# OC Pecos smoke stack/exhaust?



## daveman92789 (Jan 13, 2020)

I have an OC pecos smoker. I've noticed the smoke stack is 5" id pipe but the opening in the smoke chamber is only 4". The biggest problem is if any water goes down the stack its pain to get out. No way to drain it without drilling a hole on the bottom side.... which really isn't a big deal but would rather have the ability to pull it back into the cook chamber. 

If I cut out the lip in the chamber would it affect air flow or anything else?

See attached images. Obviously you can see there's water in my stack. Storm came through right after I got done bbqing!


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## Alphonse (Jan 18, 2020)

I don't own one but like you, I would get the water out.    I think the material on is going to corrode out pretty quick otherwise.

I seriously doubt that slitting or opening that hole up for a drain is going to have any noticeable effect on the thermal performance of the grill. 

I have built pits and it is apparent to me that their fab method here was one of simplicity to save cost on fabrication and material thickness.    The smaller stack hole is likely designed to make it easier to fit up and attach the stack.   It also leaves a bit more rigidity to the stack connection vs. opening the end up more.    Opening a bigger hole in the center of a sheet metal cap makes it less rigid. 

Alternatively I would consider putting a metal bucket over the stack and keep the water out.


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## daveman92789 (Jan 18, 2020)

I believe your right on making it easier to attach the smoke stack. It's not perfectly centered on the opening.  I know the pit isn't the thickest but i think its thick enough to support the smoke stack without the extra material. 

I looked at a bbq pit calculator & my size pit with 4" exhaust, the stack should be 22" long. With a 5" exhaust, the stack should be 14.5" long. Currently the exhaust is 15.5" long. I did add the baffle/convection plate which I'm sure restricts the air flow some so I wouldn't think cutting the lip out would effect thermals all that much. 

Just didn't want to screw anything up.... I guess if it messes anything up I could always weld in a plate or use the damper on the stack.


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## daveman92789 (May 11, 2020)

I ended up cutting that lip out. I can say that there is a noticeable difference in the air flow through the cook chamber and it actually got my temps closer from end to end.


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## Smokin Okie (May 11, 2020)

Backyard offset builders like Workhorse pits,  Aaron Franklin's pit,  and Mill Scale's mod 94 ... have large " collectors " ,  a manifold like device ,  funneling air into the stack.

I have wondered if that large opening has an impact on end-to-end temps.   I know it would have a large impact on air flow.

JD of Workhorse pits,  did a Quetorial vid on modifying a Yoder Wichita.     He took out the Yoder convection plate and put a collector on the stack end and he says it now has even temps.


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## daveman92789 (May 11, 2020)

Smokin Okie said:


> Backyard offset builders like Workhorse pits,  Aaron Franklin's pit,  and Mill Scale's mod 94 ... have large " collectors " ,  a manifold like device ,  funneling air into the stack.
> 
> I have wondered if that large opening has an impact on end-to-end temps.   I know it would have a large impact on air flow.
> 
> JD of Workhorse pits,  did a Quetorial vid on modifying a Yoder Wichita.     He took out the Yoder convection plate and put a collector on the stack end and he says it now has even temps.



I actually watched that video a few weeks ago. I haven't decided if I'm ready to take on that kind of mod. I can say that I really enjoy doing different mods just to see how they work. Its like a science experiment. Also one day i really want to build my own pit and i would rather know how these mods impact cooks & air flow now before building one. Plus so far to date i haven't done anything to the pit that couldn't be undone.... other than cutting the lip out which so far i have no regrets. I ran a small butt and a rack of venison ribs last week. Both turned out great. Even when i put the ribs behind the butt it still got color and even cook across the rack.


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## ryebrookbbq (May 6, 2021)

daveman92789 said:


> I ended up cutting that lip out. I can say that there is a noticeable difference in the air flow through the cook chamber and it actually got my temps closer from end to end.



do you have a pic of the lip cut out for reference? Have a new pecos coming snd will want to do the same.


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