Evans Coolant

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Shibby!
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Re: Evans Coolant

Post by Shibby! »

That's why I don't care to use it.

If it's boiling over, it's boiling over for a reason. If it's not and it should be, then the bike is just running stupid hot.

Install a fan.

(Sorry, I haven't read most of the thread. Just adding my 2 cents, which is now worth nothing)

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Re: Evans Coolant

Post by trailguy »

Shibby! wrote:That's why I don't care to use it.

If it's boiling over, it's boiling over for a reason. If it's not and it should be, then the bike is just running stupid hot.

Install a fan.

(Sorry, I haven't read most of the thread. Just adding my 2 cents, which is now worth nothing)
I'm guessing a fan isn't an option. He likely has an older SX 525 with a 540 kit installed, so no battery.
I know you haven't read the whole thread Shibby, but your reason's for not using Evans are a common misconception with Evans. Anotheroldtrailrider touched on some of the technical aspects of Evans, what that boils down to ( sorry ) is your bike without Evans is getting hot spots on the cylinder walls - not good, and this creates even more heat, Evans doesn't do that, plus it is more efficient at cooling the motor. After your bike has popped and is running stupid hot, Evans bikes can continue to safely run in low air flow situations for a long time before temps get scary hot. I've tested this for years, esp. on KTM SX 50 which are the hottest running bikes I know of ( I was getting 225 F outer cylinder temps under normal riding conditions on those little rockets ). A buddy of mine also tested it with his 450, he ran Evans, silicone rad hoses and rigged up a tiny digital temp gauge he mounted in his crossbar pad. We ride alot of tight nasty terrain and it wasn't very often he would have to shut his bike off due to temps getting up around 300 F. Like Anotheroldtrailrider mentioned a good mod is running a aftermarket impeller/cover. Due to my 4 stroke not having a kickstarter, I don't run a fan just the hoses, Evans and temp strips.

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Re: Evans Coolant

Post by anotheroldtrailrider »

That danger of running too hot for too long is the whole controversy with Evans - some riders prefer to see the bike boil so they get immediate notification things aren't right, my personal preference is to try and be aware of what the motor's doing and keep the coolant in - if I have to shut off and let things cool down, OK - but at least I've still got coolant in the motor when I start back up again. With "normal" coolant, when it boils - now you're out on the trail somewhere, and your only choice is to use your drinking water to refill - if you've got any. Now, you're even worse off, because the straight water boils even more easily than the coolant, and it can be a long limp back to the truck. Opinions are like belly buttons - everyone's got 'em, and most of 'em are different.

I boiled my old 525's at real high elevation a couple times with it, but for sure that's getting into the oil breakdown range (yet another reason to switch to synthetic as soon as the rings are seated) - change it immediately. (But - you should be changing the oil every serious ride, anyway - if it comes out dirty, you waited too long - that's another whole thread by itself.)

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Re: Evans Coolant

Post by anotheroldtrailrider »

I forgot to mention - even if he's on an SX, the early SX's had a small lighting coil (I used one on my street convert for a while) - you could always retrofit the early stator to run a fan.

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Re: Evans Coolant

Post by Shibby! »

Food for thought.

Still glad I don't have a bike that is sensitive to boiling. haha.

Fans can be added to any bike, battery or not. Just depends how much work you want to go through. Even if the coil only has minimum power output it only costs around 50-90$ to rewind yourself, or you can buy one for approx $150-250.

I've done both, but I enjoy doing things myself so I wound my XR650R (which has no battery, no E-start but has a fan, heated grips, HID lighting, LED signals, GPS plug, blah blah). 35,000 KM's and plenty of rough offroad and no issues. Baja twice, Moab twice, Mexico twice, Belize, Guatemala, Continental Divide Trail, and soon to be Idaho Tour Challenge.

If I had a hot running dirt bike I'd wire it up to run a fan. Either manually, temp sensor, or even all the time. Keeping in mind it might run cool without a t-stat.

SPAL Pull or Push fans are about 50$ on E-bay. Most rads can fit fans with basic brackets. SPAL fans are used in automotive OHV applications all the time. They are weather sealed and work very well. They are also the factory KTM fan kit fan at a fraction of the cost (just need to build brackets, plenum optional)

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thirtyseven
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Re: Evans Coolant

Post by thirtyseven »

If I had a hot running bike, Id sell it and buy a 2t then jet it just a tad rich. :lol:
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axel99
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Re: Evans Coolant

Post by axel99 »

Shibby! wrote:Food for thought.

