Valve lapping tools

[glennster]

Any sources for a good valve lapping tool? I am putting together a 20hp Kawasaki engine on a John Deere mower. New short block (complete engine not available, new heads and new valves. Bought a set from o’reilleys, but the cups won’t stay on the valve.. seems everything I found is the same I have, about 15 dollars. One shows up on a search the is drill powered. I was taught back and forth. I don’t know if it’s good or bad. thoughts?

 

[Jeff NWOH]

Right or wrong, I just put my cordless drill on the stem and use it to rotate the valve and am also able to pull and put a little pressure to help it cut. Never had a real lapping tool that would stick to the valve very good.

 

[glennster]

Right or wrong, I just put my cordless drill on the stem and use it to rotate the valve and am also able to pull and put a little pressure to help it cut. Never had a real lapping tool that would stick to the valve very good.

if i cant find a set in a couple days, i will use your method

 

[Stan Coryell]

Any sources for a good valve lapping tool? I am putting together a 20hp Kawasaki engine on a John Deere mower. New short block (complete engine not available, new heads and new valves. Bought a set from o’reilleys, but the cups won’t stay on the valve.. seems everything I found is the same I have, about 15 dollars. One shows up on a search the is drill powered. I was taught back and forth. I don’t know if it’s good or bad. thoughts?

I bought a Lisle brand from Amazon. It was fine. Not as good as the old ones, but serviceable. Make sure they are oil free and add a dab of spit.

https://a.co/d/069VMB3u

 

[Ray,IN]

The old hand-crank lapping tool, would advance the valve once in a while then return to the back N forth motions. Use valve lapping compound for a better finish on the seat and valve angle.
I assume you had to install new seats too, measure to insure they are fully-seated.

 

[buickanddeere]

A proper valve job does not benefit from lapping .

 

[T.R.K.]

Kawasaki says that their new valves do not need to be lapped into new seats.

That said, I always dusted them a bit with lapping compound before I put the heads on.
I can see their point, if you don't use lapping compound on the valves there is no chance that it can damage the piston rings.

My best crank-type lapping tool was bought off a flea market table years ago. I also have two of the 'Zim' brand, I think, A comparison of both revealed the older flea market tool had cut gears and the newer tool has sheet metal tabs the push the shaft back and forth.

Either way, the spring under the valve and light pressure on the handle is the key to making them work properly.

 

[UncleTom]

Try chucking a valve stem in a drill and you can push it on the face of the valve and forward and reverse the drill.

 

[glennster]

A proper valve job does not benefit from lapping .

These are brand new cylinder heads and brand new valves straight from John Deere.all the top end parts were purchased individually.

 

[JOCCO]

Glen, auto parts store have some basic stuff. Their is a lot on line too sites like evil bay. I have acquired a lot of stuff over the years valve and seat machines and other valve tools. You may look into a local machine shop (automotive).

 

[Welding man]

If the parts are all new, they do not need to be lapped. I do not know of a single machine shop in my area that laps a valve any more. They cut the seats and face the valves and put them together. If it makes you feel better, you should be able to put a small amount of compound on the valve and rotate it back and forth for about 30 seconds and it should be seated. Excessive lapping will do more harm than good. You will make the seating surface too wide.

 

[glennster]

here is a picture of one of the new cylinder heads from john deere. as you can see it is a bare head. did not come with valves

 

[jimg.allentown]

The only reason to lap a new valve would be to see the contact pattern. Otherwise, there is no need. You can do just as well by assembling the head and putting liquid in the combustion chamber with the head inverted, and look for leaks, No leaks - no need to lap.

Consider: would you put a new brake drum or rotor on a brake lathe? Or would you just put it on and use it? Valves are no different.

 

[Phill Tibbetts]

I bought a Lisle brand from Amazon. It was fine. Not as good as the old ones, but serviceable. Make sure they are oil free and add a dab of spit.

https://a.co/d/069VMB3u

That's what my BIL always did, a little spit
. It worked for him for years. Rest his soul

 

[JOCCO]

The only reason to lap a new valve would be to see the contact pattern. Otherwise, there is no need. You can do just as well by assembling the head and putting liquid in the combustion chamber with the head inverted, and look for leaks, No leaks - no need to lap.

Consider: would you put a new brake drum or rotor on a brake lathe? Or would you just put it on and use it? Valves are no different.

I hate to be a ding a ling here JMG. But I have seen new rotors and drums that were out of wack ad had to be turned.

 

[jimg.allentown]

I hate to be a ding a ling here JMG. But I have seen new rotors and drums that were out of wack ad had to be turned.

If they aren'g good and true right out of the box, they go back for a warranty replacement. The minute you put them on the lathe, warranty is gone.

 

[JOCCO]

If they aren'g good and true right out of the box, they go back for a warranty replacement. The minute you put them on the lathe, warranty is gone.

Today they probably would do jut that. Also I have seen new valves and heads that needed work. Guess it pays to check things out.

 

[Hobo,NC]

here is a picture of one of the new cylinder heads from john deere. as you can see it is a bare head. did not come with valvesView attachment 151334View attachment 151335

That head looks like a reject are damaged I see some serious damage. Look between spark plug hole and intake valve seat. To check for seal use a thin liquid such as mineral spirits, gasoline, are paint thinner. Never use water!.

 

[jimg.allentown]

Today they probably would do jut that. Also I have seen new valves and heads that needed work. Guess it pays to check things out.

Trust but verify? A few years ago, new brake rotors were very reasonably priced. It didn't pay to turn them at the time. But in the last couple of years, the prices have been substantially more. But, still, if I pay for a rotor, valve, or any other part, I expect it to be right, right out of the box. If I need to do any machine work to a new part,I consider it defective, and back it goes!

 

[glennster]

That head looks like a reject are damaged I see some serious damage. Look between spark plug hole and intake valve seat. To check for seal use a thin liquid suck as mineral spirits, gasoline, are paint thinner. Never use water!.

Good catch on that Hobo. I just pulled that head out of the box and took the pictures to show the head is new and bare. It does look like a crack between the seat and spark plug. I will return this head and re order another new one. Just because it’s new doesn’t mean it’s good. Btw, what tool do you use for lapping? So far haven’t had any recommendations on a quality one. I will check with our Mac and Snap on guys next time they stop at the shop.