How-To: Lap Valves (by hand and drill method explained)
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- Опубликовано: 28 авг 2024
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Valve grinding compound
amzn.to/33UrZYS
Small valve lapper
amzn.to/33VwW3N
Large valve lapper
amzn.to/30iG41x 
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Great video. I didn't tune into find out how to lap valves. I tuned into to find out his results using a drill. I've got carpal tunnel and didn't want to aggravate it by hand lapping. I cut my hand lapper in two and drilled a hole in the handle and epoxied a piece of 1/4 tubing in for the drill to chuck up on. 1st valve I lapped had very negative results. The valve seat was grooved up like one of his. I stopped knowing not to proceed and make things worse. Fast forward a week or two and I found this video. Seeing him chuck up on the valve stem made me cringe just a bit but I've done worse in a pinch. The reason for the grooves is slightly more complicated than he describes but he is not wrong. It's not so much the grit as it is the metal being removed by the grit that creates the grooves. Hand lapping gives more relief for the particles of metal to move out of the way due the reverse in rotation and the slight side to side movement. Another thing that hand lapping does is cause you to stop, clean, and check the valve seat more often which also removes any removed metal. One other thing not mentioned is compound grit. Typical grits found at auto parts store are 120. Do not under any circumstances use those with a drill. I went back and lapped another valve that had only a few minor pits using a drill with 220 compound. Ten sec in one direction and then ten sec in the other. Cleaned the valve and seat and since the pit wasn't quite gone I repeated. I followed up with 600 grit compound using the same method with the drill two more times cleaning and re-applying compound each time. I finished with a quick min or two of hand lapping with the 600 grit. Results were good and my hands don't hurt.
I repair engines since young age and I always use the drill and never had any grooves like you describe in your drowing. I use to alternate the spinning speed and direction, pushing in and out with different pressure .
I also start with coarse granulation paste using slow speed and little pressure and finnish with fine granulation and more pressure.
Exactly, why would anyone just go in one direction? The drill has a forward and reverse so why not use it? I also have never seen ridges form, but of course it is easy to end up with too wide contact areas...
Just to make it sure use hand for finishing
that is what I was thinking I am buiding a performance boat engine on a budget and time and was thinking why not use a drill at a slow speed and just float it up and down then you can reverse the dirrection. I wonder if you can use rubbing compound
You can put a few inch section of vacuum line or fuel line around a drill bit and plug the other end with the valve rod, that way you know there's even pressure against the seat and no possibility of gouging the rod and no residue from the tape
I really like the vacuum line method but I recently found the Neway cutters there awesome. After you cut your angles I followed up with a fine lapping compound I made from regular valve lapping compound and turtle wax polishing compound. Its not as abrasive and takes the chatter marks off.
Good idea I am going to use that
Get your lapping stick and thin it down in the lathe where your hands would be , you'll find it a lot easier, get your valves refaced , your seats need top and throat cut to get the seat ⅓ down and ⅔ up on the valve face . Get the seat width right and it will cut the carbon .Yes I am an engine reconditioner by trade , and was in charge of the head bay for years .
Great explination. Im getting those micro grooves eaven tho i`m lapping by hand. I`m not using a drill. I bought new valves and lapped them the way you explained and the micro groves are forming
What was the solution
Valve grinding compound
- amzn.to/33UrZYS
Small valve lapper
- amzn.to/33VwW3N
Large valve lapper
- amzn.to/30iG41x
There is a tool for your drill that rotates just like your doing it by hand great to start off with and finish by hand .we also have a 2 course vale grinding paste course and fine this way saves a lot of time
i like lapping them with a 6 inch piece of 3/8 rubber hose attached...then i clean everything ,put the valve back in and hold the valve closed with only my finger then pour gas in the port to check it...if there is any wetness at all do it again
The thing is, you can switch drill direction.
That was a pretty good explanation of what happens spinning valves with a drill.
The other thing though, the valve clearance decreases very quickly as the various ridges wear away.
Also, just about all OEM motorcycle valves since late 1990's have a very thin hardened face that can wear off with even minimal lapping. Workmate with a Kawasaki ZX1100 didn't believe it.
He got 90 miles before having to strip top end (and was most pissed off about price of second head gasket
I have gotten great results with a drill. You have to set it for low speed and not use a lot of force, just lightly. Also, you have to go forward, reverse again and again. Do not tighten the chuck too far. You want no marks and it does not take a lot if you just go easy and reverse over and over again. If they are fixable it leaves a beautiful even finish. When too pitted you have to go to a pro unless you have the tools especially for valve guides and if the heads are full of gunky sludge.
i suppose you had low compression the way to tell rings or valves is add a spoon of mtr oil in plug hole if it helps comp its the rings leaking if no help it is the valves leaking
Good tip! I’m going to do this tomorrow!!!
