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Heat Exchanger requirements for 155 HP V6

T

the_tassie_devil

Regular Contributor
"G'day All,

I am planni

"G'day All,

I am planning to convert the 155 HP Buick V6 Stringer-mounted engine in my 1973 Chris*Craft from external engine cooling to internal cooling, as I will be using the boat in Salt Water for the first time in its' life from now on.

Does anyone know of what size salt water cooled Heat Exchanger I will need to construct to sufficiently cool the engine.

The reason I will be constructing it myself is that the cost of freighting one from USA to Tasmania will be cost-prohibitive, and for the money saved, I can construct one from Stainless Steel and fit it where I can, within the constraints of the Engine Bay in my Gull Wing.

All assistance appreciated.

Bruce."
 
"The initial problem has now b

"The initial problem has now been solved as I managed to purchase a Heat Exchanger which will keep the Queen Mary cool, even on the hottest days.

Now, my next question is:

"In relation to the engine, height, etc, what restrictions or specifications would there be in where I mount the Heat Exchanger?"

Bearing in mind that the outflow from the Salt Water Port is still going to flow through both the Water Cooled Exhaust Manifolds.

Can it be mounted too high, or too low?
Can it affect the flow through the Manifolds?

Thanks,

Bruce."
 
"Bruce, are you aware of the p

"Bruce, are you aware of the potential issues with converting a previously raw water cooled engine to a "Closed Cooling" system?
Potential dis-lodged rust scale and fine debris can clog up the outside of the tube bundle..... (the E/G side that is in-accessible!)

If you can incorporate some type of fine screen system in the coolant return path that could be serviced for the first 50 hours, it would behoove you to do so.
This topic comes up occasionally."
 
"G'day Ricardo E,

Yes,

"G'day Ricardo E,

Yes, I am aware of the problems with internal flaking and clogging.

This vessel looks like it has never seen Salt Water, and from what I have seen from my observations of the insides if the Block, Heads, and internal passages in the Out-drive, I am positive that this is the case.

I am in the process of re-assembling the engine with new parts, and this is an opportune time to keep Fresh Water in it, and Salt Water out of it.

My question regarding the Water-cooled Exhaust Manifolds still stands.

I know I can install the Exchanger virtually anywhere, but what would be optimal so the Outlet can be routed to the Manifolds?

Thanks,

Bruce."
 
"(E/G = ethylene glycol...

"(E/G = ethylene glycol..... H/E = heat exchanger)

Bruce, while my mention of a "Previously Raw Water cooled engine" was definitely suggesting that previous "salt water usage" would be of more concern......, a previously river/lake water cooled engine is an issue as well (although certainly not as great!)
There is still a concern for the debris build-up that can dislodge and eventually restrict the heat "exchange" between the tube bundle and your E/G coolant (I.E., reduced efficiency of the H/E).
How long this would take to build up and restrict is unknown!
Hope that makes sense!



Bruce, if your 'still standing question' is regarding elevation of the H/E relative to the Exh Mans...... the concern may be raw water that would continue draining from the higher elevation H/E into the exhaust manifolds upon engine shut-down.
I am not an engineer, and do not know how severe a difference this may make. It would be safe to suggest that it may be something to consider.

The cooling efficiency between raw water cooling, and cooling via an H/E system should, in theory, be very close to the same given that all is clean. IOW's, the exchange of BTU's will be very much the same for what is called a "half system" ( E/G cooling of engine only.... not exhaust)
Should you decide to include the exhaust manifolds, it would then become a "full system". A full system typically requires a larger H/E and sea water pump.

Good luck..... I like a good project!"
 
"G'day Ricardo E,

What

"G'day Ricardo E,

What is this E/G (Ethylene Glycol) stuff?

I will be using straight fresh water, with a bit of corrosion inhibitor in it for engine cooling, the same as I use in my cars. No need for Anti-Freeze down here in Gods' Country.

The H/E has been chemically dipped, flushed and cleaned out of all gunk by my local Radiator shop so I am not that concerned with stuff floating inside the engine, and it is the Salt Water that goes through the internal tubes. It is 27" long, and should be able to take care of the needs of the Engine and Manifolds

Plus, it is my intention to run the Salt Water, once it leaves the H/E, into the Exhaust Manifolds, and then to combine with the Exhaust Gases and out through the Stern Leg.

