Farmall Cub Cutting Exhaust Valve Seats

Hattrick · Aug 13, 2018

I have a Farmall Cab that I am trying to save. All of the valve seats are good with the exception of one exhaust valve seat. I know the right thing to do is pull the motor and have a new seat installed but wondering if anyone has had any luck with the Neway cutters? If so what size would I need?

Also I know that when cutting in a new seat it is intended to be done with a machine but is there anyway that you can cut them in yourself? I am trying to avoid splitting the tractor if at all possible.

Thanks

rustred · Aug 13, 2018

its machine shop work. unless you knew of a place you could take the whole tractor, to save removing engine.

Janicholson · Aug 13, 2018

Or a person willing to travel with the mandril and cutters. Jim

gene bender · Aug 13, 2018

most have the newer machines and the block needs to be torn down bare

ih560 · Aug 13, 2018

You can buy the neway cutter, pilot, acc. kit and wrench for around $135 and do it yourself.
I just completed a full valve job on a cub using the following.

Neway KACC246 Accessory Kit
3/8" Hex Nylon Fiber T-Wrench
CU122 Cutter
5/16" pilot

I had to replace a couple of valves due to some damage. The seats cleaned up great and the valves lapped in perfectly. I also installed new guides.

Hattrick · Aug 13, 2018

(quoted from post at 03:23:12 08/14/18) You can buy the neway cutter, pilot, acc. kit and wrench for around $135 and do it yourself.
I just completed a full valve job on a cub using the following.

Neway KACC246 Accessory Kit
3/8" Hex Nylon Fiber T-Wrench
CU122 Cutter
5/16" pilot

I had to replace a couple of valves due to some damage. The seats cleaned up great and the valves lapped in perfectly. I also installed new guides.

Thanks for this informTiation. I may give it a try. How deep can you cut before there is no more seat?

rustred · Aug 13, 2018

its probably been ground already once. if the seat is bad and pounded out it has to be replaced.you dont want the valve recessed too low. plus need a good margin on the valves or they will just burn. valves are the heart of the engine, poor job there and the rest will show.

MikeJM · Aug 13, 2018

Where are you located?

I like my neway cutters, I’ve had very good luck with them, did seats on a 251 Chrysler last winter.

How bad is it? I would cut till it was cleaned up unless it needs a seat installed and then you’d have to find someone with a quikway seat cutter for working on flat head engines like me or the machine shop I use has. You’d be surprised what can be salvaged, last winter I salvaged a JD D head for a fellow, exhaust seats were badly pitted.

If the guides are worn out it will be very difficult to get a good true seat cut.

Hattrick · Aug 13, 2018

I am in Washington north of Seattle. Can I cut in new valve seats with a quick way? Sorry. I am not familiar with them. Thanks for the help.

BarnyardEngineering · Aug 14, 2018

You've got nothing to lose by trying.

A few years back I did a 240 head with a basic 2-angle Neway cutter I got off Ebay for $60 or so. Just cleaned up the existing seats and lapped in new valves. Far as I know the tractor is still running. Had to sell it.

Butch(OH) · Aug 14, 2018

No, you do not need a valve seat machine to preform quality work. The Neway system works great. I have used them in the shop for going on 20 years BUT! like any other guide piloted seat tools if the guides are not up to snuff your seat work will not be either. It also takes a certain amount of finesse to operate the cutters as you can easily bend the pilots if you lean into things. Standard practice in my shop is fix the guides first, either install new ones, or liner them or in some cases might knurl and ream. Next when replaceable seats are needed I use guide piloted K-line seat equipment to cut the recesses for the seats and knock them in. Last work is preforming the actual seat work. The Neway cutters are all over Ebay and often found cheaply there. Try to find a kit complete with teh adjustable pilots. its usually much cheaper than assembling what you need form individual complainants

MikeJM · Aug 14, 2018

(quoted from post at 04:23:39 08/14/18)
I am in Washington north of Seattle. Can I cut in new valve seats with a quick way? Sorry. I am not familiar with them. Thanks for the help.

If you need an valve seat insert installed they made a setup that bolted to the deck for cutting the counterbore on valve in block engines.

Your a little too far away to stop by and get it fixed up.

Hattrick · Aug 14, 2018

Looking at these parts it looks like there are three 5/16 series 100 pilots. One is just a 5/16 tapered pilot. The other two are 5/16 plus .001 and 5/16 plus .002. If my valve guides are pretty tight do you
think I am OK with just the 5/16 tapered pilot and not going over sized?

Hattrick · Aug 14, 2018

What model Kwik Way Cutter do you have? I see that the Model "M" is available on e-bay. Might be worth buying one. Would need to learn how to use it.

Thanks

Hattrick · Aug 14, 2018

I see that they sell three different 100 series pilots that are 5/16. One is listed as a 5/16 tapered which is shown as feature a 0.0007" taper per inch of length. The other two are 5/16 plus .001 and plus
.002. If my guides are pretty tight do you think I am OK with going with the standard tapered or will I need to go over sized?

Hattrick · Aug 14, 2018

(quoted from post at 03:23:12 08/14/18) You can buy the neway cutter, pilot, acc. kit and wrench for around $135 and do it yourself.
I just completed a full valve job on a cub using the following.

Neway KACC246 Accessory Kit
3/8" Hex Nylon Fiber T-Wrench
CU122 Cutter
5/16" pilot

I had to replace a couple of valves due to some damage. The seats cleaned up great and the valves lapped in perfectly. I also installed new guides.

I see that they sell three different 100 series pilots that are 5/16. One is listed as a 5/16 tapered which is shown as feature a 0.0007" taper per inch of length. The other two are 5/16 plus .001 and plus .002. If my guides are pretty tight do you think I am OK with going with the standard tapered or will I need to go over sized?

ih560 · Aug 14, 2018

If your guides are worn and you're not going to replace them (they are really cheap). Then you may need 2 or 3 pilots like 5/16", +.001 + .002, to get a tight fit. I installed new guides and I had the expanding pilot that expands to fit a wide ride around 5/16". The only problem with the expanding one, you can't use it with the lifters in the engine (on the cub engine), therefore it requires cam removal. The tapered pilots are cheaper, so I'd just buy the three mentioned above.

ih560 · Aug 14, 2018

Edit: I meant "I had the expanding pilot that expands to fit a wide [b:0ea2b7abde]range[/b:0ea2b7abde] around 5/16"".

ih560 · Aug 14, 2018

Also, you might try and find the pilots on ebay used for cheaper. The pilots seem to be a little more expensive than I remember. You could try the standard 5/16" one first, but if it is loose at all in the guide, do not cut the seats with it.
I bought all the neway items I got from Cylinder Head Supply because they were the cheaper of everywhere I looked and all the kits that were other there for small engines didn't have the right sized cutter for a cub engine. The CU122 will do the intake and exhaust seats if you adjust the inserts properly. After you cut the seats, use a little lapping compound on the valve face and make sure there is even contact all around the valve. You can adjust the contact pattern using additional cutters to narrow and widen it. If there is not enough valve margin, you want to replace them with new. They aren't all that expensive either.

I replaced all the intake valves in mine because I believe the same guy that scored that crap out of one of the cylinder walls, also drops a couple valves on the ground and dented the margin, causing the valves to not seat evenly.

Farmall Cub Cutting Exhaust Valve Seats

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