Question Regarding Block Water Pressure

[78Southwind]

I just checked the water pressure in my block by putting a water pressure gauge where I had a pipe fitting cap. I checked it from the front of the manifold next to the water outlet divider tee. At 3,000 RPM it was 20 psi and at 4,000 RPM it registered 35 psi. However, a friend of mine said that I probably got a false high reading (possibly by as much as 10psi) because I should have plumb the gauge on the back side of the manifold. He explained that this would give a more true reading because it was somewhat in the middle of the water flow. Would the location of the water pressure gauge really make that much of a difference in psi?

[victorfb]

no, i think were you have it now would be the best place. toward the end of the system. that way you know you are getting a reading of what preasure is actually in the block and intake manifold. my guage is run straight off the intake manifold next to the thermastat housing. though my preasure is way too low and had a problem useing the basset "T" valve. it wouldnt open because of the lack of preasure. i also run a preasure regulator but wasnt able to increase the preasure enough at that time. a new regulator or deleting it entirely is next. good luck. by the way, your readings are not bad. but id like to see a little less at the higher rpms. you need 15 PSI for the basset "T" valve to open, and when useing the banderlog valve the preasure is not an issue. dropping one size on the water lines should help you control preasure fluctuation from lower rpm to higher. the larger lines allow more water to be pushed into the motor during higher rpm.

[78Southwind]

Vic
My readings were with my old plumbing 8AN all the way around and the Basset Tee valve. I could never get the Tee valve completely set right (probably because of the high psi) and for some reason my driver side header would always blow water earlier than the passenger side (the injectors fittings look like they are the same size). Also, my lines and fittings are over 20 years old and possibly have calcium deposits. I thought it might be a good time to replace them and fix this problem because I found a good deal on some hardly used 10AN lines and fittings. I don't think I will have any problem using the 10AN for the engine and 8AN for the headers. But I am now going to add a thermostat and banderlog valve to help fix some of these problems. I am going to use the thermostat to run another dump line to lower the psi along with bring the water temp up a little. I always run the river and the temp never gets past 120.

[PC Rat]

78,
Maybe you should just try shutting down the valve on your supply line a little bit since you have high pressure and low temps.
Brian

[FOURQ]

78,
Maybe you should just try shutting down the valve on your supply line a little bit since you have high pressure and low temps.
Brian
thats what i was thinking too

[LVjetboy]

"I just checked the water pressure in my block...I checked it from the front of the manifold next to the water outlet divider tee...at 3,000 RPM it was 20 psi and at 4,000 RPM it registered 35 psi."
35 psi is high at 4k. Especially if you turn more than that as I'm sure you do? If checked at outlet as you say, then that will be less than average block pressure.
"...a friend of mine said that I probably got a false high reading (possibly by as much as 10psi) because I should have plumbed the gauge on the back side of the manifold. He explained that this would give a more true reading because it was somewhat in the middle of the water flow. Would the location of the water pressure gauge really make that much of a difference in psi?"
The sender location WILL make a difference and could be as much as 10 psi or more depending on flow rate and engine cooling passage design.
The lower psi reading will be at the outlet not upstream of the outlet. So if you're running 35 psi outlet then you're running more than 35 psi average block pressure. That's a lot of pressure. Does that make sense?
"for some reason my driver side header would always blow water earlier than the passenger side...the injectors fittings look like they are the same size."
Uneven header cooling flow is common. Not related to overall block pressure. A very small difference in flow restriction or pressure on one side or the other can cause this imbalance. No matter how matched the original design. The solution is independent or adjustable flow control to each side. Been documented, posted on this forum several times...history.
jer

[bp]