Super helpful mate, Great video
Thanks!
You guys that are using drills you're going way too fast! I work in a machine shop I am a professional engine rebuilder I have lapped well over 1,000 valves and I do use the drill in same manner this feller did he but he is using Way too much speed! You want to simulate the speed of doing it by hand which is barely pressing the trigger of that drill. You also need to spend in One direction until it gets quiet push the valve out switch the drill spit it in the other direction back and forth just like that.
Thanks for the info! Is it a must to shave heads after lapping valves n or can they go back n? Thanks
There is a spec for warpage, for a typical 4 cylinder inline head it is .0025 or less. Subaru head I believe is .0015 because the head is half the size. Most of the time the head that was never overheated is ok but will start to warp around the exhaust valve side of the head due to the heat running 100k+ miles. At minimum it should be wet sanded with a very flat block and 320 grit.
I might use lapping compound start with a course and step it down. Thoughts?
I'm a shade tree mechanic and he's chewing that bitch up.
Probably best video for newbie s.
No it's not. The mating surfaces should be a ring about 0.045" wide. After his drilling he is more then double that. He took waaaayyyy too much off.
So wouldn't it make more sense to run the drill at the low speed, and keep tapping and changing direction?
that is what I was thinking go slow
so diligent and clean
Hand is the best method 😊
You need a variable speed reversible drill i go way slower and check often, i haven't gone too far yet doing it like that, if the seat width goes past 2mm thats where trouble begins
I thought about using a drill too, and at first I was going to do it from the stem side lie you did, but I thought better of that. I was planning on pulling the suction cup off the wooden part and put it on the end of the drill instead. That way there is no chance of biting into the stem with the chuck. I haven't tried it yet though
I didn't want to "cut" my tool up. But yeah that would work.
@@HTMR I think I was actually able to buy the suction cups separately
If you lap valves with a drill you have speed control, only a fool would drill lap flat out. Secondly, you don't just lap in one direction, use the reverse switch, thirdly you lift the valve every now and then. Some people just don't have much of a clue.
Great video. Cheers from France
Thank you for sharing this!!!
Some solution that I done. Change the rotation of your drill. Forward and reverse and repeat.
In our shop this is what I do. I also try to keep the drill speed very slow as faster speed always produces that shiny deeper pockets while slower speed always produces a good surface finish.
One way I check for a good seal is to install the valves w/springs and giving it a light tap and screw the spark plugs in then put some gasoline over the top to submerge the valves, then with compressed air, blast the intake and exhaust ports if the seal is good you wouldn't see bubbles leaking out of the valves.
It seems to me from a machinist stand point you screwed it up, when you went lazy with the drill and don't understand what you're doing you trashed the heads. See when you grabbed it from the stem any and all tolerance between the stem and guide transfered to not running true on the valve seat making the sealing surface wider meaning you just trashed it and now are past tolerance. Nice work on showing what not to do
Don't worry the heads went to the machine shop for a valve job.
@@HTMR then what’s the point of the video?
@@Make-Asylums-Great-Again The point of the video is to make money to pay for the machine shop work
@@HTMR Just came across this and usually have a high regard for your content Matthew. My understanding is that the valve and seat angles are intentionally supposed to be different, so that the seal is created by a small ring/interface. Since pressure = force / area, where force would be that of the valve spring, having a smaller area to project that force onto produces a higher interface pressure with better sealing.
I also believe that most lapping should be done only to make a determination of the contact width between the valve and seat, and generally after a proper machine-shop head overhaul (with guide replacements) that there should be no lapping as you'd be degrading the quality of the job.
If you had qualified your statements that the lapping is only being done for illustrative purposes, to show the pitting in the valve and seat, then I'd be OK with that.
Kind regards, Terry
Slow rotation 3 seconds / reverse slow rotation 3 seconds / forward slow rotation.........
Medium Not excessive pressure. Let the grit do the work. Putting too much pressure squishes it right out.
Intro blew my ears out
Excellent explanation. Thank you!
A cordless screwdriver is a better option than a drill, BTW. Lighter and slower.
Yes, it works GREAT!
Nice video. Thanks for the close ups.
You have the Drill on High Speed...
I Put Mine on the Lowest Speed Setting and Everything Looks Just Fine...
