470 Heat Exchanger

[Russell48]

Hope somebody can help answer this,, The 470 motor I have is a 1980 an still in the Bass boat I have, When I got the boat I found out that the heat exchanger was takeing off an all hose'es are hook straight up to bypass the heat exchanger,, So the lake water was running all thru the motor an keeping it good an cool,, So will it hurt anything to keep it like this to run the boat just a couple times on the lake?? I am in Ky an have already drain all water out an got A/F in the motor, When I got the boat I took it to a boat ramp an just backed the boat in the water but didn't take er off the trailer, So I could let the motor run for a few,, An the temp gauge was at normal an everything doing what it was pos to do, An a few I am talking about would be about 30 to 45 min's running time, Motor running great an outdrive an all is great,,

 

[dn010]

Re: 470 Heat Exchanger

Only thing I'd worry about is the gunk you might pick up from the lake water and deposit in the coolant passages... The exchanger may have been the small less efficient one or damaged - and that's why it was removed

 

[Bondo]

Re: 470 Heat Exchanger

So will it hurt anything to keep it like this to run the boat just a couple times on the lake??

Ayuh,... Maybe, maybe Not...
You have an aluminum block, 'n a cast irom head,...
That's why it was given closed cooling...

If this is purely for diagnostic purposes, I'd say give it a whirl,...
My guess is, that motors probably already got more problems, than just a by-passed H/E....

 

[Russell48]

Re: 470 Heat Exchanger

Well I do know that I have 145psi in all 4 cyl an she really runs good an smooth an even given er the gas she takes it then let go an she just set there an idels good an smooth,, An do know where I was at the boat ramp that the water was good an clear an no mud,, So I guess it would be better to get the heat exchanger an put back on it,,

 

[EddiePetty]

Re: 470 Heat Exchanger

....and my vote would be to return to the closed cooling system utilizing the 4" heat exchanger.
The closed system is so much easier to winterize, maintains a more constant engine temperature and eliminates most of the possibility of foriegn objects clogging the block/head. As previously mentioned, you have a cast head sitting on a siamese alloy block and cooling problems are your last desire.
Additionally, when replacing the cooling water supply hose from the transom nipple to the heat exchanger raw water inlet (assuming you no longer have the water-cooled voltage regulator), instead of the original type hose, use nylon reinforced clear tubing to allow you to monitor your cooling water flow, especially nice when on the muffs to avoid air bubbles.

 

[stonyloam]

Re: 470 Heat Exchanger

I think you are asking for big trouble here. Unlike seawater cooled engines the engine is not designed to be drained. For example there is no drain plug on the manifold, it drains through the heat exchanger. Same with the engine water pump, I am trying to remember, But I do not think the engine water pump will drain even with the hose off, it should stay 1/2 full and it is pretty fragile aluminum. Also debris from the water could very well plug the water pump weep hole and sand could damage water pump camshaft seals and dump water into the crankcase. It would be best to find an exchanger and go back to the original configuration. With the water pump you should be able to pull the hose off underside of the intake manifold (that goes into the front of the pump) and dump some antifreeze into the hose to make sure you get some protection to the pump.

 

[Russell48]

Re: 470 Heat Exchanger

Oh ok, Thanks guys,, An I already got A/F in the block an water pump an all,, So I don't have to worry about any freezen in the motor,, I found out where I can get a H/E an waiting to see what size it is,, I have no idea what size is pos to be on there but will need to find out, So far I have read where there is a 3 inch an a 4 inch, So I am hopein I can get a 4 inch so it pos to be better,,

 

[dn010]

Re: 470 Heat Exchanger

You'll want the 4"... It is what Mercruiser went to when they found the 3" wasnt efficient enough... There are also ones with and without a drain plug if that matters to you, otherwise if you need to drain it you need to pull an end off it.

Oh ok, Thanks guys,, An I already got A/F in the block an water pump an all,, So I don't have to worry about any freezen in the motor,, I found out where I can get a H/E an waiting to see what size it is,, I have no idea what size is pos to be on there but will need to find out, So far I have read where there is a 3 inch an a 4 inch, So I am hopein I can get a 4 inch so it pos to be better,,

 

[stonyloam]

Re: 470 Heat Exchanger

4 inch is the one you want, make sure it has all of the brackets with it. Good luck.

 

[Russell48]

Re: 470 Heat Exchanger

Ok, Thanks guy's I will be sure to go with the 4" for sure, The guy said he has a use on so I still waitting to hear from him so I can find out what size it is, Thanks again,,