Just got home from Stockton.
Been wanting to do this for a while now...
A thermostat setup from Rex or the like is the CORRECT and preferred method,
Says who? NONE of the manufacturers seem to think so, that is over a period of almost 40 years.
Let me tell you why a thermostat and the lack of a circulation, automotive style water pump has issues that I can not seem to get passed...
All a thermostat, even the one with the bypass does, is slow the water flow down from the top of the intake manifold. I guess I should ask how this differs from reducing the opening with a valve before the water enters the engine, but I wont.
By reducing the flow out of the manifold in this way, the water has the opportunity to go from the water pump inlet holes, right up the block, out the restrictor holes in the head gasket and out the stat housing. There is nothing to guarantee that there is any water moving in the rear cylinder area of the crankcase. That being said, ever look at the 454 Chevy in your truck or motor home? There is a 5/8" bypass hose on the top of the water pump to the front of the intake manifold UNDER where the stat housing is. Ever wonder why? It is to ensure that water is continuously moving in the engine even with the stat 100% closed.
I have absolutely NO problem with a thermostat kit on an engine with a block mounted water pump. This would actually work killer, especially if you have an automotive spec machined engine.
We have seen idling engines have a temperature difference with an infra red camera with over a 40* difference from the front to the back of the block, this was with a 160* thermostat and the block pressure was about 3#, that water was as close to flash steam as you could get on the rear cylinders of the motor...
a regulator seldom has enough VOLUME to properly cool the engine,
Sorta kinda depends on the size of the regulator does it not? This statement has no factual value what so ever. I will not expand further.
the next best way is to use a bypass regulator, sold at Graingers and is adjustable to 40 psi. Install it after the gate valve, set it at 20 psi max, run the overpressure dump line thru the transom.
Agreed... If you MUST add something unneeded, this is worth doing for some insurance, but will probably be stuck in the closed position when you really need it because they are not designed for brackish water. All of these valves and regulators I see these poor guys running are designed for city or treated water, not the sandy, salty, brackish crap we normally see.
Leave the gate valve wide open. A partially closed gate valve will allow the engine to run warmer, thats true, BUT when you are wide open and you can't watch it, the temp WILL spike hotter.
Noooooo... The temperature while running WFO will drop lower, how the hell would it get hotter with more flow?, they run warmer at idle... (pretty sure I already covered that).
This assumes that you have a reasonable amount of HP.
Again, has little to do with anything as long as the flow rates are even close.
Use 12.8 BTU's per min, per HP (12.8BTU's/min/HP) for gasoline engines.
So, 500 HP X 12.8 btu's X 60 minutes = 384000 BTUH.
Here is a cool little formula.. BTUH= Delta T (F) X GPM X 500 (whereas the 500 is the specific heat of water [1] times the weight of water [8.33#/gal.] times 60 [minutes in an hour]).
So that 500 HP motor needs to cool 348000 BTU's worth of heat (for the most part 1/3 of the heat generated by the fuel).
So lets say you want the motor to run at 130*F.
The lake you mostly run in is approx 60*F.... So now what? well, 348000 = 70*F delta t X GPM X 500... Anyone?
You need approximately 11 GPM of lake water to keep her cool at 500 HP, much less at idle, or 10 HP... A big block Chevy holds about a gallon and a half to two gallons of water, so how much time does it take to shoot water from the dump again?
A partially closed gate valve contributes to cylinder head cracking.
NOTHING you have proposed thus far will work any differently than a partially closed (insert type of valve here)...
Scenario: you just raced somebody, you stop to discuss it, the water in your now hot engine drains back into the lake, your upper block and heads are now empty of water, but still hot. You start back up, stomp the throttle, and the partially closed gate valve prevents the heads from fully filling for about 20-30 seconds,(how long dos it take to fill your radiator?),
First off.......What? Simple physics folks.... When a hot engine shuts down, the water going through the block was leaving at about 120*-130* if done "the old fashioned way"... That being said, when the engine shuts down, how is the water "draining back to the lake"? the engine is cooling off because it is no longer running generating more heat and is "heat soaking", as the water becomes acclimated to the block it will quite soon begin to cool and create a negative, this will keep 90+% of the water in the engine... Your mom ever can anything? what happens when you screw the lid on a hot jar of preserves?
If your engine is taking more that a few seconds to fill with water, especially after a quick shut down, you have more problems than just pressure issues. I have some videos somewhere that I will need to find of boats starting... Not one of them takes more than a few seconds to piss on the guy next to you.
meanwhile your heads are getting hotter, then the nice, cold lake water hits the hot chambers and exhaust seat areas. This is why we often see exhaust seat cracks in jetboat heads, but almost always on engines with partially closed gate valves and over 400 HP.
Calling BS, basically because you said exhaust seat, this is 99% of the time due to something called reversion from too close of lobe separation from somebody trying to use an automotive grind cam in a boat with injected headers...... Your camshaft lobe separation should never be closer than 8* if you are planing injected exhaust, i would rather see you go with 12*, plenty of proven cams out there do achieve this. you can also advance the cam a bit to get the torque numbers a jet requires at the top end of the RPM range.
A cold engine DOES NOT MAKE MORE HP THAN A WARM ENGINE!
Yeah, actually is does.
Unless you have too much timing, bad gas, or an overly rich mixture.
It is because of two of these three that you can make more power with a cold engine.... guess which two?..
Heat moves the piston down, heat moves from a hotter to a colder surface. Cold heads remove more heat, quicker than warm heads. We, and most other race shops, polish or ceramic coat the chambers and pistons on HP motors to decrease or insulate the surface area of the chambers, these both decrease the cooling effect on the burning mixture, and that equals more HP! TIMINATOR
This is so far off, I don't really know exactly where to begin, so here goes...
"Heat moves the piston down," Really? I though it was the act of combustion of a superheated air/fuel charge ignited under extreme compression... Heat is the by product.
"heat moves from a hotter to a colder surface." Hey, you got one right! (sorry, that was just rude... My bad.)
"Cold heads remove more heat, quicker than warm heads." OK. Heat is the root cause of detonation.
"We, and most other race shops, polish or ceramic coat the chambers and pistons on HP motors to decrease or insulate the surface area of the chambers, these both decrease the cooling effect on the burning mixture, and that equals more HP!" Oooh sorry... NO again. The polishing of the chamber reduces surface area within the combustion chamber keeping the surface heat from getting excessive and keeping a concentrated "flame flower" or "bloom" without creating "hot spots" in the chamber that can cause detonation, a cool head does the same thing... Coating the piston is the same principle. By doing this process you have basically allowed the operator to run a fatter mixture with a tad more timing... Hmmm, take a look above again.
I am not trying to be a shit swizzle stick, but I have a problem when someone posts something on a forum where people are trying to learn something who may or may not know when someone is blowing smoke up their ass...
You can look up anything I have written in this post and will be able to back it up... Not so sure the same can be said of the rest...
Regards
And my humble apologies to the OP, I hope the answer to your original question is hidden in here somewhere.
GT
