Pro's and Con's

[Crossbow]

Was wondering who has eliminated their water circulating pump (bravos)and replaced it with the crossover pipes available at many aftermarket sites, this summer one of my pumps sprung a leak ,so 2 hrs. and $165.00 later, back on the water ,now while winterizing i notice that the other one is not looking good either,so i am considering eliminating them altogether,i figure less moving parts the better,anybody been there ,done that ? results,good or bad? any feedback would be helpfull thanks Rich :confused: :D p.s. with thermostats or not ?? availible both ways eek!

[harbormaster]

I think poodle eliminated his....

[HP 600SC]

what lower do you have?

[Crossbow]

I have stock Bravo's 1988s with a raw water pump in the lower left hand side of the 454s, I've thrown the circulating pump belt once or twice ,seems to have no effect on water temp ! :( Does this make it a good candidate for pump removal? wink

[ALLAN BROWN]

We make them. A complete kit is $299. Definitely get the one with the thermostat. If you boat in really cold water, get a pre-heat.

[Crossbow]

Just trying to keep this topic alive ,sure would love some :p more input on this

[Ed Donnelly]

I have Brownies sys on my criterion,with thermostat.Works great!!!!Ed

[Crossbow]

Was you rig always setup with crossovers or did you chuck the water circ. pump? :confused:

[Donzigo]

I would not take them off, Crossbow.

[BigGrizzly]

I've done it both ways- mine uses a thermostat. No belts were eliminated just a shorter belt for the alternator. I like oiltemp above 190 and less than 210f, the engine temp is 160f. With the bb chevy, the pump provides a internal bypass which recircs the warm water doesn't allow pure cold raw water to enter the block and cause thermoshock. This isn't a large problem but does exhist. I never lost a big block for this reason but did lose my 351 Ford Clevland because of this reason, twice, before I figured it out. I now have closed cooling systems on all my boats so the this is a non issue anymore. One more point. On OSO there was some thread about giving you 20 extra HP by eliminating the pump but that is real BS maybe 2->6 but boat speed isn't changed at all on either of my boats tested.

[Christian]

Hi gang!,
the experience that i have had with cross overs is that most of the big power motors run them. up here in NJ where the water might be just right for those apps. so Bownie and Madpoodle have it right! i was looking into replacing ours on the 18 (sbc)and decided against it b/c the motor would not get up to temp. so the only motors i have seen with the crsover are big blower motors that run lots of hp.

best to all
Christian Del Collo
http://rosebudracing.tripod.com

[Bryan Tuvell 33ZX]

This is a good post, I will keep it alive, I truely do not understand the whole deal, need basics, I have read alot but only on pro's/con's, so what are you removing, and what do you really accomplish?

I run (502) 180 all day long, not hard to tell if she gets hot, BEEP!

Also I have read about the small hole drilled in the stat????

Some say cooler is better but I think BGrizz told me the EFI's need the higher temps, sorry if that is a misquote Grizz.

Which pump are you deleting?

I have not bought my Gaurdian Flusher yet due to the literature on running your boat at home, like a nasty day to get her hot for a fluid change! Two hoses required, drive and gaurdian, trying to get cooling water smart???? Great system, but I want to run my engine, THEY claim ears is BAD, you need 11 gallons a minute for a 502 and a hose won't provide it????

So someone open a cool beverage and explain the whole thing for us rookies. Pro's con's, why's etc.
Thanks in advance, a great post.
Bryan

PS... I did not understand what SMarine meant about their exhaust tuned ports and water by-pass until it was in my hand and could see inside of one.... neat mini want to be header, can't wait to get them on the boat..... much much better than stock Merc.

[Bryan Tuvell 33ZX]

Big Grizz: I am waiting on a long post with all the answers????????
Where are ya?
Bryan

[Bad-Tat]

Bryan,
The Grizz was out playing mini golf last night in 38 degree weather!!! His fingers might be frozen!!

[Donzigo]

Bryan, I'm with you on this one. I guess my earlier answer was uninformed.

Let's have somebody out there explain this fully for us dogs in the back of the dogsled team, (where the view never changes).

Madpoodle, where are you?

Grizz?

Brownie?

Others?

[BigGrizzly]

I will explain this when I get home to night. Christian I have a big blower motor - if you concider a 698 Hp blower motor big.

