Intake manifold water ports
 

My current intake manifold has 4 waters ports. 1/2 NPT on each corner.. the rear starboard side has the water pressure sender.. The rear port side is pluged.. The front starboard side has the warning buzzer.. The front port side has the water temp sender..
I have seen people running hoses from one ore mores to one (or more) ports. What advantage does that have??? Front to back? Side side??

I have always had a strange issue.. My buzzer "used" to be on the opposite side.. Where the temp sender is now.. BUT.. kept going off.. temp sender would read @130 or so.. switched them.. temp says 170 (cycles due to crossover) and buzzer is never heard from.. Why the difference in water temp from side to side??

thanks
John

Some manifolds can trap an air pocket at the rear of the manifold. The idea is to allow the air to bleed out by running pressure relief line to a forward port. Another method is to use a small bleed hose from the rear ports and dump the water/air over board.

Ben
I found a thread on that.. I would like NOT to drill anymore into the back.. Running a line from the front to rear is easy.. Some 8an fittings.. but I am confused on how to mount the sensors? I was hoping to see someone take a pic of their setup...

Put a "t" in when you're rigging the manifold and you should be fine. I can't post a pic of mine cause I dump overboard but for my overboard dump, I ran "2" #6's lines into a tri-y fitting and a single #6 overboard.

I wouldn't go as large as #8's, I'd use #4 or #6 hose. You're relieving air pockets, not changing flow pattern. My .02 in what I learned with mine...

Do I run side to side, or back to front???

Panther.. Re-read your post..
you are saying the "T" installs into the intake.. The "T" consists of 3 ends.. 1 end is 1/2 NPT for the intake.. One end is 6an to the other "T".. the other end of the "T" is a female thead.. 3/8 NPT for my sensor.. right????

I run 2 #6 lines from the back to the front. 1 on each side. If yuo want, you can T the back and run it into 1 of the front holes. Or you can run the line back into the neck, or into one of the exhaust lines.

Your water pressure should allwaus be installed as close to the pump output as possible to maintain accuracy. Your water temp needs to be on the top in front of the intake as this is where the water exits. What other sensors do you have??

Water temp diff from side to side usually means you have a clog somewhere.

Pull your block drains out of the bottom of the block and flush the engine out. Make sure there is no sediment in there.

You can use a regular old temp gun to check this. Warm the engine to operating temp and check each head.

yup, 1/2" male npt to the intake, other two ends are female. Install the sensor in one and connect the hose to the other.

On mine I have 1/2" male NPT, to two female 1/2" npts. Then a 1/2" npt sensor in one hole and a male 1/2" npt to -6 fitting in the other.

Stainless looks better but you can also get it in brass, whatever your fancy is! :coolcowboy:

I have water temp and water temp buzzer warning up front and water pressure in the back with the other rear pluged

Thanks Jeff.. I drain the block 2 times a year.. Summer sometime and in Nov/Dec when I lay it up for the winter.. its clear.. the temp flux started the day I fired it up.. has to be something to do with steam pockets.. I have lived with it for 5 years.. but would like to clear it up.. maybe it could be the intake gaskets not "right"? I am using felpro 1275 with a Hurricane intake and Canfield heads.. they are the proper intake gaskets according to Canfield AND Professional products.. (Which is the intake manufacturer)

I can do that.. so where does the 1/2" npt to -6 fitting go? over board on yours?? is it ok if that just goes from front to back on mine?

Also.. I have CMI etops'' They have a plug in them right at the collector.. Can I dump water into that??

I've seen a few of the bigger HP boats tie the dump into the tailpipe's, just never saw it tapped into the header like that. I suppose maybe you could but it might be more cluttered??

You can dump back into the front, no problem. I dumped overboard because #1 I wanted to loose a few pounds of water PSI and #2 I wanted to be able look over the side of the boat at any given time to verify the engines were pumping water without having to climb over sun pad to see exhaust pipes! Eddie marine made a really nice fitting that I could hook the #6 line up to inside the boat. :drink:

Thanks Panther. I might just run a 6an from the back of the intake holes to the front intake holes.. "T" 3 of them.. back "T" for the water pressure and front 2 "T"'s for the water temp and buzzer senders

STEAM POCKETS are usually the wrong head gasket, not intake gasket. No other symptoms in the engine? Really strange.

There are thousands of engines out there that don't channel the water from the back of the engine. Maybe check your exhaust for a hairline crack? Crank the air pressue up pretty high as the problem might only show up once the engine reaches temp.

Same thing with a possible hairline crack in the head??

Just thinking out loud? Try dumping the water first, but if that doesn't help, you might want to start looking somewhere else.

