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MG MGF Technical - Tappets. If they make noise, is it bad for the car?

Hi, I have noisy tappets in my car, probably 2 ~ 4 of them. My mechanic whilst working on my car for loose camgear / cambolts, left engine not running for more than a week, and couldn't get the engine started without pressurising the engine (so I was told = I am guessing that oil was fully drained out of the tappets), because it has 2-4 loose tappets. The mechanic reckons the noise wasn't there when he got it runnning again, and was all good. But kind warned me that if it gets really loud and annoying that we should replace them.

Today in the morning (left it overnight), I started it and there was the tiny knocking not sure if it still had knocking after warm up, I can't hear anything in the car, just outside with my head close to the boot vents.

Hopefully nothing to worry about.

So having a tiny noise making tappets.. is this bad?
or am I safe...

Oh also, the clutch. I couldn't feel anything between
the pressed or released clutch before (while releasing the fully pressed clutch), but now I can feel a tiny feel of kinda gear bind feeling... don't know how to explain. (feels like very weak steps while releasing the clutch pedal...)
Do you know what this is...

Please let me know!

Hanah Kim

Well, my tappets have been getting progressively noisier over the last four years, to the extent that I think that they need replacing very soon.

Not quite an answer to your question, but so long as the tapping subsides quickly after start up, there isn't anything too much to worry about. The important thing to check, as usual, is the oil level, in case now that the oil has had a chance to circulate, the level has dropped a bit.
Rob Bell

In the past{not on a F] I have had positive results on engines which have started to be noisy because of hydraulic valve lifters,
By draining the oil,using an engine flush{I do not use Forte as I feel its too abrasive}refilling with a good oil and then using Wynn's for oil.
This product contains additional EP additives that can minimize wear at high pressure parts of the engine eg cams,valve lifters valve stem tips.

I would not do this on a low milage engine only one that is starting to suffer the effects of HIGH milage,and as a possible solution before major surgery.

I believe the K series has hydraulic tappets so may be noisy at start, but should quiten down within a few minutes of start-up.
T Green

What's the difference between a Tappet and a Cam follower?


Hannah, I can't remember you saying that the valve gear was dismantled, so the tappets should have remained primed whilst the head was off. In any event the first startup by the mechanic should have primed the tappets OK. My 1.8 has a half-second clatter from the tappets on cold startup, but from then on the valve gear just rustles. Even if I leave the car for a couple of weeks it's still the same initial half-second clatter. If this is what you're getting then I shouldn't worry. I don't. Funny though, my 214 at 70k miles is quiet at cold startup, and I have listened with the bonnet open!

The tappets have a non-return valve in them so that once primed they do not rely on a high-pressure oil feed to operate. When the cam starts to depress the valve the oil feed is cut off from the annulus in the tappet. When the valve returns to rest the oil feed just tops up any loss in operation and any necessary adjustment for heat expansion, etc. Loud and constant ticking from the tappets is either poor running clearance or defective non-return valves, so much so that the oil supply can't keep up with the oil loss in the zillionth of a second the valve is at rest.

Steve, I thought I could explain the difference between a tappet and a cam-follower but I quickly became bogged down. The K series engine has hydraulic tappets between the cams and the valve stems, that's all. Cam followers are usually found in OHV or SV engines where the cams are some way from the valves. Of course OHV and SV engines can have tappets, and hydraulic tappets too, but these.. Oh I give up.

Regards, Kes.

Rob and others thanks for the replies.

Kes, no the mechanic didn't open the head, as he wanted to keep the repair cost to the minimum, and he thought that there was no damage to the internal of the engine after few tests. Maybe I should give him a call tomorrow. As today I am working at a dental clinic full time. The engine was left as it was. I don't know if it was there before the 'mishap' either, because it's not that noisy to pick up. I just became so picky on noises now since then.....

I think he said 'the headgasket shouldn't go off, but if it does let's change the tappets then' ...

maybe that's a good idea...
Hanah Kim


I am confused because the dealer has said my ticking noise is faulty cam followers. Last time I had this noise was in my Ford Capri back in the early 1970's - it was a lovely car! Archives seem to suggest Tappets the cause. As long as they get rid of the noise, I do not suppose it really matters.


