Valve job

Gary Mitchell · Mar 13, 2020

What does it cost now a days for a valve job on say a 4 cylinder tractor head? I always had a guy grind mine and I seated them myself. I just read a post about a fellow that was picking up his "stuff" from a shop that was done with them. Just curious. gm

rustred · Mar 13, 2020

well to go through the complete head could be 400-500.00. I don't know how you could have the valves ground and seat them yourself. grinding the seats and positioning them on the valve face with different angle stones is the hardest part. resurfacing the valves is the easy part.

Gary Mitchell · Mar 13, 2020

I don't understand why you sound so skeptical. It's simple enough if you have a Sioux valve seating set you picked up worth the money, had no grinding machine but a pal who'd grind them for a buck a valve. I leaned from a pro, (Bill Corbin), almost 50 years ago how to grind and narrow seats. It's a little tedious like most machine work if you want it right, but it really isn't at all complicated. gm

MSM · Mar 13, 2020

50 years ago you would grind the seats. Now the seats are cut or replaced depending on how many times the seats have been ground or how far the seats are hammered down, or are old style soft seats which will wear quickly since the onset of unleaded gas not having any lubrication for the valves and seats. Now there is a spec for valve standout, especially on diesels. If the valves are too low compression is affected and the engine will be hard starting even when hot.last 4 cylinder gas head i had done was right at 500.it was resurfaced, seats and guides replaced, a couple of valves replaced. Last 4 cylinder diesel head I had done was 750. All new valves and seats, valve guides, flat surfaced, guides machined for umbrella seals, assembled and pressure tested.

jimtrs · Mar 13, 2020

(quoted from post at 11:27:19 03/13/20) What does it cost now a days for a valve job on say a 4 cylinder tractor head? I always had a guy grind mine and I seated them myself. I just read a post about a fellow that was picking up his "stuff" from a shop that was done with them. Just curious. gm

Costs last one: Last year, 4 cyl OHV (IH C123)

Wash Head - $25.000
Magnaflux Head - $25.000
Resurface Head - $60.000
R&R Valve Guides - $10.000 ea $80.00
Resurface Lifters & Rockers - $7.000 ea $56.00
4 Cyl Valve Job - $125.000

rustyfarmall · Mar 13, 2020

I own a Black and Decker valve grinding machine, and a couple of valve seat refacing machines. I know how to use them, but the valves from a 60 to 70 year old tractor are usually too far gone to be ground, however they CAN be turned in to razor sharp cutting tools. Valve seats are the same way. By the time you get a good, clean mating surface for the valve, the valve will set so far down into the head that it just won't work. Only solution is for a good machine shop to cut out the old seat and install a new one.

So new seats, new valves, new valve guides, and the labor all adds up quickly.

rustred · Mar 13, 2020

not meaning to be skeptical. going by what little info is here. you didn't say you are experienced in valve grinding. I also learned to grind valves over 40 years ago. I know whats all involved. you just made it sound like you are having the valves ground then do the seats at home. no idea on how you would be doing it. a lot of people on here think that you just lap the seats to the valves and good. well not so. as with so many posts lots of info don't get posted. I basically answered the post with posted info. then people make it out like im being rude. not so. and also just because new seats are installed they are still ground.

JDEM · Mar 13, 2020

I saw a four cylinder head come out of a local NAPA auto-machine shop with a $420 bill. New guides, valves, seat inserts, springs, resurface, etc. A lot of money perhaps not well spent for an old tractor that likely is not run hard all day, every day. Most of these older tractors have seats that are (or were) induction hardened and have no seat-inserts. If you grind them, they will be soft at first but will eventually work-harden. I have done many and they have worked fine with unleaded gasoline.

Dick L · Mar 14, 2020

If your asking if you could do your own by buying your own equipment I would say sure. Just make sure you follow the specs for the head's manufacture rather than advise from every Tom, Dick or Harry. I was taught to grind valves in the late 1950's. Over the years I bought the tools and equipment. Guides are cheap and easy to replace. The condition of the head when starting is a key factor. If the seats are pitted or burned bad it my need to be cut and new seats pressed in. Another option in that case is to go to larger valves. I do both. It just takes a little research to find parts.

The first picture is a head that was in fair condition and grinding usable valves. The second picture I milled .1500 off and installed oversized valves. It is also ported with some polishing.

Dick L · Mar 14, 2020

Costs for tooling go up a tad when milling heads.

560Dennis · Mar 14, 2020

I put new valves ,guides, and install new steel seats to run unleaded gas . Have the shop put a three angle grind on the valve and I assemble the head , so that adds up . But that s hard to say so many head designs

jacks · Mar 15, 2020

If you are planning to use the engine at lower engine speeds (typically less than 3000 rpm) you will not get much if any benefit by installing hardened seats. Most old farm tractors can do their work running in the 2000 or less rpm range. If the seats in the block can be cut or ground satisfactorily, they will be fine for lower rpm use as described. Gasoline engines which will see hard service above 3000 rpm should have hardened seats installed. On a diesel engine, as has been mentioned, seats cut too deep into the head will cause hard starting. Here is a link to a field study done by the SAE (society of automotive engineers) and the US department of Agriculture which arrived at the the conclusion stated.
SAE field study of valve seat recession on older engines unleaded gas

Valve job

Gary Mitchell

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rustred

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Gary Mitchell

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MSM

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jimtrs

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rustyfarmall

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rustred

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JDEM

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Dick L

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Dick L

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560Dennis

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jacks

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