Still glad I don't have a bike that is sensitive to boiling. haha.

Fans can be added to any bike, battery or not. Just depends how much work you want to go through. Even if the coil only has minimum power output it only costs around 50-90$ to rewind yourself, or you can buy one for approx $150-250.

I've done both, but I enjoy doing things myself so I wound my XR650R (which has no battery, no E-start but has a fan, heated grips, HID lighting, LED signals, GPS plug, blah blah). 35,000 KM's and plenty of rough offroad and no issues. Baja twice, Moab twice, Mexico twice, Belize, Guatemala, Continental Divide Trail, and soon to be Idaho Tour Challenge.

If I had a hot running dirt bike I'd wire it up to run a fan. Either manually, temp sensor, or even all the time. Keeping in mind it might run cool without a t-stat.

SPAL Pull or Push fans are about 50$ on E-bay. Most rads can fit fans with basic brackets. SPAL fans are used in automotive OHV applications all the time. They are weather sealed and work very well. They are also the factory KTM fan kit fan at a fraction of the cost (just need to build brackets, plenum optional)
Most of these smaller fans run on 12v DC current so you cannot hook them up to the lighting coil on the stator directly, you will nned to go through a rectifier. I recall a decent rectifier costing around $50.

Shibby, you must already have a rectifier on you 650 if you are running HID. Did you have any issues with the HID losing its arc if the RPM drop to a idle or did you run a capacitor in lieu of a battery?
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Re: Evans Coolant

Post by Shibby! »

You are correct. Must be DC. I'd go with the Trailtech unit. Decent peice of kit. Ask Andreas how it's not worth messing around with a cheap rectifier and having no lights riding across half of the US... We fixed it in Moab...

I've ran a cap before but I believe it eventually got damaged, or seemed to stop working. The HID would normally work but sometimes start to flicker at idle. I then went with a tiny battery we found online for 7$. Has been working great since, but only powers the lights for maybe 1-2 minutes once shut off. What I like better about it is that it keeps my GPS on when the power cuts off (stall, quick shut-off, etc) so you don't have to constantly turn it on, or lose map data (with how my Garmin Oregon works it was possible to loose you track by pressing the wrong buttons upon powerdown)

The other huge benefit is it charges your cell phone at night when your camping, which is mostly what I do when dual sporting often away from a power source for 3-5 days in a row.

So you need a stator capable of powering an additional 1-2 amps (higher on startup), AC/DC conversion using a rectifier (AC only bikes just have a regulator), and then because you are running AC and DC it's always a good idea to float the grounds opposite of the AC system (which is generally to frame).

With a fan a cap / battery isn't required. It would just run slower at idle when the voltage/amperage isn't there. When winding a stator though you can tune them for off idle output, or high RPM power output by varying the times wrapped and guage of the copper wire.

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Re: Evans Coolant

Post by bigsky300 »

I got mine at Cycle Works. Put it in, plus 1.8 bar cap (not sure I needed the higher pressure cap), no problems since.

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Re: Evans Coolant

Post by noenegdod »

anotheroldtrailrider wrote:<Evans will not boil>

Well, it will - just not 'till 375 F / 190 C

It's also more efficient than ethylene glycol
Hi Art, Im going to try to learn a little from you 'cause I think your a pretty smart old bird.

So I have never understood why it is that propylene is considered (or is) more efficient than ethylene. Unfortunately a quick look didnt produce tables with the same ranges of information but we should be able to infer a little, I think. Looking at tables from the engineering tool box:

http://www.engineeringtoolbox.com/propy ... d_363.html

http://www.engineeringtoolbox.com/ethyl ... d_146.html

A 60% ethyl solution has a specific heat of 0.83 Btu/lb/degF at 200 degf
a 60% prop solution has a specific heat of 0.801 Btu/lbs/degF. Unfortunately they dont expand the table to include different temps or even tell us what temp that value was at. (is that because it is linear? I kind of doubt it, do you know?)

Ignoring the fact we dont have a temp to make a direct comparison ethylene has a slight advantage with its ability to carry heat.

