Stupid 470 question im sure

hadaveha · Sep 19, 2013

I keep reading everything I can about these 470's, and something Ive noticed keeps showing up, running hot. the water pump at the end of the cam seems to have its own batch of problems, with that being said would it be possable to fab up some kind of external higher volume water pump to move coolant through the engine at a higher rate dropping the operating temp of the engine. I know the engine like all engines have a perfect operating temp, and maybe you loose a little performance due to lower than perfect temp, but extending the life, and making it overall a lot more dependable would be well worth small loss in performance. Just something that Im sure someone can explain why it wouldnt be a good idea.
Thanks everyone

wrestling coach · Sep 19, 2013

Re: Stupid 470 question im sure

The water pump you refer to circulates your antifreeze mixture through your engine and heat exchanger. This is not usually a problem. Your impeller in your lower unit pulls the lake water to your heat exchanger to cool that antifreeze mixture. This is often where the failure is. That impeller is neglected and fails to supply the heat exchanger with a good flow of water from the lake and the ability to cool the antifreeze is reduced and temps go up. In addition these engines had a 3" heat exchanger that had to work like crazy to keep up. Then the more desirable 4" exchangers were installed and helped that situation. Change that impeller every other season and keep the other components clean and maintained and these engines will run at the temps they were designed for.

Dennis

nola mike · Sep 19, 2013

Re: Stupid 470 question im sure

The problem isn't with the water pump, it's that the seals on the cam leak. So that solution wouldn't do much. I've had my boat for 5 seasons now and have yet to come close to an overheat.

EDIT: Reread your post, maybe you're saying why not circulate more af and run the engine cooler? Again, the weak point isn't usually on the AF side.

stonyloam · Sep 19, 2013

Re: Stupid 470 question im sure

Like the guys say the problem is not the engine pump circulating coolant through the engine and exchanger, it is the outdrive impeller pumping water through the exchanger (should be changed at least every second year). I have never heard of a engine waterpump impeller failing. Spend a weekend and fix the seals with a spedi sleeve when they start too leak and you are good to go for ten years or so. Forget trying to lower the temperature, run it at 160-175 and you should be OK.

generator12 · Sep 19, 2013

Re: Stupid 470 question im sure

Uhhh, how would a greater water flow reduce operating temperature below the setting of the thermostat?

achris · Sep 19, 2013

Re: Stupid 470 question im sure

generator12 said:
Uhhh, how would a greater water flow reduce operating temperature below the setting of the thermostat?

It doesn't... What it does do is cool the freshwater side of the exchanger better, and keep more water in with the exhaust gases to keep them cool, protecting the rubber tubes, the water pocket cover and the water pump housing...

stonyloam · Sep 20, 2013

Re: Stupid 470 question im sure

achris said:
It doesn't... What it does do is cool the freshwater side of the exchanger better, and keep more water in with the exhaust gases to keep them cool, protecting the rubber tubes, the water pocket cover and the water pump housing...

The exhaust gasses are cooled by the raw water exiting the exchanger which is pumped by the impeller in the outdrive, but I know you knew that Chris.

achris · Sep 20, 2013

Re: Stupid 470 question im sure

stonyloam said:
The exhaust gasses are cooled by the raw water exiting the exchanger which is pumped by the impeller in the outdrive, but I know you knew that Chris.

Yeah... that's exactly what I mean....

So, more flow from the sea water pump, the better for keeping those gases cooler...

hadaveha · Sep 20, 2013

Re: Stupid 470 question im sure

I quess what I was wondering was if you mooved the anit freeze through the system at a faster rate cooling in more as it makes more passes through the cooling part of the heat exchanger, would it not keep the overall system cooler, I understand about the raw water impeller almost every boat I know of has one but they dont seem to have the over heating problems the 470 has.

achris · Sep 20, 2013

Re: Stupid 470 question im sure

If you're getting a lot of overheating, try putting a section of clear hose in the incoming water line. I bet you'll see lots of bubbles.

As for moving the AF through the heat exchanger faster.... All that would do is have the AF in the heat exchanger for a short period of time, thus losing LESS heat from it, not more....

Chris......

stonyloam · Sep 20, 2013

Re: Stupid 470 question im sure

The thermostat would prevent the antifreeze from moving through the system faster, that is what it is designed to do. Keep the temperature in an optimal operating range, not too cool, not too hot. I'll bet 90% of the overheating problems with any marine engine are due to lack of maintenance of the raw water pump impeller. I change my impeller every second year, every one that I have changed looked perfect, but they get changed anyway. While some engines can survive a overheating with little or no damage the 470 is less tolerant. So don't worry about all of that other stuff, do your preventive maintenance on your raw water pump and you will be OK.

Eric 3.7LX Alpha 1 · Sep 20, 2013

Re: Stupid 470 question im sure

hadaveha said:
I quess what I was wondering was if you mooved the anit freeze through the system at a faster rate cooling in more as it makes more passes through the cooling part of the heat exchanger, would it not keep the overall system cooler, I understand about the raw water impeller almost every boat I know of has one but they dont seem to have the over heating problems the 470 has.

The 470 is NOT prone to overheating..... it does not do well when it does overheat... that's it's problem. The dis-similar metals of the block and head cause the head gasket to blow most of the time after an overheat.

The remedy is proper maintenance on it and the drive.

Stupid 470 question im sure

Petty Officer 1st Class

Petty Officer 1st Class

Vice Admiral

Vice Admiral

Senior Chief Petty Officer

More fish than mountain goat

Vice Admiral

More fish than mountain goat

Petty Officer 1st Class

More fish than mountain goat

Vice Admiral

Captain