clive
Rover Rookie
Posts: 44
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Post by clive on Oct 5, 2019 20:04:48 GMT
My Mk 1a 3 Litre drives really well, the only issue is when it's cold the engine is quite noisy with a ticking sound this will quieten down a bit after short time when it's warmed up. The car has nearly covered 70 000 miles on it original engine, it's had regular oil changes since I've owned the car now 33 years. Does anyone know what this noise might indicate and what should be done to rectify it, many thanks Clive
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Post by Phil Nottingham on Oct 5, 2019 21:36:49 GMT
Try SEARCH but apart from the limitations of diagnosing remotely when it cannot even be listened to it could be 1 of 2 things commonly.
Tappets adjustment/flat on cam roller OR most likely blowing exhaust manifold gasket because the manifold has disorted and needs planing flat. It very often becomes distorted because the manifold clamps are refitted the wrong way round and overtightned. Has the exhaust system been disturbed or a decoke done?
Nice to hear you have had it 33 years though - any pictures?
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clive
Rover Rookie
Posts: 44
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Post by clive on Oct 6, 2019 8:29:12 GMT
Thanks for getting back Phil, I very much doubt it's the exhaust manifold gasket, I had that done some years ago and it's sealed very well. So it's looking like it might be the other suggestion, the tapping noise is very regular and certainly coming from under the rocker cover and increases with speed with the revs. A picture as requested.
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Post by Phil Nottingham on Oct 6, 2019 9:07:12 GMT
Best to remove top and side rocker covers and check tappet clearances to see if any one is looser than the others. At this stage it can be done with engine cold but the inlet valves must ultimately be set HOT ie engine fully warmed up after driving.
Inspect all the cam rollers to see if any flats are present.
If they seem OK start the engine and see if you can pinpoint one tappet - note that rocker pads (inlet especially) can become concave when worn so the correct gap can only be set with a Click adjuster - not feelers. Rocker shafts can also wear but I would be surprsed if they are at this low mileage unless the oil feed is restricted. Again this can be readily checked with the rocker covers off.
It useful to see if the knock is at engine speed, half of it or just 1 cylinder or random
You will need new cork gaskets.
There are other more serious causes eg camshaft, small ends, piston slap! It may even be an anciliary such as dizzy, water pump or dynamo.
Good luck!
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Post by charlie on Oct 6, 2019 10:50:51 GMT
Years ago I had a mk1 Morris Oxford 1952 model side valve I had the ticking noise which increased with engine revs turned out it was head casket, I never lost any water while the noise was present, when head casket had been replaced ticking noise was gone, it was on less than 70,000 miles. Also I seem to remember someone replacing dizzy cap to stop a ticking noise which it did as Phil mentioned.
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Post by Eric R on Oct 6, 2019 16:47:02 GMT
Does this apply to the V8 engine also? I have similar experiences (see previous thread) like a stone in a tyre. Taking all steps like copper grease, shims and even replacing front bearings has not effected any improvement.
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Post by lagain on Oct 6, 2019 19:11:28 GMT
Years ago I had a neighbour whose hobby was rebuilding 1930s MGs. If he had a noise that was difficult to locate he would use a stick as a sort of stethascope (sp !) It seemed to work
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Post by westoz on Oct 7, 2019 5:13:03 GMT
As you have stated that the noise seems to come from under the rocker cover this will not apply, but as an ex-mechanic I can tell you about a bottom-end knock that turned out to be a hard lump on the fan belt. I have also seen a v8 truck engine missfiring on one cylinder that turned out to be worn points. The lobe for the misfiring cylinder must have been fractionally lower than the rest!
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Post by Warwick on Oct 7, 2019 5:32:41 GMT
Years ago I had a neighbour whose hobby was rebuilding 1930s MGs. If he had a noise that was difficult to locate he would use a stick as a sort of stethascope (sp !) It seemed to work George, my Dad taught me the same technique, but he used a large screwdriver. A long shaft and a handle big enough in diameter so you could hold it against your ear-hole without any risk of it going in if bumped.
