SoCal Jet Boats
Tech Talk => Engine Mechanical / Electrical => Topic started by: Ckaz21 on May 22, 2015, 09:08:49 PM
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Right now I have a hose coming straight off the pump that feeds the engine/headers w water. There is no valve in place to control how much water pressure goes to the engine? Thoughts on installing a gate/ball valve?
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Install a gate
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x10000000 Put a gate valve on it.
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If that hose blows, you'll have a hole in your boat. You should install something.
As far as controlling the water flow for temperature/pressure, ::). It's been covered a million times with different opinions.
One person says they've never had a problem with just a gate valve. Another says you need a pressure regulator with a gate valve.
Another will say you need a bigger dump line. Try a search for "gate valve".
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Right now I have a hose coming straight off the pump that feeds the engine/headers w water. There is no valve in place to control how much water pressure goes to the engine? Thoughts on installing a gate/ball valve?
What pump.
The gate valve will be the best investment you will make on your boat.
I have been using the Red and White 3/4" gate valve for decades. You cannot miss.
GT
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Run hard line from pump to the gate... then whatever you want after that. I'd run a separate valve for headers but not a ball/T. If sand gets in there its either stuck open / closed.
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Run hard line from pump to the gate... then whatever you want after that. I'd run a separate valve for headers but not a ball/T. If sand gets in there its either stuck open / closed.
Why hard pipe?
I don't care for rigid anything on s boat. Unless in can be braced very well.
I just run some 5/8" Push-Loc and clamps (overkill city). If you buy clamps for silicone hose is bulletproof.
JMHO.
GT
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Coming off the pump to the gate with hardline is the easiest way. It's really just about 6-8" worth of nipple, then the gate, then flex line. That eliminates having to figure out bracing/brackets for the gate valve. Not enough hardline to be a stress break issue at all. Well, at least that I've ever experienced or heard of. Short runs keep it all out of the way, and keep the weight from being a stress issue at the pump end of the threads.
Just my 2¢.
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Coming off the pump to the gate with hardline is the easiest way. It's really just about 6-8" worth of nipple, then the gate, then flex line. That eliminates having to figure out bracing/brackets for the gate valve. Not enough hardline to be a stress break issue at all. Well, at least that I've ever experienced or heard of. Short runs keep it all out of the way, and keep the weight from being a stress issue at the pump end of the threads.
Just my 2¢.
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So here's the thing.
Brass fittings have to be lead free. That being said, there is no more a such thing as red brass.
I have been a union pipefitter now for going on 20 years. The new brass is GARBAGE.
If you install a current 3/8" X 8" brass nipple in the pump and screw on a 3/4" gate valve and a reducer bushing, I would bet you a 1.75 of tasty adult beverage I could snap it off with one finger.
No thanks. I would rather install something I can stomp on and not harm.
GT
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Heater hose is very reliable. Nothing wrong with using that. It's lasts a very long time exposed to heat in the engine bay of a car, so in a boat it will last even longer.
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Heater hose is very reliable. Nothing wrong with using that. It's lasts a very long time exposed to heat in the engine bay of a car, so in a boat it will last even longer.
Except.
The pressure from the pump to the gate valve can be extreme on a high horsepower deal. In excess of 150 pounds. Heater hose has a typical pressure rating of 140 minimum burst.
Push-Loc is good for over 500.
GT
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What is this PUSH LOC you speak of? Any pics?
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What is this PUSH LOC you speak of? Any pics?
It requires special barb fittings and can be purchased virtually anywhere Weatherhead, Parker and Eaton house and fittings are sold.
http://ph.parker.com/us/15551/en/push-lok-plus-multipurpose-hose-801
GT
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So GT.... Are you saying you have only the barbed fitting coming off your pump, then the hose, valve, then hose? I am using a 6 inch nipple, valve, then fitting then hose. But i am using the push loc style hose and fittings the rest of the way.
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So GT.... Are you saying you have only the barbed fitting coming off your pump, then the hose, valve, then hose? I am using a 6 inch nipple, valve, then fitting then hose. But i am using the push loc style hose and fittings the rest of the way.
Yes, the pump has a Push-Loc barb fitting and it goes to another Push-Loc barb at the gate valve.
I use hose clamps for silicone hose because I am OCD.
Nothing rigid.
GT
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Have you seen the nipples break with just vibration alone? I figured as long as it wasnt very long that it wouldnt be an issue.
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Short hard line off pump to gate is a bit safer than a blown rubber line. It's just time or luck before an issue arrises.
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Short hard line off pump to gate is a bit safer than a blown rubber line. It's just time or luck before an issue arrises.
How are you going to blow a rubber line rated at a higher pressure than the brass fitting?
I have seen more broken brass nipples than I have blown Push-Loc.
To each his own I guess.
Ten years ago, maybe. But again, the new brass blows......
GT
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Stainless pipe and fittings are easy to find, use them. You need the gate or ball valve for safety reasons, like when a freeze plug blows or rusts out, you don't want to sink the boat over that. Do not use the valve as a restriction to limit the water flow to the engine to get the temperature up, if you want the temp up, buy a jet-boat thermostat kit. When you are sitting in the water B.S.ing about whose boat is faster, and start up and floor it, it can take 40 seconds to near a minute to fully fill the block, and there you are at full throttle..... when the cold water hits the hot head, you get cracks, they start out small, but they grow. Try this yourself, with a dry block, connect the garden hose to the pump side of the valve at the opening you normally run it. Turn on the hose and see how long it takes for water to come out of the dump line. Put a pressure gauge in the motor and see how much pressure the pump is supplying while underway. The municipal water system is 50-60 pounds. Do the math. Just sayin' TIMINATOR
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I have push lock on my entire engine....except for the hardline from pump to gate. I've replaced every push lock in the two years I've had em an going on the 2nd round. To each his own I experienced!!!!!!!!!!!!!!!
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I have push lock on my entire engine....except for the hardline from pump to gate. I've replaced every push lock in the two years I've had em an going on the 2nd round. To each his own I experienced!!!!!!!!!!!!!!!
Question one, why are you having to replace the hose? I have some 20 year old Weatherhead Push-Loc on my motor home. I would hp in it and drive it to New York today.
Question two, how dis you determine these hoses needing replacing?
Not throwing punches, just very curious.
GT
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Stainless pipe and fittings are easy to find, use them. You need the gate or ball valve for safety reasons, like when a freeze plug blows or rusts out, you don't want to sink the boat over that. Do not use the valve as a restriction to limit the water flow to the engine to get the temperature up, if you want the temp up, buy a jet-boat thermostat kit. When you are sitting in the water B.S.ing about whose boat is faster, and start up and floor it, it can take 40 seconds to near a minute to fully fill the block, and there you are at full throttle..... when the cold water hits the hot head, you get cracks, they start out small, but they grow. Try this yourself, with a dry block, connect the garden hose to the pump side of the valve at the opening you normally run it. Turn on the hose and see how long it takes for water to come out of the dump line. Put a pressure gauge in the motor and see how much pressure the pump is supplying while underway. The municipal water system is 50-60 pounds. Do the math. Just sayin' TIMINATOR
This is me keeping my mouth shut in the corner in total disbelief that you just said all of this again.
GT
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Stainless pipe and fittings are easy to find, use them. You need the gate or ball valve for safety reasons, like when a freeze plug blows or rusts out, you don't want to sink the boat over that. Do not use the valve as a restriction to limit the water flow to the engine to get the temperature up, if you want the temp up, buy a jet-boat thermostat kit. When you are sitting in the water B.S.ing about whose boat is faster, and start up and floor it, it can take 40 seconds to near a minute to fully fill the block, and there you are at full throttle..... when the cold water hits the hot head, you get cracks, they start out small, but they grow. Try this yourself, with a dry block, connect the garden hose to the pump side of the valve at the opening you normally run it. Turn on the hose and see how long it takes for water to come out of the dump line. Put a pressure gauge in the motor and see how much pressure the pump is supplying while underway. The municipal water system is 50-60 pounds. Do the math. Just sayin' TIMINATOR
TIMINATOR,
Just to play nice.
On the thermostat kit for a jet boat.
I have used them. The do seem to control the OUTLET temperature of the cooling water. But what keeps that same cold water from entering the front two cylinders?
Answer; nothing at all.
On the taking 40 seconds to fill the block?
This is so fundamentally wrong I don't know where to begin.
My challenge is, I would love to see you prove this.
Jet boat in the water, previously warmed up. Let the boat sit for as mind long as you want, hit the key and monitor the dump line.
If this takes more than a second to go from bubbles to clear water, you have blown head gasket. Plain and simple.
As for the not restricting the inlet water for control of flow. I am speechless.
GT
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The cooling system seals on an engine are only designed for 13-15 psi or so. Putting 50-60 psi in an engine is stupid. It may hold on some engines, but there is no reason to raise the boiling point that high. A proper cooling system needs a restriction on the outlet (valve or an orifice in t-stat housing) to raise the pressure above 0 to raise the boiling point over 212F and to help keep steam pockets from forming.
If you really want to control the temp correctly a closed system with a heat exchanger would be a better idea.
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The cooling system seals on an engine are only designed for 13-15 psi or so. Putting 50-60 psi in an engine is stupid. It may hold on some engines, but there is no reason to raise the boiling point that high. A proper cooling system needs a restriction on the outlet (valve or an orifice in t-stat housing) to raise the pressure above 0 to raise the boiling point over 212F and to help keep steam pockets from forming.
If you really want to control the temp correctly a closed system with a heat exchanger would be a better idea.
The flow into the engine is the best way to control pressure. The outlet capability determines that flow. Really should not be the other way around, but I see where your headed.
GT
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..........when we return to "what floats your boat" will gt prove his point again, will another gate valve be used, will this turn into another 30 page discussion. Stay tuned and find out.
We will be right back after a short commercial break.
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The cooling system seals on an engine are only designed for 13-15 psi or so. Putting 50-60 psi in an engine is stupid. It may hold on some engines, but there is no reason to raise the boiling point that high. A proper cooling system needs a restriction on the outlet (valve or an orifice in t-stat housing) to raise the pressure above 0 to raise the boiling point over 212F and to help keep steam pockets from forming.
If you really want to control the temp correctly a closed system with a heat exchanger would be a better idea.
So, at 13 to 15 lbs on the block gives a boiling point of...???
At 135*, how long will it take to get to 212*, or 242*?
When using raw water cooling, why would (any) one run the engine temp more than 50* to 60* above lake temp?
Just questions...
Dan'l
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Keeping an engine too cool will reduce combustion chamber temp. You want heat in the combustion chamber to make power. Tuning also changes with temp so a boat that has an engine that does not fluctuate temperature will be easier to keep in tune.
There is a reason the average car runs between 210-220F. It's more efficient and you end up with a cleaner burn than if the engine is at 150F.
(https://www.socaljetboats.com/proxy.php?request=http%3A%2F%2Fwww.artisan-distiller.net%2FphpBB3%2Fdownload%2Ffile.php%3Fid%3D696%26amp%3Bsid%3Dc17e19a56fb6249a62e17f213e255ff5&hash=651ab7cb9a493049a50c09086b1fe833a13999e5)
You want pressure in the block to raise the boiling point, even though the engine will mostly run at a set temp, some parts of it will be warmer and cooler than wherever your sending unit it. That means some spots could get over 212F (boiling point at one bar) and create a steam pocket. Once that steam pocket is created there will be no cooling at that location until it is removed.
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Keeping an engine too cool will reduce combustion chamber temp. You want heat in the combustion chamber to make power. Tuning also changes with temp so a boat that has an engine that does not fluctuate temperature will be easier to keep in tune.
There is a reason the average car runs between 210-220F. It's more efficient and you end up with a cleaner burn than if the engine is at 150F.
(https://www.socaljetboats.com/proxy.php?request=http%3A%2F%2Fwww.artisan-distiller.net%2FphpBB3%2Fdownload%2Ffile.php%3Fid%3D696%26amp%3Bsid%3Dc17e19a56fb6249a62e17f213e255ff5&hash=651ab7cb9a493049a50c09086b1fe833a13999e5)
You want pressure in the block to raise the boiling point, even though the engine will mostly run at a set temp, some parts of it will be warmer and cooler than wherever your sending unit it. That means some spots could get over 212F (boiling point at one bar) and create a steam pocket. Once that steam pocket is created there will be no cooling at that location until it is removed.
I'm going to circle back to this at lunch.
GT
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..........when we return to "what floats your boat" will gt prove his point again, will another gate valve be used, will this turn into another 30 page discussion. Stay tuned and find out.