Details regarding laping is good in reaching quality I'm having a question when we replaced with a new tappet valve's could I done any modifications to the top of the stem reasoning me some issues while clearance seating isn't correct at the bottom of shims and camshafts.
so if i buy new valves do i have to lap them before i put back in the head. also there not titanium
Hi. I buy new valves tomorrow fpr an old cylinderhead, the head looks good. Do i do lapping before i put the new valves in or? Its a car engine from 2011. Or do i just put valves in the head as them are from new
I put all new valves in my 4.6l ....... hand lapping is very easy with new valves $80 for all 16 valves new
Thank you very good info for me thank you
Can we clean off the carbon deposits on the valves using petrol n scotchbrite instead? Intention is to use a softer material than metal , so as not to remove the metal material of the valve... TIA for the advice...
Scotchbrite works ok for light carbon like on intake valves, but I find it much easier and faster to use 80 grit sandpaper, use go slow and stop and check often.
Look at the state of the valves on the back where the fuel is pulled in...that's perfectly cleaned before I start lapping
When I run it with a drill I put a rubber hose on the end of the valve and then of course on anything that are going the drill whether it be a screw usually a screw sometimes a drill bit which obviously don't stick a drill bit up in the head but I stick it inside the rubber too the river too for one it won't let you pull so hard and also it will start to bind up we're having it directly hooked to the drill what you've done this many times so I'm sure you can feel it me I've never done it worse directly hooked to the drill and the reason being is because to me it's too tired of a situation I want to have some flex and some give if it needs to have it and that rubber too will give me that and I just move it up and down you know as I'm turning it and I turn it both directions reverse and forward and it does a pretty good job that way I never have actually hooked to the valve itself with my drill I just never have been that confident with it not saying to God wouldn't keep it straight and all that not really worried about that the rubber tube just gives me an opportunity to move the valve up and down you know and and the rubber if it gets it gets some kind of binded or gets too much pressure whatever the rubber would just roll up and it gives me that you know that gives so that I'm not damaging anything but that's just the way I do it
Good stuff!
There is a adapter tool with suction cups which does the left right turn as well. Does the same job as the the wooden handle tools. The drill version is a big NO NO... we figured that out ages ago. Only in 3rd world countries 14year old do that in some sand floor backyopard garages.
There is way more to do to a valve job than just lapping a bit. A valve job starts with a 3 angle valve seat cut. Lapping is just a small detail of 24min work for a 24V head. Still thanks for sharing!
Thank you
Great work
So use a random orbital sander attached to the valve, good to know.
There are a lot more issues than performance with worn seats. For example, the fact that you may not be able to get valve lash in spec. Also your valve spring install height changes which can make it easier to float or drop a valve at high rpm
Good work thankyousir
you alternate turning by hand but you refuse to use reverse on your drill? What gives?
I mixed my bike valves... exhaust side. Any advice?
You should also do it in reverse
BTY. when i do a seal test with water, the valves don`t leak however my concern is the micro groves
Did they work like that?
mate reverse the drill and run it back and forth from clockwise to counter clockwise, to avoid causing the problems your running into....! same way you lap by hand....
Does brand new factory installed valves need this process too?
Yes. And then they are married to that seat in the head
Pitting on the valves were bad.. seats not as bad.. maybe buying new valves and lapping them in would have been better.
Nice shop Bro, how long ya been doing it?
I've been at this shop for 15yrs. Wrenching for 25 or so.
I just bought new valves...
drill is a no no on laping all you need to do is polish the surface for air seal
can you say something about 3-angle vale seats? I intend to lap the valves (by hand) in my Honda J-series engine. I am told it has 3-sngle seats. I assume the middle cut is a full mating surface, and the two outer cuts would be partial mating surfaces with tolerances/specs as you mention. Anything else you would add?
the other angle is to channel airflow
Drill speed ridiculous. All the paste will fly out. Slow and steady ,
Could always buy a cheap hot glue gun for the toilet plunger it might actually stay on the valve
That’s just what I do.
Omg! Dude turn the drill to low speed at least. Way way to fast and you gotta open it up more and more often to keep good grit in t the cut. And secondly reverse direction after 5 seconds or so.
You don’t need to change direction, the metal doesn’t know the difference. An angle grinder only turns one way, the metal doesn’t care - physics 101
Lol
I cant take anyone that wire wheels Valves and seat
Dude you are going waaay too fast! You want about a tenth of that speed!!
Uncle Tony is laughing at this clown.
#1 If you don't understand how to grind, file, sand then you shouldn't use a drill on your valves. Spinning the drill that fast as this video shows is ridiculous. Absolutely laughable. I was shocked to say the least watching that drill hit full speed. Drills can be used very very effectively but if you are spinning the valve that fast (including the valve grinding compound) then you are being careless/clueless or both.
absolutely short slow bursts both ways
Directions unclear, please demonstrate the lick one more time. 4:19
Dai asy khor ghai
such a bad way to do it with a drill. going way to fast to start.
Stick to motorcycles