Oil cooler thermostat (bedtime reading)...

But there is a difference surely between cold oil in a cold engine and cool oil in a hot engine?

KiwiNeill said:

ashman
just taken my non oil cooled 850 off the road to replace rear chain and sprockets,sprag clutch and new Duplex primary setup and can say you would definitely get emulsified oil on short runs in the (relatively mild) southern England winter temps we have at the moment with the lowest start temp so far being minus 2°C or 28.4°F.
My work ride direct is only 5 miles but I go the long way round for 11 miles and this is barely enough to eliminate emulsification in the oil tank or cylinder head, especially on the intake side where it can be seen if the rocker cover is removed.
New route is around 15 miles with a couple of fast stretches and this only just does the trick, 25 miles would be ideal but it goes to show that in colder climates, an oil cooler with thermostat is a positive move.
My FJ1200 being used now has a stat and it,s barely open on the same route, the oil cooler only hand warm, and this on a big wet sump engine which pops the stat in 10 miles during the summer.

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Like I have always said I live in a hot climate country 3/4 of the year its hot and day time temp in winter would never get under 18c where I live, if I lived in a cold climate I proberly would never run a oil cooler but where I live the first year of owning my new Commando it run hot idled high at traffic lights and the oil was like water had no body to it after a short time but the dealers were running GTX in all their bikes, GTX in the 70s was not a good oil to run in our hot conditions, a year later after buying my Norton I put the Lochead oil cooler on it things settled down the bike was running better all year round, it idled at the right revs every thing worked perfect, I also got rid of the GTX and started to run straight Penzol 50 grade and have run that for most of its life.
I have had my share of people telling me no need for a oil cooler the bike still runs and seems to handle it and at first being young I said the same but the high idle at traffic lights in summer got to me and I brought the oil cooler, well I can tell you this it changed my bikes performace, it just ran better, never had high idle at lights everything just ran like it should, then the straight 50 grade oil also played a big part and when I did oil changes the oil felt like on my fingers as good as the day it was put in, I am no expert but I always do the finger test lol.
A oil cooler works for me, its given me long life out of my motor and I still ride it hard, very hard, its done a lot of hard miles but it keeps going.
Yes the motor has been rebuilt but its still on its first reboar and about 7 years ago I had to pull it down to replace the crank cases cracks around the main oil seal but the only thing I did was replace all bearings, I didn't even remove the pistons off the rods and still running those pistons, this bike now has over 160k miles on it, it was my only transport for the first 15 years of ownership.
Maybe I have just got a freak bike, who knows but I know what a difference a oil cooler has made to my bike and my way of thinking about oil temps in hot climates, plus way back in the 70s there was nothing about running themos or anything like that, so running for over 42 years with one and there is no sign of any problems in all them years, the Norton is still a freak and just keeps going, and the best thing is, its my freak and I luv it.

Ashley

oldmikew said:

But there is a difference surely between cold oil in a cold engine and cool oil in a hot engine?

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A oil cooler won't make the oil cold or so cooled it no good, it gets the oil that is very hot when its gone through a hot motor and to cool it down a bit before it gets pump through again, the oil still stays at working temps it just stops the oil from getting over heated and breaking down, air cooled motors run hot, maybe going through all these threads and how many Nortons have been rebuilt with such low miles, I can't say a oil cooler would have helped but then who really knows, I know it has help me to get over 43 years out of my Hotrod Norton, my freak of a bike lol.

Ashley

I'm with you and a firm believer in knocking the edge off the heat. After all it's not as if one were hooking up a refrigeration system by not using a thermostat. At the most the oil is only being kept at near a normal operating temp by using the cooler only. GTX may have been sufficient in the UK, northern US, & CA, but Sou Tx in high summer my oil looks like dark brown water after a few.

My opinion - a lot of that dark brown results from that small amount of oil that continuously gets burnt as it passes through the exhaust side of the rocker box, although blow by at the rings is likely the primary cause.

ashman said:

The oil still gets hot even running a cooler, in over 40 years of running a oil cooler without a themo I have never encountered water in my oil from the oil not getting hot enough even riding in winter, but then I don't live in a cold climate.

Ashley

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My test concurs with no thermostat required. No water.

possibly the reason for no condensation forming in the oil the Commando oil tank design breathes to atmosphere if you fit any kind of vapour trap or recirculation pipe work
as fitted to most automotive breather systems i think it would quickly form the creamy crap in the top of the oil tank

Yes, that's why oil cooler thermostats always allow a small amount of oil to flow through the cooler when the cooler is being bypassed, so the cooler doesn't become a large condensation trap.
That's why I'm impressed with the cooler arrangement on the F750 used at Daytona that was mounted in the tail section...but so little info is available about it.