water cooling a standard head.

[billet-jimmy]

ive been looking at water cooling my standard malossi head, making one from scratch on a cnc machine.
questions are:

would there be any benefit on cooling a standard head? prob not, so...

would it be better to change the compression ratio due to it being water cooled? and would i get any more power out of this?

i dont know much on compression ratios and such, still need to study that, but im just curious as to weather its been done before or if its a lost cause.

[RICSPEED]

personaly i dont think cr has any bearing on lc or not ..

lc is better then air cooled ..

[Knowledge]

If you are going to all the trouble of a water cooled head, why limit yourself to the rather antiquated combustion chamber of the original head? Starting from scratch will allow you to create a combustion chamber and plug position, and these factors may have a greater impact on performance, whether it is faster or simply more efficient.

[billet-jimmy]

In that case how do i design a combustion chamber for more speed and what would be the best position for the spark plug, or will the design of the cc dictate where it goes?

[Knowledge]

Most designs err towards centre plug with a narrow swishband around the edge. The swish bands currently seem to be smaller than the old 50/50 area rule. One might anticipate that those combustion chambers designed by Charlie Edmonds are indicative of good performance. The latest Mugello or supermonza heads look tasty.

Meanwhile, think about how you are going to construct the water-cooling side of the head. Think about where the inlet and outlet pipes will go, and how you will move the water around. Do you want a thermostat? How will you secure the head? Will the stud nuts be submerged or exposed?

[RManson]

I agree with Martin. The combustion chamber design is the easy part. Find a similar cc Motocross head and copy. That'd be a good start. That's assuming the Yamaha or similar corporation has more experience in engine building than you do.

Your statement "how do i design a combustion chamber for more speed" has me wondering if you think a new head will yield similar results as swapping a stock barrel with a TS1 for example. Short answer, it won't. If I swapped your air cooled Malossi head with a LC head with a slightly better combustion chamber (center plug for example), you'd probably never notice the difference in performance. What you would notice is the fact that the head temperatures would remain much more consistent in the LC head, detonation problems wouldn't be as bad, and overall longevity of the top end would most likely result. You might get a little bump in performance if you were able to tweak the timing a tad due to the lower temperatures, but I'm playing a bit of devil's advocate now...

A thermostat controls the flow of water through the radiator so that it's sufficient enough to maintain a consistent temp. When it's below a predetermined temp, it's closed to allow the water to warm up. Once open, it flows through the radiator and back through the engine (or head in this case). The constant circulation of water heating up and cooling down results in an average system temp (usually slightly higher than the thermostat). Compare that to the variable flow of hot air being driven by the fan through the shrouding and over the cylinder and head. In a perfect scenario it's still only moving around hot air. At idle, it's just plain getting hot. Not hot enough to typically do any damage mind you, but it's not cooling down any. Aw, hell you get the point! lol

[billet-jimmy]

I Will be having a thermostat to monitor the temp, the design I've done so far is just a hollow head for the water to flood, but thinking about it know, it would be more efficient to have a channels. The entrance and exit to water would come later as I would just drill and weld some pipes on, here's what I've got so far anyway

[billet-jimmy]

Forgot to mention that it would be the studs inside the head then a lid would bolt on, but I haVnt drawn that on the featurecam yet, I was just trying to get the main design down,eg- the O-ring seals, and water containment.

[RManson]

Looks like you're on the right track, that's how I would do it. I think the two piece design is the key. Inlet and outlet via two bungs is easy, but I would keep the two ports seperate, as opposed to one big channel, just to keep the water moving through the head and reduce turbulence.

While you're at it, why not do a cylinder?!

[billet-jimmy]

Don't think I could make a cylinder, we only have a 3 axis machine, if he had a 5 axis then I probably could make a mold for one, but just sticking to the head for know, I'm also working on putting a px disc onto a standard set of anally forks with a self made disc and bracket,caliper and such will stay the same.