Where can i find a water cooling head for a .46 nitro motor? I have no idea where to find one i looked and didn't see anything. The head has six bolts in it.

an old trick is to wrap copper pipe around the head with heat sink compound that you use for electronics an old guy told me that when i was in my local model shop said that what he used to do before you got marine engines or you could make a top for the hull with the head sticking out the air and water splashing on it keep it cool

Just looking for where the water runs through it. If anyone has one can they send me some pics of it so i can see how it is made?

What temp should the motor run with a water cooled head? I may have someone make me one for free.[sm=lol.gif] The motor is a .46 7.7cc 5 hp 20,000 rpm

I've never been able to get a good reading on a water-cooled head. If you have an infrared temp gun, shoot for the glow plug.
Other than that I just tune them by adjusting the carb until they sound good on the water.
On an engine that size I'd use 6-32 threaded water fittings. I'd say nipples but some guys get giggly when that word is used.

Is it possable to have it too cool? About how much water should flow through the head per min. Just a round about number of oz. So i can figure out how much water i need flowing through the head. Will any .46 head work on my motor or doses it have to be made for the motor i am running?

http://www.youtube.com/watch?v=NWATmvDngjI

It needs to be for the engine you are using, they are all different.

As to temperature, yes, you can run an engine too cool, the nitro might not burn properly and there is a chance the engine will wear prematurely. I actually restict the water flow to my glow engine at this time of year, and my water cools my pipe before reaching the engine. As a guide, after a run, I can hold onto the the head for about 2 or 3 seconds before burning my fingers.

What kind of 7.5cc engine are you running that is making 5HP?

Glenn

Yes, you've got cylinder diameter, head volume, bolt pattern and a host of other things to consider as not just any head will bolt on.
Five HP at only 20,000 RPM sounds more like advertising hype from the manufacturer. Even an old K&B .45 will turn 23-25,000 RPM but not the HP.

sounds like the one from cen. thats the only 7.7cc that i know of with that clamed hp .

Think my CMB 90 is going to get chucked out then!!

Glenn

Yes it is the cen 7.7 motor.

Hmm, if only. Still, hope you get the water cooled head sorted Little Dude.

Might be easier to just go for a marine motor, I seem to recall you looking for headers to get the pipe out the back of the boat too.

Glenn

Yes i have one on the way. Far as the head i have someone making one for me. Just have to get the water passage to get the correct amount of water.

That's good then. The water passage size is not too critical (as long as it too big rather than to small!!), ou can always restrict the water flow if the motor starts to overcool.

Be good to see this running.

Glenn

Yea thought about that and i want to make the water passage about 1/4 inch wide and 3/16 to 1/4 deep.

Glenn have you thought about a new motor?????[sm=lol.gif] Are you staying with your .90? Here is what that 7.7 looks like at take off. Here is a link to the video of the boat running with a x440/3 prop. The prop is to small for the motor. I need like a x455/3.

http://www.youtube.com/watch?v=NWATmvDngjI

Lots of HP, but not too good for RPM!

Why waste time on that, there are a lot of smaller Marine engines with better RPM than that!

Glad you feel that way hit. But when you have a truck motor and a boat then someone tells you it can't be done then you show them it can. I'm not in a race. I'm just having some fun on the water. If i wanted to race then i would buy a racing boat. The motor has 23,000 rpm i had a typeo. That is not to far from a boat motor. A few more rpm is not a factor in my boat. I'm just having fun like i said. And it's not a lot of work to convert a motor. Some people make it a big deal. I know there is more then a few parts that are not like a boat, Like ports, block, timing ect. Who gives a care not me.

And most of all the prop is a x440 last that i seen it is to small for the motor. It runs like 45mph like it is. With a bigger prop it will run faster then it is going now. So why do i need to go faster then that if i not racing? I'm just having fun not racing.

I have indeed, and I think a CMB 91 RS is called for!!

I must say that I think your little boat seems to be running remarkably well - the important thing to keep in focus - and this must surely go across all the forums on here - is to make sure you are having fun and enjoying what you are doing. For most of us, it is only a fun hobby.

Glenn

That is what i'm saying. Just have fun with no harm to anyone or anything. Just be safe at what you are doing at all times. It is just a hobby not a real boat you can ride in.[sm=lol.gif]

This is a Webra head and jacket. It is more fancy than most but contains O-Ring seals where others do not. You would most likely have to make the head button instead of reworking the original head.

The other kind is more simple to make and probably could shave the original fins off the top of the head to make it flat across, saving as much as the glow plug threads as you can.

Thank's jetpack that's what i was looking for. Now i can show someone how to make the head i need. I tryed to explane to them how to make it and they did not have a clue. Now i have some pics they can go off of.