Farmall H valve seat - will a few small pits be a problem?

andy r · Nov 24, 2013

I had an old Farmall H that sat too long and must have gotten some water in it. Engine never locked up, but two cylinders must have had some water in them. Rings were still free in the pistons. All of the valves and seats are great except the center two exhaust seats. They all cleaned up with some lapping compound except for those center two exhaust seats. They don't look bad except for some small small pits. I could keep using the lapping compound to eliminate the pits or just say maybe I am better to just stop as they will not leak anyway preserving the seat angles, etc. Will a few small small pits cause problems in a Farmall H that is going to see limited work if any??????

David G · Nov 24, 2013

You could probably grind those pits out with seat grinder. I have never put one back together with pits, so anxious to hear the opinions.

gene bender · Nov 24, 2013

I sure wouldnt worry like you said lite limited duty.

Heat Houser · Nov 24, 2013

It will be fine, have patched many on old car engine in my youth with pits in valve seats and scores in cylinder walls. Did a light lap on the valves and a light hone on the cylinders. Years ago, patched my dad's B Farmall that way. It ran for years.

Anonymous-0 · Nov 24, 2013

little pits cause bigger problems, when it developes a miss from a burnt valve then you have wasted a $100 head set,if it was on the intakes I wouldn't be quite as concernd, I think I would have them ground. If the pits don't grind out then replace the seats. No one seems to have the money to do it right the first time but everybody has the money to do it a second time. Even my low use tractors go together with good parts.

Dick L · Nov 24, 2013

I personally would face the valves and grind the seats if I have a head off that has any pits in the seats. I do that if I have a valve out for any reason. Over the years it has been the short cuts that came back to bite me.

pete 23 · Nov 24, 2013

Of course the correct way it to reface the seats, either with a stone or cutter, but that does not mean it will not work for you the way it is. I can't see them from here so have no idea how bad the seats are.
Kind of reminds me of a Nebraska test on one of IH diesel engines. For some reason the head was removed and notes were made that valve seats had pits on them. IH quickly sent out a letter to all dealers that all diesel engines show what some perceive to be pits but was actually perfectly normal. You be the judge.

Anonymous-0 · Nov 24, 2013

Have the seats ground and the head surfaced. You'll sleep better.

John B. · Nov 24, 2013

Set the head on its side with the exhaust ports facing the ceiling. Then pour some solvent in the exhaust ports and see if it leaks out around the valve heads. If it does, it'll leak a lot worse when the gasoline mixture explodes in the combustion chamber and it won't take long to burn the valves then you'll have more of an expense let alone pulling it all apart again. You're concerned or otherwise you wouldn't of asked all of us. I would have the head redone.

ASEguy · Nov 25, 2013

You may never see a problem with it, but I have never regretted doing the job right.

NoNewParts · Nov 25, 2013

depends
re-doing a tractor? get the head done
getting a 'fencerow find' tractor useable? it'll probably be fine.
I do what the other poster said, after taking the head apart and cleaning everything, then reassembly, I flip it upside down and put fluid in the valves recess and leave it awhile. If it doesn't drain out, good to go.
depends on your own personality too. you can't 'un-see' it.
if it will bother you....fix it

if it won't bother you, forget about it.
I bet we could pull down a dozen, good, no issues, running engines from any of our collections, and I bet we could find something we didn't like in ALL of them.......

rustyfarmall · Nov 25, 2013

I would never put an engine back together with pitted valve seats. That engine would never run good enough to suit me. Take that head down to a GOOD machine shop and have the seats replaced, and while it is there, have him check out the valve guides, and grind, or replace, the valves. Yes, it will cost you a few bucks, but it will then be 100% right, and you'll never need to worry about the head again. It will last you the rest of your life.

Mike M · Nov 25, 2013

If not bad a quick grind with a stone may just clean them right up. Good chance they all need narrowed a bit too. You would have to grind alot off a low compression gas engine before it really made a differance in how it ran from compression loss.

JRSutton · Nov 25, 2013

try a kerosene test.

with valves/springs installed - fill the exhaust and intake ports with kerosene.

Watch what comes out past the valve over time - it will be an indicator to how bad the problem is.

It should hold it for at least a half hour without any noticeable loss.

I'm sure there's lots of info out there on the web about interpreting the results - pretty common test.

Farmall H valve seat - will a few small pits be a problem?

andy r

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David G

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gene bender

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Heat Houser

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Anonymous-0

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Dick L

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pete 23

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Anonymous-0

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John B.

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ASEguy

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NoNewParts

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rustyfarmall

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Mike M

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JRSutton

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