We will be right back after a short commercial break.
You a funny guy.
GT
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Is the water allowed to stay in the system long enough to even reach a "warm" temperature? Or should it be?
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I'm going to circle back to this at lunch.
Please don't tell me I am wrong. I hate when people tell me I am wrong.
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Keeping an engine too cool will reduce combustion chamber temp. You want heat in the combustion chamber to make power. Tuning also changes with temp so a boat that has an engine that does not fluctuate temperature will be easier to keep in tune.
There is a reason the average car runs between 210-220F. It's more efficient and you end up with a cleaner burn than if the engine is at 150F.
For emissions, not horsepower
You want pressure in the block to raise the boiling point, even though the engine will mostly run at a set temp, some parts of it will be warmer and cooler than wherever your sending unit it. That means some spots could get over 212F (boiling point at one bar) and create a steam pocket. Once that steam pocket is created there will be no cooling at that location until it is removed.
At 135*F, what is running at 212*F +? (logs and snails)
At 120*F, what is running at 212*F +? (Headers)
Is the water allowed to stay in the system long enough to even reach a "warm" temperature? Or should it be?
On a single pass system, 50 to 60* above lake temp is fine, and with headers, 40* rise is enough.
In 55* water below Hoover Dam, Mine runs @ 120-125*F. Lake Mohave, 88* water temp in August, runs at ~140*F, and the long 'no wake zone' @ Katherines creeps up to 150-155*F.
Oil temp is more important, IMHO
Dan'l
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My set up is solid old brass to gate to double sided garden hose hookup to braided hose that tees into duel inlet. The outlet coming out intake has gauge for outlet water pressure. Duel overboard hose going straight overboard and a line that goes to a valve then a tee then the headers. I have usable pressure 5-20 at idle through 3000 Rpms. After my secondaries kick in the water pressure coming out of the engine is 70+. Still getting water in my oil.Gonna throw a relief valve on the intake side after the gate to relieve to overboard discharge. Any possibility of the water coming threw exhaust? My cam is not too lopey.
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Holly crap!! Im getting dizzy
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My set up is solid old brass to gate to double sided garden hose hookup to braided hose that tees into duel inlet. The outlet coming out intake has gauge for outlet water pressure. Duel overboard hose going straight overboard and a line that goes to a valve then a tee then the headers. I have usable pressure 5-20 at idle through 3000 Rpms. After my secondaries kick in the water pressure coming out of the engine is 70+. Still getting water in my oil.Gonna throw a relief valve on the intake side after the gate to relieve to overboard discharge. Any possibility of the water coming threw exhaust? My cam is not too lopey.
Check the gate valve if it's old. I had a Olds engine that kept pushing water until I figured out the gate valve ball was corroded away allowing it to be fully open regardless of the valve position. 70psi is wayyyy too high.
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Valve throttles. What water pressure do you guys read at idle? My gauge reads to 90 gonna switch to 30 so I can get a more accurate reading and anything higher is no good anyways
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Block pressure will vary depending on: where the gauge is installed in relation to the dump line
what size dump line and how many of them
what is the dump line fitting outlet size
head gasket design I.E. car or marine
water feed line and "T" size
max engine RPM/HP (higher RPM means more bowl pressure)
nozzle size (changes bowl pressure)
bowl and impeller type (see above)
BB Chevys depend upon the year of the block, I.E. 1,2,or 3 center/lower coolant deck holes and
Gen 4,5,or 6, they have different front and rear deck holes
TIMINATOR
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Block pressure will vary depending on: where the gauge is installed in relation to the dump line
what size dump line and how many of them
what is the dump line fitting outlet size
head gasket design I.E. car or marine
water feed line and "T" size
max engine RPM/HP (higher RPM means more bowl pressure)
nozzle size (changes bowl pressure)
bowl and impeller type (see above)
BB Chevys depend upon the year of the block, I.E. 1,2,or 3 center/lower coolant deck holes and
Gen 4,5,or 6, they have different front and rear deck holes
TIMINATOR
Not picking on you. I swear.
The block pressure will be the same from the control valve (whether it's a pressure regulator, a bypass, or a gate valve) all the way to right before the dunno fitting. If there is a difference, you won't have a precision enough instrument to read it.
