best water pressure pick-up point??
 

I guess this is pretty basic stuff here, but I have tried 2 places in the block (keeps getting stopped up with sand :( ), the thermostat housing & the intercooler inlet. No where do I get a pressure reading!! There is plenty of flow out the exhaust & thru the intercooler but at no time have I registered ANY water pressure! It is a Gaffrig (new) mechanical (1/8" tube) gauge.
What is everyone else doing or seeing for pressure???? :confused:

Good question! I'm looking for an answer too. Just installed the water pressure gage last week. :confused:

Surely someone has an answer??? :confused:

Have you guys tried to make a "T" with a sediment catcher like in home plumbing? May just help from getting all that sediment blocking things up. :)

I saw a setup like this on a fountain i was looking at a while back. It was mounted on the block near the oil pan. About a 4" long tube with the pressure fitting mounted near the engine on a "T" with the rest of the tube angled down to collect any sand or what have you. Just a thought

Wally, I have tried the "T" business, however the brass fitting filled up with junk too!. So, I don't know if the 4" pipe idea will work. Is there any place higher on the block that would be good????? :confused:

if you are having blockage problems even up high by the thermostat or intercooler, then the only thing i would suggest is adding a sea-strainer or running in some deeper/cleaner water!!! I guess you could tap into the head on the front of the engine if you wanted to but again i dont see why that wouold get blocked as well is you are having problems..... What about right at the raw water intake? Are you running a water cross over or do you have a recirculating pump? I'm thinking maybe someplace where you have alot of water movement to try and keep the debris from collecting too long in one area.
Another option if you have room is maybe to drill and tap the intake manifold next to the thermostat...that way the fitting is sitting vertical and debris will always fall down being they are heavy.... just another thought.. :)

I like the "vertical" idea using the intake manifold. I may try that. At the thermostat housing tho', it did not stop up, I just did not get any pressure!! HOW MUCH SHOULD THERE BE ??? Does anyone know????

When I had my ProCharger on my boat my water pressure gauge never moved. Since I no longer have the ProCharger the gauge reads fine.

93formula are you using a thermostat? I was told by both ProCharger and HTM that because intercooler and not having a thermostat I would not get a reading.

I have a procharger, and I put my gauge in the cross over tube. without a thermostat I was seeing only 3-4 lbs at WOT. I burned up a water passage in my head gasket after 60 hrs. I was told by a lot of engine builders, that running no Stat. the outdrive pickup cant supply enough water. I now have a thru transom pickup. and I see 13-18 lbs at WOT.
I now use the outdrive to supply the intercooler. and the thru transom Pick up goes directly to the sea pump. You should see at least 12-18 lbs water presure at WOT.
To much can be bad as well, so be carefull. ;)

All motors have to have water pressure .If not ,you are not filling all the cavitys in the engine with water and something will burn . When you don't use thermostats you use restictor plates to make the right amount of pressure .

Also ,watch out ,if you are getting sand and stuff in you gauge you are getting it in your inercooler too . It will plug it up !

I know because I just took mine apart and it was almost plugged solid .My motor had been running hot and I couldn't figure it out .Went through pumps and all and still hot and not a lot of flow out exhaust . Ended up blowing a motor from the heat .Didn't even know why untill I opened up innercooler to do service on it . My cooling system made one big loop through motor and innercooler then oput . Not anymore ,I'm puting the cooler on it's own.

I had the same problem with HP500 EFI motors
(sand blocking up the tube tapped into the block) I moved the water preasure pickup tube to the side plate on the oil cooler (had to drill and tap a hole) has not pluged up since!!!

:) I was probably misstating the facts in my case.....it probably is not sand but heavy sediment (like iron,rust, etc) in the block not real sand. I say that because I have no sediment in my intercooler. I had already pulled it off to check it. Remember, it does not take much to stop up a 1/8" tube. Maybe (has anyone tried this???) I could install a filter (like a fuel filter) in the block port. Would this work????
I have never had an overheat problem. I am very cool! I have tried thermostats (140 deg) & restrictors & still show no pressure. go figure???

93Formula, Do you have the Merc Thermostat housing with the Check-balls for the exhaust manifold feed hoses? Without those. you won't have any presure. Or if the spring is missing. It will bypass most of the water to the exhaust manifolds. resulting in no block presure. Just a suggestion. ;)

I have mine installed vertical at rear of intake,you will need 15 to 18 pounds of water presure.

kanookster,
yes, I do have the Mercruiser housing with the balls & spring. Mine is a rough cast bronze "T" out of the housing (not black like most Mercruiser stuff).. Is this stock or after market item? Possibly the spring is weak? How would you test it?
The place I originally tried was at the Thermostat housing & put a "T" with the temp sensor. It did not work there, but that is on the "out" side of the thermostat, if I remember correctly. Would it show pressure before the thermostat opens (it's drilled like Procharger says to do)???
This really is a big help guys, & I get the feeling there are others out there with this same problem. Help & info is appreciated! :)

93Formula I agree that it seems no one really understandw the best place to put the Oil temp and Water Preasure sender as there are so many opinions on it. :confused: :confused: :confused:

Maybe a week spring 93Formula. I have my presure pickup in the Intake Manifold water passage, before the thermostat. After the thermostat you prob. won't see any presure. There's no resistance there, because it flows out the exhaust manifolds. Check the presure in the heads, or Intake, but not after the thermostat. ;)

:D Thanks for all the help & suggestions guys....everyone works as a "team" here....this is good...very, very GOOD !! :cool:

93

What type of outdrive is it. I know an alpha I gen 2 will show no pressure. Any bravo type will show pressure.

Mine comes off the intake manifold. It goes vertical for about two inches. I have tried several different locations and the pressure readings have been very close. I like it there because if it leaks I will see it. My biggest concern is too much pressure and blowing my intake manifold gaskets and filling my motor with water.

If you have an alpha i gen 2 let me know and I can tell you the theory.

:D :D :D