The it's the money that matters.... as well!
Hanah Kim

On older engines, there was a cam follower that rode on the cam, then a push-rod, and then a tappett (attached to a rocker) which allowed the adjustment for the above elements to control the valve.(1 per valve).
ON newer engines, the cam (Over head cams) - the cam almost acts directly onto the valve. To allow for differing clearances, temperatures, etc, in between there is a cam follower that is adjusted by the oil pressure in the engine. Thus when the engine is cold you can hear the cam-followers clatter before the oil pressure has adjusted them to remove the clearance.
Thus as long as this disappears quickly, it is working as designed.
T Green

I think my car still has tiny tappet noises after warm up.

Oh... so what does it mean..? is it gonna kill my engine (probably not).. [I can live withit, as it's almost not hearable from inside of the car]

or is it just an annoyance?

is there a drop in performance.

Very curious.

Hanah Kim

Kes, I just read your reply again, it explains a lot, but I am not that techinical enough to figure out if it answers my question...

Help! :)

Thanks in advance!
Hanah Kim

The base line is that Hydraulic tappets/followers that are not filled with oil will make a noise that does more damage to your ears than the engine parts, subject to the noise being due to blockage of the oil hole in the tappet and not a general lack of upper lubrication.

However controlled leakage, due to clearance between the follower body and the gallery it sits in, and past the sealed inner piston of the follower can occur and if greater than designed will lead to noise. Some oil must be present otherwise the noise is very loud.

It is also the case that even when the tappet is empty there is more than enough lift applied to the valve to enable the engine to start. More applicable is the fact that when the engine has been apart it is always more reluctant to start and often stutters for a few seconds whilst the engine 'clears it's throat' with smoke from this in the exhaust. This even though care and cleanliness applies during the work.

Purging of most air occurs within seconds of a start up. However some air may take a while longer and need a few revs for a few minutes to completely clear. Certainly experience with V8 hydraulic followers occasionaly showed that you could bget a difficult tappet that needed the engine to be revved quite high and kept there for a few seconds before it completely cleared. However the Rover V8 runs a low pressure high volume oil supply with pressures between 25 and 33% lower on average when compared to the K series.

Mention of the Ford OHC Pinto engine with the 'death rattle' from the top end also raised similar thoughts on the early GM OHC family engines that also suffered.

Roger Parker

Thanks Roger for further explanations.

Then, what I will do it as the noise is not noticeable unless I go outside with my ears to the boot, I will leave the tappets until my head gasket goes... or if it gets a lot noiser will get them replaced.

How does that sound? Is that what you would do too?
Hanah Kim

taken from a rover BBS FOR 820 RANGE OF ROVERS!!

I have some good news for all those noisy Rover 827's. As discussed previously, the engine sounds fine from cold to about 2 minutes into running. Then ....the tappets become very audible, eventually becoming quieter once the engine shows a normal working temperature. I have found an article in an old car magazine (What Car?) form 1997 that deals with the experiences of a car mechanic who troubleshoots all sorts of problems over different makes and models. The Rover/Legend 2.7 24v V6 suffers from a build up of "sludge" in the oil. This is usually evident in cars that have done well over 100,000 miles or cars that have been poorly serviced. The solution is to remove the sump and gain access to the oil pump/strainer. The sludge builds up in the gauze filter inside the pump. This needs to be removed and thoroughly cleaned. It will then be ok for many more miles.The build up of "sludge" ( tiny black sooty deposits) restricts the free flow of oil around the engine and oil galleries. Only when the oil is hot and therefor thinner, does the problem rescind. With this in mind I decided to change the oil ( Synthetic "Magnatec") which had only been changed 2000 miles ago, and run an engine flush through it as well. I filled up with new synthetic oil and replaced the oil filter. The results were dramatic. The engine runs near silent. I have yet to clean the gauze filter in the oil strainer as the engine flush has done a remarkable job in dislodging the "sludge".

I should also check the positive crankcase ventilation valve in the front breather hose.* This should be removed and cleaned as well.

