Valve configuration

[Patsdeere]

I was wondering if it really matters what angle you have in a valve seat/valve combo. I just replaced all the seats and was curious if I could just use valves made for some other type of engine, knowing that they need to be the right length. They were all essentially the same size originally if that matters.

Thanks.

 

[Dick Lemmon]

I grind the seats and then grind the valves to match. The main sealing angle will have to be the same.

I put small block Chevy valves in my Allis Chalmers C. I first had to change the outside diameter which removed all the original angle. The picture shows the difference.

 

[Janicholson]

The angle on the seat should be 1/2degree more than the angle of the valve face. This puts the contact at the outer edge of the seat, and within 1/32" of the margin of the valve face. this ring of contact allows for perfect initial seal, and long operating life of the valve and seat. No lapping in is needed JimN

 

[Dick L]

Here I have been doing it all wrong for over 50 years. I wonder if I should see how many I should re do.

 

[george md]

Dick,

I'm with you ,been doing matching angles
for 35 years , Print with bluing and vacuum
test when done , don't have leaks or comebacks.

george

 

[Dick L]

Some don't know about bluing and wouldn't if thay had a dab on a finger, er end of the nose, er on the ear, whats that on your chin. ^D

 

[RandyB(MI)]

It's refered to as "interferance angle". Was taught in auto mech. class back in '68 that this was the way to do it. The mismatch will "seat in" quickly and virtually match in time so you will still get the heat transfer efficiency of full seat contact. I might question the need of this with todays more precision and accurate methods of cutting seats but I would still do it. Can't hurt.

 

[Anonymous-0]

Dick Lemmon-
Are you the guy from MI, used to have the old Fire trucks?