Old Leafsprung Land Rovers
General Category => Technical tips & Questions => Topic started by: FenTiger on 24 March 2013, 09:56:01 pm
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I managed to eradicate a rather worrying arrhythmic "rugga-dagugga-ruggadugga" noise from my chain tensioner a while back..... it had caused this.... obviously my attention was not a moment too soon.
(https://fbcdn-sphotos-e-a.akamaihd.net/hphotos-ak-ash3/548277_10150898861820308_1089211577_n.jpg)
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:rolleye0012:
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The noise that I had from my cam follower was wholly disproportionate to the physical evidence. Damage around the outer edge of the flat face of one side of one cam wheel was very minor and easily missed (or dismissed).
At a later time someone on here posted pics of a cam follower wheel that resembled a distorted and misshapen thruppenny bit. Mine was nothing like that! The noise, however, at it's worst, was horrendous.
I think these things are case hardened and that with mega miles over lots of years the hardening is wearing through hence the probs.
Richard
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I had an annoying rattle ...(Well more of a metallic 'tinging' if that makes sense ) for ages ...
Then the cam chain broke ... :eek:
Although it did do it shortly after i repaired the none working wipers ...
Moral of the story is leave the minor things broken, less you upset the law of Landrover physics that describes that only 80% of a series landrover can work at any one time . :smiley-furious:
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:thumbs: Hope it is the annoyingly irritating problem FT.
Trust you had a pristine lab coat on with the listening device casually slung around your neck :smilewide:
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Did some further investigation over the weekend, in between other jobs. With patience, Mrs FT starting it and use of my stethoscope, I think we have traced the rattle to the cam followers. So it looks like the next job, when a suitable window presents itself, is to have the head off and inspect the damage. I hope it is just the followers and the cam is still good.
Photos will follow...
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Worked out what my rattle is.
Nothing more complicated than the Alternator casing catching slightly on the corner of the engine block.
Should be easy to sort!!
Mark
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Leafer109 if you are going to be doing the timing chain then do look at the tensioner components for signs of wear especially on the idler and whilst on the topic of noisy tappets take the time to remove the rocker shaft and examine it for wear. Also examine the rockers for bush wear by placing them on an unused portion of the shaft. Do also check the very small oil feed holes in the rocker are clear before assembly.
Many people omit these simple checks during a rebuild and suffer the consequences, they need SH><. if they don't.
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I remember reading somthing in a classic car mag about rattly tappety noise and about no matter how much you ajusted the tappets it wouldnt go away when in fact itwas a worn streached timing chain making the noise.I have a similar problem noise and am thinking of doing the timing chain at some point.Will be very interested in you findings Mr FenTiger.
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Due to the frequency of the noise, my only other thought is that it could be little ends. Not sure how to check this in situ though. Think the pistons will need to come out if this is the case. Either way, timing chain is going to be first port of call, them sump off for and investigate. If all looks good there, the head will be coming off next. I think I fitted a composite gasket, so not looking forward to scraping all the shot off and keeping everything clean...
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^^^ thinking outloud here;
Under load, the pistons are excerting more pressure ( with less revovery time) back against the valves, through the rocker, down the push rod and onto the tappet slide 'n follower highlighting minor defects in the follower or cam lobe; in tickover or overrun the follower has time to 'ride' over minor defects as it isn't being forced so hard onto the cam lobe.
does that make sense?
I dunno, just a thought??
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As someone who also has a "chat chat chat" under load I to am curious about this.
Silly question but why would a cam follower start bleating when the engine's under load and not overrun?
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Fingers crossed obviously and anyway it is difficult to diagnose over the forum, still the not initially using choke to start will give you some idea on things.
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Really hoping it isn't mains, but as I will be dropping the sump, it won't hurt to look. I don't think it is as the noise is more of a rattle like rappers, rather than the deeper noise that mains make. When I say the house is there under load, it is more noticeable at higher revs than lower.
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My first thoughts were main bearings.... followed by timing chain tensioner....... but if the rattle comes back with the engine under load that would for me rule the tensioner out. To qualify this I'd try checking the ignition timing in case it is too far advanced as this may be the cause of the noise under load to try and eliminate this possibility.