But, from what you are saying, I can still cool both the Engine, and Exhaust Manifolds with Fresh Water, and still have the Salt Water leaving the ends of the Manifolds, but I don't want any chance of "Back-wash" into the Cylinders.

This now begs the question "Should the H/E be low so that there is no chance of the Salt Water getting into the engine, via the Exhaust Outlets"?

I am trying to understand the "Complexities" of the Cooling System with this engine fitting, and there are pipes going all over the place, especially from the Manifolds.

I can follow the Engine Cooling cycle, but the Manifolds receive water at both ends, and have a crossover pipe at the rear (large diameter) and smaller ones at the rear-most fittings on the Manifolds.

Can I plumb the inflow to the H/E from the fitting that is fed by the Intermediate Housing, and then send the divided flow from the H/E Outlet to the other rearmost fitting on the Exhaust Manifolds? Or, wouldn't there be sufficient flow from the Water Pump in the Leg?

Or, can I do away with the Leg Water Pump, and simply install a skin fitting in the hull to draw Salt Water to supply an external Water Pump, Engine driven, and then this water feeds the rear fittings to leave via the Exhaust pipes?

Thanks for your patience.

Bruce."
 
"Here are a couple of pictures

"Here are a couple of pictures.

Bruce.


295306.jpg
Engine out"">
295307.jpg
Manifold
 
"G'day back to you, Bruce

"G'day back to you, Bruce!

What is this E/G (Ethylene Glycol) stuff?
I will be using straight fresh water, with a bit of corrosion inhibitor in it for engine cooling, the same as I use in my cars. No need for Anti-Freeze down here in Gods' Country.
Bruce, a mixture of Ethylene Glycol & H2O is used for Engine Circulating pump <u>seal lubrication</u> as well as engine over-heat prevention.
In the USA, it is commonly referred to as "Anti-Freeze" or more properly, "Engine Coolant".
I'd not recommend using straight fresh water, even with corrosion inhibitors.... E/G/H2O is a better choice, IMO!


The H/E has been chemically dipped, flushed and cleaned out of all gunk by my local Radiator shop so I am not that concerned with stuff floating inside the engine, and it is the Salt Water that goes through the internal tubes.
Understood. However, it is the potential contamination <u>from the Engine Block</u> that is my concern for the H/E... not the other way around.

It is 27" long, and should be able to take care of the needs of the Engine and Manifolds
You will want to run calculations in order to know if this unit is capable of both Engine and Exhaust system.


Plus, it is my intention to run the Salt Water, once it leaves the H/E, into the Exhaust Manifolds, and then to combine with the Exhaust Gases and out through the Stern Leg.
Correct! this is common!

But, from what you are saying, I can still cool both the Engine, and Exhaust Manifolds with Fresh Water, and still have the Salt Water leaving the ends of the Manifolds, but I don't want any chance of "Back-wash" into the Cylinders.
If "fresh water" means E/G/H2O coolant, then yes!
As for including the exhaust in the Closed Cooling system...... again, see above and you must be able to separate the coolant flow between exhaust <u>manifolds</u> and the <u>risers</u>. Risers only will deliver the salt water into the exhaust stream.



This now begs the question "Should the H/E be low so that there is no chance of the Salt Water getting into the engine, via the Exhaust Outlets"?
I had somewhat addressed this.... but yes, I believe this would be best!

I am trying to understand the "Complexities" of the Cooling System with this engine fitting, and there are pipes going all over the place, especially from the Manifolds.
I could almost plumb one of these in my sleep, but maybe you could post a few photos of your proposed plumbing for us.


I can follow the Engine Cooling cycle, but the Manifolds receive water at both ends, and have a crossover pipe at the rear (large diameter) and smaller ones at the rear-most fittings on the Manifolds.
Again, maybe you could post a few photos of your proposed plumbing. Sounds as though you have what is referred to as a "Full System".

Can I plumb the inflow to the H/E from the fitting that is fed by the Intermediate Housing, and then send the divided flow from the H/E Outlet to the other rearmost fitting on the Exhaust Manifolds? Or, wouldn't there be sufficient flow from the Water Pump in the Leg?
I can't help you regarding the raw water pump......Just make sure that it's capacity is adequate.
As for splitting the spent raw water (sea water), yes...... it will generally be divided as equally as possible before entering the exhaust system!