RPM will change the bowl pressure unless you change impellers, not when you change impellers.
The head gasket type can alter the pressure but should not alter the flow requirement.
GT
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My pressure rises with more rpms
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Pressure gauge is located where the thermostat would be.(outlet)
There are also two 1/2 outlet lines going overboard ,as well as the water line going to the headers, coming off the same tower.
I want to know what your water pressure is at idle so I can know how far I can throttle down my gate valve on the inlet without getting steam pockets
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GT I disagree.
You all figure it out since I don't like to restrict the flow anyway.
The abovementioned info was a result of over 40 years of being both a performance machine shop owner/operator specializing in boat engines AND pump builder/ machinist.
Others experiences may vary.
TIMINATOR
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GT I disagree.
You all figure it out since I don't like to restrict the flow anyway.
The abovementioned info was a result of over 40 years of being both a performance machine shop owner/operator specializing in boat engines AND pump builder/ machinist.
Others experiences may vary.
TIMINATOR
I'm not going through the pedigree thing again.
However, you have to restrict the flow in one way or another. It could be something as simple as the original Berkeley JA and JB pumps with the pump fitting that was 3|8" X 5/8" hose barb with the 1/4" hole size.
A hard running jet can develop about 25-30 GPM of cooling water flow, that's a lot of water being as it takes about 5 GPM to keep 600 HP cool.
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So your saying 5 is enough got it
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30 gallons per minute is a gallon every 2 seconds, thru a 3/8" hole......... somebody take a garden hose which is 5/8" I.D, and standard municipal water pressure is 50-60 lbs, and see how long it takes to put a gallon in a bucket. Question everything, it makes you smarter. just saying.... TIMINATOR
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Does water pressure measure gpm or psi?
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But is 5 enough to keep er cool without steam pockets (gpm or psi)
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But is 5 enough to keep er cool without steam pockets (gpm or psi)
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No, I blew that number out of my ass. It's closer to 11.
Sorry.
Not sure what you are going to do with that info anyway.
Keep the pressure at WOT below 20 and above 12 and your gold.
GT
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Trying to keep water out of my oil is what I'm trying to do with the info
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I think he means that you are most likely not going to connect and monitor a flowmeter.
Pressure is the result of resistance to flow and would be measured in Pounds per Square Inch (PSI)
Flow is stated in units of volume over time. Depending on the flow rate, could be Gallons Per Minute (GPM) or Gallons Per Hour (GPH).
You can have pressure with no flow, but for flow to occur, a pressure differential must exist. Flow is always from an area of high pressure to an area of low pressure.
Not trying to stir the pot here, but, in an open loop cooling system; if a pressure gauge is installed at various points in the system, starting in the jet pump bowl, then in the cooling line just as it exits the pump, again in the cooling line as it enters the engine at the water pump bosses, in the drain plug, in each of the core plugs in the block, in both of the core plugs in the head, at both ends of the intake manifold, in the thermostat housing, in the hose just as the water exists the engine, and lastly just before the water dumps over the side; (little long winded there) you would observe that each gauge indicates a pressure drop. The bowl would have the highest pressure and just as the water dumps over the side, it would be at 0PSIG. This is because of fluid friction. Every hose and fitting is a restriction as are all of the passages in the block, heads, and manifolds. The surface finish of the inside of the engine, hoses, etc. adds to this fluid friction. The shape of the entry/exit of each of the fittings, be it squared with just a drilled hole, chamfered, or fully-radiused. Are the fittings 45 or 90-degrees? Drilled or smooth bends?
The question becomes, where is the correct location to take a reading? If in the thermostat housing, everything up to that point is going to be higher pressure than what the gauge indicates. Right before the water enters the engine would be the safest, at least the water pressure beyond that point will be less.
Cheers,
Joe
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I would like to state the Jetfever is in no way affiliated nor does not endorse this thread.... and ladies bikini tops are not optional - Like Tpain said TAKE YOUR MOTHAwoopin shirt off.
I am not sure why this is always a debate.
Its easy on the wallet to try the gate.
It did not keep oil and excess pressure out of my block I had to use a regulator to keep pressure down on my boat. I also only drive in lakes not sandy rivers. It was worth the money in my setup. We all have a preference we swear by but this kept water out of my oil.
