SoCal Jet Boats
Tech Talk => Engine Mechanical / Electrical => Topic started by: WORD on October 30, 2009, 05:59:07 PM
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I am about the re-plum my boat. I have some questions regarding hose sizes. First off i have very mild built BBC.
1. Hose that comes from the pump to the engine............-8, -10, etc.
2. Hose from the water oultet to the water dump on the transon........-8, -10, etc.
3. from the Basset T-Valve to the headers.........-6, -8, etc.
I have all of the water regulator valves (2 of them).....one on the hose to transom and one on the hose going to the Basset T-Valve.
Any input would be appreciated and if you are running a mild BBC, what sizes are you running?
I know that this varies from boat to boat........just trying to get an idea before i buy and the stuff.
THANKS!!!!!!!!!!!!!!!
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I've had mine plumbed a couple of different ways, valves at inlet, valve at outlet, plumbed to the seat for dialing in, temp. and headers.
Last go around on advice from my jet boat guru, plumbed in a pressure regulator, simple house type, set at jet drive outlet pipe, adjusted to about 20 psi, temps. stays right on, and at WOT header run nearly dry, no gate valves to mess with, has work flawlessly for 6 years now. 468 BBC,tunnel w/dual 750s, Bassetts, boat runs mid. 80s. :thumbup:
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ive used -10 in and out with no problems as well as, -8 in and out no probs -8 for the bassett. some people say -8 in and -10 out so it wont build pressure as easy ??? i have not done it that way but it sounds logical......
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Ralph........thank you for the info. >:D Happy halloween
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I am about the re-plum my boat. I have some questions regarding hose sizes. First off i have very mild built BBC.
1. Hose that comes from the pump to the engine............-8, -10, etc.
2. Hose from the water oultet to the water dump on the transon........-8, -10, etc.
3. from the Basset T-Valve to the headers.........-6, -8, etc.
I have all of the water regulator valves (2 of them).....one on the hose to transom and one on the hose going to the Basset T-Valve.
Any input would be appreciated and if you are running a mild BBC, what sizes are you running?
I know that this varies from boat to boat........just trying to get an idea before i buy and the stuff.
THANKS!!!!!!!!!!!!!!!
I am just throwing this out there because this topic gets beat into the ground on a regular basis.
Unless you have a 60# pressure fluctuation from idle to WOT you only need to install a gate valve on the outlet of the jet pump.
I have used the same method for over 20 years and have yet to have an issue on a pleasure boat deal. I did have one problem on the race boat, but that pump made way more pressure than we could ever use at WOT and it seemed silly to just dump it all over the side.
On that boat, we used a Sea Strainer and a pressure regulating system because it literally blew the freeze plugs out of the block at speed.
If you have headers, I would recommend the following;
Jetpump (assuming Berkeley or similar), gate valve (preferrably a ten turn), to a tee with a splitter into the front of the block 2X, out of the T-stat housing 2X with one line going overboard, the other to a header water control valve, either manual or spring regulator (Bassett valve), then you are pretty much done. If your headers are set up correctly, you do not need to regulate the flow to them, they should have restrictor jets in them, but I sometimes use a ball valve for emergency control if the Bassett valve takes the big Poo Poo.....IMHO you also do not want lake temperature water going into the headers, I like warm water going to them, cold water (we routinely see 45-50* water), especially if there is a slight reversion problem, can destroy an exhaust valve due to subcooled liquid flashing off in the header pipe. Hot water (130* or so) is a little bit less likely to do this because it is half way to the boiling point. :thumbup:
If your system is set up like this and you do have a system pressurization problem, simply tee into the header water feed line and install a blow off valve, but make sure it is set above the header valve opening point or you will not have cooling to the pipes.
I hope I didn't confuse the issue further. :-\
I see no value at all in having larger leaving hoses than entering (like Ralph said he's seen), you actually want a little bit of pressure in the block (less than 12#) to keep the boiling point up. But I have seen it a lot and still don't see any positives, only negatives, especially if you run on a river with sand/silt, or idle a lot....
edit; I almost exclusively use AN-8 or 5/8 inch hose, anything larger would be overkill and more expensive IMHO, the holes they typically go to are almost always 1/2" FPT.
GT
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Thank you very much GT.........big help!!!!!!!
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Nice Info to have.. ;D
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I thought AN-10 was 5/8? ???
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I thought AN-10 was 5/8? ???
Not that AN-10 is not 5/8", it is, but an 8 will flow water at about the same rate as 5/8" standard hose.
AN-8 measures in at approx 1/2" but the inside of the hose is much smoother and has less surface tension than 1/2 hose. it also has smoother bends when installed... :thumbup: