BDM Oil Cooler

Energy One

Little-Boo

Well-Known Member
Troop Supporter
I have not seen or taken one apart, but would assume it has to be a coiled tube inside. Interesting question I would like to know myself.

Carlos :D
 

ringo

Active Member
IM thinking the oil is in direct contact with the tubes ID with the heat being transfered directly into the aluminum and of course disapated by air flow. I wonder how they have the inlet and outlet seperated to force the oil to take the longest path possible between the two. I can invision the tube having a wall between the two running nearly its full length, so hot oil coming in has to run up and over this wall to get to the other side, exiting the cooler and returning to tank. But I dont know...
 

stlmikie

I wish I had more money.
I wouldn't be surprised if it was just an open cavity. One line in and one line out.
 

BWG56

Guru
Its a turned part so it would be easy to make and bore out the inside, tap 2 threaded holes in the bottom and attach a threaded tube (inside) to the inlet side about the length of the tube and cap it off.
Just my opinion,:confused: but thats like a$$holes, everyone's got one.:lol:
 

Fibersnake

Banjo Playing PsychoBilly
Not sure but I would hope they had more than tube in and out. Similar ones would have a U tube going between thin dics (tube sheet or tube and fin) that are stacked with spacing and those would then be pressed into to insure good contant to the tube to allow for good disapation of the heat to the alumin cylinder and out to the atmosphere.

But unless one takes one apart or one of the in know people can confirm, it could be something as simple (and thus ineffcient as an in-out BS!
 
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Vince81

Banned
I've been to Daytona and Myrtle Beach & Laconia in Stop & Go traffic with Daytona being the WORST (for heat & humidity) and even with My 155 C.I. S&S Motor the heat hasn't been too much of a problem-or should I say "an issue" so with that said......I cant say that the BDMs *need* an oil cooler unless that same type of heat ,traffic and humidity are a Constant weather condition that you ride in All The Time .
Yes they work well , and are neat looking units-and "cool " oil is your engines friend .
But the 103,107,111,117 & 124 C.I. S&S engines are pretty robust to begin with (actually they are The Finest) and warm oil is better than COLD oil for performance issues.

As far as the internal build design of the BDM oil cooler-it's a partition divided "coil "....the warm oil coming INTO the inlet line-pumped Up and over the partition and into the coiled return line that runs down the length of the cooler and is attached to the internal wall of the face of the oil cooler that gets the air flowing over the ribbed outer cooler body-thus reducing the temperature of the oil that is flowing thru the coiled internal line attached to the cooler wall.:D
Hope this helps you out as far as build design of that unit.
I saw this information I've shared with you dudes 1st hand in an oil cooler that was damaged & taken off(and cracked open) on a BDM Ridgeback that had been in an accident(the guy rear ended a car in front of him while doing a holeshot:D)
Vince
 

Trainguy

Chromeoholic
I've been to Daytona and Myrtle Beach & Laconia in Stop & Go traffic with Daytona being the WORST (for heat & humidity) and even with My 155 C.I. S&S Motor the heat hasn't been too much of a problem-or should I say "an issue" so with that said......I cant say that the BDMs *need* an oil cooler unless that same type of heat ,traffic and humidity are a Constant weather condition that you ride in All The Time .
Yes they work well , and are neat looking units-and "cool " oil is your engines friend .
But the 103,107,111,117 & 124 C.I. S&S engines are pretty robust to begin with (actually they are The Finest) and warm oil is better than COLD oil for performance issues.

As far as the internal build design of the BDM oil cooler-it's a partition divided "coil "....the warm oil coming INTO the inlet line-pumped Up and over the partition and into the coiled return line that runs down the length of the cooler and is attached to the internal wall of the face of the oil cooler that gets the air flowing over the ribbed outer cooler body-thus reducing the temperature of the oil that is flowing thru the coiled internal line attached to the cooler wall.:D
Hope this helps you out as far as build design of that unit.
I saw this information I've shared with you dudes 1st hand in an oil cooler that was damaged & taken off(and cracked open) on a BDM Ridgeback that had been in an accident(the guy rear ended a car in front of him while doing a holeshot:D)
Vince
And that is your answer:whoop: Thanks Vince
 

Vince81

Banned
And that is your answer:whoop: Thanks Vince
You are most welcome Dude....I wanted to share that with Y'all as it's a good technical question and one that many can benefit from in all ways pertinent to the oil cooler in question for ALL BDM Bikes.:D
I just wish I coulda salvaged that unit & taken pictures of it to share with all here before I chucked it(it was dented & blasted way cool junior:( ) and of NO Use whatsoever to anyone - except to dissect & autopsy to *SEE* what it was made of and how it worked:D
BUT....:D:D:D I DID salvage a few neat and worthy pieces of that bike in question to use on my own here as the in-house *Mad Scientist* Vince that I am:flag: yeah it's all good Bro !:D
Vince
 

ringo

Active Member
IM trying to picture that but it ain't working. Im picturing a round coiled tube up against the flat curvature of the bore, is that what your saying? Heat transfer with that scenario would be poor. Theres very very little surface contact between a round and flat surface. That coiled tube must play a different role than heat transfer.
Or maybe IM not seeing what is being described.
 

