Water Pressure??? (one more time)
 

I know this has been talked about several times but I need help with my specific situation. Here goes,
My motor is a 502MAG that has been lightly worked. The obvious change when the pressure increased was the IMCO exhaust. When I got the boat back it was running 30+ psi pressure. The biulder tried to lower the pressure by bleeding off some of the water before the exhaust with T's, this just overheated and melted the rubber boots going to the tips. So he scrapped that idea and said to run it. Well Ive rebiult again and I have the same problem. My gaffrig gauge goes to 35 and the needle has gone right past that. How much pressure is too much?
What other info do you need to help me out?

I’ve been here and it’s annoying. Most builders say 18-20 lbs. is optimal for avoiding hot spots in the heads. 24 should be your maximum pressure. I ran an engine for over 300 hours with 30 lbs. of pressure with no problems. I was real lucky.

What was your water pressure before the exhaust? One cause of high water pressure is the risers not being able to dump the volume of water coming through them. Some times there is not enough room between the two water-jacketed tubes. Another possibility the hole in the end of the riser is not large enough. You need to find out if the exhaust is your restriction before you go any further. Tee off of your exhaust risers on both sides. Put a valve inline after the tee and let the hoses flow overboard. While making a WOT pass have someone open the valves equally until the water pressure drops to 18-20 lbs. If this does not drop the pressure the problem is not totally a restrictive exhaust. What year 502? Are you running a circulating pump? How many hoses are coming from your thermostat housing? How many circulating pumps have you gone through?

Dan

You have to much water pressure. The correct way to relieve it is before the motor. Bypassing the exhaust is crazy and you are lucky you didn't have a fire. If you are interested i will send you a special tee, some fittings and a dump valve. You can install it per my instructions and if it works you can mail me $110.00 plus shipping. If it doesn't work to your satisfaction you can return it to me. I have used this valve and tee to reduce the pressure of a my motor and a few of my friends. We all run thermostats, and have been successful in lowering the pressure to the desired 18 to 24 PSI at speeds of up to 105 MPH. Our temps are at the thermostat setting at all RPMs. Give me a call if interested at (219)363-4859. This is my cell phone so leave a message.

The motor is a '98 502MAG, Drive is the standard Bravo 1 w/ side pick-ups. The T houseing has two hoses comming out. Water pressure when I got the boat was just under 20 as I remember.

Ive only used the boat for a few hours since its been back. Being that I spent quite a bit rebiulding this thing again I want to make sure everyone is on the same page if I have head gasket problems down the road.

Is anyone else running the IMCO exhaust?

My 502's had the same problem my engine guy installed some
thermostat diverts by moroso problem solved. His phone is 573-374-7974

Bad to the bone,
What year 502? Do you remember how that changed the thermostat?


Tantrum,
Are you sure your water pressure was that low before the exhaust? If so I would call Imco and get their input.

I run a Gary Grimes water dump to take care of my problem. It is a Band-Aid fix for me. Its original design is to eliminate 50 lbs. water spikes when re-entering the water. WETTE VETTE's system will do the same thing but will not flow as much water. Unless you are running a 100 plus and leaving the water it should work fine. It is a heck of a lot cheaper. I would make sure the only restriction is the exhaust. If it is demand a new set of risers or to have them modified to flow enough water. If you run the tees just to diagnose the problem you will be fine. Don't open up the valves until you are at wot. Open them enough to bleed off the amount of water to reduce the pressure down to 18-20 lbs. If you can drop the water pressure using this test you know it's the exhaust. If you can reduce it some but not enough they are only part of the problem. It sucks trying to diagnose water pressure problems.

WETTE VETTE,
You came out with your setup about a month too late to help me. It should be a good seller for you. I think there is a big market for your system. All of those boats with stock power and no water pressure gauges that keep eating circulating pumps for no explainable reason. Circulating pumps give up the battle long before the head gaskets.

Dan

Chris,

As we discussed your pressure is too high. Try and dump it before it gets to the motors. I would give wettevette idea a try, as well as contacting imco and see what they have to say. Your current system loves to eat gaskets, I know. :( Send me an e-mail on how you got it resolved. :(

HI pressure easily solved
 

Call merc hi perf and ask them to send or fax info on new pressure releif valves. I'm a firm beleiver in merc engineering and testing. $114. each. Whatever you do, you must get rid of that amount of pressure. The engine will releive it if you don't. I'm running 3 of them with no problem. I mounted them in the big 2" hose between the circulating pump and the thermostat.

offshor,
Which engines did you have a pressure problem with? How much pressure did you have? Does the valve dump water before it gets to the circulating pump or is it the large C shaped hose that goes from the Thermostat housing to the circulating pump?
I'll try to get that information tomorrow from Tony Esposito at Merc. If they email it to me I'll post it tomorrow night.

Thanks for the info,
Dan

Craig/Wette Vette,

I'm interested in those special tees you have, but first I want you to take a look at my engines and how they are set up. No sense in wasting anyone's time if they aren't going to work with how my plumbing scheme is rigged. Not sure if I have told you yet, but I'm running CAM DRIVEN water pumps and I'm not sure if that is going to make a difference or not in how these special tees that you have are utilized.

Pressure relief
 

Here is the device I installed this year. McMaster-Carr Model#9763k49 adjustable pressure relief valve. Adjustable from 0-50 psi. My application is for a Berkeley jet drive where all the engine coolant water is taken directly from the jet drive that can produce VERY high water pressure to the motor. I installed the relief and adjusted my WOT pressure to about 25 psi. No problems and with my thermostat never exceed 160*.
$35.00 plus S&H. Not bad!

Paul

KAAMA, I agree. I would like to check out your cam driven pump and the rest of the installation and we can decide if this type of system is right for lowering your high water pressure. In a couple of weeks I will have some time to take a ride north and I will be sure to bring some tees and valves and maybe we can experiment with them. I look forward to seeing your boat and taking a ride. I plan on putting some more hard time on the WETTE VETTE this weekend on our little lake this weekend. I also plan on running my blue printed Hydromotive Quad IV. Hopefully I will be hitting some good numbers with it.

Candyman, I followed your posts, but didn't have my tees made or the valves on hand soon enough to help you out. Sounds like you have it figured out. Do you still have the cross overs for sale? If so I may be interested in them. Let me know.

WETTE VETTE,
Mr.Cig had the crossovers for sale.

I had high water pressure with circulating pumps. Stock 454's! :confused: The problem is corrected but not solved! I think the restriction is in the merc thermostat housings. Who knows! My top pressure is 24 lbs. I'm going to change springs to bring it down to 20.

Dan

One other thing you can try is replacing the the circulating pump pulley to a larger unit, assuming you are running a belt driven pump. Moroso makes a unit that increases the pulley size enough to reduce your high water pressure. Slower revolutions reduces the pressure. Mine was over 40lbs.

mleslie951,
I thought about that also. Glad to hear it works. How much did it decrease your water pressure?
Dan

WetteVette let me know if you want the crossovers I have 2 sets with about 3 hours on them.

Mark

I installed Eickert dual impeller pumps and immediately had to fix 5 new water leaks on the race boat including the fittings for the steam holes in the back of the intake. The water was pushing past the threads on the bellhousing oil coolers and past the oil cooler gaskets. volume is what I need and I'm still working out the bugs. My other boat has one restrictive Stellings tail pipe and that header constantly turns blue because of the lack of water flowing thru it.

Thought this should come back to the top.
How many peolple in this post are running IMCO Powerflow's?
There has to be a common denominator.