Thread:

Wiring and plumbing

Originally Posted by terrible_buddhist

If I may offer some unsolicited advice...

Go braided for your hoses. Do it once, and never worry about it again. Also, plumbing it yourself is really straight forward. Pump - shutoff valve - y connection - back of logs - front of logs to thermostat housing - dump

Two things here Buddy.... First, in the warmer climates of So Cal/Western Az, it is not necessary to warm the water first and we usually let the logs be the "out" end of the water supply.... Second, the water EXITS from the thermostat flange area. Plumb the water from the pump, "T"d to the water pump, (car/truck), flanges on the front of the BLOCK... From there, out the thermostat (split) or heater hose bosses, to the front of the logs, from the back of the logs to the Risers, (snails), and you're done..... If you use a "split" at the thermostat boss, you can use the heater hose holes for additional dumps overboard, (unnecessary if using logs), and/or temperature gauge fittings....Pluming the water "IN" the top of the engine will burn it up rather quickly as warmer water wants to "rise" inside the engine and it won't circulate properly.....
Ray

Originally Posted by Ol Blue

As Moneypit stated, no need to heat water prior to the engine in the Cal/AZ areas. The key is to adjust the water flow from the pump to keep your engine cool first. When its 110+ degrees at the river, you don't need water heated going into the motor.

Never "adjust" the "IN" water flow to maintain engine temps. That control valve should be wide open coming from the pump to the engine, and any "flow" adjustments should be made on the "out" side of the flow..... Normally with wet logs the hose sizes, reduced as they progress towards the "out" side, will be enough restriction to slow the water down sufficiently to take a little heat with it....3/4ths off the pump, split to two 5/8ths into the front, 2 1/2" coming out the top to the logs, and 1/2" from the logs to the risers... If you're looking to build "street car" heat in the engine use a thermostat at the exit. Restricting incoming water can build pressure from steam and create air pockets you don't really want....
Ray

Originally Posted by Moneypit

Never "adjust" the "IN" water flow to maintain engine temps. That control valve should be wide open coming from the pump to the engine, and any "flow" adjustments should be made on the "out" side of the flow.....
Ray

Again, just like the valve lashing, you are in over your head. These things don't have drag pickups or magnaflows. You adjust the flow thru the engine on the leaving side you your asking for gasket issues. Ray, I don't think you have a clue how much pressure one of these things is making. I love to hook one of your engines to that much pressure and see if you don't change your tune.

Originally Posted by Moneypit

Never "adjust" the "IN" water flow to maintain engine temps. That control valve should be wide open coming from the pump to the engine, and any "flow" adjustments should be made on the "out" side of the flow..... Normally with wet logs the hose sizes, reduced as they progress towards the "out" side, will be enough restriction to slow the water down sufficiently to take a little heat with it....3/4ths off the pump, split to two 5/8ths into the front, 2 1/2" coming out the top to the logs, and 1/2" from the logs to the risers... If you're looking to build "street car" heat in the engine use a thermostat at the exit. Restricting incoming water can build pressure from steam and create air pockets you don't really want....
Ray

and, as usual, i disagree with everything you said... tell me, if the water goes "too fast" through the engine, will the "fast water" take any heat with it???

Originally Posted by bp298

and, as usual, i disagree with everything you said... tell me, if the water goes "too fast" through the engine, will the "fast water" take any heat with it???

I didn't see where he used the term "fast water" Put he is trying to apply a drag system or a water pump system to a jet boat. I agree with him the IF you are going to restrict the water, it SHOULD be done on the outlet side. But it doesn't work that way on a jet unless you employ some sort of bypass over board regulator on the inlet side so you can't build too much pressure in the engine. For some unknown reason, Ray cannot accept the idea that a jet can over pressurize a engine if you don't restrict the inlet.

maybe hooking one of his engine to a garden hose full blast and restricting the outlet for a couple hours on one of his engine will convince him.

Originally Posted by gn7

Again, just like the valve lashing, you are in over your head. These things don't have drag pickups or magnaflows. You adjust the flow thru the engine on the leaving side you your asking for gasket issues. Ray, I don't think you have a clue how much pressure one of these things is making. I love to hook one of your engines to that much pressure and see if you don't change your tune.

Bob, I currently have two running jetboats that are plumbed my way. Neither has any type of additional restrictions on the "IN" side. One has headers and 2 regulated exit "dumps" in addition to the header cooling lines. The other has logs and no additional dumps. Neither "milks" the oil. The header motor (402) was built in the late 80s and is still running strong.... It seems that some "builds" can stand the pressure on the gaskets, and some can't. Mine can, and do.... And again Bob, arguing with success is getting kinda redundant, isn't it?...
Come on up to Bullhead and we can go for a ride anytime, and you can check the oil for water yourself....

Originally Posted by bp298

and, as usual, i disagree with everything you said... tell me, if the water goes "too fast" through the engine, will the "fast water" take any heat with it???

The term "fast, or faster, water" will in fact not cool as well as "slower water".... The water must absorb some heat before it's gone, or the heat remains in the metal. Have you ever seen a grocery getter that runs hotter after the thermostat is totally removed? I have. There is a "desired" rate of flow, and there are flows that are too fast, or too slow, to efficiently remove the heat. A jetboat uses the entire body of water for cooling so it is not necessary to speed up the flow to adequately cool the engine. It is necessary however to have an adequate volume of water flowing into all the nooks and crannies of the block/heads, (possible steam pockets), to properly circulate the water and remove the heat...It would seem the ideal set up would be a electric sender mounted on the top of the intake that triggered an electrical valve in the "IN" supply line.... But then again ALL the temperature controls, (thermostatically controlled poppets mounted at the exit), I've ever seen are regulating the "exit" side only. Why is that??....And wouldn't that build excessive pressure in the engine until it opens?? A simple cable controlled "ball" valve on a dump line can, and does, control how fast/slow the water supply moves through the engine. Want more heat? Reduce the flow until the trapped water gets hotter, but that will create more pressure against the gaskets. Most jets have a 3/8ths pipe fitting for the water supply. Some, like mine, are now 1/2" pipe... Compare that to the size of either radiator hose on a vehicle. The pressure drop right out of the pump is great when filling a 3/4 ID hose from a 1/4 or 3/8ths ID fitting. Then look at the volume the engine takes before the pressure even starts to build.....A good working "dump" system can, and does, prevent excessive pressure build up while regulating exit water to maintain engine temps....

IMO, any gasket that gives up was an inferior seal to begin with.....
Ray

it is painfully obvious that you are educationally challenged when it comes to physics, as in heat transfer, fluid flow and thermodynamics. and i'm not going to spend all day writing equations to demonstrate how incorrect your assumptions are. i will just say this. warm or hot water cannot absorb more heat than colder water. it is a physical impossibility. heat transfer is based on temperature difference between two bodys.
i have no doubt your 30 year old junk can work. people can get away with all sorts of nonsense in jet boats with 200-250 absorbed hp. unfortunately (or fortunately), most jets on this forum are way past that hp level. and trying to follow your suggestion in a moderately high hp jetboat would be an engine's death sentence. so when you're suggesting this nonsense to people with 600-700hp in their river jets, don't worry, i'll be there..
i don't know that gn would be up to driving to bullhead to go for a ride in a jetboat that'll almost run 50 at wot. but if you want to show up at windsor at 6:30 tomorrow morning, i'll take you for a short spin and show you what a real jetboat is all about... and it has ZERO restrictions in the cooling water exit path...