USCA Sidecar Forum

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Oil Cooler or Not?


I asked this question in the panhead forum on another site and got mixed answers. Harley didn't start using oil coolers on FLs until 1977. With our hot weather here, I was thinking about putting a Lockhart on if I could find a nice old one, closest to 1965. My logic is that drag from a sidecar makes the motor work harder and hotter. For clarity, I'm not suggesting that I ride my bike when it is 120F here but do ride when it is near 100. It would not be "original" or correct but the bike already has repops that diverge from being totally "correct." Technically, what is the opinion here about sidecar use = oil cooler in hotter climates? - AZP

AZP, It is going to help the motor and the oil in the more extreme heat add to this the drag from a sidecar or even a head wind its going to make the motor work harder, I wouldn't think twice.

I am currently working on a 1957 panhead with a late 40's Goulding sidecar and I do intend to install a lockhart oil cooler

My personal opinion, anything that will increase cooling capacity will increase longevity, and I would install it. If you plan on putting miles on the bike (as opposed to letting it sit as an "original" museum showpiece), by all means, take care of the engine.

As Homer Simpson would say............Ummmmmmmmmmmmm, a Goulding! Nice! The conflicting responses are partially technical and partly customary. The "customary" part is simply matching equipment with the time period of the bike. In this case, Harley wasn't doing oil coolers for several more years. My rides are not museum pieces in any sense but often sit unridden for extended periods. When I bring one out, it usually gets a few hundred miles of use and then gets put away again. I've gotten too old and lame for long hauls. Actually, Blondie supported the sidecar simply so I couldn't fall over! lolololol. I am guilty of inattention and pay the price when it comes to resurrect one that got pushed back in line for attention. So far, the preponderence of opinions agrees to put one on. I have a "V" bracket but no cooler so far. I let a NOS one pass a while ago and am now kicking myself. I would think a thermostat is also mandated although there isn't much chance of too cold oil here after letting the bike warm up properly.

Thermal bypass valve!
And Cooled stays longer running.
I once did the mistake to rebuild a 1960 Willies and did continue with the original design errors like weight saving holes in the main supports. Bullsh..t that was a built in fuse by the factory,,,

Since you're discussing oil coolers, I have a question. I had to remove the HD accessory cooler and thermal valve/oil filter adapter in order to get the front lower sidecar mount to fit my 2005 FLHTC. I have thought of mounting the cooler to the sidecar frame and pick up the oil from the fitting that returns oil from the crankcase to the oil tank. Run the oil by hose to the cooler, then from the cooler to the tank. I have only seen this on one Harley, and often wonder why the factory didn't do it that way. Any thoughts. Would it affect the scavenge pump's ability to pull oil from the crankcase?

AZP, May be able to find this in one of your local bone yards with 50's or early 60's cars

We use to use the finned cooler tube off of old power steering pumps, not a factory item(for a bike) but it would give the older/pantina look from "back in the day"

I don't think it would matter with a little more in the oil tank to compensate for longer lines. The one thing that would be important is to allow more time to warm up the motor before revving. - AZP

When I put my Harley cool cooler on my 02 Ultra they did not use the oil filter adapter and the lines run to the oil tank and motor under the little cover on the right side between the motor and trans. It does have a by pass valve mounted in the lines between the cooler and oil tank and motor as too cool oil is just as bad as too hot. I have my cooler where most are mounted just under the regulator. I have been running it like this for 97,000 plus miles. I would not run a twin cam with a cooler as the get really hot and was the first thing I put on mine after checking oil temps. I ran coolers on my shovel heads as well. I would not run it on really old HDs as I feel the pump is not up to handling them.

Do you run a manual bypass valve or one that is automatic based on oil temp?