Farmall H valve guides

DRWNY · Mar 18, 2014

I"m in the middle of rebuilding the engine on my H, bottom half is all done, installing new exhaust valves springs and guides on the head, Machine shop says if I install new guides I can"t lap the valves, the seats would have to be cut. What are your opinions or experience"s on this? Thanks in advance guys. Dan.

David G · Mar 18, 2014

Just have the shop do the valves and seats. Why would you want to lap the valves when they can be ground?

teddy52food · Mar 18, 2014

Seats will have to be ground.

randy hall · Mar 18, 2014

they are telling you the correct way. just have them put new guides in and they will do the job right, guides are very cheap.

DRWNY · Mar 18, 2014

Thanks for the replies guys, just trying to do as much of the work myself for self satisfaction and also trying to keep cost down. Dan.

rustred · Mar 18, 2014

that's right, lapping is totally obsolete. nobody does that. when guides are installed the next step is to resurface valves and seats or replace as nessesary. there is also spec's on the intake and exhaust valve seat width's. you cannot correct these by lapping. lapping used to be done after the valve and seat grind to make sure they seal. but valves are ground with an interference angle of 1 degree. the valve is ground to 44 degree's and the seat to 45 degree's. this eliminates lapping, plus give faster seating and prevents carbon from getting stuck in the seat.
also the springs are checked for proper tension.

Farmall H valve guides

DRWNY

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David G

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teddy52food

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randy hall

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DRWNY

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rustred

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