Flathead exhaust valve guide seals

Intakes only. And then use the O'ring type rather than the square ones which are a bear to install without them shearing.
 
This is a logical decision I made because the Hi Temp RTV was not available back when Hank designed the flathead. AND, that's a big and, from 32 to 48 Ford never used any seals. Now what you should be concerned with is the valve stem ti guide clearance. THIS, is where the oil is pulled under hi vacuum. I Knurl the guides and ream them for a .0005/.001 fit. The knurel will keep the guide well lubricated. AND yes Knurel the new guides you bought and ream them as well. I've done this to every engine I've build over the past 30 years.
 
Ol' Ron - The knurling makes sense to me but being an electrical engineer I don't know how it is done. Do you have to take the guides to a shop or can you do it yourself?
 
I do mine in a lathe now, however I did them in a vice with a fixture I made out of wood to hold the guide while I ran the knurling tool, and the reamer. Most auto machine shops should have the tools
 
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
 
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I don't bother to Knurell the outside of the guide the RTV takes up the room between the guide and block. However, doilg this will probably center the guide and grinding the seat with the knurelled guide in place will make a true seat. My valve grinding fixture locates on the guide bore.
BUT, we haven't addressed the stem to guide clearance here.
 
I'm still wondering what is considered proper stem to guide clearance for 8ba? Not showing up in a search.
 
Bored&Stroked said:
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:
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Click to expand...
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226291
 
On one hand knurling the outside is good because it makes the guide tight in the block so the valve seat remains solid in place but you also lose about 30% contact area which relates to a LOT of heat transfer capability.
In a street engine you may not notice the shorter life.
 
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