Vince81

Banned
IM trying to picture that but it ain't working. Im picturing a round coiled tube up against the flat curvature of the bore, is that what your saying? Heat transfer with that scenario would be poor. Theres very very little surface contact between a round and flat surface. That coiled tube must play a different role than heat transfer.
Or maybe IM not seeing what is being described.
The *coiled* return down the face of the front of the inside of the oil cooler is just ATTACHED AT THE TOP & BOTTOM with small forged brackets-the coils themselves are suspended inside the face of the tube(facing frontwards for the cooling effect to *hit* the machined fins on the outside and transfer the cooling process to the inside isolated tube w/coils.) like an intercooler theory(kinda....?)
But the coiled cooling fins are NOT attached top to bottom on the inside of the BDM oil cooler...they are suspended-get the picture I'm describing...?:D
Vince
 

ringo

Active Member
no sorry, but I am in the process of drawing one up. I'll post a .jpg when IM a bit further along. I'll do a cutaway so we can see the inside.
I have a divider as well, ensuring the oil cannot enter and exit without spending some quality time in the cannister.
What is the inside diameter of those units?
This would be a fairly simple part to make in its basic form.
 

Tom Chop

Active Member
:flag: ringo; I understand what you are saying. I also have trouble envisioning what someone else describes. I must be contaminated after 35+ years of Ironworking. Give me a blue-print or a sketch and we`ll be fine. I have two BDM oil coolers on my K9 and I am not worried about the oil being too cold since my home is Alabama. In winter if the oil stays too cold to ride---it`s too cold for the kid anyway!!! I cannot remember the company`s name but in the Jegs catalog they carry a style of oil cooler which has a "turbolator" in the oil cooler`s tube causing maximum contact with the sides of the aluminum. Mabe I was wishing too hard but I had hoped for the same type of arrangement with the BDM oil coolers. Oh well...... :2thumbs::choppersmiley: Tom Chop
 

Fibersnake

Banjo Playing PsychoBilly
It is an interesting design, doesn't sound very efficinet but probably more so than just in and out oil.

By chance was the tube fairly good size on the inside, wondering on possible restriction.

Do appreciate the thread though, give me some idea of how to design one similar with a modified tube bundle machined right into a solid billet rod. Seems would be fairly easy to do, machine and make look very nice and allot more efficient and only reuired a solid rod of aluminum and some machined end caps.

May have to kiill some time and put the Microstation to work and come up with preliminary calcs.

Thanks for the idea
 

ringo

Active Member
When you start drawing one up you quickly realize the bore itself is small assuming an OD of around 2.5 in. I've never seen one the units in person so IM not sure about the diameter and length.
 

Fibersnake

Banjo Playing PsychoBilly
I got about 75% of a prelimn design done up where I would basiclly take a approx 3" Aluminum Cylinder billet, have cooling fins machined in the sides going down, (similar to the BD) to depth of about 3/8 inch, then inside have array of 10 bores cut along 270 of cricumfrence (top to bottom) to act as my tubes and then larger single on back side as return.

Machine caps on top and bottom. Still playing but basic design seems like it may be doable and workable.

Plan to work it more when I get home and run flows through some programs to get basic ideas of thermodynmics and efficiency. If things look good, send out to cousin or someone to proto one CNC and see how it would work.

If anyone else is thinking, maybe they have some ideas also.

May post up a prilimanry PDF here within a week or so if so one wants to add input or suggestions.

Concerns are how close I can bore the tubes into the billet in relations to the cut fins and addition to actual thermo efficeincy, concern about strength. So until I get home with a good basic design and run some basic FEA, just ideas at this point.
 

Th3InfamousI

Administrator
Staff member
I would think something simple as this would pull heat from the oil.
I dont see a dividing wall, I think you would lose efficiency without something.

With this being a low pressure system, I assume you would want to have something to ensure the flow back down is restricted just enough to maximize the time in the cooler.

Additonally, as I am only drawing this up in my head and have ZERO experience with an oil cooler on a Air Cooled VTWIN. The Oil cooler will be mounted higher than the oil filter, will this cause additional strain on the pump? Potentially causing an earlier failure?

Just as an FYI - I was reading through the 107 manual on XMAS :D It had said unless your oil is continually running >280F. (Ideal temp is 250-280)There was no need to run an oil cooler. On the flipside if you were seeing temperatures below 180 constantly to add a cover to your oil filter. Just food for thought!

I just grabbed one of the oil temp gauges on your oil cap. Living in Dallas I am keen to see temps come summer time. I rode the other day in 50'ish degree weather and was seeing temps around 180-200 running through traffic. Long runs I was getting down to 150-160.
 
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