dumbguy123

'96 BBC engine, carb & v-belt, that I added a closed cooling system to a few years back. Ever since it was installed, it burns out an internal tip flap every 2 trips. It's getting old having to replace the flap all the time. A few years back I took the boat into a well know shop in Corona, CA and dropped a decent sized chunk of change there to get it figured out once and for all. Well...that was a waste of $$$ because the problem persists.

I realize most here probably don't run closed cooling, but I'm looking for help to figure this problem out. When the boat is on the hose out of the water, you can clearly see the water volume difference from side to side. I suspect it is being caused by the hoses going from the heat exchanger to the exhaust manifolds. The starboard side has a clean shot from exchanger to the manifold. Port side(where flap burns out) has a convoluted pathway and is up against the ps pump and bracketry. In my opinion, the water is taking the past of least resistance out to the exhaust so the 1 side is water heavy, leaving the other side water light.

I have a few pics showing the hose routing. Is this the correct hose routing on the port side? The hose fits snug & slightly flattens out around the ps pump on it's way to the exhaust. Edit.....apparently I can't post attachments. Any way to get pics up here? I have them posted on another boating forum if I can link that?

Any suggestions how to correct this....I'm all ears?!?!? I'm tired of changing internal flaps already! Thanks in advance.


P.S. Sidebar question....I changed my sea water pump impeller this weekend. It was a real ***** getting the bolts back in....the round plate that they attach thru had slid over. I think it was the belt tension pulling the assembly out of alignment. Once I figured out that I needed to grab the pulley and move it to get it back into alignment it went back together as it should. Is this a normal thing that happens when the sea water pump is taken apart?

smiklos@sunprint

iTrader: (1)

Send pics to me. PM for email address.
Steve

blue thunder

On my closed cooling the sea water exits the heat exchanger with a single hose and there is a tee fitting that diverts water to each header. The hoses are equal length and routing and I have no trouble with even distribution. It is possible you need some restriction in your tailpipes to even out any distribution irregularities.

smiklos@sunprint

iTrader: (1)

It is hard to tell much from the photo's. I agree with Blue Thunder that you may need a restictor to EQ flow. The guys a monitor marine hae always told me you want good block pressure on the closed side and at least 35lbs on the sea water side. I would look for a blockage by back flushing.
Steve

dumbguy123

I have seen that style heat exchanger and that is not the style I have. The one I have has 2 outlets(1 on each end) for the sea water to go to the exhaust. The problem most likely is that the hose coming off the one side is squeezed around the ps pump as the pics show. I guess I could add some sort of restrictor to the other side hose. Maybe a big zip tie or hose clamp around the outside?

dumbguy123

Were you able to see how the hose snaking by the ps pump is flattened slightly where it curves? That side hose(the first 2 pics I sent) has slight restriction, the other side hose(the last 2 pics I sent) has no restriction or funky bends on it's way to the exhaust manifold. Do you have a H2O pressure gauge on both sides of the system in your set up to monitor that?

dumbguy123

Old Thread Resurrection......I'm a few years later and tired of burning out flaps on the power steering pump side of the engine. PS pump is right above the alternator and on the opposite side from the sea water pump. The engine has Imco manifolds, 98% sure they're aluminum, with SS riser pipes.

I'm ready to just remove the closed cooling system and go back to open cooling like the boat had for the first few years I owned it, so it stops burning out the internal flap. At the time I installed the closed cooling, we were making a day trip over to Catalina from Newport Beach a couple times a year. The boat was always pulled out, flushed and trailered after the Catalina run.

Given how little the boat is used in salt water, is there any really good justification to keeping the closed cooling, heat exchanger in place vs. removing it? What are the reasons or justification to consider keeping closed cooling in place?