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Differential cooler

S

smokeyfan1000

Guest
Has anyone seen, heard of, or know of, a convection type differential oil cooler?

Not one that uses a pulley on driveshaft to turn a pump that pumps oil through cooler & then diff and back again.

But just a 'heatsink" with cooling fins that merely bolts to the diff hsg, and dissipates heat, much like the fins on a motorcycle cylinder/head

Is there any such thing? And would it actaully cool the diff any?

I have an idea, but unsure if the cooling effect would be worth the effort.
 
You mean a finned rear cover?

That would be a lot easier than "convection type cooler" ... :roll:

They are made for just about any rear end that has a bolt on rear cover.

Yes, they work, but would you notice or be able to measure the difference it makes? Depends on how hot your current setup gets.

finned Dana 30 cover
 

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Nope, not just a finned rear cover.but that is part of what gave me this weird idea. But....no one makes Volvo diff rear covers for the electric speedo diff cover anyway.
Let me explain my idea. And keep in mind, it's just an idea that crossed my mind when I noticed those holes in mtg flanges on the diff.

Now... on pass side of diff. hsg. on my 91 244 there are two mounting flanges with drilled & tapped holes in them. One hole on each flange.

I was wondering .....what if i made a thick steel plate to bolt to one or both mtg flanges.Drill & tap it for small bolts to screw into said plate. (if floorpan clearance will allow it)

Then cut some short 1/8" long or so ,small diameter sleeves for spacers.
Find, or fab some thin sheet aluminum.
Cut them into same size pieces.
Drill holes in a pattern, so as to allow them to be stacked(like fins on an oil cooler) 1/8" apart.
Bolt the bottom plate to the thick mtg plate that'll attach to diff mtg holes.

I'll end up with a series of stacked aluminum fins to use as a convection cooler that'll maybe dissipate heat away from diff hsg, thereby (possibly) cooling the diff & diff oil temps.

Only problem is, not sure how large said cooler would have to be ,to do the job. I'm thinking not enough room under there for this thing to actually do any cooling of diff. But I'm thinking it might be worth investigating?

I need to read up on heat loss/heat gain formulas I suppose. I doubt this idea of mine will be very feasible/worth the effort.

And I'd have to investigate on exactly how to mount it for proper clearance/air flow. Like I said, just a weird idea that "popped" into my head.

See pic below and notice the star drivers are inserted into the threaded holes where mounting flanges are already cast into the diff hsg.

Now..look at this pic. This is a pic of my 91 240's diff.

100_6660.jpg
 
I have not found anyone making a finned cover for the Volvo 240 86-93 diff w/ electric speedo. I made a post sometime ago here, & everyone said no one makes them for 86-93 240 diff.
 
OK like the strengthening of the suspension arms and links---where its easy to do so the cost benefit calculation is an easy one, you have to ask "what and how much improvement will this accomplish?"

Temp in the back axle might be around 130 degrees---maybe 140. I have asked somebody somwhere a long time ago. It was in conjunction with the Saab box with a nice clutch plate differential and in my car then 5.83 final drive and i had seen the slight discoloration on the surfaces above the normal oil level that was clearly condensation of oil vapors.
My advisor may have been former works Saab rally driver...and i had seen for the 99 and 900 a Sport and Rally back cover with in and out bungs..

He said OK in the 99/900 where the motor sits on top of the gearbox case--which is in unit with the sump that gearbox and diff got pretty damn hot since its right there as a unit with the hot engine and engine oil, so they used a cooler (about the size of the stock Volvo turbo engine oil cooler, maybe 2 rows less.

And of course we've seen rear drive applications with coolers but you know lots of those circle track guys run really short final drives (liek 5.1 or 5.8, and 9" Fords with extreme hypoid gears so lots of reduction (heat) and loys of slinding contact.

As for thermosiphon effect, I just don't think its going to happen but thats not answer the first question: what problem are you having that is caused by how much heat..

So like a lotta things there's a kernal of truth, but the degree of the problem---whatever it is---the significance is not established..

So what problems have you had?

and why are you trying to avoid a simple Facet red Top pump?---and a little 12 fan. The facet interrupter pump will do fine, ya aren't pumping Brent Crude but hot oil....

And before you get too far IF you're going to do it, why not do it right?
 
Weird ass double post with another post in between.



And folks before suggesting all sorts of silly solutions we really ought to concentrate on the supposed problem and if it needs a cure...
First things first and all
 
Read the explaination again Homer. "Cooler" would be made of aluminum fins bolted to the diff hsg. Mounting plate can be aluminum too if need be. Only thing I'm wondering is if it'll actually do enough cooling to make it worthwhile to make it. Plus might not be enough room to mount it as I'd like.