I was told that the use of this type of auxiliary rear to front water passage was developed many years ago with both endurance road racing and desert racing. Both (depending on tracks of course) have long extended periods of WFO throttles. Depending upon one's throttle hand, this does have it's merit in marine performance use too.

Idea is that it allows complete circulation of water from all parts of the engine. Water does accumulate in the back and does not escape the back of the engine. Thus making the rear of the engine slightly warmer than the front.

Drag racing guys used to tell me that I needed to do this and I would make more power.

I actually have a set of twins thaat are plumbed this way.

I did not have the water by passes installed when I dynoed the first engine. The water bypasses are installed on the second engine. I will let you guys know if anything happens after I dyno it.

Bothe engines are set up exactly the same.

Nice.. that is what I am looking to do.. but instead of 90 degree right angles I need to run a “T” and put my sensor and pressure senders in.

I have heard that a steam pocket can be “developed??” due to no circ pump and a crossover. Not sure how true that is..

Maybe..... But there sure are a lot of really big HP engines that don't use a circulating pump.

Let us know what you find.

Nope.. no other symptoms. I hear it is common to have engine temps fluctuate a bit with a crossover. I know the head gaskets are correct. Merlin III block and canfield heads. spoke to both companies before I put the long block together.. Exhaust was just tested when I had the O2 Sensor bung & Pyrometer bung installed. CMI did it. I also run a mercury pressure dump valve right after the sea water pump and a pressure gauge.. pressure never goes over 30 psi.. and plugs look great at every change. leak down test was awesome as well as compression.. motor runs fine.. real fine.. going on year 6 now.. just a small (and livable) temp issue.. I will try the lines and see what happens.

All summer I was fighting a problem with #8 cylinder sticking exhaust valves. I took out I think 3valves this summer, hit the piston on all occasions and bent the valves pretty bad. Luckily they did not take out the piston, Good Ferrea inconel valves.

I did some testing on the hose with an infrared pyrometer. Cylinder heads around #1 #2 and #7 were running around 190*F and cylinder #8 was around 300*F. :eek:

I took the heads off to look for obstructions in the block and I found none, I drilled more water ports on the head surface of the head and still no help. I then drilled out the back of my manifold and added dumps. This seems to have fixed it. I have 4 Merlin heads and same head gaskets on my twin engines. These heads were on other engines with no problems and I had GM 088's prior with no problems. I can't explain why I had this problem but the drilled out rear intake manifold solved it.

Wow.. big difference indeed... Sounds like a world of trouble. gives me an idea though.. I should grab one of those guns from the local shop and see what temps I am running..

Panther
Any ideas where I can find stainless?

McMaster Carr should have what ya need!
http://www.mcmaster.com/#stainless-s...ttings/=5l2u9y
http://www.mcmaster.com/#stainless-s...ttings/=5l2uw1

So.. after much thinking and discussing I have decided to break out the drill and go through the transom..

Can I just run a 90degree fitting on one side to a "T" and a 90 degree fitting from the other side to the "T" then from the "T" out the back? I am assuming we never touch the front 2 holes in the intake.. Just the rear 2?

What fitting did you use from Eddie???

One of the most popular and trusted marine performance motor uses a recirculating pump-----Merc HP525. I will be using a recir pump and thermostat setup. I just like the fact that the motor is in control of the water and the consistency of temps within the motor itself.

Yup.. I have heard it from my builder many times.. Big Merc fan.. works on them all.. from 496 up to the new 1075..

but my setup is done and I don't want to add belts, therm. housing redo all the plumbing ect.. many people here make a crossover work and they work well when setup properly..

Spoke to Hardin marine today in great length.. They think (and perhaps rightfully so) that my crossover is at fault. the bypass is a small 8an line.. only 7/16 thick. so.. when the thermostat opens a ton of water rushes through the block.. cooling down quickly.. then, the thermostat closes.. temps rise.. and the process starts again.. they said I need a cross over with a bigger bypass and that will help a ton.. also going to try their thermostat spacer.. run the rear lines from the manifold to the spacer..

and if that don't work circ pump here we come..

After you mentioned that. There is the old trick where you take off the bypass, and drill a couple small holes in the thermostat base. This lets a little water bypass through to keep the exhaust from overheating and still allows the thermostat to work properly.

This keeps the drastic ups and downs from occuring, and the engine stays at a more consistant temp.

I have drilled my thermostat.. depending on how many I drill, I can regulate the temp "OK".. like a 140 thermostat with 3 holes I can get to around 130 constant.. BUT.. each side of the intake is at different temps. as much as 15-20 degrees... i know the larger bypass will help a bunch.. also.. moving water from the back of the intake up front will make a difference as well.. might run a 4an line from/to each front intake port as well..

You have one of those engines with a gremlin in it sounds like. Might want to consult a preist???