Performance Boats Forum banner

1 - 20 of 20 Posts

·
Registered
Joined
·
57 Posts
Discussion Starter #1
I am looking for pictures of the parts I need, and the parts themselves. One thing off the bat I know I need is the cast thermostat piece with the multiple hose fittings. I assume the pump is a generic automotive short shaft.
 

·
Registered
Joined
·
57 Posts
Discussion Starter #3 (Edited)
I really do not want to offend anyone. What is the purpose of jetboating - I thought it was to have fun. The reason I say this is I have completely pissed off the admin at the Socal Jet Boats Facebook page. This was to do what started with a difference of opinion, but escalated very childishly into full blown arguement.

In other words, I do not want to offend anyone. Please do not read, "I am right, you are wrong", into any of the following. Not anyone.

The Berkeley Packajet cooling system incorporated a circulating pump, as in a car. There are at least four reasons for this.

1) Elimination of air bubbles / pockets / steam traps (engine longevity)
2) Equalization of temp in the cooling passages - everywhere (engine longevity)
3) Elimination of temperature swings (engine longevity)
4) Temperature control to within one degree, across the power band. (fuel efficiency)

Mercruiser and OMC (I have only seen their schematics recently) and probably many others still run circulation from the factory.

Circulation is not for everyone, especially extreme racing. Cooler the better, and longevity is a non issue. I am sure there are other very arguable reasons to not run circulation.

I am making the choice to run circulation, because I am building a boat I don't want to touch again, engine wise, and am handing it down to my sons in the future.

Here is a Donzi. I just found this a minute ago.
00j0j_68eSVWdFweo_1200x900.jpg
 

·
Registered
Joined
·
307 Posts
Yes, your original post/diagram would work fine, assuming you are running a thermostat in that system.

Due to possible high water pressure from the jet, you probably should add a pressure relief and/or regulator between the jet pump and thermostat, especially if you plan to turn high RPMs.

Good luck
 

·
Registered
Joined
·
57 Posts
Discussion Starter #5
Real McCoy - I will not be turning more than 5000 RPM. It will be a family boat. Do you think that will give me a pressure issue? I assume these pressure issues have to do with water not being able to get out of the system fast enough. I hate to put any restriction into the system, but would rather allow the water another way out. Do you have any thoughts on any of this? I very much appreciate the information.

To the responder regarding a closed system. That is without a doubt a superior idea. I am gonna run with it this way I guess. I don't run into sand in Maine, I guess I am gonna chance it. I really appreciate the insights. Have been considering a strainer though. Any thoughts are appreciated.
 

·
'74 Sanger ski hydro
Joined
·
432 Posts
I see now that you're doing something different and my posts were of no benefit to what you're doing. I do have to ask, how does this setup work any different than a bypass thermostat setup minus the automotive water pump?
 

·
Registered
Joined
·
57 Posts
Discussion Starter #7 (Edited)
As I am led to believe, a boat would lose those 4 items I listed above, if there is no circulation pump. The entire mass of water in the engine and heads is kept in motion, in a manner similar to what the engine designer intended. I would have done it anyway, like with a 350, but the 400 (I am using) has siamesed walls and is suseptible to steam pockets, so, it's just a way to help mitigate that too. It's more an investment in the future than anything else, I believe.

There is a person getting me some pix of an unaltered Packajet engine tonight. I made another drawing. All this is open for correction. I still don't know if I have it right.

My pic v2 mod.jpg
 

·
Banned
Joined
·
3,397 Posts
My CVX-20 has a 1977 berk packajet/460 Ford and has no water pump.....Only the pressure/flow from the jet drive.....It goes in the front cover, from there it goes into the block AND up into the Thermo housing, where the thermo housing then also has the hoses connected from the exhaust manifolds......I drilled a number of holes thru the thermostat to bleed water/air thru- I have used this setup for 12 years with no problems.....I go water skiing every weekend in the Delta and spend two weeks up at Trinity lake every year....I use it a lot and it works very well...warms up quickly and then stays between 160 and 200 depending on when I am idling or hitting it. I use it in the Spring/Fall when the water temp is 55 degrees, and at Trinity were the water temp can be as high as 87 and the air temp is 100*.