If those finned diff cover do any cooling, then seems to me a bunch of ..say maybe 5" x 12" aluminum plates stacked 1/8" or so apart would do some cooling.

Or are you saying the aluminum plates wouldn't absorb the heat away from diff hsg.?
 
Read the explaination again Homer. "Cooler" would be made of aluminum fins bolted to the diff hsg. Mounting plate can be aluminum too if need be. Only thing I'm wondering is if it'll actually do enough cooling to make it worthwhile to make it. Plus might not be enough room to mount it as I'd like.

If those finned diff cover do any cooling, then seems to me a bunch of ..say maybe 5" x 12" aluminum plates stacked 1/8" or so apart would do some cooling.

Or are you saying the aluminum plates wouldn't absorb the heat away from diff hsg.?

I'm saying the diff housing is horrible at transferring heat. The fluid doesn't transfer the heat efficiently to the housing nor would the "fins" pull it away from the housing efficiently.
 
Glad you saw this John. I know about the oil pump driven by drive shaft, and figured an electrical pump is probably made also.

Both are out of my price range, and most likely do more cooling than I''ll really need for highway use. However, how many degrees or range of degrees do those coolers atually cool the diff oil?

My Diff is 3:31 ratio, and I have NO idea what temp it runs at. (Scientific huh) ,

However, I'm trying to come up with a very cheap, maybe some what innovative, back yard/garage/spare parts/odds & ends /stuff laying around.. TB diff oil cooler.:)

And would my idea work/do any effective cooling to begin with? It'll be for a street driven car that sees a lot of 65mph-75 mph hiway miles. So a modest heat reduction is all I'm looking for.
 
If I read that correctly, you are trying to increase the surface area of the diff housing by adding fins/materials to it?

Anything bolted to the diff will absorb and radiate heat (as long as it is not an insulating material)

What you need is more surface area...adding material like mentioned or you could remove material from the diff housing by cutting slots which would create fins into it and thereby increasing surface area

Back to the bolt on fins, one problem you are going to run into is the heat transfer from diff to new fins, it won't be ideal, you'll have air gaps unless perfectly machined, then you have to deal with dissimilar materials which will cause corrosion which will kill the heat transfer

Crazy idea time , I'd add a bolt on fin assembly to the rear of the drive shaft to "blow" air across the diff housing
 
How effective would the heat transfer be from the iron housing to the aluminum? Not very well, if at all. The housing is in contact with the fluid in which you'd like to cool. Pump to an external cooler or go home. You could try welding fins on to the stock housing, but I dont see that doing a whole lot.

If you really want to, mod the finned one for your sensor.

Get a pump and external cooler.

Or analyse the situation.
 
I'm saying the diff housing is horrible at transferring heat. The fluid doesn't transfer the heat efficiently to the housing nor would the "fins" pull it away from the housing efficiently.

The housing is cast iron; way worse than steel at heat transfer.
 
Hmm, cast iron engine block gets hot & so does the cam cover. Must be some cast iron to aluminum heat transfer going on there I'd think. I know the engine oil is part of it
Even on a Harley engine, the old ones had cast iron cylinder & aluminum head. Both had fins. Both dissipated heat.

While my idea surely isn't as effient as a pump & oil cooler, seems like it'd do some cooling if the fins were big enough & placed in decent airflow.

But maybe not..........and like I said, it was just an idea I came up with.....
 
There is also oil flowing through them. They also had fins as part of the original casting, and were designed in such a way as to dissipate heat effectively.
 
We'll probably be modifying an aluminum cover from a 940 for use on our 24hr Lemons endurance race car. The modified G80 was just creating a lot of heat at the last race, so the housing (and fluid inside) was quite hot. How hot? No clue. It was really, really hot. How much time and money will be spent on this project? Probably not much. Will it help? If I think it has helped, then it has helped, so that's all I require. We'll probably fit the diff too if we have time after welding bits onto the aluminum cover.
 
Yes, I realize that, but I was hoping ther would be enough heat transfer to do a little, say maybe 10 degrees ,of cooling. I'm not looking/hoping for a 30+ F* of cooling from this idea.

Oh well, maybe I'll just find out if it cools the diff to any degree by just trying it out. I have plenty of things to make it out of, and thin aluminum shet shouldn't be too hard to come by.

I do wish one of the TB machinist guys would cast a finned diff cover that'll bolt right on our electrical speedo diffs & sell them.

I would like to know how many F* those oil pump types cool the fluid by though.
 
The horizontal rib that extends from the input yolk to the axle tube, machine it flat, bolt an electronic heat sink to it. It won't do much, but it may help you feel better.
 
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