Head Restoration

[King]

Hi All

Our club is having our annual technical session just after New Years to sober up and get some focus on our winter projects. This year I‘ll be bringing the original heads for my 51 Pan which I would like to restore. Currently I am running STDs with a Bendix , but would like to shift back to the original heads with a Linkert. The major problem with them is the valves are “pocketed”.

I seem to recall some time ago a mention here that one could use oversize valves to get around the pocketing. Is that feasible and what valves would one consider??

Thanks

King

[kitabel]

what valves would one consider?

One would consider "oversize valves", and you can get them from any shop that deals with Dixie or Eastern.

[Cotten]

King!

As Kitable suggests, Dixie's have been the industry's bottom-line standard for decades.
But that doesn't mean that a Rowe or Kibblewhite might not please you more, if you can afford them.

A pro head man will cut down oversized valves to their minimum anyway.

I have installed full OS intakes and exhausts into machines, and frankly,.. subjectively,... they ran one helluvalot better than the average Pan!
(It might have been other things involved...)

Full Chubblehead intakes are something I would avoid unless absolutely the last resort, however.
Been there done that, too, on my own machine.

....Cotten

[kitabel]

Manley, Ferrea, SI etc. will be happy to make you a valve of the exact size you need to clean your seat up.
Don't use any bigger valve than you need. The new seat need not be the same depth in the chamber as the original, a shallow top angle of 20 or 30° allows a smaller O/S.
The 3/16" O/S shovel intake looks like a good idea, but frequently the guide center isn't well placed in the cast-in seat, and the 1-15/16" seat runs off the bronze on one end.
If the new valves are stock length, the stem height above the guide flange will be more than original, which tips the rockers up (and may strike the inside of the cover).
This slightly relaxes the springs -, add the same thickness shim as the stem height change under the lower collar.
The lower rocker block (stand 1/2) can be shimmed slightly for rocker geometry correction, the amount is always less then the stem height change. For the pan's valve stem inclination, the correction is 77.7%: if the stem is .050" higher, .777 × .050 is added to the rocker or .039". No gasket should be needed, make sure that all the dowel pin and oil holes match the head.
The intakes and exhausts may be different, calculate them from the actual stem heights.

[steve_wood]

King:

Are the valve seats original? Just wondering if maybe a rebuild by headhog would be feasible....

steve