FYI, I had forgotten, there is a pencil zinc in the port end of the heat exchanger on the early model Universal 12's, at least on the 1986 model.
Has anyone put a larger heat exchanger on the Universal 12?
Thanks
regards charlie
No, why would I? Engine never runs too hot.
Hey Nicolina:
Our original '86 did not run hot either. The surveyor thought that the engine looked as if it might have been running hot, larger water pump, fan in engine compartment. He recommended a larger exchanger.
The engine fired today,OH BOY. it is almost ready to go back into the water.....as soon as I can loosen up or replace the stuffing box. I have been soaking it with solvent, using big wrenches, and appropriate words. It still will not budge...
Any suggestions on replacement?
regards charlie
It's a matter of flow I think ... The zincs need to be changed out when they are about 1/2 the original size. Don't fail to change these. It's cheap insurance.
One of the parent's house boat was fitted with twin Chrysler 383 engines with Velvet drives between the engines and the outboards and had one festooned bronze strainer and a very tiny bronze heat exchanger. These had zincs in them.
The darn thing was a tube in a tube about 6 inches round and 18 inches long, and that thing took care of all the heat generated by two engines. I was amazed just watching and touching it work. The inlet from the Illinois River water was cool while the engine water was an indicated 160 degrees on the gauge.
The only overheating problem we had was keeping the floating condoms sucked up from the river out of the strainer's basket while in the Chicago River and heading from the city to the Illinois River. This was the river that was reversed to flow from Lake Michigan to the Mississippi River.
Thinking about it. The piston is in the bore and the temperature in the bore is about 1550 degrees hot while less then 1/4 in away on the other side of the cooling jacket it's about 160 degrees warm. That's some exchanging to be sure.
When I was building industrial power spray washers running at 130 deg. F. the tanks are heated with indirect gas fired [2.5 to 6.0 million btu] Maxon Tube-of-flame burners fitted with immersion tubes.
These had a calculated exchange rate of 15,000 btu's per square foot of tube in the tank for water and a 12,000 btu's per square foot of tube in the tank for iron or zinc phosphates ... phosphates tend to build up a coating on the tube and the exchange rate decreases. You guys get the idea.
Keep your exchangers clean and the flows moving and zincs fresh.
BTW. For every 1,000,000 btu's burned about 7 pounds of water vapor is made and the tubes need a weep hole between the burner and the tank's wall so the condensed water can drip onto the factory floor. Otherwise the tube fills up with water.
skip.