I think we all should listen to everyones advice and experiences choose what works for us collectively and not beat each other up over any of it. Afterall that is one of the reasons we are all on here right.
:beer:
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I think we all should listen to everyones advice and experiences choose what works for us collectively and not beat each other up over any of it. Afterall that is one of the reasons we are all on here right.
:beer:
Well said!
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Well said!
X2
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I think he means that you are most likely not going to connect and monitor a flowmeter.
Pressure is the result of resistance to flow and would be measured in Pounds per Square Inch (PSI)
Flow is stated in units of volume over time. Depending on the flow rate, could be Gallons Per Minute (GPM) or Gallons Per Hour (GPH).
You can have pressure with no flow, but for flow to occur, a pressure differential must exist. Flow is always from an area of high pressure to an area of low pressure.
Not trying to stir the pot here, but, in an open loop cooling system; if a pressure gauge is installed at various points in the system, starting in the jet pump bowl, then in the cooling line just as it exits the pump, again in the cooling line as it enters the engine at the water pump bosses, in the drain plug, in each of the core plugs in the block, in both of the core plugs in the head, at both ends of the intake manifold, in the thermostat housing, in the hose just as the water exists the engine, and lastly just before the water dumps over the side; (little long winded there) you would observe that each gauge indicates a pressure drop. The bowl would have the highest pressure and just as the water dumps over the side, it would be at 0PSIG. This is because of fluid friction. Every hose and fitting is a restriction as are all of the passages in the block, heads, and manifolds. The surface finish of the inside of the engine, hoses, etc. adds to this fluid friction. The shape of the entry/exit of each of the fittings, be it squared with just a drilled hole, chamfered, or fully-radiused. Are the fittings 45 or 90-degrees? Drilled or smooth bends?
The question becomes, where is the correct location to take a reading? If in the thermostat housing, everything up to that point is going to be higher pressure than what the gauge indicates. Right before the water enters the engine would be the safest, at least the water pressure beyond that point will be less.
Cheers,
Joe
Whilst I totally agree.
The actual readable pressure differences within the block (from the water pump adapter fittings to the thermostat housing) will be so small, an analog gauge will not be adequate to see them.
Obviously this is if the smallest port is the actual dump fitting (normally is).
Actual control of the water flow (as it pertains to temperature) and pressure (as it pertains to rpm) can be done literally dozens of ways. I always shoot for something as close as possible to what you have now. There is no reason to completely reinvent the wheel. IMO.
GT
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You don't need a flowmeter, install the gauge at the inlet to the head, perpendicular to the inlet flow (to get an accurate reading use a standard "T", the inlet from the pump goes in the side of the fitting, the gauge in one end, and the block at the other end), then read and record the inlet pressure at idle, at say: 2000RPM, 3000 RPM, 4000 RPM, and every 1000 RPM to max RPM while running down the lake. Then while at home, install a garden hose to the inlet hose after you remove it from the pump. Now set the garden hose pressure to the idle pressure, and run the DUMP water onto the ground, run the hose at that pressure to fill the engine and when water is flowing freely out of the dump line, then put the bucket under the dump fitting, and run the hose for one minute and remove the bucket, read the amount of water in the bucket, and this is how many gallons per minute the flow is at idle. Empty the bucket and repeat at every 1000 RPM and record all of this info. You will now KNOW the ACTUAL gallons per minute of cooling water that is going thru the engine. No guessing here! Then let the engine empty itself of water, some take longer than others, (the boat must lean back on the trailer at the angle that it sits in the water/lake), turn on the water at the full RPM pressure the motor can run and time the length of time until the water is FULLY FLOWING from the dump line. This is how long it takes to fill the system from sitting empty in the lake, to full throttle with full cooling. If that doesn't bother you, do the same at say idle and 3000 RPM. The first dozen times we did all of this (about 30+ years ago,) we were surprised, and that's why we don't restrict the inlet. Yes, I'm anal about everything, so I don't have to guess. You don't have to believe me about anything, try this yourself. TIMINATOR
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I broke this up so it would be easier to decipher.. ;)
You don't need a flowmeter, install the gauge at the inlet to the head, perpendicular to the inlet flow (to get an accurate reading use a standard "T", the inlet from the pump goes in the side of the fitting, the gauge in one end, and the block at the other end), then read and record the inlet pressure at idle, at say: 2000RPM, 3000 RPM, 4000 RPM, and every 1000 RPM to max RPM while running down the lake.
