water cooled head that will fit...

[Steve Best]

Actually, in Canadian it is pronounced "ah-RYE",
which is also a very popular Canadian drink.

Spent the day out sledding. Warmish -1c, lots of sunshine.

I run thermostats on everything. The sled, my KTM Blaster and the enduro bikes.

 

[Frankenstein]

when i did my little setup, i contemplated the idea of using a (rather large) fuel pump for water circulation. never actually tried it.

and of course, it would be nice to trim most of the cylinder fins away and wrap the whole lot in one big cylinder, weld it up and have the cylinder water cooled as well. seems a bit silly to only have the head water cooled.

for the amount of heat, i dare say thermosiphon is adequate, main issue is conveniently sized (and very effective may i add) radiators only have 8mm fittings, so thats the size pipe i used. for good thermosiphoning, bigger is better. you only need a very slight temperature difference to start the flow, but you have to minimise turbulence as much as possible. worth reading up on some technical stuff from 1900's era when the water pump was only just starting to be considered. it made the patternmakers job a lot easier, not having to consider gravity and thermal "traps". but, as long as cold water can be "sucked up" through the heating element (head) and "squirt out" at the top, it works fine.


meh, no idea what happened to all the files i had for the one i made, but i would have to draw it all out again anyway to suit the 80's stud pattern. biggest challenge was drawing it so a suitable size end mill would fit! and working with the lump of ally i had handy... finish that attachment i made for the lathe for cutting the hemispherical combustion chamber. another challenge, having an ideal hemisphere volume, and just the right length for the spark plug thread!


copper may sound like a good choice, but try and find the price of a 3 inch bar of it...and then try machining the crap! best to stick to straight ally. and two piece, dual metal heads are not ideal, theres a huge resistance built up between the joins of any two metals, regardless of how good they are at conducting, and how well they contact each other.


heat loss through the pipes is irrelevant also.

awry?

i havent heard that word since i used it in an english essay (for which i got 100%) and the girl that just had to get the top score in everything said it wasnt a real word...boy, did she kick up a stink.... and then shut the hell up when i handed her a dictionary

whats "AWE-REE"? so much for getting top marks, didnt even have a decent vocabulary!

the teacher of course, kept her mouth shut through all of this, just sat there smirking...

OK, well first let me illiterate for too long as normal and say that I still don't have definite plans on this cooling idea, it's still in the concept stage and may end up staying there, I realized that as I was asking a friend about the tube size. Anyway according to him the 3 small tubes in the head in the radiator are sufficient for heat removal, while the transfer tubes between the 2 should be at least twice the diameter (3 times the volume, makes sense) and both are better off being 1 single tube from and too the head for the best flow.

No not interested in a denser copper head, not what I'd think was a good idea unless tubes or holes drilled from front to back and hooked into a radiator like that. Aluminum should be fine with copper tube fitted in, according to him heat transfer between the copper and aluminum should be at least 85% of heat at the barrier. I don't know what the total surface area of contact would be which would tell me how much heat would be transfered but I believe it would be sufficient enough if done. He pointed out one could always drill holes in the head at a 45 degree angle and that would probably triple the surface contact, and one could always drill smaller holes but more, which also increases surface contact while keeping the same amount of fluid at the head.

He mentioned too small would probably boil the water or coolant and had no real idea how small that that becomes a problem at but said with the tube I want it shouldn't be a problem unless you approach 700 degrees, but at that point my solder would have melted and sprung leaks if the engine doesn't melt down first.

He keeps asking why I want a radiator on a 66cc engine and I'm starting to question it too. Then again though I'm not always in it for the practicality and often the challenge alone is enough. Still, if I ever want to add a large motorcycle style tank this would be pretty good insurance against overheating, and the same idea if I added covers to the sides of the bike, which tends to trap heat, an automatic radiator could offer protection at longer idle periods or those wonderful traffic lights. Helps on those hills with a little less fear too.

It will also look just too damn cool.

He also said that vibrations can help the water heat up easier and is a relatively new way of making (believe it or not) thermosyphon type reboilers more efficient, but those are at ultrasonic levels of vibration and may not be all that effective on an engine's frequency. Also vibration can lower the viscosity of fluids but flow rates on smaller streams of fluids can be held up by strong enough vibrations, so as the diameter of the water tubing gets smaller, the worse it's affected by vibration. I think it's because vibration obviously shakes stuff, and if something was moving one direction and gets knocked off course then it has to make up for it by stealing kinetic energy from something else already going in the direction it's supposed to be going.. Or something. I don't know I don't work with fluids often enough.

So still quite a bit more to pour over on this idea, if I even want to pursue it in the first place.

 

[Steve Best]

All good things to think about. I like it!
Ah! You are thinking of drilling the coolant passages in a solid head.
All of a sudden the multiple small pipes and passages make sense.

Most of the water cooled heads I've seen have been of the "sandwich" variety:

http://crossman11.tripod.com/

My son runs one of these on his Banshee:

In my search for a Banshee picture I found this head, which is what I envisioned you had in mind:

http://www.pocketbikesunlimited.com/BANSHEERACETRICKHEADKIT.html

They have it pictured on a liquid cooled cylinder so there is no inlet pipe, but you get the picture:

 

[Frankenstein]

Actually, in Canadian it is pronounced "ah-RYE",
which is also a very popular Canadian drink.

