06-22-2010, 09:14 AM
Kind of hard to explain in just plain words, too bad you werent there for my demonstration when I brought in a head.
The head has holes in it where the valve body pushes through, and where it goes through the head (inbetween the spring, thru the head, and to the exhaust/intake ports) is lined with a valve guide. This can be made out of a few different materials, and they rarely go bad unless something else is terribly wrong/you bent a valve or something. Id say 98% of head builds dont even bother to replace those valve guides. HOWEVER, you do want to replace valve seals anytime you "build" a head. They simply, like every other seal/gasket, age. so go ahead and do those, they prevent oil from seeping into the passages, as you can see in your pictures above.
PS- have a machine shop check that extra head before you throw it in. Just have em disassemble, tank it, check it for cracks and straightness, and make sure the valves are seating properly. (of course they will check to make sure the valve guides are straight. Blue Ridge Machine Shop charges $75 a head for all of that which is cheap. Dont not do this and be like well ill just pull it off if its bad, then youve wasted your headgasket, time, and multiple one use items. Do it right first, itll save money in the long run.
The head has holes in it where the valve body pushes through, and where it goes through the head (inbetween the spring, thru the head, and to the exhaust/intake ports) is lined with a valve guide. This can be made out of a few different materials, and they rarely go bad unless something else is terribly wrong/you bent a valve or something. Id say 98% of head builds dont even bother to replace those valve guides. HOWEVER, you do want to replace valve seals anytime you "build" a head. They simply, like every other seal/gasket, age. so go ahead and do those, they prevent oil from seeping into the passages, as you can see in your pictures above.
PS- have a machine shop check that extra head before you throw it in. Just have em disassemble, tank it, check it for cracks and straightness, and make sure the valves are seating properly. (of course they will check to make sure the valve guides are straight. Blue Ridge Machine Shop charges $75 a head for all of that which is cheap. Dont not do this and be like well ill just pull it off if its bad, then youve wasted your headgasket, time, and multiple one use items. Do it right first, itll save money in the long run.
2020 Ford Raptor
2009 Z06
1986.5 Porsche 928S
2009 Z06
1986.5 Porsche 928S