Tappet Noise

[myquest]

I know this is not new but.....I've had the car for 30 years and rely heavily on my ears to sense anything changing. Recently, on start up, a tappet noise has started from the left hand bank, it goes after about a minute, certainly no more and then doesn't return until the next cold start.

Is this just clearances or something worse?

Thanks

[Lingen]

You could always check the shim clearances, but I wouldn't worry too much about it unless it is loud, or starts to get worse. It always seems to happen on the l/h bank. I suspect it is one of the cam followers is getting a bit worn, so yes, a bit too much clearance, but not where it can be adjusted! As long as the noise goes away as the engine heats up and expands, and the oil gets circulating, you could just keep an ear on it. I have done so for many years.
Others may disagree.
Mike.

[barkerwilliams]

Have you identified where the noise is coming from with either an engineers stethoscope (£4 delivered on ebay) or piece of wood, or perhaps a screwdriver to the ear?
Don't rush off to the tappets until you have tracked down the noise.



Please do not rush to dismantle and work on parts until it is confirmed you have identified a problem. Amazing the things you can hear through a stethoscope - just don't stick it on a plug lead on a running engine!

Alan

[Alanmax]

Could be a leaking exhaust manifold, they can often sound like a tick and then seal up when warm.

[mjheathcote]

Could be a leaking exhaust manifold, they can often sound like a tick and then seal up when warm.

I've had this issue with tubular exhaust manifolds, before replacing the gaskets with new ones.

[mole42]

Mine was the crankshaft sprocket wearing out. Hope yours isn’t.

[richard1705]

I have this noise too on start up someone said cam follower bucket is worn as mike says is this a big job ?

[Mark S]

I rebuilt my engine around 14 years ago, re-bore and practically everything new inc cams. (all the old buckets were slightly barrel shaped but weren't noisy) and it ran perfectly after the re-build with the most mechanical noise coming from the dizzy. 15000 miles on, the LHS bank, now has a "tac" kind of noise that has developed over the last few years. It comes and goes and sometimes is worse than at other times. I've had the cam cover off a couple of times, no visible issues, cam ok, all buckets turn and "feel" ok, gaps spot on but haven't removed the cam and can't find anything without going further.
The paperwork says the valve guides were changed on a previous rebuild (around 25 years ago). I didn't replace them during the re-build as the new valves were a good fit. Has anyone ever experienced a loose valve guide and would it give these symptoms? Would it more likely be a weak or broken valve spring? I could remove the buckets, check and replace but would they wear this quickly?
If it was excess flashing under the bucket wouldn't it have made the noise from day one?
I've tried to stop worrying about it but would appreciate anyone's experience and thoughts.

[Jeff]

I've had this since my engine was rebuilt by a Stag specialist and it seems quite a 'common' thing. As Mike says it goes away after a few minutes of starting from cold and does not re appear until next cold start.

Another Stag anomaly.

[richardthestag]

Indeed Jeff

normally left bank towards the rear cylinder #6 or #8. furthest point from the oil pump?

Until everything warms up the cam buckets rock slightly (i heard) in the heads and cause a tick. I have one valve that does it. I spoke with Tony Hart about it years ago when he was running HRS. replacement head was the only successful cure he found at that time. There was a chap on ancient email stag digest who dremel'd out a tinsy piece under the offending cam bucket and posted instructions. I have them someplace but have no plans to do that unless the head ever comes off again. In fact it has been off at least twice since I found the instruction and I never bothered.

I ticks away to itself on a cold start for a minute or two and then goes silent.

Now if it taps all the time then I might check clearances, also not impossible for a valve guide or seat to be loose but that makes a much louder racket and not for very long either!!!!

[wilf]

Mine taps sometimes, it comes and goes, I put it down to the cam bucket being slightly oval and turning in its bore. (which is normal, the turning that is.) It's a "characteristic" rather than "fault" so far as I am concerned. And yes, it's no 6 cylinder.

In other words, it ain't broke, so it doesn't need fixing.

[myquest]

Thanks to everyone. I am firmly of the 'If it ain't broke don't fix it' school so I think I may just keep an eye (ear) on it. I did use the screwdriver listening tool and it is indeed on the last valve on the left bank so maybe just oil a little slow in getting there. The oil is relatively new but I may try a change.

[Mark Serj]

Cam buckets would be my guess. Next time the cam is out, see how much wiggle variation there is across all 8 in the bank. The bucket may be worn, or its bore, or both. I have had a few bored oversize in the past, but new buckets are quite cheap and make quite a difference. You could always buy the one new bucket and slip it in each position as a wiggle comparison, then decide whether to buy some more std size and replace others. Get a nice strong magnet on a telescopic aerial type tool to help get them out.

[dagstag]

i agree that maybe the fault is the one bucket turning and giving the odd tick when cold . Possibly see how it progresses but just as a thought i have found on one occasion a cracked bearing cap , due to a casting fault, on another a cracked spring collar allowing collets to "break" taper. . Incidently do you have an early mk1 head which has drain holes drilled at all four stations which means there is inadequate oil at start up . This can be remedied by plugging these holes as per all other heads . Hope this helps.

[Mike J]

I have a similar problem, but mine doesn't go away when warm. Left hand bank possibly no 6 . Was going to change the shims. Is this a tricky job? Mike