Finned Oil Return Tubes?

[KTL]

I see EBS Racing is offering these now. They're made out of machined/cast alloy.

https://app6.websitetonight.com/projects2/6/2/9/0/790926/uploads/EBS_RACING_NEW_PRODUCT_SHEET_FINAL_V4.pdf

Any thoughts on these? Given that the return tubes are pretty close to the exhaust system, I wonder how much effect they have? That said, they are right there in the path of the fan air that runs across the heads. Although alot of that air is interrupted by the sheetmetal baffles. So i'm wondering if they really get much forced fan air at all....

I don't need new oil return tubes. Just curious on others' thoughts.

[schumicat]

there was a longish thread on these a couple of weeks ago.

[KTL]

Dang............ I did a bit of searching before posting and didn't find anything

[zippy_gg]

I see that they are one piece so you cannot replace them without removing the heads. Is this a correct assumption?

[James Brown]

yes that is true, they are not the collapsible type

[KTL]

And to further James' point, you do have to remove the cam housing to remove these. That is, if you don't want to destroy them.

The OEM steel one-piece tubes are crushable and you can mangle them enough to remove them from the tower & case to get it out. Then you can use the 2-piece replacement. These one piece aluminum ones look like you'd have to whoop on them pretty hard to crush them? I suppose you could cut them with a hacksaw too......

[911pcars]

Just thinking. Being aluminum, would the drain tubes absorb or radiate heat? From physics, heat transfers from hot to cold. Is the oil inside the drain tube cooler or hotter than the cylinders above, air flow from above or the adjacent exhaust system? What effect do the surrounding aluminum parts have on heat transfer to/from the drain tubes?

Sherwood

[James Brown]

i doubt much, seems like a bling part like a finned oil sump plate and the ever popular cool collar. Oil cooling is done with fender (s) and front mounted oil coolers. P.T. Barnum stuff. IMHO unless ESB has some info otherwise. remember, the scavenged oil goes to the oil cooler and/or the front cooler then to the tank so... BTW, the elephant finned oil cooler lines have a long run in cool air to make a difference.

[CaptainCalf]

KTL, if you want fins and real oil cooling ability I'd recommend a set of these:

Finned Oil Lines for Porsche 911 / 930 - Elephant Racing

I have a set that I'm running and so far the results are great! I'm seeing cool temps even w/o running a motor mounted oil cooler...

[HarryD]

Originally Posted by James Brown

i doubt much, seems like a bling part like a finned oil sump plate and the ever popular cool collar. Oil cooling is done with fender (s) and front mounted oil coolers. P.T. Barnum stuff. IMHO unless ESB has some info otherwise. remember, the scavenged oil goes to the oil cooler and/or the front cooler then to the tank so... BTW, the elephant finned oil cooler lines have a long run in cool air to make a difference.

If you think about it, the oil coming from the heads is warmer than the cooling air blowing down from above so there is a slight cooling effect.

Also, according to my VW buds, the pushrod return tubes in their engines (like our oil return tubes) provide some cooling on a VW motor which has been evidenced by folks seeing higher temperatures when they replace the factory tubes with the collapsible plastic ones that are offered as a cheap alternative to the aluminium versions.

I am sure the effect is small but meaningful.

[KTL]

I was thinking along the same lines as Sherwood- is the tube a sink collecting heat or is it radiating heat? Seems that the oil in the cam housings should be fairly hot, as it's in contact with the head which is one of the hotter parts of the engine

I'm good on cooling. I've got a large center cooler in the front bumper with a duct cut in behind it. I think the ER finned lines are a really great product. But they don't fit my application since i've got a mix of factory and custom made braided stainless lines serving my oil tank (relocated Peterson tank), thermostat and front cooler.

Thanks for the feedback everyone.

[Bill Verburg]

Originally Posted by 911pcars

Just thinking. Being aluminum, would the drain tubes absorb or radiate heat? From physics, heat transfers from hot to cold. Is the oil inside the drain tube cooler or hotter than the cylinders above, air flow from above or the adjacent exhaust system? What effect do the surrounding aluminum parts have on heat transfer to/from the drain tubes?

Sherwood

My guess is that it absorbs heat at the top near the head and radiates at the bottom, but then so does the older style. I have no opinion on the net effect, maybe add heat shields on top as is done w/ oil lines near exhaust components

[chris_seven]

I was discussing tubes with a guy who used to be a design engineer at Serck Systems in Coventry and his opinion seems reasonably valid.