Note; I have the Center-rise exhaust, so the water goes in and then flows up into the riser and then dumps into the exhaust and out the back...If you have logs, with the pre-heat then yours hooks up differently......By the way, I can not see the diagram you posted.
 

Attachments

·
Registered
Joined
·
6,575 Posts
I don't think that's a "packajet" setup. the multi-port thermostat housing you're showing is the same one that's on my mercruiser. on that, there is a separate water pump that supplies the front mounted engine water pump. the two small ports you are using to supply the snails are used for a temp sensor, and another sensor. water from the water pump is supplied to one of the two inside ports, the other inside port is routed through an oil cooler, then to the exhaust. engine water pump supplies the engine, creates pressure. it's all factory, not easy to see everything with all the junk in there.

on my placecraft, i run a meziere water pump with tank, a closed system. if you have a thermostat housing that's at a point elevated above all other water passages, there's no reason for "pockets" to form, unless there is no flow. i DO NOT use a thermostat because I've had them break before, and that can lead to problems. for the placecraft, the thermostat housing discharges to a small old mercruiser oil cooler, tube side. water from the jet drive is routed to the shell side, flowpath reversed from engine coolant flow. this has worked fine for 3 years. under load with rpm elevated, engine temp is fine, around 150-160. if i have to idle for extended periods, engine gets too warm. i think the next size up cooler would work just fine. i knew another guy that had a much larger heat exchanger; jet water was cut way back to keep the engine above 120.

you could use a belt driven engine water pump the same way i'm using the mezeire. just need a separate tank as an accumulator/fill for a closed system (the system you are contemplating is not closed). the closed system has the benefit of preventing corrosion/erosion in water passages, which has already cost me a pair of fairly expensive heads and a block. also damaged the current expensive heads, but it was repairable.

in an open system, with a jet drive supplying water, as long as you have continuous flow, the issues you listed aren't really issues. not too sure what the benefit would be running a water pump on the engine, when the pump is supplying the water. the other thing you should understand is that, at low rpm, flowrate from the jet drive is substantially less. if that water pump is trying to pressurize the engine, and supply the snails at the same time, jet drive flow may not be enough and you could be creating vapor gaps in the engine unintentionally.

so - just my 2 cents. if you're intent on using a water pump, it would be much better to design a closed system that can actually protect the engine from real potential problems, rather than imagined ones.
 

·
Registered
Joined
·
307 Posts
Real McCoy - I will not be turning more than 5000 RPM. It will be a family boat. Do you think that will give me a pressure issue? I assume these pressure issues have to do with water not being able to get out of the system fast enough. .
You would likely not have an overpressure issue. That said it would be cheap insurance to install a pressure relief so you can bypass any extra water - no restriction, just releases if pressure exceeds preset amount. Hi-Tech Performance (Duane) and some others sell kits or you could buy the hardware separately.

.....Have been considering a strainer though. Any thoughts are appreciated.
A strainer is a good idea for any cooling system drawing from the lake or river or sea. (almost all the systems out there). If you put one in, don't go cheap and clean it regularly. They keep the crap out of the engine, but can plug and restrict water flow and cause overheating.

Your "new/improved" layout shows you pre-heating the water through the exhaust manifolds before going into the engine. That is rarely done when you run a thermostat and circulating pump and adds some complexity to the system. Most modern systems (including MerCruiser) cool the engine and then go out through the manifold and riser.

Doug
 

·
Registered
Joined
·
57 Posts
Discussion Starter #12 (Edited)
Doug, I really like the idea of a pressure relief. Thanks for that tip. I will look into getting one. [EDIT: Just watched the CPPerformance video - looks awesome]

On the water going thru the logs first. Yes. I am trying to find the logic of going through the logs first, or just going the way you have noted (I have seen it as well many times). I got some detailed pics last night of a Packajet setup (I asked for them for the thermostat plumbing), and I was surprised - they are feeding the logs first off the jetpump. I also saw someone who built up a Glen - L plywood hotrod. The man that built it was ultra meticulous in every detail of construction. He did not have a jet pump, it was a V drive, but he took water out of the lake, ran thru a strainer, then went to the logs too.