[BigGrizzly]

First lets start with, why are boat engine water temps so low 1) Salt crystalizes at above 170 deg F. 2) Most exhaust systems are covered or below decks 3) Old thinking had engine temps in the 140F->160F in all applications 4)Law requires water jacketed systems in enclosed areas in marine applications.
Every one should know that the hotter the engine the more efficient the combustion is, to a point. Oil temp is most efficient between 195 F and 210F. After 240F oil actually loses its lubricity. Therefore an engine operating above 210 (cooling jacket temp) is impractical in normal applications. In 1982 GM did an extensive engine durability test. They found that below 140F(operating temp) engine wear increases 20% to 40%, because of the inefficiency of the oil to function around the piston and cylinder head area. At these low temperatures fuel also passes by the rings causing oil dilution. This is a real problem and exists even today. There is also condensation in engines that are run too cold or aren’t run long enough to bring oil up to temperature. This is one of the reason cars have a positive crankcase vent system. Case in point because of higher engine temps and unleaded fuels, engine sludge is all but gone in modern day engines.

In an application where the water pump is removed and a direct entry system is used without a thermostat the cooling water will enter cold and get progressively hotter as it moves through the block. Therefore the first water jacket it hits is cold (inlet raw water temp) and the last is much hotter. Even with restrictors the water entry is too cold even if outlet is correct which changes with rpms constantly. The water temperature differential is too great for good combustion. Now add a thermostat and temps are more even on the out let and inlet areas, but still too cold. In this application a bypass must be used or the exhaust won’t get water until the t-stat opens. In a preheat system the raw water is heated before entry into the block by the exhaust manifold. This is much better because water temp is higher when it hits the first cooling passage. Still uneven temps, but better providing raw water temperature isn’t too high.

Where the water pump is used there is a cold/hot water mixer in the thermostat housing which recirculates warmed water through the block. In a 454/502 there is one from the intake manifold to the water pump also and should not be plugged or removed. This helps to keep water moving through the block at a better speed and a more even temperature.

Closed cooling system the best of all. In a properly designed system the water temperature differential is between 25F and 40F degrees. This is water in vs water out of the block. The other advantage is that antifreeze has rust inhibitors in them. The closed system keeps raw water, such as salt and mud out of the block which leads to internal rust. Which leads to improper cooling in the later life of the engine.

People with large blower motors eliminate the water pump because of fit and clean uncluttered look. Some applications such as Wipple eliminate the thermostat all together. Their engine temperature is too cold down below 140F at idle. This causes condensation and ECM tunning problems on this type of setup The other reason blowers run cold is to prevent detonation on some setups. Most have avoided closed cooling systems on blower motors because. up until now, a heat exchanger was either too large or inefficient to use. Most good engine guys will agree that a closed cooling system will eliminate many problems in a marine application. Engine set up would be easier and more durable. I have a closed cooling system on my blown 502 (698HP) and it now runs more efficient and with a more even temperature. The size of my system is 4 inches ib diameter and 30 inches long and weighs about 30 pounds. There is one high performance engine builder that is making packages of blower motors with closed cooling systems. Mercury is now in the process of doing it on their SC motors too. There you have it folks

[Fish boy]

Big Griz,
thanks for explaining it in a laguage even I can understand. Great explaination.

Fish

[Donzigo]

Thanks, Grizz, great explanation.

I'm starting another post to ask another related question. Please respond.

[Philip47]

I swithched to a non thermostat crossover and had basicaly no water and low oil temp, talked with engine builder and with the cam and compresion I am running he wants to keep the water temp low.

I bought a Keith Eickert oil thermostat and run a constant 215 degree oil temp

[BigGrizzly]

Phil, I don't agree with your builder at all. I have a 10.5 in my Corsican with a very large cam ant I run it at 190F, and never had a problem. I will say if you run it that cold your asking fot increased wear. I will bet your intake valves will carbon up too. Keith Eikert builds nice stuff and decent engines too, but I won't run less than 160F on anything. All majior engine guys will say the same thing. Below 140F my 698 HP motor idles crappy and has bad fuel consumotion and will condensate-don't know about oil dulition, I'm not that brave to test my own engine in that area. I've been doing this for over 30+ years and have seen it. Its your motor do what you tink is best. Just remember the colder the engine the more wear and less efficient it is, so where does the unburnt fuel go, in the oil of corse, Good luck

