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Piston Temperatures of an Air Cooled Engine #5082412 04/22/19 06:43 AM
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Shannow Online Content OP
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Finally Found the paper again...
Interesting in the viscosity and piston temperature, and how much (little) effect was gained by cutting off access to oil spray under the pistons, indicating that viscous shear on the cylinder walls played more of a part than "cooling" from the oil.

(Yes it's old)

http://naca.central.cranfield.ac.uk/reports/1940/naca-report-698.pdf


If it's the truth....it can handle the pressure !!!
Re: Piston Temperatures of an Air Cooled Engine [Re: Shannow] #5082600 04/22/19 10:21 AM
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FlyNavyP3 Offline
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Really cool article Shannow! Thanks for sharing!


Luke
P-3C and P-8A Maritime Weapons and Tactics Instructor, Instructor Tactical Coordinator and Mission Commander
Re: Piston Temperatures of an Air Cooled Engine [Re: FlyNavyP3] #5082964 04/22/19 04:56 PM
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Shannow Online Content OP
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No probs...I'e been trying to (re) find it for months and months


If it's the truth....it can handle the pressure !!!
Re: Piston Temperatures of an Air Cooled Engine [Re: Shannow] #5087936 04/27/19 07:17 AM
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53' Stude Offline
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Originally Posted by Shannow
No probs...I'e been trying to (re) find it for months and months



Good read so thank you mate smile

Cheers Cheers1



Re: Piston Temperatures of an Air Cooled Engine [Re: Shannow] #5089717 04/28/19 06:14 PM
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MolaKule Offline
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Didn't you and I both prove some time ago, on separate continents, that a reduction in engine oil viscosity resulted in cooler head temps using riding mower engines and IR guns?

As I recall(?), I went from from a 15W50 to a 15W40, to a 10W30, to a 5W30 and noticed head temp reduction each time.

Last edited by MolaKule; 04/28/19 06:17 PM.

"You ... sadist," said Mr Cummings, "you try to make people think." Ezra Pound (1885-1972)
Re: Piston Temperatures of an Air Cooled Engine [Re: Shannow] #5090045 04/29/19 01:10 AM
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Shannow Online Content OP
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Molakule,
yep, you did the heads, I did the bulk oil with a type K thermocouple down the dipstick on 5W20 through 20W60.

Given that the temperature DRIVEs heat expulsion, through radiative (T^4) and convective (T^2) mechanisms from an air cooled engine, clearly the oils were generating less heat, not carrying away more.

Cheers2


If it's the truth....it can handle the pressure !!!
Re: Piston Temperatures of an Air Cooled Engine [Re: Shannow] #5095545 05/04/19 09:15 AM
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Rand Offline
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Interesting, however I dont think it will sway me to go thinner in the 1980's tractors.

1 jd316 had been running thousands of hours on 20w50, now it probably has another 1000+hours on 15w40 (purchased new ?1986?)
the hour meter doesnt work now.


we have 2 more of this series tractor and they all have provided no oiling issues on 15w40..(less history with these 2 they were purchased well used)

they get worked hard.. not sure a 30wt would protect as well when they are run hard mowing fields and such.
(if it aint broke dont fix it)

In fact I snagged a case of havoline 20w50 for $1/qt that will be going in the 3000hr+ jd316.

Thanks for posting that article.. was a good read.

Last edited by Rand; 05/04/19 09:16 AM.

2019 Jeep Cherokee Trailhawk 2.0T
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Re: Piston Temperatures of an Air Cooled Engine [Re: Shannow] #5095635 05/04/19 11:46 AM
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MolaKule Offline
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Since most 4-cycle air cooled engines used in Outdoor Equipment specify somewhere around a 30 grade, and if i had a mowing and landscaping service, I think I would use this:


10W-30/SAE 30


Last edited by MolaKule; 05/04/19 12:01 PM.

"You ... sadist," said Mr Cummings, "you try to make people think." Ezra Pound (1885-1972)
Re: Piston Temperatures of an Air Cooled Engine [Re: Shannow] #5188079 08/15/19 04:36 PM
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red7404 Offline
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WAY over my head..

Re: Piston Temperatures of an Air Cooled Engine [Re: Shannow] #5229220 10/03/19 10:01 AM
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10W30 Rotella or 5W40 T6 HDEO work well in my air cooled OPE


2012 Ram 2500 SLT 6.7L Cummins 4x4
2018 Dodge Durango GT 3.6L 4x4
Re: Piston Temperatures of an Air Cooled Engine [Re: Shannow] #5234447 10/09/19 02:52 AM
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I tried multi weight in a air cooled and didn't like having to keep it topped off due to consumption. I went back to mono weight and no more oil burning and if it runs hotter so be it.


1996 Chevy 1500 4.3 V6. Harvest King 5W40 Fram XG3980 oil filter
Pennzoil sycromesh >> transmission
Shell rotella nitrite free ELC >> radiator
Shell Spirax HD 80W-90 >> rear axle


Re: Piston Temperatures of an Air Cooled Engine [Re: Shannow] #5238072 10/12/19 07:47 PM
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Cujet Online Content
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I own a Cessna 177RG with the air cooled Lycoming IO360 angle valve, 200HP engine. Using thin oil (15W-50) results in higher oil consumption and lower oil pressure. Some people claim the thinner oil may result in faster ring and cylinder wear in hot conditions. Not sure I accept that.

But oil temperature is lower by about 20 degrees.

I'd use the straight 50 viscosity oil, however, the semi-synthetic oil prevents exhaust valve sticking our operations.


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