Evanscool

[Miller618]

Anyone using Evanscool in their RMZ? The past 2 harescrambles (both muddy conditions) i have been overheating badly. Today was really bad. Im hoping i didnt do any damage to the poor bike. I have to look it over tomorrow. But, i have decided i have to try something new for coolant, and maybe invest in a return reservoir. Just wondering if the Evanscool is worth the money..or am i still going to burn all of it out like i do the 50/50 antifreeze.

[DEMI]

I run Evans in all bikes... but, it really just raises the boil over point though, which may not be a good thing. Try a 1.4, 1.6, or 1.8 rad cap and a coolant catch bottle first. Go to a 60/40 or 70/30 water/anti-freeze combo too...

[alfie]

Ive been running evans npg in all our bikes, really good stuff highy recommend. no problems with heat issuses

[Miller618]

Thanks guys. Ill try out the Evans i think. I normally dont have an overheating issue. Just the last 2 harescrambles have been nothing but a muddy mess. Basically paddling your feet through a foot deep mud ruts for 2 hours. So these 4 strokes tend not to like that. Not going fast enough to get any air through them. On our practice woods track (which is really tight) i dont overheat. So the Evans really is just something to keep me at peace if it ends up being a muddy mess sometime again i dont have to run around trying to think of what im going to do. Unfortunately..i still have to check the bike out and do a damage assessment from last week..really hoping nothing is wrong, but it wasnt sounding good at the end! ?

[davidl9999]

Figured that I'd chime in here since I have reasons *not* to use Evans in a bike.

First off, straight PG, EG, or PG/EG mix lowers the heat transfer coefficient of the bike's cooling system. In a nutshell, that means that the engine must be hotter with straight EG/PG/EG+PG to move the same amount of heat as quickly it did with 50/50 (or better yet 60/40 or (better yet 70/30 )) water/coolant (coolant being EG or PG or EG+PG blend).

So, the consideration (imo) is how to maximize the flow of heat out of the engine to the air and at the same time prevent bulk-boiling in the coolant (which is what causes the loss of coolant and the obvious DNF soon after).

+1 on DEMI's suggestion to run a higher pressure cap. This will help control the bulk boiling, and if that's all that's needed, you won't have to worry about a catch can because you won't be pushing coolant past the cap. But, a catch can is a definite plus and prevents sucking air back into the cooling system when you can move some air across the rads again.

Going to a 60/40 or 70/30 water/coolant mix helps with the heat transfer flow, but also reduces the boiling point of the coolant. A higher pressure cap can offset this, but maybe not since you still have to get the heat out of the rads.

Going to a straight EG or PG or EG+PG coolant raises the boiling point of the coolant from about 220F to 388F (EG) or 392F (PG) which sounds great since you don't even need a pressure cap (in a sense), but the hotter the engine gets, the harder it is on the reciprocating parts as tolerances decrease (due to metal expansion) and it can affect the ability of the lubricating system to maintain an adequate film on moving parts and properly cool the bottom end of the engine. That's not to say that people who run straight EG/PG/EG+PG coolants can't do so safely. But it should be clear that you won't know if you're overheating the engine without additional monitoring since that type of coolant doesn't boil and let you know of the overheating condition early before damage occurs.

The other way to get heat of the the engine faster is to increase the volume of the heat transfer surfaces, and you know where that's going...

So, my 2c: If you're still boiling excessively with a higher pressure cap and trying 50/50, 60/40, and 70/30 doesn't work out for you, the proper solution to keep the engine (heat source) temperatures in the proper range is to get radiators with a larger surface area. - or force the air to move over the rads, but most people don't put fans on their dirtbikes and with mud, trying that is probably futile.

I hope that makes sense.

[RY54]

I was running the zipty (same as evans), and during a hare scramble race my bike started to knock just a little. I believe the bike overheated, but never boiled over due to the very high boiling temp of the evans. After I rebuilt it, I went to engine ice, but was still boiling over on a long hare scramble. Then went to a 1.6 rad cap with engine ice. Still boiled over just a tad, but not as much. I'm not sure what my next move is. Might try the boysene impeller, go to a catch tank. Anybody ever use the zipty engine oil cooling additive? http://www.ziptyracing.com/products/product_detail.aspx?id=MTMyNw==

[davidl9999]

I was running the zipty (same as evans), and during a hare scramble race my bike started to knock just a little. I believe the bike overheated, but never boiled over due to the very high boiling temp of the evans. After I rebuilt it, I went to engine ice, but was still boiling over on a long hare scramble. Then went to a 1.6 rad cap with engine ice. Still boiled over just a tad, but not as much. I'm not sure what my next move is. Might try the boysene impeller, go to a catch tank. Anybody ever use the zipty engine oil cooling additive? http://www.ziptyracing.com/products/product_detail.aspx?id=MTMyNw==

Maybe a 1.8 cap? I've heard good things about the boyesen impeller. Never used one though. Wouldn't touch the TwoCool stuff; I don't see the need to mess with the 300v that I use in my bikes. Oil being "thermophillic" (or heat-grabbing) like the website says (oils can be thermophobic too, so I have no idea what oil they're talking about) is a property that makes oil work as a coolant since thermophillic oils would migrate toward the hotter parts of an engine rather than migrate away from them. Why ZipTy would want to change that is beyond me. ?

