Brinkmann Smoke’n Pit Modifications

The SnP is a great smoker out of the box, but tehre are a few things that you can do to enhance the performance and tune it into a very sweet, consistent pit.

here are some modifications that i have done so far to mine, and a few more that are in the works.

first, i took dryer vent tape and sealed off the two large holes in each end of the lid. i am assuming these were made for installing a rotisserie, but as it is, they draw off a lof of airflow, smoke and heat.

second, i went to my muffler shop and bought a length of new 2.5-inch exhaust pipe. the length was 9.5 inches, and i had a 45-degree angle cut at one end. after having him expand two inches of the end of the pipe to fit the base of my chimney (which is somewhere between 2.5 and three inches), it is now sitting very snugly in the base and extending 7.5 inches down into my smoking chamber. this forces the air, heat and smoke to draw across the bottom of the smoke chamber, rather than skirt straight up diagnally from the firebox to the chimney at the far end.

nexx up is my manifold project, which will deflect much heat away from the opening right at the firebox and dissipate it across the length of the smoking chamber. a detailed explanation will follow, but the 1/4-inch-thick steel plate will help very much in keeping temperatures constant across the chamber and will also prevent a hot spot right at the junction of the firebox and smoking chamber.

here's a diagram of the proposed manifold. please excuse the bad menmanship and that lack of straight lines for the vents.

this design obviously needs a lot of tweaking, but i figure that this is a good place to start.

i am currently working with RIVET on compiling a "manual for modifications for this smoker model. looking forward to some finished results!

Ron is doing a lot of great brainwork in fine tuning modification designs. If anyone of you all has or is gonna get a Smoke N'Pit or Smoke N'Pro, these are the details to make that unit run like a champ. 

Ron, the more I think about it, I believe what you need is a combination of the top and the bottom drawings.

Check out my theories and let me know your opinion. Really push back if you think otherwise!

1) I think you are correct in wanting the handle moved EAST to accomodate the water pan. That is a nice feature.

2) What is the extra length of the Manifold versus mine you wanted? If I recall, your design was to extend fully half-way across the smoking chamber, correct? Mine is a bit shorter.

3) I think with your super-duper cold weather up there, on the canted portion, you'll need bigger, or more, (either way) holes to allow for more heat entering the smoking chamber and less "blocking" of the heat. Mine has 3 columns of 5 rows of 1/4 inch holes - as you look from south to north as you cook. I'm guessing same number of holes, but 1/2 inch? What are your thoughts?

As an aside, the canted portion is the "engine" of the manifold which does most of the work. The flat postion is the "transmission" wich channels the work to the food. Thus, we need to "tune" your engine to your particular needs, which are, deeply cold weather. We need to allow for lots more heat into your chamber than I need here, just to maintain operating temps. Does this sound right?

4) Given the above, you also need a lot of plate steel "transmission" to maintain and radiate heat across the cooking expanse. Because of that, I think you may want to limit the amount of smoke-apertures to less than some of your drawings suggest. What do you think of a combination of sorts~ the "center" third portion of the manifold itself (canted to the left, east end to the right) looking like your top drawing  with 4 columns, 2 rows and the East (or right hand side) third having 3 colums of 5 rows like the bottom-most drawing?

These are just my thoughts, and the ultimate decision and design is yours. Be aware that blowing holes as Andy does is not nearly as exact as drilling them out and the sizes are approximations.

5) You need and want another small "extension" plate/manifold for the far East end of the smoking chamber that is separate and removable from the main manifold.

Any ideas on the dimensions?

Check out the next PM I send you with more thoughts on this. It'll have pics.






Edited by TasunkaWitko

I agree with all your points. You definitely know your weather, smoker and applications.

The ultimate design has to be yours and what you are happy with.

Definitely agree with the canted portion openings now that you spoke of them.

As far as the water pan, you have to decide. Are you EVER gonna want to use one or not? If you ever think you will, then you should have your design reflect that option- meaning the handle placement. There's nothing worse than having something custom made and then damning yourself for missing some minor tweaking. Just think about it.

Think about the size and placement of the the smoke vents you want on your manifold, both the summer one and the winter extension part.

Let me know.  I didn't know there was that much heat coming to the chimney part, but that makes sense. All the heat is concentrated into a cone going up the pipe!

Do you think you need to baffle the smoke at that point? I mean, are you putting that much meat near the chimney? I'd think that a couple columns of 3/8 inch holes would be good. Remember, you don't want to choke off the smoke flow from you unit just to save BTU's. Better to burn a bit more fuel (and maintain a clean draw) than to choke off your meat in the smoking chamber.

Okay...So I'm getting that you want the secondary one to be "big" in the sense of taking up "most" of the space not covered by the main manifold?

Now I am getting much clearer picture!

Is your drawing roughly to scale, meaning that you want a decent bit of clearance between the secondary manifold and the east end of the smoking chamber, along with room for slightly less clearance between the secondary and the primary manifold edges?

OR actually, you want the secondary manifold to be close within the primary manifold, AND EXTEND TO THE EAST as far as the edge of the chimney extension?

If so, how many inches do you envision between the primary and secondary manifolds?










Edited by rivet

I'm thinking your idea is better. Leave the "gap" at the EAST end of the smoker and butt the secondary manifold up against the primary one for really cold weather. In milder (for you all) weather you can pull the secondary manifold away from the primary one an inch or so, and still have a nice gap underneath the chimney, the eastern half anyway.

