Board index Flathead Power-Technical Questions, Answers, and Suggestions K-Models Valve Guides?

Valve Guides?

Post Tue Apr 27, 2010 3:41 pm

Posts: 240
Location: Kirkland, WA, USA

Ok, I know there are lots of opinions on this, but there are really only a couple of different types available. I have a machinist friend that says get the guides +2 over what ever you are at, and then turn the guides down in a lathe to the size that fits the hole that you are fitting to. Makes sense since it is easier to get guide than repair jugs, or heads... Now the question, Steel or Brass, and why?

Post Tue Apr 27, 2010 5:23 pm

Posts: 543
Location: Wa, USA
I won't go into the size question as 100 machinists or builders will give 100 different answers, but cast iron is the best material. Bronze needs a lot of clearance or the valves will stick. This is not fun. When I did it on a UL, I had to remove the cyinders and pound the valves out of the quides. The valve material galled and destroyed the valves and the bronze was untouched. Cast iron is much less problematic.

Post Sat May 01, 2010 9:02 am

Posts: 240
Location: Kirkland, WA, USA

Thanks Woody,

Cast would be the way then. I will still have to figure out what size the starter holes are, as I am working with a couple of Sleeved KH cylinders I got from Bill's Custom in PA. I appreciate the advice....
Best regards,

Post Sat May 01, 2010 9:30 pm

Posts: 607
Location: Menomonie, Wisconsin, USA
In my opinion cast iron guides are the only way to go. Bronze guides are used in motors not intended for high miles - ie racing motors. They were also a quick fix in the early 80's when the lead was first taken out of the gas. I wore out the bronze guides in less than 15,000 miles in those days. I now have a knucklehead with probably 65,000 miles on a set of cast iron guides with the old Drag Specialities seals (too bad these are not made anymore) and no evidence of a problem and I know guys with twice that milage on them.


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