Valve Guide R and R Brodix Heads

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Hrdlx62
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Valve Guide R and R Brodix Heads

Post by Hrdlx62 » Tue Mar 13, 2018 7:52 am

Hello all. I've been tasked to switch out a set of valve guides in a set of Big Block Chev Race Rite heads. Whats the "best" method to replace the factory (Brodix) bronze guides?

GOSFAST
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Re: Valve Guide R and R Brodix Heads

Post by GOSFAST » Tue Mar 13, 2018 8:37 am

Fairly easy task, assuming you have some type head machine?, use a core drill (468") from the topside, drill down until you have about .500" left undrilled at the bottom of the existing guide. Read the P.S. below. Turn the head over and tap the .343" hole with a 3/8-16 tap. Just need a few threads.

Put a short bolt in the tapped hole, turn the head back over once more and drive the "weakened" guide out with a drift. Easy fix!

If you follow this procedure closely you will almost be able to push the core-drilled guides out by hand by pushing down on the drift!

Thanks, Gary in N.Y.

P.S. Don't try this with the 3/8" threads from the top side of the guide, you will simply end up breaking off the seal section. The threads MUST be at the guide bottoms. If the guides protrude deep into the ports you will need deeper tapped holes. The 3/8" threads must be into the guide where it is still in the casting. On occasion we machine the guide bottoms first until they are reasonably flush with the casting, then tap the threads.
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Hrdlx62
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Re: Valve Guide R and R Brodix Heads

Post by Hrdlx62 » Tue Mar 13, 2018 9:56 am

Thanks. I guess my question was referring more on the installation methods being employed. Heating the head to a specific temp range, guides in the freezer overnight, dry ice, liquid nitrogen? Most of what I do here is cast iron diesel so its R/R the OEM guides, K liners or 1/2 OD repair guides. Aluminum heads make up a very small part of my workload, hot rod stuff even less.
By the way these Brodix guides have to go out from the chamber side as they have a slight shoulder just under the seal surface

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Re: Valve Guide R and R Brodix Heads

Post by jcisworthy » Tue Mar 13, 2018 10:53 am

Drive out the old bronze guide and install the new one, Hone to size and do the valve job.

Use a little press lube, engine oil or something in the guide hole before installing the new guide. No tricks necessary to install just drive them in and seat them gently.

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