Because these engines run on unleaded fuel only, and donot have the cleaning qualities of lead, unleaded fuel with high levels of detergent is recommended. I have read that Texaco clean system3 is such a fuel.

* I visited my local Honda garage and explained the problems. They were not aware of this tappet problem but suggested checking and cleaning the P.C.V valve. some engine flush prior to replacing the oil and filter, follow the instructions and see if it has an effect. If this is limited, remove and clean the oil strainer gauze.


Hello again , Just a note to say that my 94 tapping sterling no longer tapps. Gave the engine a complete flush and replaced the filter with the smaller original Honda spec one. It is physically smaller in size and cost 16 from a Rover dealer. Filled with Castrol Magnatec and couldn't believe my ears when I started her up - no tapping at all - even when cold. Presumably there is an increase in oil pressure to the tappetts at the top end by using the smaller filter. Thanks for all your information and everybody who mailed me.

I think flushing is well worth a try to cure the tappets noise !!


Hi Tony thanks for your info.

I will try this later on... as I just had an oil change some 200kms ago. :)

I don't like the oil in the car (as it's a protec), but will use it for awhile, then change it later.

But your note will be printed and showed to my mechanic.

Hanah Kim


Hannah, I'm no engineer and I can't give you an absolute assurance, just an opinion, and that is if you're getting a light ticking then that's OK. I've listened carefully to my 1.8 F and I can't really hear any ticking, just a rustling sound at hot tickover. With my 214, at 70K miles, there is a definite tick at er, tickover.

Before the general adoption of hydraulic tappets (and if you convert the F's hydraulic tappets to mechanical operation) valve clearance would be set to a specified clearance by using either a locked screw thread or shims. Figures from 0 to 15 thou (inch) clearance were common, usually with a cold engine. So engines would tick cold or hot and rarely would the valve gear be silent. I guess in theory hydraulic tappets run at zero clearance at all times, but in practice a little leakage gives a thou or two clearance. Not a problem.

You may remember I had my tappets replaced a year ago as one had a pronounced tick. There is no doubt when a tappet is defective, the 'tick' is loud enough to be heard some 20 or 30 feet away. Don't rush into replacing the tappets, B&G are quoting 228 to supply a set of 16 and fitting them is not easy. By the way B&G insist in calling them cam followers, truly they are a conservative company.

I've had a trawl through the K-series engine manual and pulled out such gems as the tappet diameter is between 32.959 and 32.975 mm, so from too tight to worn out is a mere 16 thousandths of a mm! I also counted at least 37 pressure-fed oil points: the major gallery to the main bearings (5) and thence to the big-ends (4), the secondary gallery up the front of the engine and then to the camshaft bearings (12) and the tappets (16). Hmm, don't put off changing the oil!

Regards, Kes.

I agree with what Roger said. The working stroke of the hydraulic Tappet is about 2mm (1 mm either side of the nominal position) and the cam lift is 8.8 mm (8.95 if you include the ramps) so an engine with completly sunk down tappet should start OK . It would be bloody noisey though. I dont think you should continue to run your engine with noisey tappets, you will break somthing, most likely you will loose an exhaust valve head. The noise you hear is the valve hitting the seat too fast. The tappets Rover use are from Eaton and have anti drain features including an internal reservoir, so if they are working properly they dont need an imediate supply of oil and shouldn't sink down. They are very reliable and durable. Whenever they are returned under warranty no fault can ever be found. I favour the gumming theory. FLUSH THAT ENGINE NOW. Let it run on no load as long as you dare 'cause the oil in the tappets changes very slowly. Stop and start a few times leaving hours in between. You could put your newish oil back in then. If all this dosnt work try the viscosity enhancer suggested above.
I should know what I am talking about as me and my mate Keith designed your valvetrain
Paul Hollingworth


One other thing to talk to your mechanic about

The K series engines all suffer from aeration of the oil - mainly due to the low capacity - ie not enough time for the oil to loose air while travelling around the circuit - thats why the tuners above have got rid of the hydraulic tappets and made them "std"
There is also mention of a "air eliminator" put into the oil circuit which helps as well and also a "dry sump cure"


All in all the tappet noise is annoying - but generally causes no damage - so if it isnt too bad just live with it and try the cheap options - oil flush and a different oil === NOT THICKER OIL - TRY THINNER!!!!


