water psi ??

[BA Kurtis]

I have a blown 502 with chiller and dry exhaust, 2 #8 lines from pump to block and 2 #8 lines dumping out from intake manifold no t stat, chiller has separate water source. Temp never gets over 100 and Im Getting a little water in oil, Im thinking to much psi, any ideas on how to regulate :confused:

[ColeTR1]

12 to 15 psi in the block and cooler no more

[BA Kurtis]

I know I have to much psi, so how do I regulate it down to 12 to 15 lbs. any ideas? Thanks Cole.

[ColeTR1]

I know I have to much psi, so how do I regulate it down to 12 to 15 lbs. any ideas? Thanks Cole.
I have two #8 from the intake and they go into a T #12 and out the back of the boat #12. What type of pump do you have? I have also heard of people cutting every other fin off the impeller.

[BA Kurtis]

I have a magnaflo pump and it seems to be moving a lot of water, 1 #12 on pump inlet 2 #8 from intake manifold to 2 dumps out the back, at idle its shooting water out dumps about 2 feet, Do you think cutting fins off impeller will work? Has any one else ever heard of doing that?

[Fiat48]

Cutting every other fin works for the drag boat stuff but not sure about lake stuff. Probably fine unless you idle around a lot.

[Kindsvater Flat]

Mine was like this.
http://www.v-drivevideo.com/mike/plumbing.JPG
Now I have removed the fixed orfice. I still have a problem pushing water from the head gasket. I'm just used to it now and change head gaskets twice a year. :D

[BA Kurtis]

Thanks guys for the help, I think I will try cutting the impeller :cool:

[Prime 8780]

You might try increasing the water outlet size. When an engine builds too much water pressure it is sometimes necessary to bleed off water or increase outlet sizes.
As for as cutting off the blades on your impeller, it is not the best thing to do especially if you use the boat on a regular basis.
Hope this helps
Good Luck!
Mike @ Prime Marine
www.primemarineusa.com

[LVjetboy]

BA Kurtis, have you considered downsizing to #6's pump to block...keeping the dual #8 dumps and not cutting the impeller? Cutting the impeller seems a hack way to control water pressure...
jer

[Lookin for Liquid]

You might try drilling and tapping one of your -8 fittings right after the pump and restricting flow with an Enderle main jet in the .200 - .250 range. Make sure its after the pump and before the motor as between the pump and the restriction it will increase in pressure. You can then adjust your temp where you want it with just a simple jet change.

[LeE ss13]

When ever I use a MagnaFlow, I only use one outlet of the pump to feed the engine, and the other outlet to go overboard. By putting a gate valve on the overboard side only, you can control how much water you waste, (waste gate).This way, there is very little pressure on the block and the water pump. This is especially handy when running aluminum heads where you need them to be at least 180 degrees and ideally 200.

[superdave013]

I did it like LeE SS13 but I had it going to a valve that opens at 25psi.
I seem to plumb a lot of jet boats that use pressure regulators. Some use the dump style and others just use the regulators that they get from Grainger. Both seem to work well.

[shirkey4750]

I run mine through a dump valve also, and the water temp stays around 170 - 180 deg., also this way you can adjust for changes in lake or river water temp. changes. I also adjust my water press to the headers through a #4 line with an ajustable in line relief valve which I set at 5 psi with an .080 orfice going into each header line. Get just a light fog coming out of the headers.

[BA Kurtis]

LeE ss13 or superdave, thanks for your imput that sounds like a good way to regulate press. If I T out of one side of pump into block and then out the other with waste gate should I add another dump or tie into the 2 I have for water out?

[LVjetboy]

"a lot of jet boats use pressure regulators."
Some do, I don't. I think the jet pump feeds a wider pressure range from idle to full throttle (compared to engine cam or electric driven pumps) So for a jet, at some power level a regulator makes sense. At my power (650) and impeller size, I can still control full throttle pressure to 20 psi with inlet and outlet line sizing alone...and maintain idle flow to 150 F on aluminum heads w/no steam.
Simple is better. So I ditched the regulator.
If I go much higher on power, I'd probably need a regulator to control full throttle pressure yet maintain adequate idle flow. But I'm no fan of dump valves, and not convinced typical car water temps (180-190) a good measure of boat engine happiness. I'm leaning towards oil temp as a better measure.
I'm also not as familiar with the cam driven Magniflow, but guessing it may not have the same wide pressure variation from idle to full throttle as a jet. So the "need" for a regulator maybe less? Either way, if you're trouble-shooting a pressure problem, maybe you should measure that pressure to know if and by how much your changes make a difference? I know, I know, most v-drivers only need is a big-ass tach on the dash. Not oil temp, water temp/pressure or anything else. But a temporary (dampened) water pressure gage may help troubleshoot no matter the drive choice.
The other thing is, once you leak a seal, it will leak at a lower pressure. So one man's "don't exceed xx psi" may not equal anothers. Take that for what it's worth.
jer

[BK]

"a lot of jet boats use pressure regulators."
Some do, I don't. I think the jet pump feeds a wider pressure range from idle to full throttle (compared to engine cam or electric driven pumps) So for a jet, at some power level a regulator makes sense. At my power (650) and impeller size, I can still control full throttle pressure to 20 psi with inlet and outlet line sizing alone...and maintain idle flow to 150 F on aluminum heads w/no steam.
Simple is better. So I ditched the regulator.
If I go much higher on power, I'd probably need a regulator to control full throttle pressure yet maintain adequate idle flow. But I'm no fan of dump valves, and not convinced typical car water temps (180-190) a good measure of boat engine happiness. I'm leaning towards oil temp as a better measure.
jer
OK now I understand the simpler is better thing, im a big fan of it but......whats so complicated about this setup (or somthing simalar)?
http://www.hi-techperformance.com/images/Water_Bypass_Kit_DCP_0726.jpg
It doesnt affect a single thing until its needed, set it at the maximum psi you want your motor to see and wallah! Anything above thats dumped overboard. If nothing else its piece of mind to know your never gonna get more pressure than you want in your block, simpler than changing gaskets!!!

[BK]

Oh and LV, what would you concider to be a good oil temp range? I just added a oil temp guage/sender and havent had the boat out yet, im currious to know at what point I should be concerned? Thanks!

[LVjetboy]

I'd agree, not too complex. But corrosion or debris can cause even a simple bypass regulator to malfunction. In which case you could get more pressure than intended to your block. On the other hand, if you design coolant delivery so you don't need it...why use it?
Oil temp: If you're looking for a hard number good luck. A matter of degree. Of course you want it high enough to burn off moisture and contaminants, I'm guessing most lake boats run that. But not so high you prematurely degrad oil quality. That depends on dino or synthetic. I run synthetic. I've measured oil temps exceeding 260 F at cruise. Even though my cruise water temp never topped 120 F.
I'd say that's on the high side, ok with synthetic and regular changes but could be better. I'd like to see my oil temp 200-230 so I may add a cooler.
My point, at least for jets, water temp is a poor measure of engine block or oil temperature. And I think oil temperature is more critical to engine health. I'd like to know what oil temp you run when you test yours BK.
jer