SideStep

Have heads off, valves out... what am I looking for in excessive guide wear???

BAD2000TA

iTrader: (6)

Correct me if I'm wrong, but an LS1 does not have valve guides. The rockers are mounted on a shaft to position them properly.

SideStep

You are thinking of push-rod guides...

Valve guides are the brass (or iron) sleeves the valve stem slides up and down in....

Check out post #6
https://ls1tech.com/forums/generation-iii-internal-engine/643713-valve-guides.html

Ryan02SS

iTrader: (3)

There's really no way to visually inspect the valve guides without pulling them. Performing a leakdown test is a good indication and will tell you if they are bad. About the only way I know of without pulling the actual guide would be to pressurize the cylinder so the valve will not drop, pull the valvespring and move the valve with your hand to see if there is any play back and forth and side to side.

GuitsBoy

iTrader: (4)

The seal will be the major factor in leakdown / compression. I just give it the wiggle test. See if you can find a good set of heads and see if you feel and extra play in your heads.

SideStep

Will do....

oange ss

iTrader: (50)

bronze or cast iron

1BADAIR

iTrader: (1)

how will the seal or guide show up in a leak down test??
The valve is closed so no air will get to that part of the valve. The compressed air will also most likely firmly plant the valve square on the seat even if the guide is bad.
Pull the spring then move the valve slightly off the seat and wiggle it. Then do it again at about .500 lift.
The best way is to pull the valve and measure the stem then measure the guide

SideStep

.. yupper... I typed brass, but was thinking bronze, same color, right???

vettenuts

iTrader: (4)

Correct clearances are very small and need to be measured to 1/10,000th inches to ascertain any wear unless they are really bad. You need to disassemble the heads.

GuitsBoy

iTrader: (4)

Duh, youre right. I dont know what i was thinking. Im sure you could rig something up on a bench though...

Brian Tooley Racing

iTrader: (13)

You need a dial bore gauge that will measure the 8mm guide and reads in at least .0002" increments. If you can't find a shop local send one head to me, I'll check em for you at a good deal