Tappet adjustement

[daverclasper]

Hi .

 

Thought I'd check clearance's today as stopped using lead substitute a while back. 3 were a bit tight. 1 exhaust, 2 inlet and a couple a bit big.

 

I assumed that normal wear (not valve recession, from using unleaded) would show as the bigger gaps.

 

Also never sure on how tight to do up the nuts. I think I may go unnecessarily tight, as take a bit to undo?. Don't know how much load the nuts take when running?.

 

Any help great please.

 

Cheers, Dave

[Pete Lewis]

Dave,The nuts are only half thickness so a light nip with a normal spanner is all thats needed ,

they only have to hold the screw from being turned by action of the revolving followers and push rod

many get done up by a gorilla and then they are hard to undo , the threads get stretched and

they are stiff to adjust on the tappet screw

 

you need to do many many miles to see recession most wont ever find it

 

the wear under the rocker will give a stepped face which most feelers will bridge so checking the actual gap can be difficult, dont see them around much but a wire feeler would work well as it fits in the wear platform

there things like click adjust these eliminate the wear but you need to to set it acurately on one rocker to

pre judge the number of clicks

there are some with a micrometer style barrel which is better so you close the gap then back off the 0.010" but they are more expensive and harder to find

 

most of my gagets stay in the unwanted draw and feelers used with care get my vote

 

if thats good waffle

 

pete

[Guest]

Hello Dave.

 

Valve recession wil close the gap as the stem moves closer to the rocker arm face; however that will take many thousands of miles and engine thrashing to start such a process. A lot lead memory is held within the valves / seat faces.

 

You will need to do the securing nuts up tightly, but you may also find the the thread the nut sits on can wear slightly through the process of adjusting the clearances; again it will take a long time for that to occur unless the nut has been cross threaded - unlikely. I doubt you are overtightening the nut as it is very definite when its maximum "pinch" has been reached, the fact that the nut feels tight to undo is a sign that it is secure and doing its job. However some owners fail to tighten the nut sufficiently and of course the obvious occurs. 

 

A common problem for incorrect gaps can be opertaor error. By this I mean the rocker arm may not have been at the zenith of its rise prior to moving back down when the gap is measured. If the arm is not at its peak you will have an incorrect gap to begin with and any adjustment will follow suit and compound the situation.

 

There could be wear on the face of the rocker arm and this can cause inaccurate measuring when using the feeler gauge.

 

If you have a Click-Adjust then I would certainly recommend using that as it is very accurate and does iron out incorrect initial rocker arm settings.

 

The other problem and it's human nature is that when the nut is being tightend there may be minimal movement on the adjusting grub at the same time; that of course will throw out your initial gapping.

 

It's a case of double checking all the time to ensure that the optimum rise of the arm has been achieved so that the correct gapping can be achieved.

 

Can I ask why you have stopped using lead substitute - unleaded head conversion ??

 

Hope the above is a "starter for ten" ??

 

Regards.

 

Richard.

[Pete Lewis]

Theres no torque given in any triumph manuals

 

my father in law always stripped or sheared the tappet screws on his cortina, hence the gorilla notes

 

only the spherical tip is hardened the threads are just normal ,

if you take a full 5/16 nut hard face fixing as 18 to 20lbft then a half nut max is 10 lbft

and possibly a bit less

 

pete

[daverclasper]

Hi and thanks.

 

Richard, I have no unleaded head conversion . Stopped using lead sub, as folks experience, suggests that on engines with some good miles on them, will survive with lead memory.

 

Cheers, Dave 

[Guest]

Hello Dave.

 

Fair point and mirrors my comment on such.

 

I have a Click-Adjust which I am happy to loan you if you wish to give that a try ??

 

If you are at Stoneleigh next Sunday I can bring it along or post - needless to say absolutely no charge whatsoever even to cover the postage. Let me know.

 

All the best.

 

Richard.

[damson]

I find that I use a 10thou feeler to slide in and out easily and a 12 thou feeler which won't go gets it right.

I have a click adjust but haven't the patience to figure out how to use it!

[Pete Lewis]

You set a tappet to the desired gap, with feelers

Fit the click and turn it to zero the clearance and count the clicks as you turn the knob.

so next rocker fully up you turn to zero clearance and unscrew the number of counted clicks

you should end up with the previous desired feeler clearance

 

Well something like that

 

pete

[daverclasper]

Thanks folks and thanks a lot Rich, for your offer of click thingy.

 

At least I have opened up the possible tight gaps.

 

In the past I appear to have identified the noisy ones with engine running and length of hose to ear and tother end close to valve, then closed it up until it feels the the same as others by rocking the rocker by hand.

 

Will give that a go again for now, unless this is an bad way of doing it?.

 

Cheers, Dave

[Pete Lewis]

If you sense a noisy one use a old feeler with engine running , ifit goes quiet expect the wear to

have upset your feeler feel.

 

on the bright side a noisy one with a actual gap is better than a tight one without enough gap

Pete

[haggis]

Hi dave, I'm sure this will be controversial, but I used to attend a classic car maintenance club at my local technical college ( know idea why I stopped going as they had all the equipment you could possibly dream of for £5 a week) the guy who ran it was a technician there and on a couple of occasions I tried to resolve my noisy tappets on my Vitesse, struggling with this I asked his advice and he suggested tightening them up until the feeler was very stiff to pull out and put in. I've got to say the results have stood the test of time and even with partially worn parts never had any valve noise and the car has performed fantastically. i guess that every rocker has its own wear so using a flat feeler just doesn't take up the best shape of the recess. Pete's wire feelers sound the best option, any idea where can I get some?

I have got through about five sets of feeler gauges in ten years.

 

Hag

[Pete Lewis]

https://www.amazon.co.uk/TOOLUSA-SPARK-PLUG-GAUGE/dp/B00VUGMDBC/ref=pd_day0_200_14?_encoding=UTF8&psc=1&refRID=1FNGPZZGDQVMK9Z64EKW#productDetails

Something like this is the idea but cant see the feeler sizes these probably too thick need to search
or keep a look out at boot tool sales

 

they seem to be hard to find these days ,  plenty for spark plug gaps but not found any 0.010"   0.254mm

 

why not make one from a fettled paper clip ???

pete

[daverclasper]

Thanks everyone

 

Pete. With regard to the paper clip idea. Does the wear platform have an open front in the recess , where the end of paper clip would push in?, if this makes sense, please.

 

Cheers, Dave

[Pete Lewis]

yes the wear normally gives instant access to the valve stem without any real problem  

 

on a sunny day with the rockers off    a little careful work on a grind stone you can fettle the  wear ridge off,   the tips of the rockers are tough but not overly hardened

its not hard to follow the contour of the wear  face  even with a block and some wet  and dry 

 

have you found a paper clip or wire at   0.010"  yet ??

 

dont get too carried away or overly concerned about these wear points , it not the end of the world .

[daverclasper]

Cheers Pete

 

Not looked for wire yet. Will aim for doing it that way.

 

Is the refacing is so you can use feelers conventionally and accurately.

 

Dave 

[Pete Lewis]

Yes , its possible to reface the stepped face back to a more original contour thus allows a feeler to slide in without bridging a wear step.

 

just take them down to the wear face, some makes are not hardened, some are just tip hardend by gas flame or induction , even wet dry will attack the step with care and patience.

 

Pete

[JohnD]

If all you have is a set of  millimeter feelers, then a near approximation is that 0.25--0.26mm brackets 10 thou(sanths of an inch)

 

See picture.  Worth keeping a copy in your tool box.

 

John