coolant

by Michael Sweeley in General Tech Discussion 9 years ago

Does anybody have any idea why Evans is now not allowed by Rotax. I cannot figure out what difference it would make, with reference to the new temperature probe location. I sure would like an explanation from Rotax.
Mike

Page 1 of 3

Start
Prev
1
2
3
Next
End

Re: coolant

by Rob Seaton » 9 years ago

Rob Seaton

3 1.32k 240

Here is what I was told:
It is allowed; You can still use Evans with the old style heads.

Reason for not allowing Evans with the new heads:
1) The heat transfer is worse with Evans.
2) The new heads only measure the coolant temp, as Evans has less thermal heat transfer capacity it is possible in some installations (with poor airflow)to exceed the thermal capacity of the engine causing damage.

Report
Re: coolant

by Roger Lee » 9 years ago

Roger Lee

126 5.13k 4.53k

Hi Michael,

This is in line with what I have heard and personal experience.

Michael,
Nothing really wrong with Evans. It just has no water so the heat transfer is worse than with 50/50 and carries with it a 20-30 degree heat penalty over 50/50. Water coolant does a much better job of carrying away heat because it transfer heat much better and faster than waterless Evans. Evans was looked at originally because of some boil overs. 50/50 coolant boils down around 270F and Evans is around 370F. It may stop a boil over, but causes over heating in many applications. Better to figure out why someone is boiling over or over heating instead of using Evans.

in cold country or in some fully open air engines Evans may not be too bad.

Roger Lee
LSRM-A & Rotax Instructor & Rotax IRC
Tucson, AZ Ryan Airfield (KRYN)
520-349-7056 Cell

Report
Re: coolant

by Michael Sweeley » 9 years ago

Michael Sweeley

8 25 0

Roger and Rob,
Thanks for the info...now i understand the reason they require 50/50. Although i live in Alaska so it is possible that Evans would work just fine I think I'll stick with 50/50.
regards
Mike

Report
Re: coolant

by MARK JACKSON » 9 years ago

MARK JACKSON

12 332 11

What a load of tosh!

There is nothing wrong with Evans coolant. It has more good points than bad. It is better for the engine. It may run hotter in aircraft designs where there is a problem with cooling or radiators that are too small have been fitted.

How can you say that a coolant is not recommended because the way the temperature is measured has changed. The temperature of the engine hasn't changed, just the way it is measured.

Report
Re: coolant

by Roger Lee » 9 years ago

Roger Lee

126 5.13k 4.53k

Hi Mark,

Rob isn't saying there is anything physically wrong with the coolant itself. Just the different types of engine installations make it a poorer choice over water based coolant at times.

I don't think there is anything wrong with Evans nor do people think it's bad. I think part of the point was the old CHT was more a metal area temp verses an acutual in the coolant probe temp. There would be a few degrees difference.
And like you said the only reason it didn't work for some was the cooling isn't as good for some and put them over temp. I think they were originally looking to help some with boil over issues, but Evans doesn't exchange heat as fast as a water based coolant. This is why fire departments use water. It's the best heat transfer and it's cheap to use.

There are a few factors that make Evans work for some and not others.

Roger Lee
LSRM-A & Rotax Instructor & Rotax IRC
Tucson, AZ Ryan Airfield (KRYN)
520-349-7056 Cell

Report

Page 1 of 3

Start
Prev
1
2
3
Next
End

You do not have permissions to reply to this topic.

Title	Category	Replies
Normal range of coolant temperature	915iS Technical Questions	2
Pink Coolant - Evans?	General Tech Discussion	6
Coolant Temperature Measuring/ 912	912 / 914 Technical Questions	11
Coolant expansion tank cap leaking?	912 / 914 Technical Questions	21
Coolants and what you thought you knew about them	General Tech Discussion	2

coolant

Recent Videos

Safety First!

ROTALK News

Prize Giveaway!

Log In/Out

Login