Author Topic: Water Temperature FL350  (Read 7016 times)

dham

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Water Temperature FL350
« on: July 05, 2012, 03:41:31 PM »
I have a water cooled head on my FL350 and my radiator fan does not come on until the water temperature is 210 degrees. Is this Ok? What is ideal water temperature? What is Danger Zone Temperature?

Factory 45

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Re: Water Temperature FL350
« Reply #1 on: July 05, 2012, 04:57:06 PM »
I would think there really wouldnt be a dangerous temp...boiling point perhaps? Seems your fan relay is set on a 210 sensor...can you confirm temps @ the water sensor and the relay are close to the same? PS my pilot with cool head sees 190 from time to time.

LiveWire

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Re: Water Temperature FL350
« Reply #2 on: July 06, 2012, 03:11:16 PM »
210 sounds fine. Coolant and being a pressurized system raises the boiling point. I run a cylinder head temp gauge instead since I had one before going water cooled. It will tell the efficiency of the head, not just that of the radiator.

dham

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Re: Water Temperature FL350
« Reply #3 on: July 06, 2012, 05:05:02 PM »
If I am running 210 radiator fluid temperature what would an exhaust temperature be if I did have an exhaust gauge?

LiveWire

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Re: Water Temperature FL350
« Reply #4 on: July 06, 2012, 05:11:09 PM »
They are affected by different things which is why you would have two different gauges. If you have 1400 degrees on the exhaust, it will burn up the piston regardless of what the water temp is. Hitting 500 degrees cylinder head temp would still hurt the engine even if the exhaust temps are under 1200.

dham

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Re: Water Temperature FL350
« Reply #5 on: July 06, 2012, 07:29:48 PM »
The radiator fan does not come on until 210 degrees. I just want to make sure that the motor does not over heat. Should I get a different thermostat that kicks on at say 190 vs. 210?

dham

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Re: Water Temperature FL350
« Reply #6 on: July 07, 2012, 06:22:59 PM »
My radiator is set up on a thermosyphin system. At what temperature would you guess does the water start circulating?

LiveWire

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Re: Water Temperature FL350
« Reply #7 on: July 09, 2012, 10:51:10 AM »
With an Aftershock head, I would guess maybe 20 degrees above the air temp. With a Rand and most other's, I would guess pretty close to the 210 you are seeing.

Thermosyphon requires a narrow passage for the water. Otherwise, the water will just roll within itself. So heads with large open cavities, the water just rolls around in the head. The heat will slowly climb both hoses until it gets to the top of the radiator through the hose that connects there. When the hot water hits the top of the radiator tubes, it will kick in the thermosyphon in a big way. The cold water in the radiator will dump into the head forcing the hot water in the head into the radiator. After the initial dump, flow will drop off and even out.

The Aftershock head with fins around the combustion chamber induces thermosyphon between them right away. Water flow starts slow and speeds up as temps rise.

dham

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Re: Water Temperature FL350
« Reply #8 on: July 12, 2012, 05:20:18 PM »
So an aftershock head will run alot cooler than other heads is that correct?

LiveWire

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Re: Water Temperature FL350
« Reply #9 on: July 13, 2012, 07:40:21 AM »
Once warmed up, it will run a little cooler head temp for a given water temp due to increased heat transfer from the head to the water.

It will run a lot cooler for a brief amount of time just after the engine has reached normal temp. What I saw with a Rand head was the head temp would actually spike to it's highest before dropping off.

odypilots

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Re: Water Temperature FL350
« Reply #10 on: July 13, 2012, 03:08:26 PM »
You know, Steve, this conversation about the merits (or dismerits) of particular heads would carry more weight if you had, or would, document some temperature figures. Come to think of it, I never saw any data from other head makers, although I never attempted to seek any out.
The usual 'my two cents' disclaimer applies. :)

dham

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Re: Water Temperature FL350
« Reply #11 on: July 14, 2012, 12:43:19 PM »
I have a Rand head and my water temp is hitting 210. The fan kicks on at 210 and then cools down slowly. Seems to stay between 195 and 210 constantly. Should I be concerned?

odypilots

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Re: Water Temperature FL350
« Reply #12 on: July 14, 2012, 07:39:36 PM »
I have a Rand head and my water temp is hitting 210. The fan kicks on at 210 and then cools down slowly. Seems to stay between 195 and 210 constantly. Should I be concerned?

Not if your jetting is correct,  but 175 - 185 fan activation would be better, from what I hear.   Proper jetting is WAY more important to me than water temp control when the goal is a long lasting 2 stroke. Within that 210 temp limit. Much hotter, then all bets are off.  Definitely fits in the IMHO MTC.
The usual 'my two cents' disclaimer applies. :)

LiveWire

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Re: Water Temperature FL350
« Reply #13 on: July 16, 2012, 07:02:16 AM »
You know, Steve, this conversation about the merits (or dismerits) of particular heads would carry more weight if you had, or would, document some temperature figures. Come to think of it, I never saw any data from other head makers, although I never attempted to seek any out.

I had posted some actual numbers back on Kiowa's board when I first made the heads. That was when I had Rand numbers that were worth comparing. It was on the same machine with the same radiator, etc. At this point, I'm not going to buy a Rand head in order to test it. A Rand head is a huge improvement over a stock head in terms of cooling. My biggest concern with them is that the last two I have seen (didn't check before that), the combustion chamber was quite a bit off center from the stud holes. So the squish band was very tight on one side and very loose on the other. What made it stand out on the two was signs of detonation on the tight side and heavy carbon deposits on the loose side.

There was someone who made his own head and tried to compare numbers I posted coming from a CHT with numbers he got using a hand held infrared temp gauge. That testing method if worthless since my temps on the CHT would drop off the moment I let off the throttle. By the time you stop, get out and point the gun at it, they would be very low.

odypilots

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Re: Water Temperature FL350
« Reply #14 on: July 17, 2012, 04:41:55 AM »
Thanks, Steve. Yeah, I can see where the temp gun would be incompatible with info gathered with a temp probe, and maybe worthless due to the delay you mentioned.

And just one more instance for me of the loss of all that info on that old board.
The usual 'my two cents' disclaimer applies. :)