Theory ... water flow
 

If you dont run a bypass ( pictured below) What is the path of the water to cool the exhaust ? No Thermosat ? If there is a thermostat seems the sea pump would be dead headed until the thermostat opens. I have seen holes drilled in the thermostat but seems no way that would be enough flow ...m

Re: Theory ... water flow
 

Over half the water flows to the exhaust at all times. Once the thermostat opens then water flows in the block too, but it always goes to the exhaust, all of the routing is done in the thermostat housing.

Re: Theory ... water flow
 

junk the stat

Re: Theory ... water flow
 

I agree. I don't run stats in my Formula. It has bypasses.

As a matter of fact, I'm in a chitstorm argument on another board where a guy says that it won't cool without a thermostat, which is totally against the principals of physices.

http://forums.boatfreaks.org/showthr...?t=6120&page=8

See if this info is helpful at all.
http://www.perfprotech.com/home/tech...oling-tips.htm

Re: Theory ... water flow
 

I understand how the stock Thermostat Housing works ... Mainly refering to a bypass setup and specificly the setup posted.... I assume no thermostat ....

But just for argument .. Maybe the thermostat never really closes ? Just Restricts flow ... Less flow as the thermostat moves to the closed position ? I had on go bad or stick a cpl of years ago and the motor temp was fine at idle ..but if you tried to come on a plane it would get Hot ....

Re: Theory ... water flow
 

No bypass hose, running a t-stat (even with holes) = blown intake gaskets.

From the above picture, ALL of the water flows thru the motor, then to the exhaust. May have a problem building up any heat.


T stats do close all the way, well maybe not a 100% seal, but real close.

Re: Theory ... water flow
 

But just for argument f that. go talk to your wife. just kidding. theres enough arguing on this site with out asking for it.

more importantly, junk the stats. judging from the picture you do not have a stock boat, nor power , therefore those theories do not apply.
1 1/4 inlet hose, water comes in, goes thru coolers, in engine. out heads, thru intake. out stst housing v.i.a 1" hose for the pupose of slowing the flow of water. out exhaust.
no back pressure problems. leave it alone.

just do it.






do it.






p.s is that a cigarette, looks like cig bilge.

Re: Theory ... water flow
 

Have to ask Old School, that's his old boat.

Re: Theory ... water flow
 

I run a small restrictor plate instaed of the t stat, if I put in a tstat my motor will blow. which it did. ;) (ok, i was parking the trailer while it was running in the water with my wife watching and she states when i got back in 5 min, :why is the new motor smoking like that") I still run too cool now with the smallest restrictor - dont know why. without it the temp gauge dosnt even move...strange.

Re: Theory ... water flow
 

I would bet that there are no stats or ones with a few holes in them.

Re: Theory ... water flow
 

There are only 2 ways to plumb a cooling system with a crossover. (1) use a crossover with a bypass hose going to the thermostat housing. The hose is 3/4 to 1" dia and allows water to go to the exhaust manifolds while the thermostat is closed. (2) Use a crossover without a bypass and do not use a thermostat. Without a bypass, when the thermostat closes, all water to the exhaust manifolds is cut off leading to too high water pressure in the engine and possible fire from too hot exhaust manifolds.

Re: Theory ... water flow
 

Cuda
There is Some truth to that. The theory says you need to slow (regulate) the flow of water so you have some heat transferred to the coolant. You don’t need a t-stat, a restriction will do the same thing. Negative affect will be a build up of pressure.

Re: Theory ... water flow
 

Some of this theory must be about water pressure. Without any water pressure, steam pockets will form more easily. Of course, where there is a steam pocket, there is no transfer of heat. Having a restriction in the thermostat housing raises the pressure in the block, preventing the formation of steam pockets. As far as slowing the water down to remove more heat, that goes against all of the laws of physics. If all the water is in contact with the hot metal inside the block, cooler water will remove more heat than warmer water. Period.

Re: Theory ... water flow
 

From what I understand it is better to run a stat then not. For the reasons above and cold water will flow through the block like a river while the hotter water stays closer to the metal. You will not get a even cooling which will cause hot spots in the block. There is a lot of little passages that the water needs to push through and it will not happen with out a little back pressure. Also running cold water though the block constantly will no allow the motor to achieve a good operating temp. If its still getting hot (to full operating temp) with no thermostat then you have more issues then just a thermostat.

