Closed cooling system
 

I have recently changed out a stock set of iron heads to Ederlbrock aluminum marine heads on a 502MPI. I have done some research and would like to know who sells a closed cooling system kit for this motor? We spend more time in brackish-to-salt water here around the Gulf of Mexico and concerned with corrosion in the heads. The heads are anodized with Cometic head gskt but still not confident that is enough? I do have the Mercathode working......

I am a firm believer in closed cooling. I would recommend a system from Monitor Products.. I have used them before with success.

http://www.monitorpro.com/

Man, after looking at the kits that cost $800+, it seems like someone with some decent mechanical aptitude could put together their own system at a fraction of the cost. I have a buddy who works for an outfit that does a lot of stainless steel welding and fabricating, and this has the wheels turning for me. ;)

http://www.offshoreonly.com/forums/g...ng-system.html

Not sure if you saw this when the thread was active, but the above link will get to a thread I started a short time ago. Its regarding a pair if 575's I built this winter. I had to fabricate a closed cooling system for these engines. I only wish I could have bought a pre made kit for $800 and be done. It must have cost nearly that much in parts anyway, not to mention the hours and hours it took me to make everything. If you are lucky enough to find a kit for your engine, buy it and just bolt it on...

Looks like the blower complicated that installation considerably. I'm thinking that my NA installation should be a lot simpler, but I'm sure there are several "gotchas" that I'm not seeing. Still, the concept is so simple that it's surprising that Merc didn't equip their motors with this from the outset, especially the expensive blue motors.

I was thinking of doing the same thing but I shelled out about $1,200 and got the monitor system...... I picked it up from the factory as I live in Tampa and I am very happy with it. I talked with some of the people there and they do a ripping business supplying systems for OEM manufacturers namely Yanmar. There facility was cranking out stuff like you would not believe! I have been taking it easy so far with my new NA 502 and so far I have not exceeded 4,000rpm and the water temp has not even got above 170 yet...... I have aluminum heads, intake and exhaust and needed to go closed cooling here in the salt water. I did think about getting a used system and making it myself but having a proven setup that will work at my horsepower level with a warranty as well made the decision easy........ TBF

TBF, did you go with the full system that includes the exhaust, or just the block and heads? I might add the block system as a future upgrade to mine, since I am running the AFR aluminum heads (non-adonized) and aluminum intake. I am running in fresh water, which will help, but I will get in the habit of pulling my block plugs after running it just in case.

Speaking of block plugs, has anyone ever tried just plumbing some fittings leading up to some ball valves instead of the plugs? It would make it real easy to drain the block without worrying about dropping the plugs in the bilge, but I could also see it getting blocked with silt.

I have the full system as I am using aluminum 496 Exhaust..... I did have them ceramic coated inside and out but I need all the help I can get being in salt water! I have stainless risers and they of course see the exhaust sea water from the heat exchanger but they should last a long time as I fresh water flush after every use with salt away as well...... I would say the half system would be fine for you if you are always in fresh water. Having anti-freeze and the corrosion protection in your block all the time has got to be a bonus.......

Also, I forgot to mention that did you say you were going to drain the lock after each use? I would say that is a bad idea as rust and corrosion will really get bad when all that air hits the wet cast iron....... Keep the water in the block as oxygen is what is the real culprit that causes all the rust......

Running a monitor system as well. Have it on my 548 tall deck. Running a half system as I have CMI's. Never had temps above 170 and the system performs great.

http://www.monitorpro.com/products/i...i=14&f=14&c=20

TBF, I'm more worried about corrosion and mineral deposits in the aluminum heads and intake than I am worried about the cast iron block rusting. We almost never see rusted out blocks around here, as it is exclusively fresh water. However, the water is pretty hard (high mineral content), and therefore we can get some mineral deposits building up in aluminum water jackets and causing blockages. I have read that aluminum oxidation actually provides a protective layer against further corrosion, so it would seem that draining the block wouldn't hurt in this regard with fresh water.

I think one of the major issues with aluminum heads / cast iron blocks is galvanic corrosion between the dissimilar metals. I'm seriously thinking of looking for some kind of screw in anode that I can install in one of the water ports on the intake manifold to help with this. Also planning to make sure everything is grounded together.

I am not a chemist or chemical engineer by any means..... but I would say why not do your own cast iron rust/corrosion test? Got a used mild steel bracket or two or something similar? Drop one in a bucket filled with anti freeze/water and hose the other one down real good and leave it outside...... after a week, which one would you like your cooling passages to look like? Raw, wet, cast iron will rust superfast when exposed to air........ faster in a salty environment for sure..... I always flush my raw water cooled wellcraft engine after each use and use salt away as well. It is a rust and corrosion preventer and remover....... I would say it would be a good idea for you too, but I would never leave my block exposed to ambient air unless it was either full of anti-freeze/corrosion inhibitor or pickled with some kind of petroleum product..... rust never sleeps!

TBF, since I'm raw water cooled right now, the proper test would be to take a piece of cast iron and aluminum bolted together, drop one in a bucket of fresh river water for a couple weeks, and dip the other in the water and then let it sit out for a while. However, to be truly representative of what goes on inside a raw water cooled boat motor, the test would probably have to be carried out over a few years. Now if we wanted to make things interesting, take a third bucket and add some stray current to it.

In order to pull this test off, it would mean that my engine build would take even longer, and I would incur the ridicule of OSO! ;)

I would love to hear from some folks who have done it both ways - leave the block full of water all summer, versus draining it down after each use.

i agree with tbf,oxygen in the block speeds the oxidation[rust]in cast iorn and steel.

What about aluminum?

I would go on the salt away website and check it out.... I know you are not in the salt but I think it would be a good idea to use it anyway..... It foams up and leaves a protective coating all throughout the cooling passages in your engine..... Maybe there is another product to use but I bet your engine will rust/corrode ten times faster if you drain it after each use and let air get to it.... Maybe check with your machine shop and see what they recommended? Notice how fast freshly machined engine parts rust?

I would install a half closed cooling system if you are so concerned about the rust/corrosion issue. It should work fine for many years..... Look at the millions of automotive engines on the road with cast iron blocks and aluminum heads and accessories..... Anti-freeze with corrosion inhibitors built in are surely the way to go. Your engine will warm up quicker and stay at an efficient temp and probably last longer than if it was raw water cooled. I would say spend $6-700 on a good system and your problems are solved forever!

It's tempting to install the closed cooling, but honestly I have already dumped way more money into this old boat than I should have, and there's a fair chance that I may swithc back to stock power at some point and drop the 489 into one of my Camaros to play with on the street. I have run aluminum intake manifolds on my engines for many years and seen very little if any corrosion in them. Like I said, I think the larger issue around here would be mineral deposits instead of corrosion, although I'm sure it could happen over time, especially if you have some stray current involved.

Thanks for the info guys - this has been an informative thread.

if you are running in any kind of salt...won't matter will eat the hell out of the aluminum parts quick....you can drain all you want...closed system is the ONLY way to protect them..

San Juan Engineering in Bellingham, Washington is another option for closed cooling systems as well as oil and power steering coolers. They do custom work as well as regular kits.

used closed cooling system...just the heat exchanger will cost 200 to 400 bucks. and used come from common sportfish engines. 454 inch 330 hp. I am gonna get one for my 350 small block that will spend the summer tied to the dock in jersey ocean water, but for something with 10% more displacement and 30 to 50% more power than the engine it was made for I wouldn't think a used crusader-mercruiser setup would do the trick very well.

OP,

http://www.keitheickert.com/c-1527-c...ling-kits.aspx

PM me for a quote.