Is there any way to change the valve guides on the stock 85 heads. I am getting AFR heads with tax return, but need to sto the smoking. Any ideas, I've never tried this. When I used to race stock cars, I just took the heads to my head guy........ :D

 

For only 6 mo you may get by with just new valve seals.

 

Yes! :yesnod:

L98s are notorious for the seals wearing out, in addition to a lot of valve guide wear. Fresh seals should hold you over for a while. Guides aren't the "easiest" thing to do. :)

 

Yes, but can I do this with the heads still on the car, without major tear down? :rolleyes:

 

Seals, yes.

Guides, no!!!

 

To replace the valve seals do the following:

1) Decide on which type of seal you are going to use. stock/"O"ring
style/Teflon/umbrella/etc.

2) Get a spark plug hole adapter, air hose quick disconnect & a valve spring
compressor tool.

3) Put the car in neutral, block the wheels & disconnect the negative bat cable

4) Remove all the plugs and valve covers

5) Remove the intake & exhaust rockers, install the valve spring compressor
tool, squirt a bit of oil in the cylinder, bring the piston to TDC, install the
plug adapter & hook up the air. The piston SHOULD NOT move to the bottom of the
cylinder and you can now remove the valve spring locks (I use a magnet), valve
spring & valve seal.

Note - If the cylinder moves to the bottom you are not at TDC. You do not want
this to happen because if you loose air pressure and the valve does not have the
spring and locks on the valve will drop into the cylinder.

6) Replace the seal, spring & locks. Now repeat for the other valve on that
cylinder.

7) Remove the air and reinstall the rocker arms. Be sure to put them back on
the valve you took them off of. Don't try to adjust them now, just snug them up.

8) Then repeat for the other 7 cylinders.

9) After all the seals are done. Bring number 1 to top dead center and set the
valve lash on half the engine. Rotate the crank 360 degrees to top dead center
number 6 and set the other half. I don't have the exact order with me but it is
in just about any good repair book.

10) Reinstall the plugs and valve covers (new gaskets) and your done.

 

My $.02 to JonM's technique. Step 7. DO adjust the valves at this point. You already have the piston for that cylinder at TDC on the compression stroke. Skip step 9.

SBC valve guides are integral with the head casting. They can only be repaired at a machine shop with the heads off of the engine.

More $.02. New seals will be of limited value and short lived. Since the guides are probably worn, the sloppy valves will take out the new seals in short order. Since there is relief in sight (6 months), I think you would be better off living with it in the meantime.

CFI-EFI


[Modified by CFI-EFI, 11:11 AM 11/8/2001]