burnt exhaust valve what is it?

[ximy]

It has been said... without proper exhaust (open exhaust ports on the head), the valves can cool too rapidly, then warp. This little warp-age doesn't let the valve face seat properly, then the valve head starts to burn, crack, or split thus "burned exhaust valve" Of course there are other causes.. too lean, too hot, high mileage, etc.

[fordman]

great thanks

[no_treble]

How long would you have to drive it that way before the valve is affected? Does this happen within minutes or hours or days?

[ximy]

that is pretty random... sometimes they never seem to fail, no matter how abused... other times the slightest particle of dirt can destroy a motor fast...

I've seen a lot of mechanics and machine shops test run engines with open exhaust.. I'd never do it, but others think nothing of it.

I'd have to say.. hours

[fordman]

so i could probably make a 30 mile trip and be ok. that is what i am guessing.

[ximy]

.. I don't know.. are the exhaust manifolds on?.. that would help

[fordman]

yes i thas manifolds. and only a pipe on the passenger side. no pipe on the drivers side. yet anyway. the radio and origianl speaker in this truck works i can barely hear it. if at all. i never listen to the radio anyway.

[ximy]

Yeah, that should be fine.. just loud.. taking it to the muffler shop?

[fordman]

my dads shop. he has a lift and a welder. plus i can work inside where it might be warm. well warmer than it is outside in the wind.

[ximy]

sweet!

[72Highboy]

KINDA NOT FOR LONG THO.

It has been said... without proper exhaust (open exhaust ports on the head), the valves can cool too rapidly, then warp. This little warp-age doesn't let the valve face seat properly, then the valve head starts to burn, crack, or split thus "burned exhaust valve" Of course there are other causes.. too lean, too hot, high mileage, etc.

Hey Ximy
How do you know if your truck is running to lean, how can you fix it. Im replaceing my headers and there is quite a bit of black soot, is my truck running to lean or is it normal.

[ximy]

72Highboy... usually black soot is way too rich... adjust your carburetor mixture screws

[convincor]

A vacume leak will also cause burnt exhaust valves due to the lean condition it will cause.


Also notice how the seat wears also from the lean/hot condition allowing the valve to sink into the head.

[mlheppl]

Is there any way that you could run 3 ft of pipe on the drivers side just for temporary. That would give you enough pipe to keep from burning a valve. Even if it wasn't a perfect fit/routing it would get you by for now. I'd hate to see you burn a valve. You've already put a lot of work in getting the truck going from what I've read on your posts.

[papabug71]

I agree with ximy, its totally random. I ran straights on my truck for years in highscool, & it has straights on it now. No problems.

But the muffler fell off of my '60 Ford 800 tractor & it burned a valve in 2 days.