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Post by djm16 on Oct 7, 2019 5:43:42 GMT
I am with Phil. Perhaps the commonest cause is a leakign exhaust manifold, either from where it mates with the block, or the juction with the down pipe. Holding a length of garden hose to your ear and the other end wave around the manifold until you her the noise clearly. If it is due to a tappet / cam follower / cam lobe, then using a feeler gauge to temporarily remove the tappet clearance with the engine running will isolate the problem to a single valve. I had something similar a few years back. The prominent ticking disappeared when I replaced the roller cam follower that had a cracked rolling surface. See: roverp5.proboards.com/thread/9362/ticking-noise-engine
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Post by MK IA Norway Viking on Jun 15, 2022 21:49:37 GMT
Best to remove top and side rocker covers and check tappet clearances to see if any one is looser than the others. At this stage it can be done with engine cold but the inlet valves must ultimately be set HOT ie engine fully warmed up after driving. Inspect all the cam rollers to see if any flats are present. If they seem OK start the engine and see if you can pinpoint one tappet - note that rocker pads (inlet especially) can become concave when worn so the correct gap can only be set with a Click adjuster - not feelers. Rocker shafts can also wear but I would be surprsed if they are at this low mileage unless the oil feed is restricted. Again this can be readily checked with the rocker covers off. It useful to see if the knock is at engine speed, half of it or just 1 cylinder or random You will need new cork gaskets. There are other more serious causes eg camshaft, small ends, piston slap! It may even be an anciliary such as dizzy, water pump or dynamo. Good luck!
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Post by MK IA Norway Viking on Jun 15, 2022 22:14:07 GMT
Hello Phil and Clive,
I have an MK IA 1962 in-line 6 cyl IOE and have been dogged for a very long time with excessive tappet noise.
The engine has been sounding like a diesel.
Whenever I adjusted tappet clearance the noise would be reduced but not go away. There would always be one or two tappets making noise of which one would make a noise giving the sensation that the valve is turning. Very peculiar noise indeed. at tick-over can could clearly hear that one single tappet making the noise. Quote annoying to say the least.
I replaced all 12 valves in the '80ies or early 90'ies by fitting hardened valves (and seats) that should cope with the deletion of lead in the petrol. I got the new valves and seats from Roverpart in London at the time.
I can't believe such valves and seats would induce any noise.
I have in the past serviced the cylinder head and replaced rocker shafts, rocker bushes and even valve guides both inlet and exhaust. To no avail.
Every time the tappets were reset they would soon develop noise again.
Finally, I grabbed the bull by the horns and obtained a good second hand camshaft and have fitted this during the winter. I replaced all rollers/cam followers as well as new shafts with bushes for the rockers both inlet and outlet.
The original cam was well worn and some of the rollers/cam followers had pittings and flat spots.
Various parts in the distributor were replaced, for the rotor did not stay in correct position. New spark plugs etc. I have had Lumenition electronic ignition for many years and keep it for the sake of limiting causes for error.
Tuning the tappet clearance reduced the noise, and this time the noise would NOT "restore itself".
It will seem that replacing the camshaft and the cam followers has done the trick. Getting the distributor right has also helped. I switched from W5-40 / W10-40 oil to W20-50 semi-mineral oil. The oil pump was not so happy with the thin oils. It clearly likes heavier oils to work with.
Still, I was not satisfied - too much noise although considerably better plus stable noise.
To experiment, I proceeded to overtighten the tappet clearance by using a slightly thinner blade on my bladeseeker. I have done the tuning with the engine COLD for otherwise I burn my hands and fingers ... ouch.
Inlet is supposed to be 0,15 mm and exhaust 0,25 mm. I have set the tappet clearance at 0,12 mm and 0,22 mm respectively, and now the tappet noise is gone and the engine ticking over nicely.
Question to members is whether the tappet clearance will increase or decrease as the engine gets hot. I don't want to end up with burned/sticking valves and possible engine damage due to overheating / excessive carbon build-up.
Member advice shall be most appreciated.
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Post by Phil Nottingham on Jun 16, 2022 6:13:03 GMT
Thanks for the update. It has been troublesome!
The camshaft does wear as do the roller tappets eventually.
The exhaust clearances do not change hot or cold. It is not practical to do them hot properly.
The inlets must be done when the engine if fully warmed up and HOT. If you take too much time it will cool down. Set them initially slightly loose and and warm up. They clearance will change from cold state and close up as the expansion coefficients of the aluminium head and cast iron block are different. It is better to have them on the loose side than the tight side
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Post by MK IA Norway Viking on Jun 16, 2022 6:42:52 GMT
Thanks for the update. It has been troublesome! The camshaft does wear as do the roller tappets eventually. The exhaust clearances do not change hot or cold. It is not practical to do them hot properly. The inlets must be done when the engine if fully warmed up and HOT. If you take too much time it will cool down. Set them initially slightly loose and and warm up. They clearance will change from cold state and close up as the expansion coefficients of the aluminium head and cast iron block are different. It is better to have them on the loose side than the tight side It has been troublesome but, when the result is good (acceptable) the satisfaction is so much greater ! VEry helpful to learn that thermal expansion on the exhaust valves / rockers / clearance is not having any effect, so that I can concentrate on the inlets. It is only the exhaust side where my hands get burned. I will re-set the inlet valves when the engine is hot. Fortunately I've done it so many times I can do it blindfolded, and have learned techniques to get the airfilter and cover off quickly so as to expose the inlet valves and rockers. Thank you, Phil, for your staunch support !
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