[watermoccasin]

Try adding Redline Water Wetter or similar to your coolant mix. It is a surfactant that makes the coolant adhere better to metal, so it can pull more heat from the engine and dump more heat into the radiators. My bikes run substantially cooler since I started using it. Also make sure your radiators are completely full before a race - a slightly underfilled radiator overheats much worse than a full one.

http://www.redlineoil.com/Products.aspx?pcid=10

[RY54]

I believe I found my problem. When I recently put the bike back together, somthing must have happened, and my head gasket must be leaking. It will idle just fine for a long time without boiling over, but when I give it a lot of throttle real quick, it is leaking exhaust gas past the gasket, and into the water jackets overpressurizing the cooling system and puking a little coolant out. I have a new OEM head gasket (I used cometic) coming tomarrow and already have it apart. I should be testing it this weekend.

[Miller618]

Figured that I'd chime in here since I have reasons *not* to use Evans in a bike.

First off, straight PG, EG, or PG/EG mix lowers the heat transfer coefficient of the bike's cooling system. In a nutshell, that means that the engine must be hotter with straight EG/PG/EG+PG to move the same amount of heat as quickly it did with 50/50 (or better yet 60/40 or (better yet 70/30 )) water/coolant (coolant being EG or PG or EG+PG blend).

So, the consideration (imo) is how to maximize the flow of heat out of the engine to the air and at the same time prevent bulk-boiling in the coolant (which is what causes the loss of coolant and the obvious DNF soon after).

+1 on DEMI's suggestion to run a higher pressure cap. This will help control the bulk boiling, and if that's all that's needed, you won't have to worry about a catch can because you won't be pushing coolant past the cap. But, a catch can is a definite plus and prevents sucking air back into the cooling system when you can move some air across the rads again.

Going to a 60/40 or 70/30 water/coolant mix helps with the heat transfer flow, but also reduces the boiling point of the coolant. A higher pressure cap can offset this, but maybe not since you still have to get the heat out of the rads.

Going to a straight EG or PG or EG+PG coolant raises the boiling point of the coolant from about 220F to 388F (EG) or 392F (PG) which sounds great since you don't even need a pressure cap (in a sense), but the hotter the engine gets, the harder it is on the reciprocating parts as tolerances decrease (due to metal expansion) and it can affect the ability of the lubricating system to maintain an adequate film on moving parts and properly cool the bottom end of the engine. That's not to say that people who run straight EG/PG/EG+PG coolants can't do so safely. But it should be clear that you won't know if you're overheating the engine without additional monitoring since that type of coolant doesn't boil and let you know of the overheating condition early before damage occurs.

The other way to get heat of the the engine faster is to increase the volume of the heat transfer surfaces, and you know where that's going...

So, my 2c: If you're still boiling excessively with a higher pressure cap and trying 50/50, 60/40, and 70/30 doesn't work out for you, the proper solution to keep the engine (heat source) temperatures in the proper range is to get radiators with a larger surface area. - or force the air to move over the rads, but most people don't put fans on their dirtbikes and with mud, trying that is probably futile.

I hope that makes sense.

Yes, makes perfect sense. And i was actually thinking at work about how maybe raising the boiling point of the coolant might not be such a good idea. Im going to try the high pressure cap, and run a 70/30 or 60/40. Hopefully this does the trick. If not, then i guess the testing goes further. Our practice track is really tight and i dont have a problem overheating there. Its not so much when im in the tight stuff in the woods..its more the running the piss out of the bike in the MUDDY tight stuff. So i think that as long as this rain business quits and the tracks start drying up, i should be alright with that combo. Getting a different bike is NOT an option unless its a newer RMZ. I love this bike. I love it on an mx track and in the woods. Its the perfect bike for me all around. So im bound determined to make this work!?

[Tailender]

I"v heard good things about the oversize radiators on e-bay for $170 to $200. Some other threads were talking about them and didn't seem to have any problems with them and they are a lot bigger capacity than stock. That may be the next thing I get when I have the cash.