ADA head the best?

[waxhead]

Evidence no
but if your cylinder is not cooled correctly then you cant run your engine as hard as it could go
Therefore you try and run it hard find it nips and blame it on a lean sieze or something else

So you richen your ski up and the problem goes away as well as the expensive heat energy that you spent so much to make

so no it has been blamed for any blowups no it hasnt
has it caused any ??
well i dont know but i will always go for a head that controls my cooling correctly so i can be sure when i am pushing my engine hard its all the way it should be in there

 

[Matt_E]

The proof is in the pudding...if there's a real, measurable difference to be had, the price offset may be justified.
This should be fairly easy to to with EGT's or coolant temp monitoring.

 

[waxhead]

egt or temp coolant will not show this up

because once its in the top of the head its all the same
i am talking about water flow through the cylinder

Put it this way
yamaha thought important enough to make the bolts in the end of the head at different spacing so to make sure you couldnt get it wrong

i guess if you are just doing a bolt on engine its fine
but i like to get the most out of my engines and in doing this
i like to make sure things are right and i can safely push my engine hard

 

[njfl]

if you need to control your cooling, just use restrictors on the out going lines...............

What do the restrictors do?

 

[demolition_x]

the restrict the amount of water coming out of the engine. letting the engine heat up more than with no restrictors...

 

[meatball]

Wax, I know that a girdle kit is one reason, but why else wouldnt you just cut a stock head to fit o-rings and maintain the original cooling? I can deal with ugly but not expensive...

Any real recurring problems with running a stock head at 170 psi?

 

[WaveDemon]

Does anyone know if the older Riva heads had domes that needed to be pressed in. I know I've heard that somewhere.

yes, wahoo has one.

 

[njfl]

the restrict the amount of water coming out of the engine. letting the engine heat up more than with no restrictors...

Interesting, but I thought the idea was to keep the engine from getting hot?

 

[demolition_x]

well i think that if the engine is cooled too much performance ia affected and theres a risk of cold seizure. where the piston and cylinders expand at a different rate.

i think if you were riding in cold water your engine could get too cold.

 

[meatball]

I've known some that have ridden when our brackish water was partially frozen over (freezing point at like 25 degrees,) :cool2:

 

[Big Kahuna]

Interesting, but I thought the idea was to keep the engine from getting hot?

If you flow too much water through the cylinders, you will not get the current heat transfer from the cylinders to the water, causing the motor to run hot......... This is why you restrict the water even more in really cold waters............. to allow the motor to reach the propper heat opperating range.....................

 

[crammit442]

If you flow too much water through the cylinders, you will not get the current heat transfer from the cylinders to the water, causing the motor to run hot......... This is why you restrict the water even more in really cold waters............. to allow the motor to reach the propper heat opperating range.....................

Old wives tale.:haha: NJFL(Joe) and I have been talking about this recently. The physics don't add up. You can flow the water too fast to heat the water, but not too fast to cool the cylinder. Remember we're trying to cool the cylinder rather than heat the water. This is one of Fleckenstein's pet theories.

Charles

 

[demolition_x]

well i know on dirt bikes it can happen.

i read about this in dirt rider.

that if you are riding in cold weather and right out of the box you are on the gas the piston will expand faster then the cylinder and seize.


so i would imagine if the engine is cold and your pumping a lot of cold water(dual cooling) before the ski is really hot that theres a chance, yes a chance it might seize up if the tolerences are tight and what not.

wives tale or not its something to think about.

 

[crammit442]

well i know on dirt bikes it can happen.

i read about this in dirt rider.

that if you are riding in cold weather and right out of the box you are on the gas the piston will expand faster then the cylinder and seize.


so i would imagine if the engine is cold and your pumping a lot of cold water(dual cooling) before the ski is really hot that theres a chance, yes a chance it might seize up if the tolerences are tight and what not.

wives tale or not its something to think about.

What you're saying is correct, but has nothing to do with what I was saying. You're talking about a "cold Seizure". Absolutely possible. The piston heats up before the cylinder does and expands before the cylinder has time to expand. Two completely different scenarios. Yours is right. The other one is wrong.:biggthumpup:

Charles

 

[demolition_x]

im trying to do three things.

this, dynamics hw, and stunt junkies.

my bad..

 

[crammit442]

and just to add some more .02.. it doesnt matter if you do it in cold or hot weather.. this is why you have to let the dirtbikes warm up ..

That's true and it goes for jetskis as well. Always warm up before riding hard.:biggthumpup:

Charles

 

[Matt_E]

Especially true for forged pistons and/or tightly clearanced engines.

 

[Boris]

Old wives tale.:haha: NJFL(Joe) and I have been talking about this recently. The physics don't add up. You can flow the water too fast to heat the water, but not too fast to cool the cylinder. Remember we're trying to cool the cylinder rather than heat the water. This is one of Fleckenstein's pet theories.

Charles

I might be way off base but what about the sheer point ?
If a liquid flows over a surface fast enough (rough surface or the inside of a sharp curve), the liquid can brake away from that surface causing cavitation.

The water passages are rather rough and if you get enough cavitation in a particular spot that area will get hot quick.

Isn't that the idea behind "wetter water" ,
To lessen the waters surface tension thus lowering the sheer point ?

Or I could be talking out of my a$$ as the water in a skis cooling passages never reaches a velocity high enough to cause this problem.

 

[Matt_E]

Or I could be talking out of my a$$ as the water in a skis cooling passages never reaches a velocity high enough to cause this problem.

That's it.

As far as I know, cooling outlets in these motors are restricted to cause longer duration of cooling flow. That increases operating temperature.

 

[demolition_x]

i think we veared a little from the topic.

wasn't the original topic about why riva's design was much better than ADA's?

i can see for a certain extent but i can't see huge improvments over the normal engine conditions which it could be a problem.