Exhaust guide seals

[Randall]

Should I use seals on the v8 flathead exhaust guides?
Thanks

[alanwoodieman]

no point, ford originally had two types of guides, one with a seal one without for exhaust

[jimTN]

If you can get the guide with them on it in, go for it. I could not get them in on the last one I did.

[Randall]

Thanks

[Bored&Stroked]

The original Ford guides from 49 - 53 has a "solid" guide on the exhaust side - there was no place to put a seal. Also, as the exhaust is under positive pressure, you don't have the issue you have on the intake side where the vacuum pulls oil from the valley into the port.

Sealing: The carbon from combustion will "seal the guide" on the exhaust side anyway - so the seal won't accomplish anything.

And lastly, I like the solid exhaust guides as they do a better job of transferring heat from the exhaust valve into the cooling system (due to a larger contact surface area between the guide and the guide bore)..

[Pete]

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Petrfect Circle made teflon seals that had a steel clip around them. You had to machine the guide to accept them.Whether they were needed is still to be determined.

[outsider347]

Originally Posted by Bored&Stroked

The original Ford guides from 49 - 53 has a "solid" guide on the exhaust side - there was no place to put a seal. Also, as the exhaust is under positive pressure, you don't have the issue you have on the intake side where the vacuum pulls oil from the valley into the port.

Sealing: The carbon from combustion will "seal the guide" on the exhaust side anyway - so the seal won't accomplish anything.

And lastly, I like the solid exhaust guides as they do a better job of transferring heat from the exhaust valve into the cooling system (due to a larger contact surface area between the guide and the guide bore)..

Great tip. Tis

[deuce5wndw]

I have a question about the solid guides. Were they ever available through the parts department? When you look them up in the parts book it only shows the one number with the groove with a note to use the seal on the intake guide. I have never seen the solid guides NOS and have always got them used and bushed them. Thanks guys!

[Karl Wolf]

I think that one good reason to NOT use the seals on the exhaust is they may be made impossible to remove later. This would be from the heat.
One experienced builder on here recommends RTV, a thin coating.

Karl

[Bored&Stroked]

You can put RTV on the intakes . . . don't see it as necessary or doing any good on the exhausts. The carbon will seal them right up . . .

[Ol' Ron]

I've been using RTV for the past 50 years on all my buills. Just put alittle around the bottom of the guide before you install it and slide it in. Another thing I do isKnurl the guides. I just use a tool on the intakes. I bought the tool about 50 years ago place the guide in a lathe or vice runthe tool thru the guide, blow it out all done. Yes thery make better systens, but this works
Gramps

[Bored&Stroked]

Originally Posted by Ol' Ron

I've been using RTV for the past 50 years on all my buills. Just put alittle around the bottom of the guide before you install it and slide it in. Another thing I do isKnurl the guides. I just use a tool on the intakes. I bought the tool about 50 years ago place the guide in a lathe or vice runthe tool thru the guide, blow it out all done. Yes thery make better systens, but this works
Gramps

I do the same thing with a knurling tool on my lathe . . . locks them down much better than stock and the valve can't move side-to-side due to the guide clearance/slop. This increases valve seat life as the valve is not "bouncing around" on the seat - trying to find center.

[Pete]

Knurling DECREASES the area of the guide in contact with the block. This slows heat dissipation from the valve. A bad thing.

Copper plating INCREASES the contact area to the block and along with superior heat transfer properties speeds the heat transfer away from the valve. A good thing.

[Ol' Ron]

I don't Knurel the outside of the guide just the 341 hole in the middle, and copper plating cost money which is not necessary for a street engine.
G

[Bored&Stroked]

Originally Posted by Pete

Knurling DECREASES the area of the guide in contact with the block. This slows heat dissipation from the valve. A bad thing.

Copper plating INCREASES the contact area to the block and along with superior heat transfer properties speeds the heat transfer away from the valve. A good thing.

I only do this on the intake side - not the exhaust. Copper plating makes sense - just need to find a local place to do it for a fair price. About the only places I know are a couple chrome platers . . . might have to check it out with them.

[Pete]

Originally Posted by Ol' Ron

I don't Knurel the outside of the guide just the 341 hole in the middle, and copper plating cost money which is not necessary for a street engine.
G

The guides should PRESS in the block as in ALL modern engines, to insure an accurate long term valve seal, especially on a street engine.