burnt valve tricks?

[my86mj]

so making a 100 mile round trip and sarge starts jerking and popping like the timing is off. i pull over and its idling like crap and the temp spiked. it cooled down and i started it again. (still on the side of the freeway with a small trailer behind me as well) i make it home and it drives okay runs smooth at anything above 2000 rpm but won't idle for crap. sounds like its on 2 cylinders. i am led to believe that its a burnt valve. i have since run some restore and lucas tune up in a bottle in it. also retimed it. does anyone know of any tricks to fix a burnt valve? i don't want to pull the heads because at that point i will just rip the 2.8 out and throw in something else.

[Comanche County]

What do the plugs look like?

[jimoshel]

You just don't fix a valve with out pulling the head.

Unless you're a really good welder and reach in thru the spark plug hole and build the valve edge back up. :thwak:

[Comanche County]

Yeah just pull the heads, its not too hard of a job. If they're looking bad, most likely they'd need a 3 angle job, valve seals and valve guides. The cost of that work would probably run you about 400 bucks. You could just find a 3.4 out of a mid 90's Camaro or Firebird cheaper then getting the heads rebuilt. Then just use the upper intake etc off the 2.8. See the below article.

 

http://www.lunghd.com/Tech_Articles/Pro ... ect_XJ.htm

[carnuck]

It could also be carbon in the intake or exhaust valve jamming it open, bent pushrod, broken valve spring, bad plug and a couple other things I can't recall off the top of my head.

 

Ah! Stuck open EGR valve! (that's where carbon chunks sometimes come from)

[my86mj]

it was bent and burnt valves i pulled the motor apart after i got a new engine and all none of the valves actually were seated

[Eagle]

it was bent and burnt valves i pulled the motor apart after i got a new engine and all none of the valves actually were seated

That'll do it ...