire detection. Just wondering why. In my case whatever I do to get a misfire, it is not recorded by the ECU. Does anyone else have the same experience?

Just re-read this thread after the reminder email.

I looked back over my notes of my rebuild saga and I had misfire codes poping up, they only refer L or R bank but they are there. Check engine light did not appear, this occcured with a blown head gasket, subsequent massive overheat and then liners.

As for the chain, I'd look at the double row chains, availble from TRS etc. Also if (when) you do replace the cam/lifters, the main attributor to wear has been discussed recently as being due to the use of low phosphates a and sulphates or something. What I do remember is that HPR Penrites are high in these but Brad Penn Green Oil is the highest I know of, it's deare but only because you have to buy it by the box from memory (US fl.oz sizes but a box will cover 2 fills and it's only around $10- more for a fill than Penrite.

[banarcus]

After hearing the original sound file on the opening post, it reminded me of a death rattle in the bottom end on my old 2L Escort. Diagnosis on that: stuffed big end bearings. Very familiar sound.

I'd be very suprised if it is valve train related, even including the cam. That noise is related to the things swinging off the crank without a doubt.

[jiri_j]

Thank you guys! I will get a set of conrod bearings and replace them. I tried to check a play by hand, they were perfectly solid, but when the engine heats up it can be a different story... We are talking here about 50-100um movement which can be impossible to feel by hand (taking into account having oil in the bearings), I agree with you. I will give it a try.

Right now I am getting more worried about the wear on the camshaft lobes and lifters and the stretched timing chain. Even if the bearings solve the rattling problem, I feel that the cam problem will only become worse. Should I replace the cam now???

I also read about the premature cam wear problem, which is caused by a low zinc content in the oils. That is the reason I use HPR10 now which has 1100 ppm. This article very well explains the problem MOTOR Magazine Article | MOTOR Information Systems (http://www.motor.com/article.asp?article_ID=1604) and even suggests to use a zinc additive to get the zinc levels higher; I think that 1200ppm is specified as minimum by LR.

[clubagreenie]

Might be worth trying some plastigauge to see just what the clearances are on the bearings.

[davrac]

Come on Jiri.......Tell where your up to on this one. Have you found the cause of the noise yet???

[jiri_j]

Come on Jiri.......Tell where your up to on this one. Have you found the cause of the noise yet???

Hi there, ordered new conrod bearings and waiting for them... Will give you an update once I get my hands dirty :-)

[davrac]

Jiri have you fixed that engine yet?