Bad valve seats on my 4.0l

[black_demon69]

Had to pull heads due to bad exhaust valve seats
Good news is that I should have heads back from the machine shop Friday. Hopefully it will be done Saturday

 

[RonD]

Not common on the 4.0l
3.0l did have that issue for a few years

If they were burnt there may be an underlying issue that caused it, lean mix, pinging, rocker/valve stem issue

Exhaust Valves must turn/spin when opened and closed so they don't get "hot spots" which causes a leak and then burnt valve/seat

 

[black_demon69]

valves were not burnt just sucked..

machine shop said that sucked valves are common on the 4.0l because he believes that original seats are to soft.

 

[RonD]

Never read of that before

"Tulipped" intake valves I have read about on other engines, 2.3l lima for example, learn something new everyday

 

[black_demon69]

On the 4.0l the original Valve seats are cast not inserted and as I said guy @machine shop speculates that they are soft. He says that he sees exhaust valves on 4.0l like that all the time. Intake valves seem to be fine.

 

[black_demon69]

BTW truck purrs like a kitten now.