#5 exhaust valve burnt maybe pushrod/lifter?

[spiralthomas]

94 4.0 150k miles manual trans
no compression #5, other cyls. good(150 reading) seems to be burnt exh. valve... is it possible that a pushrod or lifter or both are the real culprit? like to ask before i order new heads. also, will a new top end blow out my rings as has been suggested by a shade tree buddy? i have heard this can happen...
thanks any and all!

ok so the new top end wasting the bottom prematurely is defintely up for debate so after a lo-tech leak down i'll probably just replace the bad valve(s) if everything else looks fine. weekend warriors vs. pros: it's on! will show & tell for those interested. good luck to me...

 

[trail B2]

You could give it a leak down test.You could also put no. 5 on top dead center Take off the rocker arms and put air in the cylinder with an adapter and see where it comes out.

 

[spiralthomas]

thanks trail b2- much research last night(& the old newspaper on exh. pipe) leads me to believe that a burnt exhaust is the malfunction. will give your method a try when i get her down to that point. much appreciation for the simplified leak down guide, should be able to rig my compressor to my compr. tester. what year is your 4.0? manual or auto? my manual seems to be developing a personality also 75k after a rebuild (q lube idiots always said full even though common & known rear seal leak)- 1st a little tough engaging from stop.
again, thanks obi wan, you were my only reply.
happy drivin'!

 

[spiralthomas]

problem confirmed

pulled right head, exhaust valve burnt as expected. thinking of just replacing valve & seal... have heard different opinions on levels of fixes, wouldn't mind more input before reassembly. one valve & seal? one valve & all seals? full valve job? informed views welcomed.

 

[spiralthomas]

burnt exhaust #5

 

[trxusrngr]

Just burnt #4 on my 3.0 and by the time i bought valves, seals and had a machine shop go over the headit would be almost double the cost of a re-man head. i paid $150.78 for a reman head with valves, springs, and seals... ready to install!

 

[spiralthomas]

new heads coming, getting new rockers/pushrods from delta. will monitor bottom end closely... pics & stories to come