Vic
My readings were with my old plumbing 8AN all the way around and the Basset Tee valve. I could never get the Tee valve completely set right (probably because of the high psi) and for some reason my driver side header would always blow water earlier than the passenger side (the injectors fittings look like they are the same size). Also, my lines and fittings are over 20 years old and possibly have calcium deposits. I thought it might be a good time to replace them and fix this problem because I found a good deal on some hardly used 10AN lines and fittings. I don't think I will have any problem using the 10AN for the engine and 8AN for the headers. But I am now going to add a thermostat and banderlog valve to help fix some of these problems. I am going to use the thermostat to run another dump line to lower the psi along with bring the water temp up a little. I always run the river and the temp never gets past 120.
as jer said, the readings are most likely very close to accurate. and, it's not unusual at all for water to flow to one side before the other, but that's not a t issue.
you say you'rer going to add a thermostat and a banderlog valve to help fix problems? you've only mentioned pressure and temperature, and "blowing water"? are these problems?
do you believe the water temp is causing a problem? do the heads "feel" cool to the touch during a decent run, while the water temp reads 120? "feel" warm, nice and warm, toasty, hot???? how do they feel, say, compared to how the heads in your truck feel after you tow the boat to the river?
as far as the pressure, if you do have a gate valve in the inlet, try throttling it a little the next time you're testing with the guage to reduce the pressure a few pounds at 4k. remember that by reducing pressure, you are reducing flow through the engine.
you should not be "blowing water" out of the headers. there should be a fog coming out of the headers, as in steam. the fog is essential in aiding the silencing effect at elevated rpm. if there is so little restriction in the piping-to-header manifold that you are just getting solid water out of the collectors, the flow is so great it is not heating adequately to convert to steam. you should check the fittings into the headers, to see if they are washed out - mine are brazed and drilled to .045" for each tube, and they work very well to provide just the right amount of water for each side.
personally, i don't like having restrictions in the cooling water discharge side. those are just more things that can potentially affect flow to the engine, potetentially resulting in damage. i've said it before, we are pumping 50 degree water into a steel block, heating it up to 120-160 degrees, then directly discharging it back into the river, continually replacing it with more 50 degree water. it is an open, single pass system, not a closed system.

[78Southwind]

I think this should cover most of the reply's. Thanks for the continued help.
as jer said, the readings are most likely very close to accurate. and, it's not unusual at all for water to flow to one side before the other, but that's not a t issue.
What cause the driver side to flow steam before the passenger side?
you say you'rer going to add a thermostat and a banderlog valve to help fix problems? you've only mentioned pressure and temperature, and "blowing water"? are these problems?
I was quick to say problems I mean a nuisance? I really don’t have any issues no water in the oil but water pressure was a concern to me because for some other threads that I have read. Also, I would like to build the engine next year and the HP and RPM’s will increase; therefore I believe water pressure will also increase. Basically, I just wanted to get this under control now so it wasn’t just another thing to fix once I have built the engine.
do you believe the water temp is causing a problem? do the heads "feel" cool to the touch during a decent run, while the water temp reads 120? "feel" warm, nice and warm, toasty, hot???? how do they feel, say, compared to how the heads in your truck feel after you tow the boat to the river?
I have read that running a thermostat will increase the life of your engine and possibly you will see a performance increase. Like I said I was quick to say problem it is more like trying to prevent one.
as far as the pressure, if you do have a gate valve in the inlet, try throttling it a little the next time you're testing with the guage to reduce the pressure a few pounds at 4k. remember that by reducing pressure, you are reducing flow through the engine.
The handle on the gate valve was removed, so I haven’t tried to adjust it. I guess I could use a pair of pliers but I was also concerned with reducing the flow through the engine and creating steam pockets.
you should not be "blowing water" out of the headers. there should be a fog coming out of the headers, as in steam. the fog is essential in aiding the silencing effect at elevated rpm. if there is so little restriction in the piping-to-header manifold that you are just getting solid water out of the collectors, the flow is so great it is not heating adequately to convert to steam.
I am not blowing pure water out of the headers there is steam but it is mixed with a light spray of water. It looks to me if I turn the ball valve down anymore I am going to blue the headers. I have also had vegetation from the river water actually clog up one of my lines just before the water injector that caused a nice blueing of my driver side headers. I have never been completely satisfied with the set up and thought the Banderlog valve combined with an additional dump line would eliminate some of these nuisances or at least get me on the right track.
you should check the fittings into the headers, to see if they are washed out - mine are brazed and drilled to .045" for each tube, and they work very well to provide just the right amount of water for each side.
I will check them but what do you mean buy washed out?