With the horrible rattle on start up I'd try spinning the engine over from cold for say three seconds to build up the oil pressure before pulling out the
choke as this may help dramatically and extend useful engine life.
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Problem is that the noise disappears pretty soon after fire up as oil pressure comes up, then only comes back under load at revs. So tracing it is a ****.
I have ordered some gaskets and seals up. So this weekends job will be trying to sort it out.
Noel,
I am conscious of the rocker / cover issue and have checked it. It has the shorter petrol push rods fitted for this reason.
Bert,
I have a nasty suspicion that it might be the cam followers, but not sure as noise goes when oil pressure comes up.
Problem is that the engine runs so well otherwise and pulls like a train.
Thanks all for your thoughts.
Going to pull timing case first as front crank seal needs changing anyway.
Will report back my findings after the weekend...
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Have you tried using the old engineers stethoscope trick to locate where the noise is coming from?
I used to do that at work quite often using a long screw driver pressed to my ear and then held against parts of the engine to try and locate the source of the noise. It works quite well but some noises seem to resonate through the entire block making them hard to locate.
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I think that your initial diagnosis is probably correct. My 2.25 3mb petrol developed a really horrible 'bag of nails' rattle that had much the same symptoms as yours. I was sure valve clearances but they were spot on. Eventually it was head off and closely examine the valve train time. One-only one-of the follower wheels/discs had damage to the edge of the flat face (not the working surface but the flat side of the disc) where it located in the Slider cage. I replaced it and the cage and the noise completely disappeared.
Richard
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heavily skimmed metric head with unleaded seats
After my unfortunate mishap on the M3 a couple of years back that caused me to miss Lurch's laning days I'd say pull the rocker cover and check underneath for marks. The pushrods could be hitting the rocker cover and that never ends well.
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Well, you and Abertross have given me plenty of good advice in all matters 'head' and I've acted upon them to diagnose problems. That said, when you see a worn follower such as I have its easy to diagnose what the problem is. ;D
Could you fire her up and take the air pipe off the filter and and stick it over your ear with a finger in the other to try and hear whats going on in the head? ( without giving yourself a hiccy :-) )
Could you take the rocker cover off and see how the oil feed is when running and/or loosen the oil feed banjo to check ......
Could rule out head/cam issues??
You might be checking the tappet gaps when the cam and / or follower are in a good position if your luck is as bad as mine, and if it was the cam and or followers then it might just, once in a while run right so I'd suggest something else.......
there, help in the form of eggs , grannies, teaching and sucking !!
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Will do Jim, but pretty sure it is oil pressure related as noise goes as the pressure comes up on the gauge and I think I have changed the plugs with no change to the noise.
My feeling is timing chain related, but pump may be an idea as it is difficult to tell where the noise is coming from. Either way, they are both going to be messy bastard jobs to do.
Noise sounds multiple to start with then dies to a ticking then nothing. I am well and truly stumped, and know these engines pretty well.
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Gonna sound dumb, but have you checked the spark plugs are tight? Sometimes this is the kind of noise you get....
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I remember something similar to this many years ago, I think you will find that it
is oil pump related. It's worth checking.
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Interested in this.
My new S3 petrol project has a rattle at idle, which I believe is from the timing chain, but not sure exactly what I need to do to sort it though.
Mark
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Right then.
Hattie has been getting some love recently with a view to perhaps selling her at some point in the future.
After having to replace first gear after smashing it freeing off a stuck clutch, I fired her up and took her out for a spin. I had forgotten how much poke she has (heavily skimmed metric head with unleaded seats).
When I fired her up I was reminded of a rattle she had developed, which I have been unable to trace.
When first fired up from being stood for a while there is a hell of a rattle. As oil pressure comes up it quietens and eventually disappears. The rattle only comes back under load.
I initially thought that it was a worn cam follower, but kept an eye on the tappet gaps and they haven't altered and I would have expected the noise to be constant.
I think now that it could be the timing chain tensioner that isn't working as intended (ratchet not working) or the chain has stretched beyond the ratchet for the tensioner.
Soooo, before I pull the front end apart this weekend, what are people's thoughts.