Anybody had a 3.0 drop a valve seat? My '91 4R has an intake valve being held open about 1/8 of an inch. Tomorrow going to use a bore scope to look in the spark plug hole and see if thats the problem. Earlier this week it ran fine on the way home, started it the next morning, and immediately heard valve rattle, then a skip. I'm hoping it's carbon buildup, but that's not the way my luck goes.

 

I know 3.0s burn exhaust valves on the 4th and 6th cylinder

 

Oh ya, been there, done that.

#6 intake valve seat just decided it no longer liked staying in the head all the time and that the valve had all the fun popping open and closed, so, it up and jumped out of the head one day and started riding up and down with the valve, going clack, clack, clack the entire time. I did a compression check and found low compression on #6. Check all the rest, went back to #6, zero compression. The spark plug was the only thing keeping it from moving sideways enough to hold the valve open. After I removed the plug to do the compression check, it moved over and held it open. Never touched the piston, so, no damage there.

Pic of it as my avatar.

I ended up having an oversized seat installed and both heads worked over with new exhaust valves and a valve job on the other 5 intakes. It has been back on the road fro 15k miles, runs fine.

Here is a bigger pic, just to share the pain:

 

Yep, dropped a intake seat on #2, def a new head, possibly getting a reman engine. Any suggestions on reman engine suppliers for the beast?