Valve Lapping Machine

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Brian Rupnow

Brian Rupnow

Design Engineer
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Barrie, Ontario, Canada
Last night, my old friend insomnia sat on the edge of my bed all night and kept me company.--Probably had something to do with many futile attempts to get my Atkinson engine started and not fully succeeding. I am going to pull the head off and lap the valves again. I find that the arthritis in my hands makes it somewhat difficult to rotate the valves back and forth with the lapping compound as I normally do. Not only do you have to rotate the valve back and forth against the seat, but you also have to apply a certain ammount of pressure between the valve face and the seat while doing the rotating, and every so often you have to lift the valve away from the seat to recharge the lapping compound, as it all gets squeezed out of the interface during the lapping procedure. I was taught long ago to never use a power tool such as an electric drill to do this, as it will quickly damage the valve and the seat. The rotating must be back and forth--at least 360 degrees one direction, then 360 degrees the other direction, repeated many times. Last night, I thought of a machine which would do exactly what is needed, that is hand powered, very simple to build, and best of all, I have all the material to build it right here---as in "Don't have to buy anything". It is a very simple machine, and I will post drawings, models, and pictures as I proceed with it. this will not be a long term build, but I THINK its a good idea.
 
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Brian

What you want is a round stick with a suction cup on one end to stick to the valve. Then just rub your hands back and forth and twirl the stick. Should be cheap and simple.

Cheers :)

Don
 
dsquire said:
Brian

What you want is a round stick with a suction cup on one end to stick to the valve. Then just rub your hands back and forth and twirl the stick. Should be cheap and simple.

Cheers :)

Don
Click to expand...
Great idea---done it many times. I'm talking about a valve with a head 10mm diameter. The valve has to be gripped by the end of the valve stem.
 
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Piece of silicon tube over the valve stem and a matching dia bit of rod glued into a suitable wooden dowel and away you go. The tube not only grips the valve but allows for any misalignment between valve and your dowel.

I find model fuel line works well on 1/8" valve stems

J
 
This will be the basis for the machine--A large 3" diameter steel gear pirated out of an old power TV antenna rotor, and a smaller 5/8" diameter gear that I made for something, then fortunately never used, and even more fortunately meshes with the large gear. The mill is actually running when I took the picture, but the camera "freezes" the action. I visualize a simple aluminum bracket to hold the two gears with a spine that can be clamped in a vise, a short handle bolted to the side of the big gear to swing back and forth in a 75 degree arc, and a small drill chuck mated to the shaft of the small gear, which will rotate 360 degrees in one direction when I swing the lever one way, then 360 degrees in the other direction when I swing the handle the other way. The chuck will be clamped to the end of the valve stem, and I will hold the cylinder head in my other hand to provide enough "pull" to put pressure between the valve face and seat while I swing the handle back and forth with my other hand.
GEARS001.jpg
 
Brian I have the valve lapping tool in Jason message the one that is hand powered i put small drill chuck on end it works great back and forth action while you turn crank ken
 
The hand powered tool that Jason listed works wonderfully (I've had one for years for small engine work) and you could easily make various adapters for it. In most cases you will need to access the face of the valve to use the tool. The tool rotates the valve about a half turn forward, then one third turn back, then a half turn forward again, etc., thereby working in a back and forth motion, but advancing all the way around.

Naturally, there is the problem of how to positively engage the valve when the suction cup is too big. This is solved in some cases by having two small blind holes drilled in the face of the valve, both the same distance from the center. A drive dog with matching spigots fits in the holes to turn the valve. One of those drive dogs is shown in the photo of the item for sale on eBay, and a person could always make one with spigots closer together for smaller valves.
 
I didn't know about the ones that could be purchased. All I've ever seen is the wooden handle with the big suction cup on the end, which worked great on auto engines but is a bit huge for my application. Maybe I just like the idea of building another unique machine which I actually do have some use for. It seems that every time I build an i.c. engine I run into problems with the valves, and as I get older this arthritis isn't going to get better.
 
cordles drill run in one direction a bit then reverse. Superglue a piece of al rod on the end head the rod to denature the glue . an Idea.
Tin
 
I have an antique one that has an open frame so you can see how it works. When I get home from work tonight I will snap a picture and post it.

Dave
 
I didn't get much of my own stuff done today, as I had 7 hours of "real" work plus a 100 Km trip. Good wife was supposed to pick up the chuck but got there 5 minutes after they closed the store!!! At any rate, as promised, here is my $10 valve lapping machine.
ASSYOFVALVELAPPINGMACHINE.jpg
 
As Promised here are a couple for pictures of the antique valve lapper.
Both small gears are pined to the shaft but only engage the big gear one at a time; giving the oscillating motion.

Dave

2958419440053545466S600x600Q85.jpg


2692142570053545466S600x600Q85.jpg
 
Very neat Idahoan---Definitly far more upscale than the wooden stick with a suction cup on it that I used on my flat head Ford back when dinosaurs still roamed the earth!!!
 
Made it over to BusyBee during my lunch break and picked up the $10 keyless chuck. I was guessing at the size when I made the model earlier this week, but now that I have the chuck home I have updated the model and drawing. Tonight I made up a shaft and silver soldered the brass gear to it, and drilled the shaft end for the 1/4" hex shank on the chuck and Loctited it into place. For all the kind hearted souls out there who have offered up the stick and suction cup idea, I reiterate, the valves this will be used on have a 0.157" diameter stem and a 3/8" diameter head.---A bit small for suction cup work. I am going to post the detail of the main body---I've no idea why, because the chance of somebody else in the world having the same gears I have is slim to none.
ASSYOFVALVELAPPINGMACHINE-1.jpg

MAINBODY.jpg

GEARSANDCHUCK001.jpg
 
Here we go kids---Movie of the week!!! You will notice that I got so excited about being a movie star that I said "Automotive Chucks" instead of "Automotive valves", but the director didn't want to reshoot that scene. At any rate, it shows my valve lapping machine in motion, and I think it will work fine for what I want. And----as I said in the movie, if it doesn't work at all, I'm only out $10 that paid for the chuck.---Brian
 
That's a pretty cool tool, Brian! If I can poke a little fun here, I gotta say that vice looks like it's been through a number of generations of Rupnow's? ;)

Chuck
 
cfellows said:
That's a pretty cool tool, Brian! If I can poke a little fun here, I gotta say that vice looks like it's been through a number of generations of Rupnow's? ;)

Chuck
Click to expand...
Well Chuck--We all have our vices----I'm ashamed to say, I am the original owner of that vice, but I don't think its ever been cleaned. Stuff out in the main garage doesn't get cleaned to often. I sweep up the floor because my wife parks her Toyota on the side opposite the hotrod bay, and she's kind of paranoid about nails in her tires. (With good reason). I never realized how nasty that vice looks untill I seen it in the video!!!
 
Mine looks the same way. By the way, I realized after reading my post, it should be vise, not vice... at any rate, seems like the one spot on my bench that never gets cleaned.

Chuck
 
I also have one of the hand-operated ones that I inherited from my father-in-law but I will follow your posts for the sheer pleasure of the journey. I am sure that it will be instructional and enjoyable.

Jim
 
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