Oil cooling that ain't yet is too

Hobot · Sep 16, 2011

Enjoying the path to Peel. Just leaned the TwinCam Harley's had piston oil jets since '99 and use orifices on the order of 0.025-.030". This cools piston crown by 50' F which I read it tremendous heat success as way way more than oil coolers or extra fins and internal oil flow. Its mostly to preserve pistons melt on boosted or NOS engines but also helps delay detonation and some can run thinner lighter pistons this way. Japanese research showed it took .6 liters/min on our size pistons to lower crown by 100' F. I thought that wasn't much temp change till tonight reviewing more on this. Now I need to plug in calculators Harley oil pressure for idea of the amounts they jet - to take a second look at tapping engine pump directly off head supply which apparently is excessive any way measured, even with Norton's deleted zero reading gauges.

A more serious problem was that of overheating. Piston temperatures in particular were troubling. Nicolae Glaja, a Romanian-born engineer, initially tackled the problem by installing oil jets in the crankcase, aimed so that they sprayed the piston crown from underneath. While this cooled the pistons, the oil temperature then became intolerably high. Skip Metz, engineering project leader for the engine, and his team then came up with installation of an oil cooler, with good results. However, the styling and marketing departments felt that this fix looked too much like a band-aid solution. It seemed to be an admission that Harley-Davidson had designed an engine that ran too hot. Management agreed, and the 1998 release date was also passed. Returning to the drawing board, the engineers examined the entire oil system. The excessive oil temperature was not just the result of heat coming from the piston crowns, but from the cylinder head and rocker boxes. Engineer Ben Vandenhoeven then initiated a series of test runs restricting oil flow to specific areas of the engine, with surprising results. In the initial design the concept was that flowing large amounts of oil through the rocker boxes (much more than was actually needed for lubrication) would help cool the heads. In actuality, not much cooling was provided for the heads. Rather, the heads were heating the oil. The oil flow to the rocker boxes was cut down to about one-sixth of the initial design flow, still adequate for lubrication, and this brought the operating oil temperatures to around 220 degrees. The engines were released for the 1999 model year. High operating temperatures have continued to plague the Twin Cam engines, although the engineering refinements have resulted in a reliable and smooth-running engine.

http://en.wikipedia.org/wiki/Harley-Dav ... Cam_engine

alexhobo · Sep 16, 2011

pretty interesting idea, cooler engine temps are always a plus

chapmanmd · Sep 16, 2011

Good post, Hobot.

Take a look at the newer Buell upper end cooling if you want to see something relatively ingenious.

chapmanmd · Sep 16, 2011

Hobot,

Something that Mercury Morse does for the racing XS Yamaha pistons is here: http://www.650central.com/Wrist pin oiling2.JPG

I have no idea if this would work for the C'do piston as I am really just learning about the Norton.

Just thought I would share.

Cheers!

xbacksideslider · Sep 16, 2011

Why couldn't HD install an oil cooler? Typical response, leave the problem be.

Cheesy · Sep 16, 2011

I came across this video the other day as well, bead blasting the piston crown to have a layer of soot stick and reduce heat transfer from combustion in the first place. I like how he has deep valve pockets to reduce the compression down to 14:1!!

http://www.youtube.com/user/Massegossen ... axucrs2ZrU

Hobot · Sep 16, 2011

Nothing too bizarre for me or Ms Peel. The diagram shows drillings for wrist pin lube not really heat transfer. I've Jim's pistons so no worry on pin endurance. Instead of waiting on coke layer that can actually glow red and pre-ignite Ms Peel has heat insulating ceramic like coating on all surfaces that flame heat reaches, even behind the exhaust valve. She also has entire engine done in Black Body Emission coating by Swain. Oil cooler on bike engines only cool the oil not the engine to matter much. In Nortons its between 6-10% of total heat flow out. Heat soak over time is my worry at high power burns, grasping at straws to get away with it. Ms Peel should be able to burn like 3'xs what a WOT Combat can.

I think my solution will be RBRacing small oil pump with adjustable bypass back to frame, to limit piston jets to amounts the engine oil pump can suck out. That implies about 10 gal/hr total could be sprayed and still be pumped to a 'dry' sump.

One big point of the HD quote in case was missed or I forget to mention it, oil is a very poor engine coolant and has almost no significance in over all heat dumping so as HD found out, oil coolers only cools the oil, not the head or pistons, so if oil is not too much over 200'F then its good to go and is the temp range that activates the famous ZDDP protection in oil threads. I believe that oil coolers are unneeded on Nortons or even desired d/t too cool oil, unless in some rather extreme conditions.

xbacksideslider · Sep 19, 2011

Yes oil is a less efficient heat exchange medium compared to water/ethylene glycol but internally, it is all we have!

The mid '80s GSXRs were able to add power, and whip the competition . . . . for a while . . . . until the competition upped the ante with new generations of water cooled engines. The point is that Suzuki DID increase power by way of a robust high volume oil pumping system, internal oil jets, and a big oil radiator.

You can't flush the bottom of the pistons with coolant after all.

The way to cool internal parts with oil is to do it is with volume. That means your Norton's choke point is the oil pump' - both the high side and the scavenge side too.

CNW's reed valve sump plug should handle any evacuation your system can't. Will the RBR pump deliver enough volume to handle the high side, with oil jets?

comnoz · Sep 19, 2011

xbacksideslider said:
Yes oil is a less efficient heat exchange medium compared to water/ethylene glycol but internally, it is all we have!

CNW's reed valve sump plug should handle any evacuation your system can't. Will the RBR pump deliver enough volume to handle the high side, with oil jets?

UH UH. If there is enough oil in the crankcase during normal [non-wet-sumped] engine operation to be returning more than droplets through the reed breather then you will have big problems with oil frothing and areation from the contact with the crank. The breather pickup is too high. The reed breather deals mainly with air. Jim

Hobot · Sep 19, 2011

MIght study further on the oil cooled Suzuki and others air/oil cooled, certainly helps if specially designed but it not nearly as effective as water, so fell out of favor.

The smallest of RBR oil pumps ~$250, is over kill in pressure and volume needed to significantly lower piston crown temps, yet not overwhelm factory sump side, i hope - so I will have to Tee into the pump out let to bypass most the oil back into frame tank, but this will provide bypass filter to catch the stuff that wears as opposed to just clog oil ways. If I really need to I can plumb in an extra sump pump but less expensive low pressure kind to suck out the excess the Norton one can't.

It Maney had retained the Combat low down breather it could throw back way more oil to the tank than the mere pump can.

Don't know what to do it oil jet whip of a foam, hope the travels through frame and time spend in spinal tube will settle it down before hit intake again.

xbacksideslider · Sep 19, 2011

I take your point, Jim.

After watching how the crankcase reed valve evacuates wet sumped oil back to the oil tank, I was seduced into thinking that it can serve a scavege function.

Perhaps two reeds, a new one to let filtered air in and then your sump reed to pump the air, and any oil out? Naaah . . . . getting crazy . . . .

Oil cooling that ain't yet is too

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