Nameless

I'm going to put a brand new Fluidyne in with Evans coolant. Should I flush then remove the radiator, or flush with the Fluidyne? I'm going to follow the workshop manual for the most part. But I heard there were some ways to pour the coolant in, which negates the need to burp the system. Any other tricks, or things to be wary of or any other info would be appreciated.

As far as the Evans goes, what is it that I pull off the radiator cap in order for it to work correctly?

maxcooper

I would flush first and then install the new radiator so that it is fresh. I am not sure on the caps yet. I got an AST that takes a "standard" cap, so I hope to be able to find more options for it. You might consider the same strategy for your cap.

-Max

Nameless

From what I read at Pineapple it says to run the system under pressure with the rubber seal still in for a week or so. So I am assuming it's ok to keep it on for a while.

Btw, since the system will be zero-pressure, the possibility of the AST blow up is down to nil right? Or is it still advisable to change out the AST for an aluminum one?

SleepR1

What is Evans' Coolant??

Nameless

Check it out at www.pineappleracing.com, there was a GB on this organized by Blake. It's a special coolant.

SleepR1

I couldn't get the link to work.

What is the Evans coolant in a nutshell?

Gun

It's a zero pressure system and it's suspose to run cooler than conventinal coolants. I know that there have been at least a couple of threads. I try seach and post the links later. Here's one:

https://www.rx7club.com/forum/showth...coolant+system

later Gun

SleepR1

Thanks for the link. The first page was the most informative, but the rest was about the group buy.

Man you guys are cheap. Going through all that trouble to save $2 a gallon?? The stock cooling system takes 9 quarts, so that's just over 2 gallons. What's the big in saving $4?

Whatever!

Anyhow, lemme get this straight...

Evans NPG+ boiling point is 375 degrees F. This means your motor heats up to just less than 375 F before NPG+ boils.

Regular water based coolants boil at 250 degrees F with the usual water content and a pressurized cooling system. With the NPG+, the motor runs 125 degrees hotter, and this is supposed to be good for the rotary???

I'm skeptical if not confused

I understand the convenience of a zero pressure system, and not changing the coolant ever; but running a rotary motor at that temperature is insane!

If this coolant were universally accepted, don't you think LeMans racing teams would be using polypropylene based coolants instead of plain water?

In fact racing motors run on 100% distilled water (with a bottle of Redline water wetter), and very LARGE radiators. Water is a much better conductor of heat than 100% propylene glycol (which is what this Evans stuff is). Given the proper size radiator, the cooling should be much more efficient with plain water!

FWIW, I'm not sold...

maxpesce

NO NO NO NO Because EVANS Coolant has BETTER heat transfer Properties the motor runs COOLER - The HIGHER boiling pt just means you have a GREATER safety margin before the coolant boils away and frys the motor. You DONT WANT THE COOLANT TO BOIL coolant only works in its LIQUID state - not as STEAM!

SleepR1

You've got me thinking about this now.

I'll need to look up some physical constants for water and propylene glycol.

As I understand it water transfers heat better than anything...it's just that it boils at a lower boiling point the glycol coolant.

So you raise the boiling point of water to keep it in a liquid state, allowing water to do the job of transferring heat from the metal water surrounds in the motor.

I know the propylene glycol is doing is similar thing, but at a HIGHER operating temperature for the motor...

Seems to me you're just doing the same thing as what water does with the Evans, just at a higher operating temp and the convenience of "forever" coolant and no pressure, as the promise offered by by Evans

Nathan Kwok

This has gone around the big list already, but the big +s are the coolant is inert, so you shouldn't have any kind of corrosion and it lasts basically forever, this is a very big plus imo. The high boiling point and slightly higher viscosity means no localized boiling around the turbos, impossible for the water pump to cativate, and no need to run pressure in the system. Possible minuses are, you need totally eliminate water in the cooling system because they are not compatible, this is a pain, and there are varying reports about the consequences of running 0 pressure (some people reported the temp gauge going crazy, plus the system was designed to run under pressure), so the people who have switched instead run low pressure, like 6psi. Regarding the higher viscosity, again this could create a problem if you have things that are semi-clogged. As far as cooling goes, again this was long debated, but understand this, thermal conductivity and specific heat only are a factor when the cooling system is taxed to its limit. A properly functioning cooling system with a Fluidyne should have plenty of excess capacity, in which case the coolant will run at the thermostat opening temperature when moving or at the fan temperature when stopped. Its only when the coolant cannot remove the heat fast enough that you run into problems. In this case (which for track cars is a very big deal), there was endless debate over whether the elimination of localized boiling more than, less than, or equally compensates for lower thermal conductivity and lower specific heat.

SleepR1

Thanks for bringing me up to speed. I don't subscribe to the big list anymore, so I don't know what topics have or have not been discussed.

Why are we worried about corrosion? Our radiators are aluminum? Alunimum doesn't really rust?

If the water pump has been properly engineered, there shouldn't be any cavitation in the coolant flow. The underdrive main pulley, ensures there isn't any cavitation, since the Mazda engineers had to compromise with road vehicles versus, race-only vehicles.

It sounds like your temp gauge is rendered useless with the propylene glycol.

IMHO, I think it all comes out in the "wash"...besides, there's something insidious about Evans charging double for using a glycol base with only ONE additional carbon unit (ethylene has 2 carbons, propylene has 3 carbons)

allenhah

iTrader: (4)

Anybody know where to get a 4psi cap that'll fit? Part number or car model?
Allen

93blackr1

go check out their website
www.evanscooling.com

I bought a case from them and just follow what Rob at www.pineappleracing.com wrote.

later.

corbet

I put in Evans coolant last week mainly to try to control a corrosion problem. My theory is exhaust gas leaks into the coolant, C02 makes the coolant acidic and reacts with the aluminum and is creats a white powder (Al-Oxide) that gunks up the collant pipes. So by eliminating the cathodic action that occurs in water I should eliminate that problem. I also had that gurgling sound in the dash area. At the same time I changed the thermostat and now the gurgling is gone. (Don't know if the solution was from the Evans or the thermostat). The temp guage has not gone crazy.

SleepR1

That shouldn't happen?

I dunno, the Evans sounds like a good idea, but like I posted before, it's all a wash...

corbet

Exhaust gas leaks in the coolant when the main O-ring seal between the 2 rotors starts failing as can happen with rotary engines with over 80k miles on them. Sometimes it goes the other way and coolant leaks into combustion chamber.

SleepR1

So a perfectly healthy motor should NOT leak exhaust gas into the coolant, or vice versa, coolant into the oil and exhaust...