Lapping valves the lazy man's way.

T

th62

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I thought some of you might enjoy this.
Lapping valves is just so boring, I have a lot of better things to do than sit around rubbing a stick between my hands for hours on end

Using a drill for this job is nothing new, but cordless screwdrivers are better as they spin quite slow. Sitting there, holding the trigger is also pretty damn boring, so, I rigged up this Makita screwdriver with an 8mm fuel tube over the screwdriver shaft, shoved a 6mm fuel tube into that and pushed it over the valve head.

I then attached a zip tie around the trigger, and a hand clamp around the handle to stop it spinning. Angled the head, turned it on and got on with something else. Returning every now and then to renew the paste and reverse direction.

Cordless screwdrivers are ideal for this job as they spin quite slow.
So, if you're easily bored like me, give it a shot. I should have jumped on the lathe and made a proper setup. After all, I do like making stuff.

 

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Great idea!
I have only done it the old fashioned way with the suction cup attached to the dowel and the hand rubbing motion.

The only concern I would have using your method would be the mating surfaces may become grooved if the valve is only turned in one direction for the lapping operation
 
Cordless screwdrivers, like drills, can be reversed, you can also tap them up every now then.
 
I used my cordless drill to lap valves this way on many race winning engines.

Never went to this much trouble, just lapped long enough to make a good seal.

Of course I had Quik Way valve cutters to get the seat cut to the correct angle first.

John
 
woodchucker said:
I got one word to say: egg beater drill... oh wait, that's 3 words. Egg Beater Drill :grin:
Click to expand...
To words.


If your seats are cut correctly it shouldn’t take more than a couple seconds per valve to lap them.

You’re really just looking for an even witness mark in the correct location vs removing any metal.
 
Last edited:
RaisedByWolves said:
To words.


If your seats are cut correctly it shouldn’t take more than a couple seconds per valve to lap them.

You’re really just looking for a even witness mark in the correct location vs removing any metal.
Click to expand...

This is my thinking also.

I've got some Neway cutters, that I've used on a few motorcycle engine restores. Regarding the valves, I take them to a machine shop for clean up on a centerless valve grinding machine. The faces come out better than new.
 
I always used my drill with a length of rubber hose to provide a flexible coupling. I would lift the valve every few swconds to allow the lapping compound to redistribute. No need for reversing.
 
I still have a hand crank valve lapping tool that I bought almost 60 years ago. It rotates and reciprocates, advancing every so often. This results in an even contact area for the valve. In most cases, the surfaces are quite closely matched before lapping, and very little material has to be removed.

One could easily drive this with a small motor, but it isn't worth the effort unless you were using it where a hard seat grinder should have been used instead.
 
RaisedByWolves said:
To words.


If your seats are cut correctly it shouldn’t take more than a couple seconds per valve to lap them.

You’re really just looking for an even witness mark in the correct location vs removing any metal.
Click to expand...
when you rub two pieces of metal together with an abrasive between them, you are removing metal.
 
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