 

 

Okay Ron, if you got any thoughts or ideas, let them rip! I'm gonna be doing the measurements tomorrow before the pastrami goes in and do the drawings during the smoke, probably. I think we've nailed  down everything except any last items you may have thought of.

This is exciting and gonna be cool to see in action!

over the last few weeks, i have taken the final step in maximising the potential of the outstanding properties of this pit: the manifold.

otherwise known as a baffle, tuning plate etc., the purpose of the manifold is to both deflect direct heat from the food and act as a heat retention device in order to maintain steady temperatures across a pit. we can argue semantics and the science of heat transfer of all day, but that's a good layman's description. the thick, heavy manifold takes a while to heat up to temperature, but once it does, it is like you are on autopilot and you can maintain temsperatures for a very long time with only a very small addition of fuel. the improvement in fuel efficiency is nothing short of miraculous, which is important any time, but even moreso in winter - and that factor is multiplied exponentially where i live.

this manifold is modeled on RIVET's design, with a few differences that reflect both my preferences and also the necessities imposed by geography. The manifold is constructed of quarter-inch steel plate. rivet has a spec sheet drawing with specific dimensions etc., but basically it is wide enough to sit in the smoking chamber under the grates, and long enough to reach to the midpoint of the smoking chamber. the "western" end of the manifold is canted at a 45-degree angle and butts up against the opening between the firebox and the smoking chamber perfectly. there are a series of vents blown through that start small on the canted portion and gradually get larger toward the eastern end. there is a handle for conveniently lifting the manifold in order to set it on or take it off the pit, and also for moving it east or west, if desired for temperature and smoke control. the space between the canted portion and the edge of the handle will accomodate a loaf pan, should a water pan be desired.

there is also a secondary manifold that is the same width as the primary, but just long enough to reach the western edge of the chimney. this secondary manifold is specifically designed for this north montana latitude and climate, where temperatures during the winter are so low that they don't get talked about on the news. because of our special tempeerature conditions, i wanted another level of heat retention, and the secondary manifold provides just that.

the "great northern" moniker is a reflection of the history in north-central montana and is a nod to james j. hill's great northern railroad, which blazed the trail into this area. in the winter, temperatures can be very, very far below zero; last week, i woke up to 38 below zero, no windchill. in a climate like that, you need all the thermal mass you can get!  

here's a series of pictures showing the design features of the manifold.

due to the fabrication process of the manifold, it is necessary to do a "pre-burn" in order to burn off any residues or oils. we prepared for this by filling the trusty charcoal basket (another outstanding rivet-designed mod) with cottonwood and some chunks of scrap 2x4. note: the 2x4 sections (and pine, for that matter) would NOT have been used if we were going to cook, of course, but for quick, hot heat, it works very well.

i would have used charcoal to get things going, but there were no opened baggs of it around, so this was an all-wood burn.

we set the primary manifold in place; butting it up right against the western wall of the smoking chamber:

here's a good view of how the canted portion works to deflect direct heat away while allowing smoke and ambient heat to waft into the chamber:

we then set the secondary manifold in place, off to the east of the primary, below the chimney:

here's what we had when both manifolds were in place:

as you can see, the secondary can be moved around if necessary in order to regulate airflow, smoke infiltration etc.:

we wadded up some newspaper and tossed it under the charcoal basket, then lit it up. before long, we had a good, crackling fire, but because much of the wood was wet on the outside, there  was a lot of smoke. all the better to see the vent pattersn perform exactly as advertised! soon, we were getting some good warmth on a chilly day.

temperatures took a little while to rise while the firebox lid was open (we were letting the wood catch well before closing the lid). half an hour or so later when the wood was burning well, we closed the lid, and the temperatures rose quickly and dramatically. the outside of the smoker got good and hot, too hot to touch, and i took a look in at the oven thermometer i had set in the smoking chamber at the far end (so i would know the temperatures farthest from the fire). the temps were already past 300 degrees. the manifold was doing it's job perfectly, keeping direct heat away while also evening out temperatures. it wasn't that much later that we were at 400, then 450.

i had a ridiculously easy time holding the temps at 450 for a half hour, which i figured would give enough time to burn off any residues. the manifold of course blackened as it seasoned, but it's all good, that's what it's supposed to do.

i had to leave for a while to head out to my parents' place and help my dad with something. i got back maybe an hour later and temperatures were still above 350. not bad, consideirng i was using fast-burning cottonwood by now, and it was a cold day. i put a few small logs of cottonwood on and brought the temperatures up quickly up above 450 again, and then since then have let it burn down.

all-in-all, a very successful pre-burn. i am very much looking forward to using this at regualr cooking temperatures for cooking barbecue. i was going to toss a chicken on today to cook and then de-bone/chop for a soup tomorrow, but in the end decided not to until i can clean out all ash etc. from the treated 2x4s i was burning. i will be sure to report on my first smoke with this outstanding modification package!

a million thanks to RIVET for all of his assitance with the great northern manifold project. without him, it wouldn't have been accomplsihed and i am grateful!

Beautiful looking door, and from the pictures extremely high quality workmanship. You got every bit of your money's worth on this one, Ron! That metalsmith knows his stuff. The detail on the cuts for the butterfly, the cleanliness of the contour edging...they all demononstrate superb quality work. I would be happy to have that skill for $65...and that's plain fact. Congratulations!