470 convert to open cooling system.

[zlman1970]

I did a search and the answer was not to do this conversion but they involved a motor that is exposed to salt water (aluminum block). I'm in MN, no salt water to deal with, so why not??
I'll grab a seat.
Thanks in advance for you're thoughts.

 

[HT32BSX115]

Re: 470 convert to open cooling system.

I did a search and the answer was not to do this conversion but they involved a motor that is exposed to salt water (aluminum block). I'm in MN, no salt water to deal with, so why not??
I'll grab a seat.
Thanks in advance for you're thoughts.

Howdy,


I wouldn't do it either.

With all the other "470" problems aside, the engine was designed to operate with closed cooling.

Running open cooling will expose the aluminum block and cast iron head to un-even temperature differences due to the different coolant flow rates, hot/cold spots etc.

Closed cooling is always "better" for longevity and economy. If you don't have one, you can find that 4" heat exchanger on ebay, craigslist and other places.

Even though you won't be operating in salt water there still will be some corrosion although not nearly as much.

I cannot think of a single reason I would want to "convert" any engine from closed to open cooling........

BUT, having said all the above, you could probably still get away with it.


Regards,


Rick

 

[Don S]

Re: 470 convert to open cooling system.

The cam will get rusty where the cam seal rides (allowing water into the crankcase). This will cause the seal to fail even faster than they already do. Not much rust happens in antifreeze.

 

[zlman1970]

Re: 470 convert to open cooling system.

A local 20+ yr mechanic says he's done many over the yrs, without issue.
Thanks HT32...., for not just throwing out the "don't do it" line.
I'm really considering doing it. I'll open up the heat exchanger soon, look for debris or blockage. See what I can find.

 

[zlman1970]

Re: 470 convert to open cooling system.

Hadn't thought of that, Thanks Don.

 

[Bt Doctur]

Re: 470 convert to open cooling system.

plus the 50/50 mix cools better than just plain water in a closed system

 

[HT32BSX115]

Re: 470 convert to open cooling system.

Having read all the comments about the open deck block design and head gasket problems with the 470, I might also worry about running the engine with uneven cooling that would likely happen if you did operate with open raw water cooling.....and the effect on the head gasket.

Don made a really relevant point about the cam corrosion that happens when the seal leaks (and evidently they all leak eventually)


I still think you could get away with it........but not for very long........

 

[stonyloam]

Re: 470 convert to open cooling system.

I guess the question is why would you want to? What exactly would you gain? The water in MN does freeze. The block would be full of water in the fall and would be very difficult to drain, since it is not designed to be drained. So rather than five minutes to drain the exchanger you would be fooling around trying to get all the water out of the pump and block. How does he set up the thermostat, the stock one would not work in the current configuration, I don't think it would ever open? Does he run without a thermostat? How do you cool the exhaust until the thermostat opens? So will you just be running raw water in and out? I can't see how your cam seals would last very long. You will lose all of the advantages of the closed cooling, and as far as I can see you would gain nothing. Better find out EXACTLY what the mechanic is going to do before you do this. Just IMHO. Good luck.

 

[zlman1970]

Re: 470 convert to open cooling system.

stonyloam,
I've followed many threads to which you've contributed. I was hoping to avoid the overheats by converting but maybe its more hassle and headache than its worth. I haven't abandoned the idea but I'll have to have a more in depth talk with this mechanic and bring up the concerns brought up in this thread.

 

[Don S]

Re: 470 convert to open cooling system.

Short cuts usually aren't, and end up costing more in the long run.
Change the impeller every year or every other year during winterization while you have the drive off lubing the coupler splines, checking alignment and other OD maintenance, and you won't have to worry about overheats that much. Anybody can pickup a plastic bag and cause an overheat, just don't add to the problem with old impellers.

 

[nola mike]

Re: 470 convert to open cooling system.

stonyloam,
I've followed many threads to which you've contributed. I was hoping to avoid the overheats by converting but maybe its more hassle and headache than its worth. I haven't abandoned the idea but I'll have to have a more in depth talk with this mechanic and bring up the concerns brought up in this thread.

Still haven't answered why you'd want to convert? I think that any problems you're having would be compounded by switching to open cooling...
Despite all the negativity surrounding it, the closed cooling on the 470's actually works pretty well when maintained.

 

[stonyloam]

Re: 470 convert to open cooling system.

stonyloam,
I've followed many threads to which you've contributed. I was hoping to avoid the overheats by converting but maybe its more hassle and headache than its worth. I haven't abandoned the idea but I'll have to have a more in depth talk with this mechanic and bring up the concerns brought up in this thread.

Thanks. The only thing you would actually change is removing the heat exchanger. If you follow Don's advice and change the impeller at least every other year, have a clean leak free exchanger full of 50/50 antifreeze and good flow out through the exhaust elbow you should never have an overheat problem, even with the old 3" exchanger. The reason folks have overheating problems is usually neglect of maintanance. Your best bet is to find out what is wrong and fix it. The thing to think about is that last day when you are on the ramp, just pulled your boat for the winter. Pull the transom plug on the boat, unscrew the aft plug on the exchanger and let er drain, right there. 5 min and you are freeze protected, NEVER have a cracked block in the spring. Opposed to pulling hoses and block drains and waterpump drains, and never knowing if you got all the water out. No thanks I will stick with what i have.

 

[Don S]

Re: 470 convert to open cooling system.

A local 20+ yr mechanic says he's done many over the yrs, without issue.

Did it ever occur to you that the reason he does that is because he doesn't have a clue on how to fix them the right way?

It might also explain why his method is not mentioned a lot on the internet. Everyone else already knows better.

 

[Scott Danforth]

Re: 470 convert to open cooling system.

I'm with Don on this one.