Re: Theory ... water flow
 

Yep, it's all about pressure and hot spots, vapor pockets. The whole water moving through the engine too fast was a bunch of backyard mechanics making up an explaination for something they knew to be true but didn't understand.

Re: Theory ... water flow
 

dude junk the stat.

i have installed over 200 high horsepower bigf blocks, none of which had stats. these engines where built by such greats as Richie Zul, Sonny Leonard, Sterling, J.C Performance, M.E.R Performance.

additionally steam pockets will only form if there is no restriction in the water system. if you have water pressure more than likely you have restriction.
also the inlet hose is usually 1 1/4 and then you have a 1" dump out of the water neck housing as stated earlier.if there is too much pressure or your concerned of steam pockets than simply install dumps in the rear of the intake and plumb accordingly with supply pressure.

these three are from. J.C , Sonny, and M.E.R

enough with the b.s

do it already






just doi it.

Re: Theory ... water flow
 

Well, maybe not. Heat transfer of any kind is done when 2 molecules touch. There is no "cold transfer" just a loss of heat from one molecule to the other. Now stay with me here. If you turn on your stove burner and let it heat up, you can touch it for a very short period and not get burned(cell damage from heat transfer), why? Because enough heat didn't transfer from the burner to your skin. Now inside the engine you have water molecules pushing by some parts of the engine at a high rate of speed. If that speed is too high then there is no time for that particular spot to transfer heat to the water molecules and it will run hotter in that spot. As you slow down the flow less and less spots experience this phenomenon and the engine will run cooler. This will not show up on every engine but on some that are marginal on cooling , some restriction to flow velocity is necessary to maintain proper cooling.

Re: Theory ... water flow
 

molecule,, shmolecule





hey Ted



























just do it,,,,,,











do it,,,,,,,,,,

Re: Theory ... water flow
 

Nope sorry, please go back to your old thermodynamics and fluids text books. You're analogy doesn't hold water. (ha ha)

Re: Theory ... water flow
 

Arizona Speed and Marine has 120 degree thermostats. That's what I'm running. Drill 3 1/8 holes in it and my water temps are steady as a rock. I'm running crossovers with bypasses.

Re: Theory ... water flow
 

Pressure is needed to raise the boiling point of water so you don’t get the steam/ hot spots. But if you let the coolant run through the system unrestricted there is no heat transfer. Like running over the hot coals. Run over them and it will not hurt as bad as walking. The negative point I was trying to make was the over pressure we get in boats. With out a closed system we need to regulate the max pressure.

Re: Theory ... water flow
 

Very true. Now think of all that and your Temp gauge thats reading 140......Is that a true reading of your motor temp? Nope.

Re: Theory ... water flow
 

Thermostats at 140. Drill 3 1/8 holes in it and my water temps are steady on my 540's . I'm running crossovers with bypasses.

Re: Theory ... water flow
 

Good topic. I understand both sides to the argument.

In our early spring/late fall cold waters, if we run without t-stats our oil temp takes forever to come up to a decent temp and backs down to a cold temp quick when throttles are let off.

During this cold water times of year, using a t-stat to bring engine water temps up we get more acceptable oil temps and duration of oil temps.

Since oil is on the other side of the metal than water, I would think that oil temp may be a good indicator of how well the water is removing heat from the engine.

I def agree that water psi as read in block should be looked at. Too low of psi may create cooling issues and of course too high of a psi may will create unwanted / unwelcomed leaks.

Re: Theory ... water flow
 

Naw Stole the pic from the "show your motor" thread ...

building 496's for my 311 ....

Great info here ....m

Re: Theory ... water flow
 

......

Re: Theory ... water flow
 

Yes, it's Old School 1, an 89? Bullet.

Re: Theory ... water flow
 

Nope, I like my 160 thermostats and no milky oil :D

Merc did a fine job on my stock 502 cooling systems:p

Re: Theory ... water flow
 

I run a set-up with no by-pass and no t-stat. Cold water never got motor up to temperature and I had severe condensation issues (milky oil). Installed an oil t-stat in lines between filter housing and oil cooler and problem solved. Used a simple model purchased from Summit Racing. Now oil stays free of moisture and temp gauge on motor creeps up into low range occasionally.

