TAPPET DANCING

[sloopjohnrb]

Please. may I ask how one goes about adjusting the tappets to stop tappet knock?
1962 4 door 948 cc petrol. Series 2

I've searched previous articles and posts but not been able to find anything really helpful.

Since owning my Moggie, about 4 years now, I've gradually gained confidence in mechanical areas, thanks to this here MMOC and the Haynes manual.
I've done some "big jobs", but am totally at a loss as to how to go about tappet knock, it's outside my current knowledge.

I've got tons of tools collected along the way, and would love to learn how to do it and add to the knowlegebase, if someone could give me a few pointers about how to approach it, I would be grateful, as indeed, I have been grateful for all advice over the years.
Best wishes
John

[bmcecosse]

Your faith in Haynes is misplaced! However - it is a useful 'guide'.
Easy enough to adjust the valve clearance ('tappets' in an ohv are in fact the cam followers) and this i'm sure is specified in Haynes - I suggest 12 thou for inlets and 15 thou for exhausts. But the problem is - is the noise you are hearing caused by excessive valve clearances - or is it something else! The rocker shaft and/or the rockers may be worn causing some noise - or it may be something else. Most likely is the chain driving the cam (at the front of the engine) - which wears horribly and causes slapping/clanking noises. I suggest you set the valve clearances - and then decide if you can live with the noise. It's a bit of a job to renew the timing gears and chain.

[RogerRust]

To work out where the noise is coming from Use a very big screwdriver preferable 15 to 18 inches long put your ear to the handle and touch the pointed end on different points as you work your way around the engine. Start with the rocker cover bolts learn that noise, then the cylinder head bolts, the water pump and perhaps the biggest cause of "engine" noise the dynamo so listen to each end of it.

The distributor has my favourite sound like a fast beating clock.

As you can tell I really enjoy the experience.

Just be careful near the fan belt and blades and make sure you don't have any loose clothing or hair that might get caught.

I have got a proper stethoscope, but I prefer the screwdriver. I remember my father listening to the rails at a level crossing to see if a train was coming I suppose that’s where I got it from! .

Roger

[Kevin]

Hi John if you look in the Tech tips under servicing its in there and is done with the engine cold using the rule of nine, have a look if there is anything you cant understand just ask.

[AndrewSkinner]

How do you know what valves are inlet and which valves are outlet!?? Sorry for my stupidity!

Andy

[alex_holden]

They go exhaust, inlet, inlet, exhaust, exhaust, inlet, inlet, exhaust. You can tell by looking at which valves line up with which manifold section. Personally I use 12 thou for all of them, but then I have an unleaded head that shouldn't suffer from exhaust valve recession.

[IslipMinor]

With a standard cam, the BMC 'factory' setting is 0.012" (12 thou) for both inlet and exhaust - saves all the bother of needing to find out which is which!!

Looking at the engine from the front, use the starting handle to turn the engine until the first valve (closest to the radiator) is fully open (down). This is number 1, and the other valves run in number sequence to the back of the engine, with the last being No.8.

Using the rule of '9', with No.1 open, adjust No.8, then with No. 2 open, adjust No.7 etc. As you do it you will see that 2 valves open at virtually the same time, so you can adjust the matching 2 adding up to 9 at the same time.

[sloopjohnrb]

Many thanks to you all, great advice.
I've adjusted the tappets and the "knitting needle"noise has stopped.
Also, the tip about using a long screwdriver as a stethoscope really did help, it works brilliantly.
Thanks again!!