His basic thoughts were as follows:

If the fins on the tube are small and the relative increase in area is low, then they will have a small effect. However, if the flow in the tube is fundamentally streamlined the oil in contact with the surface of the tube will be stagnant and the Delta T will fall and the fins will give little or no benefit. The ideal soultion would be to fit a 'Turbolater' into the tube to ensure turbulent flow inside the tube. This would firstly improve the basic cooling behaviour of the tube and also improve the influence of any fins

The main comment was that fitting a Turbolator could significantly improve heat rejection into the tube and improve the standard tubes performance by a significant margin.

It seems that Tubulators are quite cheap but may be difficult to install.

Just an interesting thought if we can ever find time to try them.

Turbulator Manufacturer, Wire Matrix Turbulators Tube Inserts, Stainless Steel Wire Turbulators, Heat Transfer Enhancement, Copper Wire Turbulators, Boiler Tube Inserts, Design, Manufacture, Export

[911pcars]

Originally Posted by CaptainCalf

KTL, if you want fins and real oil cooling ability I'd recommend a set of these:

Finned Oil Lines for Porsche 911 / 930 - Elephant Racing

I have a set that I'm running and so far the results are great! I'm seeing cool temps even w/o running a motor mounted oil cooler...

If you don't mind sharing, what were your before and after system components and ambient temp. conditions?

Thanks

[HawgRyder]

One other thing you need to consider....the color of the tubes themselves.
Black radiates heat better than any other color....and a slightly rough surface will increase that over a polished smooth surface.
So...theoretically...a fined, rough surface, black tube should be better at dissapating heat than a stock tube.
As to how much?
Good question.
Bob

[911pcars]

Originally Posted by HawgRyder

One other thing you need to consider....the color of the tubes themselves.
Black radiates heat better than any other color....and a slightly rough surface will increase that over a polished smooth surface.
So...theoretically...a fined, rough surface, black tube should be better at dissapating heat than a stock tube.
As to how much?
Good question.
Bob

In that regard, an externally finned drain tube would benefit from internal fins as well, but at what cost?

[RWebb]

Originally Posted by HawgRyder

One other thing you need to consider....the color of the tubes themselves.
Black radiates heat better than any other color....and a slightly rough surface will increase that over a polished smooth surface.
So...theoretically...a fined, rough surface, black tube should be better at dissapating heat than a stock tube.
As to how much?
Good question.
Bob

true, but the dominant mode of heat transfer will be convective

I agree on getting the finned oil lines to the cooler -- or more or bigger coolers.

[KTL]

Of course let's not forget the infamous Cool Collar for the oil filter.............

I've got a AN-16, 60 row Earl's cooler for the front ready to go and carbs set plenty rich for power in the <13 AFR range. So i'm not too worried about cooling. It's always run no hotter than 220 even on hellishly hot race days like last July- high 90s, humid, not a cloud in the sky = brutal weather.

I suspect the cooling effect by the finned return tubes is hardly measurable. Thinking about it a little bit deeper, the tubes are insulated from the case and cam housing by the o-rings. So the only cooling effect they provide is via the contact with returning oil. Since the returning oil is quite smooth (not turbulent) due to gravity flow, there's not much heat transfer occurring.

Although I suspect it would be quite easy to insert a spring of suitable diameter to disrupt the flow in the tube. Wouldn't be too hard to drill a tiny hole in each end of the tube to insert the wire end and secure the spring, should it decide to break?

[RWebb]

if I have the geometry right in my mind, then optimal results will be obtained if you polish the top of these things, and paint the bottoms black

go for it!

[chrismorse]

Man, I want what ever you guys are smoking.

Gotta say that with a grin, cuz i am always thinking about getting rid of the heat.
On first thought, the surface area of the finned oil return tubes seem insignificant, relative to the cooler fin area, even disregarding the radiant heat from above.

I am looking for some realistic heat dissipative data on steel and aluminum, as cast and polished and particularly with various emissive coatings.

This seem an area where "lving better through modern chemistry" is not in the public domain.

Clearly, one must avoid the smoke, mirrors and snake oil advertising hype.

At the present time, i amabout to Black chromate a new set of zimmerman zinc plated standard rotors for my 74 - believing in the magic of black emissivity.

curious,
chris