Board index Flathead Power-Technical Questions, Answers, and Suggestions K-Models K &KH valve questions

K &KH valve questions

Post Thu Jan 13, 2011 6:29 pm

Posts: 332
Location: north central Ma.
Hey gang.

My 52K has a bad practically missing valve guide on the rear Cly i noted two years ago when the last was tight trying to push in a feeler gauge the valve tip moved almost half way off the adjuster bolt.
Well with the guide that bad I'm surprised how well it runs.
Any way I recall someone saying KH valve had bigger head diameters. Is that correct? Are stem lengths the same?
I plan on having a new guide installed and the seat is likely wasted so rather then sink the valve I'd like to just cut the seat and size the valve head to suit. Were both valves in the KH bigger? i don't recall if it was the intake or the exhaust and it cold and snowy out in the garage...

Thanks and happy new year!

"Smok'in the competition NOT Tobacco"
"Transplant organs, Don't bury them!"
Why dwarf? 5/8 scale race cars!

Post Thu Jan 13, 2011 11:02 pm

Posts: 693
Location: somerset, oh usa
Only the intakes are larger and the KH's intake valves would resolve the valve seat issue if that's not what's in it already.
Sorry but I don't remember the head sizes but they will work as that's what I have in my K cylinders on a WLA bottom.
Suggest recutting to a 30 degree seating for the intakes. It'll perform better and save on the amount of seat cutting necessary.
A larger valve can also be tailored down in head size if it benefits you.
There may be oversize exhaust valves available but I'm not aware of them. If not then it's either inserts or brazing them up or relieving to unshroud them.

Post Fri Jan 14, 2011 2:29 pm

Posts: 591
Location: Crewe, Great Britain

K intake is 1"810, 46mm against KH at 1"850, 47mm.

My only experience with K was my KK, std with WR valves, 1"732, 45mm exhausts against 1"711, 44mm for the KH


Post Fri Jan 14, 2011 6:24 pm

Posts: 131
Location: BRANFORD, CT

Hi Tony,

I have in stock KR valves which I am having made to my specs by Manley.
They are stainless steel
intake is 1.875, ex is 1.625
heads are good shape for flat heads
angles as made are 45 deg, and can be reground to 30 deg
stems are .311 dia so the stock guides will have to be honed
use standard keepers

Bruce Argetsinger
AHRMA Dirt Track # 67J

Post Sat Jan 15, 2011 12:52 pm

Posts: 152
Location: Carver, MN

Bruce, those sound like some nice valves, but the guides for a K / KH are the same as a WL: 11/32" stem. At least that's what my part number reference shows. I am guessing the KR took a 5/16" stem?

Post Sat Jan 15, 2011 7:01 pm

Posts: 591
Location: Crewe, Great Britain

Hi Lee,

Not too sure WL and K are 11/32, that's .344: I had some K and KH valves made in the past for my own use, they all had a .339 stem and I use WL guides...

Early KR were same as late WR, .339 stem with just the end waisted at 5/16. Later KR are indeed 5/16 all the way to the head.


Post Thu Feb 03, 2011 11:00 am

Posts: 976
Location: Markt Einersheim, Germany


You have a PM here.


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