I went with hardened cast iron guides for the exhaust and haven't had any problems since.
stock z/28 wrote: ↑Fri Jun 06, 2008 6:14 pm Hello,
Well, I kind of have to agree with every one.
I have used the K-Line style guides for 30 some years. I have also used Winona style spiral guides for even longer, but I don't use many any more.
I use the centering tooling like Mike referred to that centers off of the seat and aligns with the guide. It seems to be very accurate.
I use a Gogsdill? adjustable rotary broach, that uses tapered caged needles that run on an angle to compress and expand the bronze material.
I have also used the carbide sizing broaches to size the liners as well.
To finish them I usually use a Sunnen hone to finish the guide to size.
I too like the hardened cast iron valve guides for heavy duty and especially propane operation. There are a couple of guides that were available in .500 that are hardened and after being honed to size they seem to hardly ever wear in a typical application.
In my opinion for what its worth, the valve itself is very important as well. I prefer to use a high grade valve with a hard chrome stem with the bronze style guides.
Jeff