Valve Seat Cutting

[WHX?? 50,740]

So I got this RE-67 from Madge at the big show. Couldn't get it run no spark but easy fix.... clean the points wich of course are under the flywheel. Since head gaskets are cheap figured I might as well pop the head and just check things out. Seemed like pretty poor compression. Maybe a stuck valve? Nope valves free but noticed valves and seats had some corrosion. Ordered some new valves and the intake lapped in nicely. Used @Achtos sharpie method to check things out. Will let him explain that.

 

The problem is the exhaust valve has a pitted seat and should be cut. Lapping does no good with even course compound but does prove there is good contact with valve to seat. 

Problem being I am a cheapskate and even a basic Neway cutter is upwards of 250. Little pricey for the hobbyist unless I run into other motors that need it but so far all the Kohler I've done never needed it. 

I have seen cheapy sets on the jungle or fleabay for the cheap anybody have any experience with them. 

BTW this is a Techy V60 with cast in seats. 

The Madge says ran good when he put it away. 

Sure would like to do right by this girl. 

 

 

[RED-Z06 2,479]

Wow that seat is really bad for sure.

 

Do you know the pilot diameter, seat diameter and angle?  I have an idea..

[WHX?? 50,740]

Yep 7.29 mm stem = about  5/16 for a pilot. Not sure of the seat dia. But valve measures 29 mm and some change. 

Manual calls for a 46 degree seat but Neway says a 45 deg will be ok as long as I don't fly her at 10,000 feet. The valve has a 45 deg seat face so I think Techy is looking for a positive interference fit. 

Edited January 24, 2022 by WHX??

[RED-Z06 2,479]

Okay, this kit has the 5/16 pilot and the cutter sizes i think will fit, and 45⁰ cutters

 

https://www.ebay.com/itm/Carbide-Tipped-Valve-Seat-Face-Cutter-Set-Of-5-Pcs-Kit-Pieces-Cutters-Tip-/184772588925?mkcid=16&mkevt=1&_trksid=p2349624.m46890.l49286&mkrid=711-127632-2357-0

Edited January 24, 2022 by RED-Z06

[RED-Z06 2,479]

Might be pretty tight on diameter..im not sure how they are measuring them..outer or inner limits..

[WHX?? 50,740]

Thank you sir I have eyeballed that one and looks like it would be ok for the hobbyist. 

I have researched this topic quite considerable and have found Neway's site to be chock full of good info from professionals. If I was building motors to put bacon on the table I would have their stuff fer sure. 

https://www.newaymfg.com/cutters

Edited January 24, 2022 by WHX??

[RED-Z06 2,479]

Neway has good stuff, spendy too.

 

Its like 3 stone hones...i can usually get 8 or 10 cylinders out of a low end one or spend 3x as much and get a little more time..but, that might be years down the road, might crack a stone or something in that time.

[ebinmaine 70,751]

7 hours ago, RED-Z06 said:

Okay, this kit has the 5/16 pilot and the cutter sizes i think will fit, and 45⁰ cutters

 

https://www.ebay.com/itm/Carbide-Tipped-Valve-Seat-Face-Cutter-Set-Of-5-Pcs-Kit-Pieces-Cutters-Tip-/184772588925?mkcid=16&mkevt=1&_trksid=p2349624.m46890.l49286&mkrid=711-127632-2357-0

 

 

What kind of machine does it take to run this?

 

@WHX??

Just an FYI. This set comes from India. Might be a bit of transportation time. 

Don't know if it matters.....

 

 

[Achto 28,788]

9 hours ago, WHX?? said:

Used @Achtos sharpie method to check things out. Will let him explain that.

 

Pretty simple trick really. Use a Sharpie to color the valve seat and the mating surface on the valve. Let it dry a few seconds. Apply your lapping compound and lap the valve. Wipe the compound off with a dry rag. Any imperfections will be very visible. This method works even better when cutting the seat. Cut the first lower angle, cut the upper angle, color with the Sharpie, cut the center angle. Now you will have defined lines to measure the width of your center angle to make sure it is with in specs. 

[WHX?? 50,740]

4 hours ago, ebinmaine said:

 

What kind of machine does it take to run this? 

Done by hand EB. Big motors with lots of valves there is a power unit. Professional stuff. 

 

4 hours ago, ebinmaine said:

This set comes from India.

There some out there in the US but good catch! 

 

This one doesn't appear to have the other two angles Dan. 

Edited January 24, 2022 by WHX??