Just as a matter of interest, has anyone here got evidence of serious engine problems resulting from "noisy" K series tappets which have been ignored? As pointed out above, if you can live with the noise and it's rarely unacceptable, why involve yourself in the expense?

Noisy tappets are NOT unique to MG-R engines. That engine flush and good quality oil sometimes improves things. I suspect the benefits here being getting the oil pressure up to spec in the tappets much sooner after engine start-up.
John McFeely

Thanks so much for last night's input.

Heaps more information.

First of all.

This is what I will do.

As I have done 27800km on the car, and just changed
the oil 200kms ago,

I will change oil again at the end of the Feb with
Castrol RS (10W60 one). I have one bottle full at home
and need to invest in one more bottle. (as one bottle
only holds 4litres)

10W60 = is it thinner? than 10w40

The noise first of all, is not recognisable unless
you stick your ear at the vents. Mechanic told me
(when I was picking up the car), that it should be
fine, but if they get noisy or anything I should
replace them later. Maybe I will stick to his option... as it will cost me less that way.. :)

So Kes, Tony, Paul, and John. Yes I will do the oil
flush in a month time. And see if that makes any
improvement. Will keep you guys posted.



Hanah Kim

Sorry - I thought this was a loud tappet noise !!!

If the tappets were bad you would hear them over the street - the rattle you may be hearing could be many mechanical noises - especially if you have your ear against the vents !! Injectors can make a tapping noise - normal - and all engines make tappety noises if your listening out for them !!! - what tends to happen is you have a breakdown and get an expensive bill - which i believe has happened to you - after which your hearing "tunes" into your car in anticipation of the next failure -

This isnt a critisism - perfectly normal !

IMHO The noises you have desribed sound normal so I wouldnt do any thing other than drive and enjoy and forget the oil changes - put the money in for fuel :)!


Hahaha.. your advice very well taken.

Yes, I guess I am a bit paranoid at the moment..

Thanks I will take your advice!


Best Regards,
Hanah Kim


Hannah, it looks like the consensus of opinion is that your tappets are OK. As for the oil, a 10W-60 will be far more viscous (thicker) than a 10W-40 at 100 deg C, which is the temperature at which the normal running viscosity is measured in the SAE grades. Funnily enough the Castrol RS used to be 10W-60 in the UK, but I noticed at my last visit to the car shop that it is now 0W-40, the same as Mobil 1. I wonder if Castrol have switched their synthetic stock suppliers? I've always been curious about the 10W-60 rating of RS; how do they get that very wide viscosity spread, and why choose a 60 rating, which is around 75% more viscous than a 40? Sometimes I wonder what Castrol were doing, as 60 is the highest viscosity grade classified by the SAE for engine oil.

I just though I'd add a little more confusion.

Regards, Kes

Kes that's right
That's the oil I have in a brand new bottle full.


Maybe I should go to Mobil 1 then...


Hanah Kim

My recolection is that Rover specify 10W40 oil. In my opinion you are wasting your money on anything else. Not withstanding head gasket failure (a subject I know too much about) the K series engine is bullit proof. Also as I intimated earlier the tappets do not rely on high oil presure. Eaton say that a supply pressure of 0.2bar (3psi) is enough. The chamber inside the tappet fils from an internal reservior and a ball valve locks the oil in the chamber. As Roger said they are designed to have a controlled leakage to purge air and change the oil. If you are buying Tappets try getting them straight from EATON, They are a propriety part costing about 3, but I gauretee there is nothing wrong with the ones youve got. What causes them to be noisey is a mystery to me as well as every one else. Can't see the supply getting blocked. Perhaps gumming of the internals of the tappet. What about valve sticking. This can be a problem on certian drive cycles. Cured usually by a good thrashing.
Paul Hollingworth

A point to mention re oil is with a VVC ONLY 10/40 oils should be used. The oil viscosity is a critical feature of VVC operation and altenrative oils can quite possibly affect this.

