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MG MGF Technical - Engine/Tappet experts required....

Greetings all

Well I’ve been scratching my head for long enough so I thought I’d request some help from you guys and gals (oh no! I sound like Jimmy Saville!).

My engine seems to be very tappety, NOT at idle but at about 1500/1800 rpm.

Solutions tried:

1) Oil flush and new oil and filter (oil semi-synthetic 10w/40).
2) Cam cover off and rotated hydraulic tappets.
3) Stand scratching head for hours on end.

Possible next step:

4) Application of one large club hammer.

Car/Engine:

1.8 Mpi with 61000 miles, maintenance history good.

HELP!

Any ideas?

Cheers in advance

Russ Fitz
Russ Fitz

Russ, you could try adding some redex to your fuel. This is an upper cylinder lubricant and will quieten you tappets. Providing there is nothing majorly wrong this will help.

PS... expert on engines, not really but you have already done all of my basic suggestions for the last person with a tappet symptom. Then some bloke who designed the 1.8 engine came on and said that all our suggests were wrong.
That's interesting I thought considering my solution actually worked. Moreover he suggested the wrong oil for the car.
So I may not have expert status, but those who claim it often are often not.


Could be a vibration from the engine, is there something catching the engine?

Ian
Redex cured the noisy tappets on my MX5.
Ian

Cheers Ian

Redex fuel additive can't hurt so might give it a go.
I'm surprised the techies haven't jumped in on this thread.

Russ
Russ Fitz

From a non expert who got told off for interferring in the last tappet thread, you could try changing the tappets/hydraulic cam followers or whatever they are called.....?

Steve :c?
Steve

Russ,
OR... you can modify the hydraulic tappets to solid type. have a look at
http://members.aol.com/dvandrews/kengine.htm .
other mods in this site really do look tempting.

cheers.
Jason

I don't own an F, but any half way competent mechanic would know that a fuel additive could have no possible affect on tappet noise. Maybe some one doesn't know the difference in sounds between tappet noise and pinking? Solid cam followers will be a lot noisier than ticking hydraulic tappets, so that's no real solution. I had to change to 20W 50 oil on my non F to quieten the tappets, even though the book calls for 10w 30. Also it is very sensitive to oil level.
George B.

>>My engine seems to be very tappety, NOT at idle but at about 1500/1800 rpm.<<

Doesn't 'sound' like typical tappet noise to me either - which should be audible from tick-over. I wonder, like Ian, whether this is a reasonance noise from something attached to the engine that has become loose.

Unfortunately, noises are almost impossible to diagnose on a forum like this. I'd recommend a trip to a friendly and tame mechanic to try and identify where from the engine the noise is eminating.

Expect the unexpected! ;o)
Rob Bell

Cheers All

Thanks all for your input.

I'm sure its tappet/cam related, I've checked cam belt and there it nothing shreading off of it, anyway the frequency of the noise matches that of tappet/cam rotation.

The noise appears to subside arround 2100 rpm.

I've read somewhere that the K series can suffer with oil aeration im wondering if this may have collected inside a hydraulic tappet and therefore its become compressible???? Any other ideas?

Russ
Russ Fitz

I had this symptom once in a 1.8i engine.

The cause was failing collets (i think they're called).
I'm not particularly technical but my best description
is that they are the tiny metal rings which make the
connection between the valves and the springs. A couple
had cracked and the valves were slipping downwards!!!!
(I guess the tapping noise was the hydaulic followers hitting the top of the valves)

As you have described, the tapping would often not
occur at idle but only become apparent at slightly
more revs.

I think if you remove the hydrolic tappets and inspect
the levels of the tops of the valves w.r.t the tops of
the springs it should be fairly ovbious if anything is
amiss.

Don't think this is a common fault, but you never know.
Mike

Russ,

I also have got an engine noise around 1500-1800rpm. After investigations by MGR and a Small independent engine specialist the noise was identified as resonance from the small cam belt to left of the head (passenger side), Aparently wide belts do humm sometimes. Not sure if the Mpi has got one there thou.


Iain
98 VVC
IJ Blanch

Iain

Thanks for the input.

As I understand the VVC has an additional belt on the opposite end to the cam belt so the Mpi doesn't have this.

Belts can produce a hum but i've got a rattle/clatter.

Cheers

Russ
Russ Fitz

The later modification is to use what are called carbon break valves which have a machined section on the stem to dislodge any carbon deposit before it can cause problems. If carbon does start to cause sticking and I have had to deal with this on a few Rover 16v engines, then the valve will not close quickly and the cam profile loses contact with the tappet. The slack is far greater than the hydraulics within the tappet can cope with and so this slack is then noted when the cam and tapet make contact again. Many fuel additives are available that are 'said to be' catalyst friendly. The early K series in the F would not have the modified valves and if the car is used gently especially in mainly an urban driving environment then the conditions for the carbon build up are greater. Additives have a limited effect and are generally only a first aid sticking plaster type of solution.

Previous M and T series 16 valve Rover engines seemed more prone to this problem which could actuaklly result in the engine running on 3 cylinders for a while. In the early stages of the problem the extra valve noise was most audible above idle speed similar to this engine. I have no real idea as to why this was so, but expect it will be in the general dynamics of the cam, follower, oil supply, etc.

Rog
Roger Parker

Thank you, Roger.

When I said surely they aren't sticking open I was aware that that would be a much more serious problem than noisy tappets alone and would cause a noticable power loss.
George B.

This thread was discussed between 02/09/2002 and 08/09/2002

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