running off headers?

[ButtNuttN8]

Is it not a good idea to run a motor for long periods of time off just headers? someone told me its bad for the engine ie buren the exhuast valves out of it whats the story?"

[Fordtrucks]

IF you run long tube headders in a not freezing enviornment you will be ok.

[GubNi]

If you are carb it doesn't matter, but EFI has problems because of the O2 sensors.

[NetBSD]

nuttin but headers in my area (PA) and we never have a proble, had LT's on my 400 for about a year and no problems at all

[Fordtrucks]

Is that why your 400 is blown up and has no oil pressure?:D

[NetBSD]

Is that why your 400 is blown up and has no oil pressure?:D


well i wouldnt call it blown up, i think i got 4 outa 8 pistons left :flipoff2: but im pretty sure the fact that i had the motor submerged in water with sand had a little bit of an affect on it :flipoff2:

[Fordtrucks]

:shaking: I was just giving ya shit.Glad it still runs.Get that 300/6 in and youll se a vast power improvement.:grinpimp:

[ButtNuttN8]

well the problem is i have a 400 carbed and the header goes right in the way of the front drive shaft so i can not have an exhaust so i was thinkin about putting stright up headers and just say hell ill run it like that but before i blew something up i wanted to check thanks

[Earlybronco42]

It will be fine. If you run them straight up don't forget to put some kind of cap on them when it is turned off.

[Aces'n'8s]

IF you run long tube headders in a not freezing enviornment you will be ok.

What does the possibility of freezing have to do with the viability of running open headers?

[Landslide]

I don't know if freezing temp make allot of difference but this is what can happen if running open headers or too short of exhaust.

If you shut engine down after it's good and hot cool air can travel back in exhaust and possibly warp or burn any open exhaust valves. I don't think it's a problem with headers as they should be long enough to prevent this. I think it's very possible it you were running no exhaust what so ever, just straight out the ports kinda thing.

Hope this makes since to ya...

[Aces'n'8s]

I don't know if freezing temp make allot of difference but this is what can happen if running open headers or too short of exhaust.

If you shut engine down after it's good and hot cool air can travel back in exhaust and possibly warp or burn any open exhaust valves. I don't think it's a problem with headers as they should be long enough to prevent this. I think it's very possible it you were running no exhaust what so ever, just straight out the ports kinda thing.

Hope this makes since to ya...


But wouldn't the radiant heat inside the header tubes at least lessen or thwart completely, the chances that cool air would rush into the cylinder head and cause damage? If a substantially fast and very chilling wind were to move up and into the cyl. head, I could understand this notion.

This is the second time I've heard of this, so I'm just trying to understand how the damage takes place.

[Stump385scj]

Its the same as if you took a really hot piece of metal and droped it into a bucket of ice water. It would shatter.

[Aces'n'8s]

Its the same as if you took a really hot piece of metal and droped it into a bucket of ice water. It would shatter.


I beg to differ. While I understand the premise, air doesn't have the same cooling properties as water. I would speculate that more damage would occur by introducing a hot object into a bucket full of chilled water than into a bucket full of cold air.

I'm just trying to figure out how the cold air overpowers the rather warm radiant heat inside the headers...

Has this happened to anyone?

[Stump385scj]

your right its not the same just same concept

[Landslide]

Like I said - I don't think it's a problem as long as you’re running headers or some type of exhaust. The length of exhaust tubing will provide some length of radiant heat to prevent cool air from getting to the exhaust valves.

I've always heard that you want the exhaust tubing length to be something like this: You want one exhaust gases from a cylinder still in the exhaust tube (not yet exiting) while a second one from same cylinder is entering exhaust tubing at an idle.

If you think that cool air contacting a red hot exhaust valve immediately after shutting engine down won't warp or burn the valve then run your engine with out an exhaust and tell us how it holds up. I'm talking straight out the cylinder heads no headers or exhaust.

[351wstanggt]

I run open headers on my Stang and haven't had a problem with it. Other then it being a bit more cold-blooded, and not lliking idling, but it never liked to idle in the first place

[Aces'n'8s]

If you think that cool air contacting a red hot exhaust valve immediately after shutting engine down won't warp or burn the valve then run your engine with out an exhaust and tell us how it holds up. I'm talking straight out the cylinder heads no headers or exhaust.

It would probably hold up fairly well...on someone else's motor. But, for me, it would probably crack the block in half. But then again, I wouldn't run any motor without exhaust manifolds...that would be stupid.

[Stump385scj]

X2 Yes running an engine without exhaust manafolds is just plain stupid. One you melt everything in your engine compartment, have a very high risk of burning your rig down, and your horsepower output takes a crap on you. Running just headers wont hurt any thing, given that your engine is not still stock from the factory(meaning its had a valve job). Go to a dragstrip and 7 out of 10 dont have any exhaust other than headers. Dont get me wrong a well thought out exhaust and mufflers will add power. you just dont get that roar:smokin:

[braxton357]

Its the same as if you took a really hot piece of metal and droped it into a bucket of ice water. It would shatter.


:confused: Metal shatters when quenched now? Or are your valves the new sodium-filled blown glass versions?

Nothing is going to happen to your valves because of your open headers and cold air...except maybe a ticket, and pissing people off on the trail. Filling your engine with a bucket of icewater may do some damage though.

[Stump385scj]

Its the same concept.