So ... I am a seeker here. I am always wide open, but I am always looking for "why".
 

·
Registered
Joined
·
6,575 Posts
Doug, I really like the idea of a pressure relief. Thanks for that tip. I will look into getting one. [EDIT: Just watched the CPPerformance video - looks awesome]

On the water going thru the logs first. Yes. I am trying to find the logic of going through the logs first, or just going the way you have noted (I have seen it as well many times). I got some detailed pics last night of a Packajet setup (I asked for them for the thermostat plumbing), and I was surprised - they are feeding the logs first off the jetpump. I also saw someone who built up a Glen - L plywood hotrod. The man that built it was ultra meticulous in every detail of construction. He did not have a jet pump, it was a V drive, but he took water out of the lake, ran thru a strainer, then went to the logs too.

So ... I am a seeker here. I am always wide open, but I am always looking for "why".
you might want to go through the logs first If you're running in cold water, like 50 or less. keep in mind that you are still creating an open system, meaning water comes in from the lake/river, makes a single pass through the engine, and returns to the lake/river. so heat removal is based on Tout - Tin, X flow rate. the temp you may read is only an indication of water temperature on the way out, not indicative of actual engine temp. if you have a set flow rate, raising the temp of the water coming in automatically results in raising the temp of the water going out.
and if you go from the jet through logs first, you won't have to worry about water pressure from the jet drive.
 

·
'74 Sanger ski hydro
Joined
·
432 Posts
Not trying to hijack your thread but I found some decently priced heat exchangers on ebay. They have them listed for the heating of swimming pools in all different sizes. Does anyone know how to calculate the size heat exchanger it would take to cool a 540? They list them by BTU rating
 

·
Registered
Joined
·
57 Posts
Discussion Starter #15 (Edited)
Regarding water to the logs first:

I have been trying to be as impartial as possible and playing detective. I have looked at packajet setups with the original clunky squarish exhaust, and later Packajets with logs (both came from the "factory" that way - or this is what I see online). The only setups (Packajet / Mercruiser / OMC / what have you) that send the warm water to the manifold, and thru the snail, and overboard (in that order) are the ones where no other option is available. To say it another way, it is not possible to plumb it any other way, such as lake water to logs first, and then into the block or circulation pump.

In regards to temperature sensor placement, if you look closely at that chrome fitting, (they do not provide a cutaway or cross section of the piece, which would be helpful), the water coming out of the block, is what is sensed, if you place the sensor on one of those three smallest holes. This water flows regardless of thermostat status (open, closed, or somewhere in between), and it flows because the circulation pump is spinning.

In regards to the concepts of how much water is flowing into the system from the lake and exiting the system, the emphasis on this factor is nearly zero with the benefit of the circulation pump. The ONLY thing lakewater is used for in this circuit, is to cool off the temperature of the mass of water circulating in the system. There are no pressure or flow considerations.

Sorry if I am getting off on a tangent. Basically you are running a car cooling system, almost unaltered, and the lake is your radiator core.

Correction: The water coming to the thermostat manifold from the Berkely pump is a lot. I will run a pressure relief near the transom and eject excess pressure overboard. The water from the Berkeley will go thru the regulator, thru an oil cooler, then split and sent to both logs, re-join together, then come into the thermostat housing on the medium sized port. The two equal sized ports on opposite sides are for the snails (someone brought that to my attention, I have it wrong in the diagram). So .. most of the time, most of the flow from the Berkeley, will be sent right to the snails. When the thermostat cracks open, water from the block will enter the stream, diluting the cold lake water being sent to the snails, with warmed water from the block.
 

