Join Our Ford Truck Forum Today

Document your Ford truck project here and inspire others! Login/Register to view the site with fewer ads.

Register Log in

open manifold question

odogf150

odogf150

YOUNG GUN
398
1
utah
i got a question about my exhaust. one time i had the exhaust all off due to binding when the pipes got damaged and the sound was mean coming from the 351w (1992 flareside) and i love it up i got to admit. okay is it bad for the truck to be running with open manifolds? or any way bad because i got to take them off for more fixing up work and the truck will do travel MAYBE by trailer idk yet depending on the outcome....????
 
blacksnapon

blacksnapon

Moderator
Staff member
9,461
301
waynesville,mo.
odogf150 said:
i got a question about my exhaust. one time i had the exhaust all off due to binding when the pipes got damaged and the sound was mean coming from the 351w (1992 flareside) and i love it up i got to admit. okay is it bad for the truck to be running with open manifolds? or any way bad because i got to take them off for more fixing up work and the truck will do travel MAYBE by trailer idk yet depending on the outcome....????
Click to expand...
As far as I know, just a fire danger or melting anything in the path of the exhaust.
 
Evan's f250

Evan's f250

963
12
Southern Indiana
CDF302V8 said:
I've always been told that it is bad for the valves...but I'm not sure if that is true.
Click to expand...

ya, same here, but honestly dont believe it. most race cars including nascar just have open headers so i dnt know. My truck has one staight pipe all the way back with no mufflers, it was like that when i bought it, idk if thats hard on it or not.
but, I think he's wanting to just run open manifolds with no pipe at all, like i stated above that most race cars do.
 
LEB Ben

LEB Ben

Arrogant A-hole At-Large
34,919
1,124
outside your house
From what I understand, the valve issue is related to shut down procedure, and idea is that the valves will be exposed to cooler air quicker and it will warp the valves. However, I've never heard of cold air rising. So I don't believe it.

One thing to remember with the racecar or high power engine running open headers defense, they're pushing more air through than your engine.

And depending on where you stand on the 'engines need back pressure' debate, you'll be losing a lot of low end torque...which I believe.

You also have to stop and think how long you'll actually like that sound and whether or not you're breaking any sound ordinances.

Other things to think about are sensors and their location, and will this cause a fuel dump.

So to summarize, will you hurt your engine...I don't think so. Would I do it? I don't think so.
 
Last edited:
odogf150

odogf150

YOUNG GUN
398
1
utah
yeah thats what i been hearing is that it 'might' warp your valves but i dont knwo about that but it guess i 'might' learn the hard way
 
odogf150

odogf150

YOUNG GUN
398
1
utah
UTfball68 said:
From what I understand, the valve issue is related to shut down procedure, and idea is that the valves will be exposed to cooler air quicker and it will warp the valves. However, I've never heard of cold air rising. So I don't believe it.

One thing to remember with the racecar or high power engine running open headers defense, they're pushing more air through than your engine.

And depending on where you stand on the 'engines need back pressure' debate, you'll be losing a lot of low end torque...which I believe.

You also have to stop and think how long you'll actually like that sound and whether or not you're breaking any sound ordinances.

Other things to think about are sensors and their location, and will this cause a fuel dump.

So to summarize, will you hurt your engine...I don't think so. Would I do it? I don't think so.
Click to expand...


that is the straight forward responses i like man. yeah i believe youll lose some power with out the pipes i should know and the sound it is a beauty so dont care if i get pulled over itll be back on in a week its not a forever without the pipes just long enough to get some touch up done on my ride
 
LEB Ben

LEB Ben

Arrogant A-hole At-Large
34,919
1,124
outside your house
^^^Oh...I missed the part that they'll only be off for a short time, in that case, have fun with it.
 
odogf150

odogf150

YOUNG GUN
398
1
utah
Evan's f250 said:
ya, same here, but honestly dont believe it. most race cars including nascar just have open headers so i dnt know. My truck has one staight pipe all the way back with no mufflers, it was like that when i bought it, idk if thats hard on it or not.
but, I think he's wanting to just run open manifolds with no pipe at all, like i stated above that most race cars do.
Click to expand...

yeah the manifolds will still be on just the pipes will be out i dont think id take the manifolds off unless i was doin some engine work or swapping em off
 

Dirky

1,320
82
No problems, other than noise complaints.

Burnt valve issues usually only arise when one runs the engine with no manifold what so ever. The problem here is that after the exhaust stroke, the valve is subject to rapid cooling because there is no "shroud" or heat soak area around the exhaust port exit.
 
odogf150

odogf150

YOUNG GUN
398
1
utah
Dirky said:
No problems, other than noise complaints.

Burnt valve issues usually only arise when one runs the engine with no manifold what so ever. The problem here is that after the exhaust stroke, the valve is subject to rapid cooling because there is no "shroud" or heat soak area around the exhaust port exit.
Click to expand...

good info man
 

Ford Truck Articles

Recent Forum Posts

Top