The 60% solution has a boiling point of 225F for prop and 232F for ethylene, again, advantage is for ethylene.

100% Ethylene boils at 386F, Prop at 375F There were no specific heat values provided at that temp and concentration for any meaningful comparison.

So looking at all that, kind of incomplete data, Im having a difficult time coming to the conclusion that there is any real advantage to running propylene glycol. I do agree that if I had the choice I would rather have a visual indication of overtemp other than boiling over so you can stop and let it cool down and continue with a full rad, but it appears the only way to accomplish this is to run a higher concentration of either glycol but this reduces the heat carrying capacity of the fluid and you would have to run ~20% hotter to carry the same amount of heat away.

Moving more coolant helps to reduce the temps of the lower specific heat fluid but it would also help to prevent the boil of the ethylene solution as well as increase the overall rate of heat rejection the same as it would for straight propylene.

Now, a hotter engine makes more power by virtue of the fact that the charge gives up less heat to the waterjacket, and of course the thermal/mechanical limits of the materials and lubricants being the line in the sand, it appears, that what ever can be accomplished with propylene can be done with ethylene.

Other than stability(taking your word for it) and reduced system pressure, which is only achieved by using very high concentrations, I cant see much of a benefit of using propylene over ethylene (other than environmental).

Please enlighten me!

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Re: Evans Coolant

Post by erniebearskin »

My brain hurts.........
Bikeless....

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axel99
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Re: Evans Coolant

Post by axel99 »

erniebearskin wrote:My brain hurts.........
No more engineers allowed to post on the forum.....oh wait that means there would only be 5 guys left :smirk:
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RJHenry
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Re: Evans Coolant

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axel99 wrote:
erniebearskin wrote:My brain hurts.........
No more engineers allowed to post on the forum.....oh wait that means there would only be 5 guys left :smirk:
And all of them IT guys!
Robert J Henry
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Re: Evans Coolant

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axel99 wrote:
erniebearskin wrote:My brain hurts.........
No more engineers allowed to post on the forum.....oh wait that means there would only be 5 guys left :smirk:
:smirk:
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anotheroldtrailrider
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Re: Evans Coolant

Post by anotheroldtrailrider »

Well, I've at least got the old bird part covered :lol:

The comparisons are a little tricky - ethylene glycol is typically used at 50% mix, while the propylene glycol is intended for use at 100%, so be careful with the charts, but one of the main factors is that heat transfer is most efficient at the "nucleate boiling" stage, where a few molecules change from liquid to steam and are immediately swept off the heated surface and collapse back into liquid - giving up some of their heat energy to the surrounding liquid as it heads for the radiators. When those few molecules accumulate into larger 'clumps' of bubbles that are unable to collapse back into liquid as soon as they leave the surface, the problem starts. When that happens (no matter what coolant) the result is steaming out the overflow. Propylene glycol is better at that borderline transition, so it gets the nod.

The only reason to speed up the flow is if the coolant (again, no matter which one is used) isn't being swept off the surface before that "nucleate" boiling changes into full-on steaming. Once the boiling transforms into real "bubbles" the situation becomes dramatically worse, because the bubbles actually insulate the surface from the nearby liquid, so it's really important to keep those bubbles washed off. I suspect propylene glycol has less surface tension than ethylene glycol - I'd bet most of the "Water Wetter" type products are propylene glycol intended to make it easier to get those bubbles washed off.

The manufacturers have started using higher pressure caps, and that's a popular change on older bikes - obviously, higher pressure raises the boiling temp, but one of the things I like about the Evans is that it already has a little higher boiling temp, so you can run lower pressure caps (I took the spring completely out of a cap and put in one just barely strong enough to hold the seal against the top of the radiator for a while on a 525), so there's less stress on the hoses, pump seals, etc. Raising the pressure on a propylene glycol system would raise the temp's even higher - already a concern, so if you leave the higher pressure cap on, be aware of what your engine's doing so you don't overheat it enough to damage something. Evans is by no means a cure-all, and it's not enough to overcome a basic problem like inadequate radiator size, damaged impeller, kinked hose, etc - it's just one more option if you're having problems.

I like the stuff, but I've never bothered to change my 500XCW over - last weekend was the first time it's ever boiled - the fan got unplugged (DOH!!), and a series of obstacles was enough to push it over the edge.

Art

edit - typo, sorry

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