Flathead exhaust valve guide seals

[Bored&Stroked]

BTTT: Here is how I just did it:

Here is the problem - all the guides I've ever used are fairly loose in the guide bore. This is something that I 'fix' with knurling. When Ron talks about knurling, he is talking about the traditional knurling of the valve guide bore to tighten up guide bore to valve stem clearances. I know some experienced racers that won't knurl flathead valve guides (especially the exhaust), they install bronze liners. The reason is that they want better heat transfer from the valve stem to the guide and tightly fitting bronze liners do this supposedly better than a knurled cast iron one.

Video: The problem with loose fitting guides (in the block):

https://www.youtube.com/watch?v=qZBXFMqHs-c

Here is the knurling process and final result:

Video: Knurling:

https://www.youtube.com/watch?v=UqYqBIy1BAI

Here are some final guide pictures - you can see my spring spacers for the Isky 185-G springs as well as the cut-back section I do on the top of the valve guides (so they don't obstruct the port).

Enjoy:

KnurledIntakeGuide copy.jpg

FinishedGuides1 copy.jpg