trouble with okj...tuning plates or horizon plate?

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fifdynutz

Newbie
Original poster
Oct 21, 2014
11
10
Hey guys, fairly new here but done plenty of reading. Recently completed a 250 gallon reverse flow trailer build and kind of got the bug for tinkering with building smokers...anyway, I recently sold my wsm to purchase an oklahoma joe highland to play with...wsm was too easy haha...well I got what a bargained for, this weekend I did a 7lb pork butt and about 5lbs of deer ribs, with the deer ribs on the left side and the butt on the right...butt cooked for 8 hours and I cooked the deer ribs 6 hours. Temps are about 25-50* colder on the left for whatever reason (using two tel tru in the 2 ports on lid...my maverick at the grates reads about 25* colder than the lid therms...When it was all said and done the butt turned out excellent and the deer ribs were completely RAW after 6 hours. This is a major issue. So far I build a mid level channel for tuning plates or a baffle and on this run I put a foil pan full of water on the far right side against the opening to try and deter heat to the other side and that definitely didn't work. I also have lowered stack inlet to grate level and build a stainless mesh charcoal box...what would you guys recommend to correct this? If it comes down to it I'll just make it reverse flow if I have to..thsnks
 
I have the OKJ Longhorn and experienced temperature differences much as you describe until I had a baffle added between the firebox and cooking chamber.  I also had the welding shop make tuning plates to cover most of the area across the chamber and build a charcoal box.  In addition, I used some 3" hvac elbows to take the stack down to grate level.  I have since had to remove one of the tuning plates but have consistent temperatures now.  I've also put insulating rope around the opening of the door of the firebox.  I recently received some tape to improve the seal of the cooking chamber door.
 
Air leaks around the door are the major problem when reading temps.... therms in the door vs temp reading on the cooking grate can vary widely.... seal the door, check temps across the grate while reading temps on the door therms... that will tell you a ton....
 
I heavily sealed every joint with fireplace cement when I assembled it, and it has 3/8 rope gasket on the doors, it is pretty air tight so it may be safe to rule that out...just trying to decide between tuning plates or a horizon style baffle...I have access to about any metal working tools needed including a cnc plasma cutter to make either...just making sure I take the right route
 
Which end of the cook chamber is the exhaust located.... that will determine if you use tuning plates or a RF plate...
 
It is in the factory location on the left...The plate I am talking about would be similar to the horizon baffle plate with small holes going to bigger holes on the left side
 
Currently a few hours into a dry run with tuning plates...still have at least a 25* difference from end to end...is this going to be inevitable?
 
Do you have an infra red non contact therm.... You can use it to check the temps across the plates.... Also, check the temp of the Firebox.... The FB and Plates should be close to the same.... Too high a temp in the FB shows a lack of flow through to the tuning plates and exhaust stack....

Try removing the exhaust elbow.... It may be a restriction in the exhaust flow... When the plates are adjusted you shouldn't need an elbow.... Heat/smoke should be equally distributed across the cooking surface.. If that theory don't work, it can always be put back in...
 
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When testing I adjusted the plates ever which way, and even tried completely removing the one to the far left and it made it worse, tried removing the elbow and it was under a 5* difference...I checked temps with 2 tel tru in the lid and a maverick grate thermometer I moved around...you think j should cut the plates narrower and try a longer stack? The firebox had a healthy fire for sure
 
When testing I adjusted the plates ever which way, and even tried completely removing the one to the far left and it made it worse, tried removing the elbow and it was under a 5* difference...I checked temps with 2 tel tru in the lid and a maverick grate thermometer I moved around...you think j should cut the plates narrower and try a longer stack? The firebox had a healthy fire for sure



I don't know what your firebox looks like, or what you have for air inlet vents.... Overheating FB wastes fuel and can warp it... Air inlets can do 2 things... control the heat output of the fuel and move the heat from the FB to the CC...

Here is what works well....

 
If your FB is really hot and it appears the CC could use more air and heat, by all means.... add a second inlet across from the FB/CC opening to move some of that heat.. Check temps throughout the smoker and determine if the exhaust is the problem.. you can do that with temp. measurements... FB end of the CC still too hot, the exhaust ain't working...
 
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I'll start looking for another inlet asap...Thank you very much for the help so far...I'll report back soon
 
It's resting against the FB... The deal is, you are trying to seal the FB/CC so all the smoke/heat travels under the plates... or something close... then the gaps distribute the heat to the cooking grates....
In the picture, the plates could have been narrower... that would have allowed for more slots to move heat upward to the cooking grates.. a more uniform cooking surface... "MAYBE".... those might work perfect.... just saying there are options...
 
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