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mk3 tappet movement

Submitted by steve_elston on Sun, 10/07/2016
Forums
Commando

Hi all

I've tried setting a noisy nearside exhaust tappet using a clock as I can't use feelers due I'm sure to an indentation in the valve stem

I was shocked by the movement anywhere between .010"to.015" up/down and considerable side play, by pushing the rocker arm to one side the tappet/valve clearance would nigh on disappear about.002"

All spring washers are where they should be and seem intact if maybe a little weak and the rocking seems slightly notched as if there are facets on the spindle

I intend to strip the head down after returning from our camping holiday and would like some advice on which rocker spindles to go for, I quite like scrolled spindle for spreading the oil as anyone used them on a commando

thanks

Steve

Submitted by john_holmes on Sun, 10/07/2016

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The Commando has full oil pressure feed to the rockers and the oil flow is restricted using the oil hole in the rocker spindle facing the wrong way. I would be wary of using scrolled rocker spindles as you risk oversupply. That said your spindles and or rockers being worn could be from lack of oil supply so the oil feed system needs checking over. Get some lash caps for your valves to restore flat surface.

Submitted by ian_cordes on Sun, 10/07/2016

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The problem does seem to be worn rocker spindles. Scrolled spindles will waaay over-oil the top-end, and are only for low pressure feed systems as found on Dommie's up to 1966 or thereabouts. Use plain.

If the valve stem has an indentation, but is otherwise sound and within serviceable limits, then you can use lash caps, hardened steel buckets which drop over the end of the valve stem. They are available from RGM, part #050465, and possibly other suppliers. They do effectively add 0.040" to the valve length, so you need to be sure you have sufficient range of adjustment to accommodate that.

If the valve is indented, you may want to check the condition of the rocker ball ends, as well as checking that all oilways are clear and correctly aligned, as this may be the cause of wear on the spindles and valve.

I have just seen John's post, which he must have posted as I was typing! We seem to concur...

Submitted by steve_elston on Sun, 10/07/2016

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Thanks for your speedy replies

After posting my original message ,I delved a little deeper into the scrolled spindle and quickly realised its not the one to use.

As for lash caps, two ordered from rgm and will fit them if I have the enough time

Is just me ,or should a lash cap be worn to your local pub

cheers

steve

Submitted by jim_hill on Sun, 10/07/2016

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Previously john_holmes wrote:

The Commando has full oil pressure feed to the rockers and the oil flow is restricted using the oil hole in the rocker spindle facing the wrong way. I would be wary of using scrolled rocker spindles as you risk oversupply. That said your spindles and or rockers being worn could be from lack of oil supply so the oil feed system needs checking over. Get some lash caps for your valves to restore flat surface.

Jim Hill, WTF are lash caps?

 


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