·
Registered
Joined
·
6,575 Posts
Regarding water to the logs first:

I have been trying to be as impartial as possible and playing detective. I have looked at packajet setups with the original clunky squarish exhaust, and later Packajets with logs (both came from the "factory" that way - or this is what I see online). The only setups (Packajet / Mercruiser / OMC / what have you) that send the warm water to the manifold, and thru the snail, and overboard (in that order) are the ones where no other option is available. To say it another way, it is not possible to plumb it any other way, such as lake water to logs first, and then into the block or circulation pump..
it is absolutely possible to plumb it either way. either through the logs to the engine. or to the engine and then the logs (and snails). it can be plumbed either way and it will operate just fine either way. I've got a hallett daycruiser in the yard that's plumbed exactly that way, and it works just fine.

In regards to temperature sensor placement, if you look closely at that chrome fitting, (they do not provide a cutaway or cross section of the piece, which would be helpful), the water coming out of the block, is what is sensed, if you place the sensor on one of those three smallest holes. This water flows regardless of thermostat status (open, closed, or somewhere in between), and it flows because the circulation pump is spinning..
that's correct. the temp sensor indicates water temp, not necessarily engine temp. as long as water is actually circulating through the engine. which is why people use oil coolers.

whether or not the circ pump is spinning, if you have a thermostat in that housing with no bypass, no water will be flowing through the engine. you can drill a couple of 1/4" holes in that thermostat that will at least allow the engine to fill before the stat opens. just because that circ pump is spinning doesn't mean it's actually moving any water. if this engine has to run for awhile with flow blocked by that thermostat, those neoprene exhaust tubes will get really hot. and if they get too hot, they can start leaking which isn't fun...

In regards to the concepts of how much water is flowing into the system from the lake and exiting the system, the emphasis on this factor is nearly zero with the benefit of the circulation pump. The ONLY thing lakewater is used for in this circuit, is to cool off the temperature of the mass of water circulating in the system. There are no pressure or flow considerations.

Sorry if I am getting off on a tangent. Basically you are running a car cooling system, almost unaltered, and the lake is your radiator core..
the lake does not act in any way shape or form like a radiator. not at all. it is a single pass system that takes ambient water in, and discharges warm water out. it's about heat removal, and if you aren't flowing enough water through that process, the engine will overheat no matter how many circulation pumps you install. the circ pump changes nothing from that standpoint. it Tout - Tin X flow rate, which determines heat removed.

Correction: The water coming to the thermostat manifold from the Berkely pump is a lot. I will run a pressure relief near the transom and eject excess pressure overboard. The water from the Berkeley will go thru the regulator, thru an oil cooler, then split and sent to both logs, re-join together, then come into the thermostat housing on the medium sized port. The two equal sized ports on opposite sides are for the snails (someone brought that to my attention, I have it wrong in the diagram). So .. most of the time, most of the flow from the Berkeley, will be sent right to the snails. When the thermostat cracks open, water from the block will enter the stream, diluting the cold lake water being sent to the snails, with warmed water from the block.
the water coming from the pump is not as much (volume wise) as you might think it is. especially at idle. and honestly, I have no idea why you would install a pressure relief where you've installed it. what exactly are you trying to protect with that relief valve? most people install them to protect the engine. but you're using a circ pump to supply the engine, but at what discharge pressure? plus, you're initially deadheading system flow with a thermostat. if you look at all the fittings you're going to have, on the suction piece, on the oil cooler, on the logs, you'll notice there's already a lot of restriction before you ever get to the thermostat manifold. then, the inlet on the manifold is over an inch diameter. so you're going through several 3/8" restrictions, before you ever T the thing together to get to that manifold inlet, which is an automatic pressure reduction.
 