[ri702bill 8,980]

I dressed the exhaust valve seat on a Tecumseh H60 engine years ago. We had been given a partially complete Shopsmith Mark V a few years prior and had been using it as a 3 speed vertical drill press. That unit has almost three feet of adjustable throat opening and an adjustable tilt table - why not give it a try? Lined up the valve guide using a 5/16" reamer and clamped the block to the table. First, I used a coarse 90-degree mounted stone at the lowest speed setting to just clean out the pits, then switched to a fine stone to remove rough scratches left by the more abrasive prior stone.

Lapped the valve by hand (it took a long time to achieve satisfactory results, but it did work), and had to grind a tad off the valve stem to get the proper clearance.

Sorry but there are no pictures of this setup, but it worked well.

Bill

[Greentored 3,220]

If you just want to get it running and not buy a bunch of tools and equipment, you CAN do it with lapping compound and a suction cup chucked in a drill. Youre gonna be there a while though. 

You're also going to have a really wide seat contact area, but on these little engine Id think youd be fine.

I did this back in the day before I knew how to do it correctly

 

[WHX?? 50,740]

Got me one of  these dodads Green and it worked pretty good on the intake  but yeah would have been there a long time with the x. Some of the pits are pretty deep and it didn't even put a shine on the high spots. Thinkin maybe the seat is hardened? It has crossed my mind just to lap the snot out of it and runnerlikeIstole her. Not like this thing is gonna compete in NHRA finals.... just pull tubs. 

 

Wonder auto parts place rent or loan cutters out? 

[Greentored 3,220]

1 hour ago, WHX?? said:

Got me one of  these dodads Green and it worked pretty good on the intake  but yeah would have been there a long time with the x. Some of the pits are pretty deep and it didn't even put a shine on the high spots. Thinkin maybe the seat is hardened? It has crossed my mind just to lap the snot out of it and runnerlikeIstole her. Not like this thing is gonna compete in NHRA finals.... just pull tubs. 

 

Wonder auto parts place rent or loan cutters out? 

Not sure if they do or not. Do you have a local machine shop that would touch it up with stones?

[WHX?? 50,740]

20 minutes ago, Greentored said:

Not sure if they do or not. Do you have a local machine shop that would touch it up with stones?

Was trying not to have to pull the motor. Ton of crap on the under side to remove. 

[ranger 1,774]

If you’re desperate, and don’t have a lathe, but have a bench grinder and a cordless drill, you can ‘Reface’ a pitted valve quite easily. Chuck the valve in the drill, sit in front of the grinder, hold the drill with both hands, supporting your arms on something solid. Then gently ‘present’ the valve to the spinning grinding wheel. It helps if you have someone shining a light from above to gauge the angle. A light Test ‘Lapping’ into a valve seat will show which way to go to get the angle required. It does work, I’ve done it!

[WHX?? 50,740]

Good advice and thank you @ranger. I opted for new valves as the old ones (exhaust) was thrashed and I found replacements very affordable. 

The big thing was a the exhaust seat which, as mentioned, is part of the block. 

So armed with a few ideas off you tube and @ri702bill idea of stones I came up with this.  Not the same as actual cutting but good enough for the gals we go out with! 

Super glued thin strips of sandpaper to the new valve. Started with 180 grit and finnished with 400 and 1000 grit and finally fine grit valve lapping compound. Under a magnifiing glass still some pits  but since I'm not going to the moon on her and it's a Tecky... Lash checked perfect at .010

Had it running on hand feeding but carb trashed and not letting fuel in.... inlet float stuck closed.  was too skeered to do a compression check...  Fuel tank leaked everwhere so the smoking lamp was out. Another thread on what to do about that. 

 

Edited February 7, 2022 by WHX??

[ebinmaine 70,751]

8 hours ago, WHX?? said:

I came up with this

 

Nice work there Jim.  

[ranger 1,774]

One tip for anyone who decides to try the valve seat cutters that look like a giant countersink. If they are not the tungsten carbide insert type, the chances are you will blunt them on the first attempt. They will work fairly well on soft seats, but where the valve has ‘hammered’ the seat over time, it will have a hard ‘skin’. Do as @WHX?? has done, or lap with coarse grinding paste first, this will cut through the harder skin and your cutters will last longer.

Doug.

[WHX?? 50,740]

'Nother good tip Ranger & that's why I didn't go for one of the cheapy sets.   If I had some other motors lined up that needed cutting I would went for a good set of Neways. Watch now next two Kohlers I open up will need it! 

[ranger 1,774]

When I next go out to my “Shed”, I’ll take & post some pics of my “Wolf” valve re-facer, & valve seat grinder, & “Sykes-Pickavant” seat cutters. Along with some semi - finished valves.

 

[ranger 1,774]

A few pics of my valve refacing / seat cutting equipment. (Yes I know it needs a good clean)!
 

Edited February 7, 2022 by ranger