I posted previously about a possible blown head gasket, well anyway, I just went ahead and pulled the heads off....

I've called around for rebuilt heads and what I have found is that the shops are only replacing the valves that are out of specs. Aside from cleaning and inspecting, is there machine work needed to swap out the valves?

I had an "ol' school" guy tell me to put water down the ports and if it leaks I need to replace the valve, well I replaced one of the valves that leaked with a new valve but still it leaks. Was this totally pointless?

Is machine worked required to set the new valves or is it possible to clean and swap so to speak?

P.S.... I have plenty of pics of everything and can provide more if need be!

 

Whew! There's a lot of questions here. OK, to start with, pouring water into a port to check for valve leakage *is* old school.... like flathead Ford 1930's old school!!! In the "modern days" we do things like compression tests & cylinder leakdown tests to determine valve problems.

Since you already have the heads off, you can physically inspect each valve seat and valve face for clean "angle" grinds. Most engines have 2 or 3 distinct angles ground into the valves and repeated into the seats to make a seal. Simply pulling a valve and replacing it without re-grinding the seat will usually result in it leaking because the seat has worn to the original valve.

*SOMETIMES* you can get away with "lapping" the valves by hand if they're not too far gone. This involves using fine polishing compound and a valve lapping tool that rotates the valve in the seat, polishing away small bits of material to make a smooth fit. Most likely, though, if the valves are leaking to start with a full "valve job" is performed. This involves pulling each valve, checking it for tolerance (and replacing it if needed). Then each valve is "cut" (ground) to specific angles, the valve seats are re-ground to the same angles, new valve seals are installed, spring heights & pressures are checked / replaced as needed, and the head is reassembled.

Check on your rebuilders... I doubt that they're skipping the grinding of all the valves. If the heads are in good shape (no cracks / warpage) then having a valve job done by a competent shop is really no big deal. While it's possible to do them yourself (if you can get a valve grinder) you're better off leaving this one to a shop.

Bob

 

Thanks for the reply! What you explained is the way I imagined it to be for re-seating the valves. After several "rebuild shops" had told me there was no machine work involved and that new valves were only installed to replace the out of spec "old" ones, I personally don't want to install a "rebuilt head" @ $320 with 100k +/- miles on the majority of the head if it is possible for me to have it done for the cost of valve(s).

I've had success with valve lapping a pontiac 403 and chevy 350 (preventative gasket failure/ maintenance repair), but the these 5.9L heads, being Sequential Injected, have inconsistent combustion chamber wear (color) which has me curious as well.

I also found a shop a couple hours away with the heads for $360 claiming 100% new cylinder head w/ valves and springs. Should I be concerned with pice vs quality at that price?

 

No because the molds come from the dealer anyway unless you go aluminum performance. So with that said, the valves will be OEM grade as well as the seats.....ect.