Agreed. Good method. I do have a flow meter that I have used in the past..... If anyone wants to borrow it, hit me up. They're super simple and super cheap. I also have an ultrasonic flow meter but the turbulence messes with the readings.
Then while at home, install a garden hose to the inlet hose after you remove it from the pump. Now set the garden hose pressure to the idle pressure, and run the DUMP water onto the ground, run the hose at that pressure to fill the engine and when water is flowing freely out of the dump line, then put the bucket under the dump fitting, and run the hose for one minute and remove the bucket, read the amount of water in the bucket, and this is how many gallons per minute the flow is at idle.
Here is where I have a slight issue, maybe not enough to negate what your saying but who knows...
The garden hose deal is a constant column of bubble free water, not the foamy bubbly crap from a jet pump spinning 5,500 RPM. The flow coefficient is all fuckered up.
Empty the bucket and repeat at every 1000 RPM and record all of this info. You will now KNOW the ACTUAL gallons per minute of cooling water that is going thru the engine. No guessing here!
What does the RPM have to do with the engine being on a hose? I assume you meant pressure. Not RPM?
Then let the engine empty itself of water, some take longer than others, (the boat must lean back on the trailer at the angle that it sits in the water/lake), turn on the water at the full RPM pressure the motor can run and time the length of time until the water is FULLY FLOWING from the dump line. This is how long it takes to fill the system from sitting empty in the lake, to full throttle full cooling.
How does the engine empty itself of water in the lake? I still don't get it... Maybe I'm a tard... :P
The first dozen times we did all of this (about 30+ years ago,) we were surprised, and that's why we don't restrict the inlet. Yes, I'm anal about everything, so I don't have to guess. You don't have to believe me about anything, try this yourself. TIMINATOR
I can tell you this for fact. The small block Chevy we just took to Nacemiento a few months ago took longer to fill the droop than it did the engine. Literally two seconds after the engine drew down once the impeller started pumping, the dump line started peeing like it had been drinking Coors Light for a week...
I feel your method may be flawed, I will have to try this and play around with it...
The air has almost no restriction as compared to the water. Not poking, just trying to understand where all this is coming from.
Man, can we beat a subject to a pulsless death or what? ???
GT
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By knowing the pressure at the various RPMs, you can figure the Gallons per minute flow at THAT RPM, and that changes with RPM/pump pressure.
Why does the engine block drain while sitting in the lake? Gravity. Water always seeks its own level.
The water jacket of the heads and almost always the entire engine block is above the level of the water outside the boat.
Water seeks its own level. The water in the engine will drain down to the level of the water outside, usually emptying most of the block, and all of the heads.
Before I moved to Phoenix, in the 1970s, we had a customer that didn't like the time that it took to refill the engine when started. So he added a check valve in the pressure line from the pump. He had almost immediate water flow upon start up, and I figured he had stumbled onto a good idea. I wondered why the boat companies didn't incorporate this feature. We got our answer next spring when the first time in the water he discovered that the block was cracked in several places on both sides in the lower water jacket area and the freeze plugs were severely corroded. It freezes back East. Lake water also contains no antifreeze/corrosion protection, so steel freeze plugs and iron blocks, and heads, whether iron or aluminum will be corroded with water standing in it all winter.
Water drains from the engine back into the pump, into the bowl, and out to the lake thru the impeller and suction housing.
Don't believe that? Remove the pump feed line to the engine and connect a garden hose to the pump itself, when you see water running from the pump you will be convinced.
It may take 3 or 4 minutes to drain the engine, but how long were you sitting in the lake putting out a skier, or B.S.ing about whose boat is faster before the time you actually raced? The heads empty first because they on top of the engine, but they are the hottest part of the engine and need the most cooling water, just sayin'.
When you put the boat on the trailer and take it out of the lake, did you ever notice how long it takes for the water to stop running out of the pump inlet? That's because the block and heads are emptying thru it. It takes just as long in the lake, but it does happen.
I did not expect this issue to become an encyclopedia, I thought everyone would have grasped these concepts much sooner, but since not everybody did, it just took a bit more explaining. TIMINATOR