Roger Parker

Seems that small amounts of air in the tappet causes the rattle - apparantly a known "issue" on the k series! - NOT a problem - just an irritation !
Thinner oil will help this as air drops out faster!


My mechanic mentioned that thinner oil will make it worse, so he got me 15W40. Hmmm.. I want to stick to Castrol RS. Currently with Castrol Protec.

I am now confused.
Hanah Kim

I think your mechanic is on the right lines. Stick with the grade of oil specified by Rover. I had a chat with one of my colleques in engine development who also does motor sport with a K series turbo. He has a bad experience with the thinner MOBIL 1. He recomends the Rally spec which was something like 5W60 for his motor. For fast road use I would'nt use an oil with a hot viscosity less than W40.
Paul Hollingworth


Hanah, now I feel embarrassed, I've just realised I've been spelling your name incorrectly all this time - it's just that I insist on breathing in the petrol fumes in the cabin. Sorry...

Is your mechanic saying that a 15W-40 oil will be thicker than a 10W-40? The answer is a qualified no. Viscosity is nothing without temperature, and it's the 40 part of the specification which represents the viscosity at normal operational running temperature, 100 deg C. The SAE has two classifications for 40 grade oils, one for automotive oils which includes 0W/5W/10W-40, and another for heavy duty oils which includes 15W/20W/25W-40. The operational running viscosity is the same in both classifications at 100 deg C. In other words all these oils must comply with the same SAE viscosity specification for 40 grade oils at 100 deg C, at least when they're shiny and new.

However the heavy duty 40 grade oils have a different viscosity specification at 150 deg C which is 27% more viscous than the automotive oils at this temperature. The HDO, or rather the SAE grading for these oils, was developed for the punishing life of truck engines and is more like a straight 40 grade oil. If I were you I would use a high quality oil developed for automotive use with an automotive additive package. I don't think you'll find any of these falling into the HDO classification.

Incidentally the lower (W) number does not correspond to a viscosity, but represents the lowest temperature at which the oil will pump and the engine crank, so it has no relationship to normal running.

The VVC engine has an oil temperature sensor on the cylinder head which the ECU uses to determine the oil's viscosity, but I doubt if this is too fine an art owing to the many temp/viscosity gradients of different makes of oils up to the 100 deg C mark, and a certain amount of leeway in the 40 grade measurement when it gets there.

I don't have my handbook next to me, but doesn't it recommend Castrol RS (recently 10W-60) as well as Shell Ultra (5W-30)? So the Castrol is 135% more viscous than the Shell at 100 deg C? Hmmm.

All I can say is just use one of the oils recommended in the handbook.

Regards, Kerry (now that will confuse you!).

take a look at this link

This chap is very highly regarded in the realms of the K series engine - especially Lotus !

Some very interesting info on valves tappets etc and also info on Head gaskets etc etc

see section on lubrication on previous link !

Kes or Kerry... baaa.. dazed and confused Hanah here. Yes you are spelling my name correctly now! Thank you. :) I am not too fussed, as people usually spell my name wrong every time.

Yes, thanks for the explanation. It is I guess best
sticking to what it was suggested in the hand book.
Castrol RS also specificially states that it is quali
-fied for Rover systems.

I have a full 4 liters at home, I will add another bo
ttle and take it to my mechanic!

Tony thanks for the link. I have been reading through
that site for ages. It's quite long and actually very
good. Just wish I was really rich.. not a student.


Hanah Kim

Hanah- If you like, you can borrow my Mini for a week-or a month- or longer, if you like. That will definitely cure you of worrying about tappety rattles.

Of course, I'd take good care of your F while you were borrowing my car...



PS Mr Green T, Tappets and cam followers are teh same thing. Those "tappet adjusters" on OHV engines are erroneously named, they are, more correctly, rocker clearance adjusters or pushrod-length-adjusters.

Got rid of my ticking noise now, garage replaced all 16 tappets, according to the girl - actually I expected this as I had read in the archives, easier to replace all of them. Glad to see they used engine flush as well, anyway they charged me for it!! What is the likelyhood of ticking tappets/cam followers damaging the cam?

This thread was discussed between 24/01/2002 and 01/02/2002

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