Worn valve guides

[B RON CO]

Hi, my replacement head is apart. I'll be doing light cleanup grinding and a port divider. I'll be buying new springs and probably new valves. The old valve guides seem to be knurled, they have ridges in there and I don't think that is factory. The valves slip right out with no suction when I hold a finger to the guide. Before I take the head to the machine shop I want to know what are the options on fixing the guides. Has anyone reamed the guides out and used 289 valves? What works best?

 

[CNC-Dude]

It's a good idea to install bronze liners in the guides to restore them to new. Knurling is never a good idea as it only temporarily displaces the metal inside the guide and reduces the contact surface area that supports the valve stems, and wears out much more quickly as a result. If the 289 valve stems are larger than the 6 cylinders, it will reduce the airflow to some degree because it increases the cross section or obstruction the air sees as it has to go around the stem.

 

[bubba22349]

X2 Knurled valve guides was an old school cheap fix that worked ok for limited type use, it allowed some extra oil to lube the valve steams but it also just didn't last very long for say like a daily driver / street use. If your valves are still good you can use a bronze valve guide liner or replace the guides with new cast or bronze guides. If you plan to replace the valves you can ream them out and use the oversize valve stems. All of them work fairly well I do lean more to the bronze guides now that we don't have the leaded fuels. Have had severial early engines (pre 1970's) wipe out the exhaust valve guides since the Feds took out all the lead. The later model head castings (from about 1972-5 up) when Ford started to flame harden the valve seats don't seam to have the same problems. Good luck

 

[B RON CO]

Thanks, I want to do it right.