Lapping valves the lazy man's way.

[Provincial]

At least on aircraft engines, I lap all the valves after the seats and faces are ground. Even if using new valves. One time I caught that the chuck on the shop's brand new Sioux valve refacer was defective. Had I not checked the seating, the compression would have been terrible!

 

[RaisedByWolves]

I will do the job myself next summer. Need the tractor to blow snow this winter, that is the thing with tractors- always seem to "need" them and hard to budget down time ...

Here's some Pics of some of the old tools I sourced for the job after it was botched and I will lap in the valves to the seats but Only After I stone grind and re cut seats and valves, actually bought a few spare new valves as well just in case.
This Old equipment did great work and excellent results on a Buick V 6 and Pontiac V8 heads I did. Sourced all of the guides replacement seats ( if to far gone to grind) pilots and stones specific to the tractor as well since these pics
A tractor head should be about the same difficulty or less.

By diamond cutting and dressing the stones the seat angles and widths can be brought back to factory specs. Also had to source New stone holders since the bearings and guides were worn on the old ones in the kit.

Pretty obvious even from the pic of the tractor head went to the "machine" shop TWICE
Actually after thinking about it ,that picture is at the machinest shop to "show" him that the valve and seat were Still leaking after the 1st job he did...
After the second time and another new head gasket and all the other fun for me of remounting the head bleeding the direct injection etc. I gave up. Until I tear it apart for the 3rd and hopefully final time .
If it isn't functional this time I can only blame myself. Some Good did come out of this, It prompted me to buy more TOOLS even if they are old.

ps I called the valve grinder a Van Norman, It is actually a Van Dorn and was surprised it only had 3-4 tenths run out when I checked the valve chucking with a new valve installed.

That’s a nice setup.

Since this is a bit of a lost art, just know that with this setup you only use the weight of the motor end that is resting on the stone and only hit each angle for 2-3 seconds.

There’s no need for prolonged grinding with that equipment and you can do damage if you take too much and shift the seating position on the valve face too much. If the valve seats too far out it will cause the valve to mushroom.

Cleaning up the valve is simple, just lightly grind it until you have a uniform face. Just know that the valve stem also needs ground to bring the entire valve back into spec.

And as mentioned, make sure your valve guides are as good as new before doing anything else. If the guides are cast iron you can use what is called a “push reamer” to raise material, then ream to size, but that is going old school.


If their brass/bronze replace them.

 

[455dan]

At least on aircraft engines, I lap all the valves after the seats and faces are ground. Even if using new valves. One time I caught that the chuck on the shop's brand new Sioux valve refacer was defective. Had I not checked the seating, the compression would have been terrible!

Even though the Sioux valve grinders are nicely built my understanding is many use a 3 jaw chuck to center the valve. Even though the Van Dorn I bought is a small unit it came with collet style grip. Luckily the valve diameters I need to do, fit in the range it covers

Agree on the need to have decent guides or replacement of them.

I have several sets of Pontiac heads and did try and do the reaming them and then hone to size with kit.

They lasted about all of 3000 miles before they were loose. so won't be doing that again. In the interim I was able to source new guides for the tractor engine since they are the replaceable type as are the valve seats if they are worn to far to be machine ground. Tractor guides were in good shape but that was almost a decade ago I sourced a couple seats for intake and exhaust as well but seat / valve recession is not good to have on direct injected diesels since it lowers compression ratio.

As I posted earlier this is why I have been looking for a complete 11/32" K Line Thin wall guide replacement kit and put off further work on some heads
They still make the standard kit but $700 is a bit steep and still hoping to find a good used one for a few hundred bucks. https://www.cylinderheadsupply.com/kl1601rx.html

 

[Provincial]

Know that the tip of the valve stem needs to be ground to compensate for the material removed from the valve and seat in the refacing process. This keeps the geometry of the valve train as original.

 

[455dan]

Know that the tip of the valve stem needs to be ground to compensate for the material removed from the valve and seat in the refacing process. This keeps the geometry of the valve train as original.

Yes, and the valve grinding machines have that ability to adjust valve length after the valve face and seat grinding have increased the valve stem height which can also change the installed height of the spring and therefor spring pressure as well.

 

[a smile]

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.

Lazy people are usually smart people. I like this lazy person

 

[Gnpenning]

Know that the tip of the valve stem needs to be ground to compensate for the material removed from the valve and seat in the refacing process. This keeps the geometry of the valve train as original.

This, as well as bevel the tip of the stem.