TOPIC:

Firstly, forgive my rambling on.


When I built the tow behind trailer for my bike, I had a stainless steel cowling fabricated to direct more air through my radiator and assist with a extra cooling. (Pictures in Photo Gallery section). This mod has worked extremely well and maintains the coolant temp fractionally below centre on the gauge, towing a packed trailer in + 95degF ambient temperatures, at a cruising speed of +/- 75 - 80mph. My problem now is that my oil temperature with the extra load etc. is certainly a lot hotter than what I believe we would deem as a normal operating temperature. I have not actually measured the oil temperature, but based on the following, have come to my conclusion:
1. I use silkolene 20W50 oil
2. Normal use of my bike (without trailer) stop/start in and around town, high speed highway runs etc. the oil pressure warning light may flicker on/off at idle (8-900rpm)
3. when towing the trailer the light will come on permanently at idle and only go off at around 12-1300 rpm!!!
4. My relief valve appears to be working as stated in the manual - cracking slightly over 5bar.

This lead me to the conclusion that the hotter than normal oil will obviously have a lot less viscosity, be a lot thinner causing my pressure drop!

I have read posts where our members have spoken about header wrap and the like to direct excess heat from the headers and exhaust away from the block and sump, but there is the concern of damaging the headers. Most of our members talk about DG pipe etc. which I don't have! I have a Cowley 6 into 1 and have no idea if the headers will withstand the excess heat retention once I wrap them, so I have now decided to install an after-market oil cooler and will explain my thought process below, but would love to get some input (thumbs up or criticism) from our fellow technically minded members prior.

Parts I want to purchase for Mod

1. 10 Row Oil Cooler
2. 3.7 GPM 12v Oil scavenge gear pump
3. AN6 SS braided hose and relative fittings
4. small 'spin on' oil filter
5. thermo fan switch On 85DegC - Off 80degC

Installation:

Place Oil cooler below radiator. Oil suction to come from a modified 'O' ring sealed banjo fitting replacing existing sump plug. Run hose from sump plug fitting through to small spin on filter with custom machined filter head, to gear pump and then on to the oil cooler. From oil cooler back to a second modified 'O' ring sealed banjo fitting replacing our oil filler plug on clutch housing. So in a nut shell, take oil from the sump plug, cool it and then feed it back into the clutch housing.

Operation:

To maintain a normal operating temperature, we don't want the oil pump running continuously, so a thermo switch is fitted in the sump and connected through a relay to the pump - starting and stopping the pump as and when required.

I have also given thought to the fact that the pump may still kick in and out frequently with this set up and then pondered on the thought of machining a custom relief valve (replacing the OEM valve) that can be installed with a fitting to direct 'overflow oil' out to the oil cooler line, T'd in after the gear pump. The relief valve should vent some oil at normal cruising speed and therefore should add a little extra cooling of the oil, preventing the gear pump from kicking in and out as frequently. Obviously there is a lot of machining and mods to the sump to accommodate my thought process.

Placement of the Oil Pump and filter:

The stock air box will be removed, and converted to pod filters as described by zed_thirteen (thank you zed_thirteen) in the carburettor section. The now free space in front of the battery will accommodate the pump and filter.

I hope all makes sense to our members and would really like to get some feed-back.

I have attached a basic circuit diagram, but note that I haven’t yet finalised the fittings required, so please don’t take those as confirmed yet.

Hi Craig,

Seems like you have put a lot of thought into your design and I doubt that it could have any adverse effects. I have to ask though: if the coolant system is working so much better could the oil be running hotter? I suppose the gearcase area is not affected by the coolant system so perhaps the two are separate, heat wise. In any case I think that having an objective reading of the oil temperature before your mod would make the case for the mod if you could document an improvement afterwards.

If you went for the heat wrap on the headers I can't imagine how it would damage the pipes themselves, except, of course, some corrosion if they spent any time wet when not being ridden.

Keep us posted.
Bill

Normal use of my bike (without trailer) stop/start in and around town, high speed highway runs etc. the oil pressure warning light may flicker on/off at idle (8-900rpm)

I had that a while ago, I have a sidecar, the drop in oil pressure was caused by a worn out shell bearing on the end of my secondary shaft, at idle the oil light came on, it went out when revved, suppose lower oil pressure at idle and the large gap allowing oil to piss out instead of being held back at pressure, hope it has nothing at all to do with that in your bike, but just thought i'd mention it, also maybe a slipping clutch causing oil heating ??, here in Queensland Australia it's hot in summer, the bike temp gets about half way on a hot day at highway speeds and gets about 3/4 when in stop start traffic, the fan is working hard at keeping her cool, anyway just thought i'd throw my idea at you, cheers Pete.

Pete....you've got my mind racing now! I have a rattle at idle and have always put that down to the clutch...the fact that you have mentioned the secondary shaft shell bearing has got me thinking. Will drop the sump and see if I can feel any play there first......oh boy...just the thought of pulling the motor out again.

Sorry didn't mean to cause any problems, but when you said a loss of oil pressure at idle makes me think, why ?, why lose oil pressure, i'd check the oil pressure to see if it is getting low before i'd think about an oil cooler, the shell bearing that failed on me was the one just behind the clutch basket, why it went is still a puzzle to me, I also had a "clutch rattle" ... turns out it was the shells rattling on the side of the basket, i'll see if I can find a photo and add it here, I hope it's not that problem for you cause I had to change the bottom cases, lucky I had a spare half motor I could use, cheers.