Freshwater upgrade for a Ford 302 V-drive.

Glad that I could kind of help.

Silicone hose "needs" different hose clamps. Please look into that; I've blown a silicone upper radiator hose off while driving and it sucks BUT at least it made the road wet and not a bilge AND I pulled off into a parking lot instead of bouncing around on waves while being pushed by current and/or wind.

I wouldn't worry about the typical scale in coolant passages and running a coolant filter in your application is overkill but there's no down side to running one beyond the initial cost and more hoses/clamps to keep an eye on for leaks. Make sure the filter is not "Pre Charged" with SCA. I'd run a gasoline-water separator/filter instead for roughly the same cost and "hassle".

Just my $0.02 worth.

 

Who says that you can't fit a heat exchanger for a small block Chevrolet to a 302 Ford?

You just need to fabricate your own adapter plate and get a couple of longer bolts for the bell housing.

As long as I'm at it I figured I'd try a Weiand Stealth aluminum intake. They're said to improve low to mid range torque. We'll see.

Tomorrow.......measuring for hoses.

 

I realized that I hadn't updated this thread in awhile. I HAVE posted a lot of information regarding this closed cooling system over in the "props" section. This new closed cooling system is part of a mechanical upgrade that includes a new gear box and propeller so that's how it ended up getting posted over there. Look for the thread "The mystery of a proper prop and terrible performance."

I won't repeat everything I posted there but briefly I just finished testing the new cooling system that I installed in my 25.5' Silverton cruiser. So far, in the yard it been a successful experience. She runs at a stable 160*. This is just at idle in the yard so I still need to test her out on the water under load. Hopefully that will happen late next week. I'll keep you posted.

Here a a few photos of the build as it progressed.

 

Well I finally was able to get this boat out for some test runs yesterday. There can be a lot of air in these systems so I expected that we might run into some issues. I wasn't disappointed. The good news was we got out and back OK, no leaks, blown hoses or anything, the 13 lb. pressure cap never released and at idle the engine was OK. The problems arose as soon as I pushed the throttle up to about 2000 RPM.

We had an infrared thermometer onboard so we could check the temperatures on the hoses manifold and exchanger. Thermostat is 160*. I drilled three 1/8" bypass holes in the thermostat in order to keep the coolant flowing during warm up so the manifolds wouldn't over heat. This appears to have worked out OK since she can idle all day with no issues.
FlowKooler 330-160 FlowKooler Robertshaw Series High Performance Thermostats | Summit Racing https://www.summitracing.com/parts/BRA-330-160

At low speeds, up to about 1000 RPM she stayed at 150 she would occasionally fluctuate up to about 175* or so. My thinking was that there were air pockets in the system working themselves out. I figured that later after she cooled down we'd find the coolant level low.

After we cleared the marinas no wake zone I decided to open her up a bit. That's when the problems started. At 2,000 to 3,000 RPM she immediately heated up to about 220* on the gauges. We checked this against the thermometer and the gauges were correct. So we shut her down for a few minutes and checked the engine over/ took some more temp readings. This is a full closed system including the manifolds. The exhaust risers were running in the upper 80* range. Mufflers nice and cool so no issues on the raw water side. None of the engine side hoses were over about 180* so we decided to start her up. Idling she cooled right down to about 150*.

Checking the hoses and fittings coming off of the exhaust manifolds we got readings of about 180*. After the coolant passed through the heat exchanger we were reading about 110*, this as the coolant came out of the exchanger heading back to the engine's water pump.

We brought her back to her slip and cleaned up while we waited a bit for her to cool off. She took about 1/2 gallon of additional coolant. I thought she's take a lot more.

After a meeting at the dock with a couple of skilled professionals we came up with the following:

#1: Bad thermostat. it's brand new but these things are known to happen. I did the check it on the kitchen stove after I drilled it out but who knows? The thinking was that the thermostat may not be opening fully or sticking. When she reaches 200+ the thermostat opens, we get an inrush of coolant. The thermostat then closes and sticks in that position until she goes through the cycle again. At low RPM the thinking is that the cooling demands are less and the thermostat is still sticking but the temperature oscillations aren't as great. Maybe I caused a problem by drilling it.