Re: Theory ... water flow
 

problem with the automotive thermostats is most I have seen run about 190* ...The word is you need 210-215 to vaporize the moisture ...which doesn't make sense .... unless with automotive water temps @ ~210 maybe moisture is not a problem ....m

Re: Theory ... water flow
 

I've run 525SC without bypass or thermostat. Water temps were generally 120-140. Oil got up in the low 200s.
When I tried this on a lower hp engine, my oil temp never got over 180 degrees= condensation = bad, mkay?
I switched over to a bypass and tried 140, 160, and 180 degree thermostats.
Like Goldilocks said. 140, the oil was too cold, 180 the oil was too hot, 160, it was just right.
Monitor your block and oil temps. Use a crossover and thermostat if needed.
Gary

Re: Theory ... water flow
 

:cool: :cool:

Never ran thermostats in that boat when I had it. Water temps were always about 135 and oil temps were 225.

My current boat doesn't have them either...but it does run a litter colder on the water temp (110-115) and about the same on oil temps.

Re: Theory ... water flow
 

How about, it doesnt make that much difference. Lots of motors have stats, lots dont and they all seem to work fine. Lots of physics review needed here....Wow.

Re: Theory ... water flow
 

not a lot of review necessary at all. the physics thermodynamics aspect of this discussion are crystal clear and as simple as it gets.

the ability of one medium to cool ( or heat) another is strictly a function of three elements:

the specific heat of the two compnents
the surface area exposed and in intimate contact
the elapsed time time the surfaces are in contact.

all the rest are constants and nothing else matters.

in the case you guys are arguing ( excuse me, DISCUSSING) all that is really in question is the efficiency that you want to cool at. in the first extreme case where you have zero water pressure and water moving at an EXTREMELY high speed thru the system, it is an entirely possible scenario that each unit volume of water does not spend enough time in intimate contact with the block to sucessfully raise its temperature ( take heat AWAY from the block) before it moves on ... in a sense, your block GENERATES move btus then you can get rid of with the coolant.

in the other extreme, where you have something above the minimum pressure required to assure intimate contact but you move the water too slowly, the the delta T beomes zero, between the two components ( tyhe "coolant" becomes heat saturated ) and you simply create an equilibrium that is higher than you want... right up until the water boils and thats that. remembering of course that the boiling point is raised by the pressure in what is essentially a linear fashion.

so....

the physics and thermodynamics are clear and undeniable. the only real questions are :

what do you really want for operating temperature

versus

how are you going to get rid of the heat youre putting in at the CORRECT rate to create that equilibrium.

the hardware aspect of that answer is whatever you care to make of it.

you want to run no tsat because god told you in your sleep that they are evil ? fine... build enough pressure to ensure intimate contact and slow the water flow down to whatever the rate necessary is to allow the water to heat and therefore tranfer the heat out of the engine. thats what restrictor plates do.

want to operate the boat at a wide variety of speeds and conditions while maintaining the necessary and desireable operating temps as defined by the metallurgy of the components youve selected for internals and clearences ? use a tsat with a sufficient flow rate at wide open to assure your max operating parameters are covered.

i have made known my opinion about running these motors or ANY motors like this overcooled... i think you guys that do that are simply giving up performance and wearing out your motors for no reason what so ever... and im not talking about the 40 psi blower motors you guys tinker with with all the bizzare combinations that you can think of... im talking about your basic normally aspirated big block with a carb and intelligent compression ratio...

my solution has always been.... define the water cooling to make the water temps 180, make the oil cooling such that they are between 210 and 240 all the time including during the most extreme sustained conditions. don't try to make one system do the job of the other.

its nothing i invented. its a concept proven correct by essentially every single manufacturer of internal combustion engines on the planet and just happens ( by shear luck i suppose, ) to be supported by the simple principles as defined by the physics and thermodynamics as they are understood by the real world for the last 150 years or so.

Re: Theory ... water flow
 

well put stevesxm

Re: Theory ... water flow
 

The theory stated above that the faster the water is moving the less time it has to pick up heat and therefore the motor will transfer less heat to the water is incorrect. The water temp goes down because the heat is transferred into a greater volume of water so the water temperature does not rise as much as when the flow is lower. If the motor is running at constant load or more specifically generating the same amount of heat over time, raising the velocity/flow of the water will INCREASE the heat transferred since the water is at a lower temperature. The bigger the temperature difference between the block/heads and the water the more heat will be transferred.