·
Registered
Joined
·
57 Posts
Discussion Starter #18 (Edited)
it is absolutely possible to plumb it either way. either through the logs to the engine. or to the engine and then the logs (and snails). it can be plumbed either way and it will operate just fine either way. I've got a hallett daycruiser in the yard that's plumbed exactly that way, and it works just fine.


that's correct. the temp sensor indicates water temp, not necessarily engine temp. as long as water is actually circulating through the engine. which is why people use oil coolers.

whether or not the circ pump is spinning, if you have a thermostat in that housing with no bypass, no water will be flowing through the engine. you can drill a couple of 1/4" holes in that thermostat that will at least allow the engine to fill before the stat opens. just because that circ pump is spinning doesn't mean it's actually moving any water. if this engine has to run for awhile with flow blocked by that thermostat, those neoprene exhaust tubes will get really hot. and if they get too hot, they can start leaking which isn't fun...


the lake does not act in any way shape or form like a radiator. not at all. it is a single pass system that takes ambient water in, and discharges warm water out. it's about heat removal, and if you aren't flowing enough water through that process, the engine will overheat no matter how many circulation pumps you install. the circ pump changes nothing from that standpoint. it Tout - Tin X flow rate, which determines heat removed.



the water coming from the pump is not as much (volume wise) as you might think it is. especially at idle. and honestly, I have no idea why you would install a pressure relief where you've installed it. what exactly are you trying to protect with that relief valve? most people install them to protect the engine. but you're using a circ pump to supply the engine, but at what discharge pressure? plus, you're initially deadheading system flow with a thermostat. if you look at all the fittings you're going to have, on the suction piece, on the oil cooler, on the logs, you'll notice there's already a lot of restriction before you ever get to the thermostat manifold. then, the inlet on the manifold is over an inch diameter. so you're going through several 3/8" restrictions, before you ever T the thing together to get to that manifold inlet, which is an automatic pressure reduction.
Sorry I think my poor writing skills are getting in the way. When I say "no other way" I am referring the exhaust with no fittings to do so, like the very old Packajet exhaust, and also some of the newer ones where you cant send water to the elbow / snail separately.

The lake is like a radiator in the sense of a source of cool(ed) water, only, albeit infinite.

Maybe I don't need a pressure relief. I wouldn't rely on 3/8" fittings to regulate pressure though. Think hydraulics. But yes on the backend (water exiting the cooling system), this setup should always be allowing water out, cool or heated, so yes, there may be no need at all for pressure relief.

This fitting is hard to see. The thermostat is not on the intake manifold, it is inset by means of a spacer, halfway up inside the unit itself. The allows water to circulate in the block 100% of the time, unless I misunderstand it. The only thing that is on/off is letting lake water into the block.

As far as water temp vs. engine temp, yes, it does not like a head sensor, unless this thing does allow circulation all the time, like I suspect it does. I have not held it in my hand yet, and the diagrams are not forthcoming. I do not know.

This system is basically a car, except water coming from the radiator is replaced with water from the lake, and water sent over board would be water sent back to the radiator.

I need to order this fitting and check it out. Pricey$$
 

·
Registered
Joined
·
6,575 Posts
The lake is like a radiator in the sense of a source of cool(ed) water, only, albeit infinite.
it is not like a radiator. it will have nowhere near the flow rate of a car cooling system.

Maybe I don't need a pressure relief. I wouldn't rely on 3/8" fittings to regulate pressure though. Think hydraulics. But yes on the backend (water exiting the cooling system), this setup should always be allowing water out, cool or heated, so yes, there may be no need at all for pressure relief.
look at the ID of the fitting that is used at the Berkeley cooling water port. look at the ID of the fittings going into and out of those logs. look at the ID of the T you are going to use to send water to the manifold. this has nothing to do with hydraulics, where a system is filled and pressure is consistent from the supply to the slave. it has everything to do with heat transfer, fluid flow and thermodynamics. when you run through that many fittings that are that small, there is a pressure drop. and at the rpm you say you are going to be running, you won't have any problems with overpressurization of the block. which is the only reason anyone uses a pressure relief valve. because they are feeding the engine directly from the jet drive, and turning much higher rpm than you anticipate turning. you are providing a supply to the engine via the manifold, but pressure in the engine is set by the water pump. at least it should be.
 
1 - 20 of 20 Posts
Top