#2 Still some air in the system. I'm doubtful on this one.

I'll check her later today and see if adding the additional coolant makes any difference. I'm not expecting to fix this with a half gallon of coolant. If she acts the same I'll drain the system and replace the thermostat.

We'll figure it out.....

Thanks for reading.

MIA

 

After topping up the cooling system this morning I started her up.

Ran her at 1000 RPM for about 10 minutes and she warmed up to a steady 160*, which is what the thermostat is rated for. No surprises so far.

I brought the RPM's up to 2500 for a couple of minutes and with the gauges still at 160* brought the engine up to 3000. Still a solid 160* on the gauges and no surprises when using the infrared thermometer.

Ran her at 3000 for 3 or 4 minutes and then chopped the throttle to idle. She heat soaked a bit as the temp ran up to about 210*. Within a minute temps were heading down and within a couple of minutes she was back at 160*.

So maybe it's not the thermostat after all. Then again these tests were not done under load. It'll be a few days before I can get some help and get her out for a test under load.

We'll see.

MIA

 

I wasn't happy with the heat soaking that I experienced the other day. I decided to try a different thermostat. Found this one.

EMP/Stewart Components 300 EMP Stewart High Performance Thermostats | Summit Racing https://www.summitracing.com/parts/emp-300

Drained coolant, pulled old thermostat and installed the new one. Buttoned her up and refilled coolant. Started boat, warmed up for 10 minutes and then ran her up to 3000 RPM for 10 minutes. She actually runs a little cool now about 150* and stable. Chopped throttle to idle and heat soak was only to 170*.

Looking for a test under load either tomorrow or Monday. We'll see how she goes but looks like the cooling issues are solved.

MIA

 

Hmm..., interesting difference. Did you notice any "shape" differences between the two thermostats, like bleed hole or disc valve dia?

 

The "old" thermostat wasn't actually old. It was the same Robert Shaw thermostat as the new one. I drilled out the old thermostat for bypass myself. I only drilled 1/8" holes, so the new thermostat has holes that are larger. I drilled my bleed holes on the copper ring or cup so the bleed holes were on the side of the thermostat. I tested the thermostat in hot water and thought that would be a good spot based on how the thermostat fit in the housing. Clearly the larger bleed holes in a different location made the difference. The other aspect of all this was finally getting all of the air out of the system. That took a few cycles heating her up and then letting her cool down over night.

Hopefully the river will have calmed down by later today and we can get out for a test run. We had some huge storms here about 36 hours ago and all the rain raised the current way up again. I helped dock a couple of USCG Auxiliary Patrol Boats last night. These guys can handle their boats pretty good. There were five of us struggling to get them into their slips.

MIA

 

Test runs complete. Cooling system functions properly. Apparently a defective thermostat or, more likely I caused it to stick by drilling the bypass holes in it. End of story.

MIA

 

Congrats!!

 

Thanks Lloyd,

It was a fair amount of work but I'm happy I did it. Before I tackled the cooling I took the time to install a fresh set of valve seals, replacing the 49 year old seals that were in the engine. Those seals were just dried out. Even though this is a gas engine, every time I started her up it looked like a diesel. I was also using a fair amount of oil. Well, after I finished everything and sorted out a few details I took off on a trip out to central New York. I went to Three Rivers, a 300 mile (+/-) round trip. Finished up with oil right on the full mark, so I learned where it was going.

This is a 302 Ford V8 with only about 1,300 honest hours on it. It was always run easy at about 1,800 rpm I'd say. It goes to show that an engine getting good regular maintenance and not being abused can last for decades and run fine.

All that's left to do is to replace the points and condenser ignition with a Davis Unified Ignition distributor in the spring of 2022.

MIA