[CDMA]

Philip,

That isn't an uncommon thing in high compression and high boost applications. These applications are prone to detonation and keeping them cooler will reduce the possibility of this occurring. I am currently going though this dilemma as we speak. Grizz is correct that running an engine cold will increase wear but the other concern is detonation. Many big blower motor guys are right on the edge of what can be run on pump gas so they purposely run the engines cold to give a little extra safely margin from detonation knowing well that they are wearing the engine out faster. The logic behind this is that they figure the chance of grenading the engine due to detonation is greater then having to rebuild the engine sooner. Grizz’s engine is sure one of the best running examples of a big blower motor I have ever experienced. That being said I may go the cold running crossover method. If I had the aluminum heads like Grizz did I would do what he did but w/o the safety margin of the aluminum heads I think it will be worthwhile for me to run her cold. I figure I will need more power before I wear her out anyway.... :) :) ...or I may freshwater cool...that is why they call it a dilemma... :)

Chris

[BigGrizzly]

Chris, My engine is over 9:1, and the aluminum heads don't make the big difference you think. If the engine is set up well it won't detonate. I have a closed cooling system and beleive me the temp is more stable than any cross over. The one thing your forgetting is thermoshock which is evident in blower motors yet not in normal aspirated engines. Where I play after work they build 4 blower motors a week, Mine being a small one in comparison. So experience is on our side. Garry will not build a engine that runs cold. His own small block (875HP)runs at 170F with a special recirc preheat system soon to have a closed colling system. Most of these guys talk of condensation and soot on their stern- mine doesn't have either. The guys your talking about also blow them up before they wear them out. Point is that setup is the key. I don't agree with running cold engines. If I were wrong all those street rods must be carrieng a ton of water in their trunk. There isn't a street rod running less than 170F at least Lil griz's sterrt rod had 600+ Hp out of a 5.0 and 14 psi of boost with no problem and you didn't want to get near his radiator. A few weeks back they dynoed a Blown 572 with close to 900 HP with iron heads and he keeps it at 160F. The reason blower guys think that way is because they have been lead to beleive it. My Corsican has 351 Cleavland 10.5:1 and I run a 195F t-stat and a closed cooling and a positive crankcase ventilation system. It has well over 500 hours on it and still burns lest than a qt of oil in 40 hours. Our 1966 16 donzi has had a 180 T-stat in it since 1970 and still has the same 302 in itwith many more hours in it then either of my boats combined. Do what you guys want, but I do know what I am talking about on this one. BTW does anyone know what the Merc SC600 with a closed cooling system runs at? I do, over 160F.

[CDMA]

Aluminum does make a difference that is why you can run higher compresssion with aluminum heads then iron. And you are missing the point...yes I agree with everything you say...I AGREE...BUT running the engine cold WILL reduce the chance of detonation in a boosted/high compression engine. Thats all I am saying. If you are going to say that running the engine cold INCREASES the detonation then I am all ears.

Chris

[BigGrizzly]

Thats not what I said. What I said above was the run it cold because of detonation on improperly set yp motors. I did say my Corsican does have 10.5:1 with iron heads with no peoblem. I said the alumimnum head don't make that big a difference. What made the biggest difference was combustion chamber mods, which can be done on most Iron heads. They do much more than you know, especially in the detonation area. The real problem with the 454/502 configuration is the lousey combustion chamber design. the 572 Imentioned is running 9.5:1 IRON heade and a little over 5 psi of boost, it runs best between 160 and 170Fon pump gass
. Yes a cooler engine is less pron to detonation, but retarding the timing wil do it more and better as will proper combustion chamber design. It is all in the setup and combination of parts. What I said is run a thermostat and run it at an acceptable temp and 140 is not it. I built mine to last, Yes I had a bad valve that took out an engine but that had nothing to do with detonation or heat in any way. I have been building engines since before I was a teen, In my passed years I havn't done bad in racing either. I am speaking from real world experience. Like you said my motor runs well. This was no accident. It took time planing and a lot of work, and I even had somone else do the heads. My goal was drivability and power in that order. I beleive I have acheived it and just the way I wanted it. Read and study all you can, as I did. Just remember experience is the best teacher, and I have had alot if that. If you have to run the engine with no thermostat and no restrictor something is very wrong.