Spent the day out sledding. Warmish -1c, lots of sunshine.

I run thermostats on everything. The sled, my KTM Blaster and the enduro bikes.

Whisky and rye, good job now American pie is stuck in my head...

I should have just became a whiskey expert instead.. That rye you've guys got sure would have made the job fun. Would have been an ideal career should I ever turn to being an alcoholic.

 

[Frankenstein]

All good things to think about. I like it!
Ah! You are thinking of drilling the coolant passages in a solid head.
All of a sudden the multiple small pipes and passages make sense.

Most of the water cooled heads I've seen have been of the "sandwich" variety:

http://crossman11.tripod.com/

My son runs one of these on his Banshee:

In my search for a Banshee picture I found this head, which is what I envisioned you had in mind:

http://www.pocketbikesunlimited.com/BANSHEERACETRICKHEADKIT.html

They have it pictured on a liquid cooled cylinder so there is no inlet pipe, but you get the picture:

No I hadn't though of drilling a solid head, HeadSmess mentioned a copper head being machined out to that design he has, I know copper is a nice choice but maybe not rigid enough? Something tells me that it should need to be a stronger alloy than what you'd see on straight copper.

If I wanted a copper head I think I would drill parallel with the mating surface and from the front to back for flow.

Those heads you posted are pretty cool, nice idea that they made the water chamber round. That banshee head also follows that linear path in a sense, uses a broad contact surface in between a single inlet and outlet. It seems like an important design with a purely thermosyphon cycled system, the simpler the path the better the system performs under its own power.

The more complicated the flow the more likely a thermosyphon fails to function, and at one point it simply doesn't work at all, which is where a pump is required..

I still need to weigh my options..

I also would love to build it, it would be fun to assemble from scratch. I also happened to have plenty of copper tube for the application, and a ton of sanding drums in the same diameter which would make it a blast and enjoyable to fit the parts flush and solder them. Several larger fittings around at the diameter that is twice the tube size.

Don't know what or if I'll follow through, though still thinking of that head that HeadSmess made, since one can still get a simple pump and force the coolant around.

 

[HeadSmess]

Actually, in Canadian it is pronounced "ah-RYE",
which is also a very popular Canadian drink.

Spent the day out sledding. Warmish -1c, lots of sunshine.

I run thermostats on everything. The sled, my KTM Blaster and the enduro bikes.

thats what was so funny. one, she thought it was "made up" and two, she didnt pronounce it correctly (even with the fact i used it to rhyme with cry or die or whatever the hell it was)... so much for being the top student.

noticed a lot of the smaller bikes usually dont have thermostats... yz 80, nsr150, cr125... mostly little ring ding "race" bikes that have no need for them.


the original OP head posted would be relatively good for thermosiphon with one or two small mods. get rid of the web thats awkwardly at the top corner, drill in the fitting at the highest point and lowest point, would probably work fine, but gawd...its a big ugly sucker, aint it?


ooooh, i didnt see the latest postings.... why bother with a HT engine and modding it ? just get one of those lil 40 cc ring dingers and feel some real power! i recall finding a link for them once but no idea where.... they really do have some punch for the size they are. already water cooled as well, pretty sure they have an integral pump too...

 

[Steve Best]

Hey HeadSmess, you heard about the Australian that arrived in Britain during WWII?
A local remarked:"You came a long way to die!"
The Aussie retorted:"I got 'ere yester'die!"

 

[Frankenstein]

thats what was so funny. one, she thought it was "made up" and two, she didnt pronounce it correctly (even with the fact i used it to rhyme with cry or die or whatever the hell it was)... so much for being the top student.

noticed a lot of the smaller bikes usually dont have thermostats... yz 80, nsr150, cr125... mostly little ring ding "race" bikes that have no need for them.


the original OP head posted would be relatively good for thermosiphon with one or two small mods. get rid of the web thats awkwardly at the top corner, drill in the fitting at the highest point and lowest point, would probably work fine, but gawd...its a big ugly sucker, aint it?


ooooh, i didnt see the latest postings.... why bother with a HT engine and modding it ? just get one of those lil 40 cc ring dingers and feel some real power! i recall finding a link for them once but no idea where.... they really do have some punch for the size they are. already water cooled as well, pretty sure they have an integral pump too...

Lol a very good point, happy time engines have been on the air cooled diet for what a decade? Not to mention the engine it copied was also feeding from the same trough...

Seems like the engines that needed the cooling system recieved one, whilst the rest got the bare bones, which seemed to be appropriate then, so why change it now?



Perhaps it's the challenge we are seeking not the need, should it even exist.

 

[KCvale]

Seems like the engines that needed the cooling system recieved one, whilst the rest got the bare bones, which seemed to be appropriate then, so why change it now?

Perhaps it's the challenge we are seeking not the need, should it even exist.

Indeed.