[LVjetboy]

"What cause the driver side to flow steam before the passenger side?"
Not related to driver or passenger, just line pressure in each circuit (and exhaust back pressure). It doesn't take much to convince flow to favor one side or the other. Like you mentioned, calcium deposits can do it so can debris. I've found that a perfect balance will seldom stay perfect every other trip to the lake. So I adjust balance as needed. It's no big deal, just a couple 1/4 balls on the front within easy reach of the driver.
jer

[LVjetboy]

"I have read that running a thermostat will increase the life of your engine and possibly you will see a performance increase."
I've read that too, but haven't seen any proof for jet boats. Yes I ran a tstat for many years and my engine lived fine. Not a high-performance engine though. And after measuring typical oil temps in jets I'd question what seems to imply car-boat mentality to promote the tstat. If engine wear and performance gains are based on bulk engine metal temperature, you have to consider not only exit water temperature but also engine oil temperature. A big difference for single pass jet boat cooling compared to closed system car cooling.
jer

[bp]

by washout, i mean the holes in the small brass pipe fittings in the headers can enlarge over time, just from the water flowing through them. when i first got my boat, i had two that had almost 1/8" holes. water flow was huge. the holes were all different sizes. these things can be taken out, cleaned, brazed, redrilled. make sure you coat them good with antisieze when you put them back in.
if you're gate valve is missing the handle, maybe replace the valve? pliers will chew up the stem. if you can get a replacement handle that is the appropriate fit, and carry it with you in the boat, fine. but the handle should be on there, marked so you know where it was the last time you moved it. they're not that expensive at the local hardware store. since you have a guage, you can set your pressure to a reasonable level, so you're able to maintain 130-140 at 4k. see what pressure you have at idle too...
the water injection isn't really there to prevent the headers from turning blue. the bluing of the chrome has more to do with the quality level of the chrome job (prep, etc.) and engine tune-up.

[oldbuck40]

"What cause the driver side to flow steam before the passenger side?"
Not related to driver or passenger, just line pressure in each circuit (and exhaust back pressure). It doesn't take much to convince flow to favor one side or the other. Like you mentioned, calcium deposits can do it so can debris. I've found that a perfect balance will seldom stay perfect every other trip to the lake. So I adjust balance as needed. It's no big deal, just a couple 1/4 balls on the front within easy reach of the driver.
jeri had the same problem on my taylor sj seems the previous owner had cut the supply line's after the bassett T that go to the headers at two different length's.???why he did that i have no clue,but i changed them out to equal lengths and it fixed! water or any other liquid will take the shortest route out with the least resistance...

[PC Rat]

The handle on the gate valve was removed, so I haven’t tried to adjust it. I guess I could use a pair of pliers but I was also concerned with reducing the flow through the engine and creating steam pockets.
If you break a cooling line, you'll wish you had the handle.
Brian

[78Southwind]

If you break a cooling line, you'll wish you had the handle.
Brian
Or really really good bilge pump. :D The handle is part of the equation and on my list.

[PC Rat]

I posted a question in a thread on cooling that I can't find so I'll reask here.
bp stated that the dump line from the block should be at the highest point. I assume that this is to release all the air, if so, why wouldn't the water pressure in the block push out all the air?
Brian

[bp]

brian, you will vent all the air with very little pressure if the vent is located at the highest elevation in the system? does that make sense? for example, if you plumbed the inlet into one water pump inlet, and the outlet from the other water pump inlet (just for an elevation example), no matter how much water you put through there, you would never expel all the air, because you would not be able to generate pressure due to the air pockets.

[PC Rat]

Thanks bp.
Now about the water inlet. On my Placecraft had the water going into the engine on the sides of the block at the bottom. I kind of liked that location for the reason that it would slightly flush out the system when the boat was loaded up since the water drained out the bottom.
What advantage is it to have the inlet at the water pump holes?
Brian