For example, if water is flowing at 15 lb/hr and you add 30 BTU of heat to the water in an hour, the water temp will raise 2 degrees since the heat capacity of water is 1 BTU/lb/deg F. If you raise the flow to 30 lb/hr and still transfer 30 BTU of heat to the water in an hour the water temperature will only rise 1 degree.

Any obersvations or problems observed to the contrary are due to other factors. I read an article where Reggie Fountain discussed keeping water pressure up to keep steam from forming in the heads which could occur in low flow areas. The point being that if you reduce flow restrictions in the motor to get more water flow the associated reduction in pressure would cause the problem since water boils at lower temperatures with decreasing pressure. But, more water flow will not in and of itself cause higher block/motor temps. The best situation for cooling problems would be to install a pump that would raise the pressure of the water. That way the increased pressure would cause increased flow, maintain pressure in the block/heads and all should be OK. However, with no pump like that readily available and raising the possibility of blowing intake gaskets with increased pressure the only option is to reduce the resistance to flow to get more water i.e. remove the tstat like I did on my modified 500 hps.

Re: Theory ... water flow
 

with all due respect, moving the water too quickly is not a theory. it is fact.

pick up a physics book and read it. heat transfer is a strict function of time. in a closed loop system , the limiting factor becomes the heat exchanger unit... water to air. in a total loss system the limiting factor is flow rate and that and that alone controls the thermal equilibrium. if each unit volume transfers only a small amount because the flow rate is too high, you are required to run an EXTREMELY high flow rate to compensate... the total heat in HAS to equal the total heat out.... if you use only 1 % of the thermal transfer capacity of the coolant per cc because you never give it a chance to transfer then you need 100 times the flow rate to compensate... which mean pumping and friction losses and alll SORTS stupidity that is avoided simply by doing it right the first time. can you make it WORK ??? sure by why in gods name would you ?

in the case of steam pockets its the same thing. his OBSERVATION is correct but his analysis is flawed. you run pressure to keep the water in intimate contact AND to raise the boiling point . IF you do these two things then no steam pockets are possible. THAT critical pressure is a function of the hardware scheme and is NOT a one size fits all answer. steam pockets are the RESULT of failing to do either... NOT the REASON you do. the REASON you do it is because it is the CORRECT way to make a cooling system. like ANY system, if you design it correctly according to the science as opposed to voodoo and folklore, you don't HAVE mysterious problems to solve.... because they don't happen in the first place.

Re: Theory ... water flow
 

you make my little peanut brain overheat ... info's flowing too fast ..........:D

Re: Theory ... water flow
 

Steve, If the water does not stay in contact with the block long enough what is the "too fast" water replaced with? It is replaced with cold water if the flow rate is high. What does the new water do, pickls up heat. Right you are though, keep block pressure between 15 and 20 with sufficient flow and all will be well.

Make sure plenty of water is able to exit the exhaust, high flow t-stat and dump the excess pressure off after the oil cooler.

Re: Theory ... water flow
 

they use the stats on staock, and on efi engines. the efi's need the temps to be at a certain range for thats were the program which haS BEEN DESIGNED TO WORK IN A MULTITUDE OF ENVIROMENTS was set from the start.

also the idea of stats on a high perf engine is not a good one.
many of the conflicting posts, and book theories, and " i read this in hot boat" and the rest of it, is all nonsense. theory is not reality. and until you have been there and done that you should not make a decision for someone else.

i stand as stated ,,,,,,,,,,,, no stat.

has little to do with oil temps and milk shake. thats what the oil cooler and stat take care of.

why is it no auto's have oil temp gauges.

you are talking about an engine which is designed to run at high rpm's for an extended amount of time.not idlinmg in traffic or shifting.

heat transfer, molecules, intimate contact.

horse poo, none of that truly has a dramatic effect at 5500 / 6000 rpm when you have it bricked for an hour on a poker run. do you really think your gonaa remove all the little tiny air bubbles,,,,,,,,,,,,,,,,,,,,,,no..

stock being too critical, aand go blow your stuff up.

lol, good luck