Or, can I do away with the Leg Water Pump, and simply install a skin fitting in the hull to draw Salt Water to supply an external Water Pump, Engine driven, and then this water feeds the rear fittings to leave via the Exhaust pipes?
Some out drives use the sea water to cool the upper gear unit.... I am not certain re; the OMC.
Again, the exchange of engine heat, in BTU's, will be very much the same (between closed system and open system) providing that all of the system is clean and free flowing.
IOW's, your OEM raw water pump should work for a half system!

Thanks for your patience.
Patience?
uhoh.gif


Edit: Bruce... I typed this Sundy PM... was interrupted... did not post until just now, Monday AM.
I'll look at the photos when I have time.
Rick "
 
"G'day Ricardo E,

Thank

"G'day Ricardo E,

Thanks for the reply.

I ventured over to the Mercruiser site and saw the article where the fella wanted to remove his Heat Exchanger, and it took me hours to read all the replies, and now I understand a lot more than I previously did.

I note with interest the fact that Salt Water doesn't like being heated up too much, so my idea of cooling the Exhaust Manifolds with Salt Water has gone out the window, as I want to keep the Engine Cooling fluid up in the higher heat range, for better performance, and fuel economy.

I will sit down and make a diagram of what I intend to do in relation to both the Closed System, and the Exhaust Gas cooling.

Can't have the Rubber Exhaust hoses getting burnt away.

Plus, I see what you mean about the internal cooling of the Leg via the internal Water Pump.

Bit hard to do much trial and testing down here, as not much chance of getting replacement OMC parts at short notice.

Back soon.

Bruce.

PS. Nobody down here uses Anti-freeze in cars, and seeing as our sea temperature gets to around 10 degrees C, I can't see much of a problem with overheating."
 
"I note with interest the fact

"I note with interest the fact that Salt Water doesn't like being heated up too much, so my idea of cooling the Exhaust Manifolds with Salt Water has gone out the window, as I want to keep the Engine Cooling fluid up in the higher heat range, for better performance, and fuel economy.
There is no problem cooling the exhaust with Salt Water..... It is Salt Water Engine Cooling where temps can cause Salt Water Crystallization.
The exhaust temps will/should remain cool to the touch on each riser, if all is good.
Bruce, your E/G solution within the engine will be "Thermostat" controlled. No worries there.... you can choose your temperature!


I will sit down and make a diagram of what I intend to do in relation to both the Closed System, and the Exhaust Gas cooling.
Exhaust gas hydrogenation and cooling has been pre-determined by OMC in their manifold design.
Not much you can do except increase or decrease the amount of sea water flow. The OMC raw water pump is already sized accordingly!
You will be just fine!

Can't have the Rubber Exhaust hoses getting burnt away.
They will not become blistered or burned so long as you have water flow!

Plus, I see what you mean about the internal cooling of the Leg via the internal Water Pump.
I can't confirm that on an OMC.... I do Volvo Penta drives.



PS. Nobody down here uses Anti-freeze in cars, and seeing as our sea temperature gets to around 10 degrees C, I can't see much of a problem with overheating.
Well, most all auto manufactures build these with coolant in mind! Like said, the Circ Pump seals are meant to be lubricated with E/G.
E/G also has a lower bp! "
 
"Looking at the picks, the sys

"Looking at the picks, the system already sems to be set up with the cooling of the manifolds integrated in the engine block cooling, and only the 'raisers' cooled by water 'out'.
I would have invested in a new set of manifolds with raisers and 'simplified' the cooling.
Saltwater cooled manifolds to keep exhaust temp down, and only fresh water internally in block."
 
"I've worked on undergroun

"I've worked on underground mining equipment with Cat diesels running 95% water and 5% Cat's supplemental coolant additive.
They typically get 10,000 hours on water pumps with no leaks. This was in a salt mine.
It contradicted everything I learned about EG vs. straight water. The water they had down in that mine wasn't great either."
 
"with the lack of lift in thos

"with the lack of lift in those "risers", I'd very closely check the water shutters in your intermediate.
Because the bellhousing and intermediate have to be split to change them on a stringer drive, it's not something you can do later. Might want to throw a new pair in for insurance regardless."
 
"G'day Hy Stat,

Thanks

"G'day Hy Stat,

Thanks for the information on the Water, and the "Water Shutters" in the Intermediate Housing. Now I have to go and have a look-see at what they are, and where they are.

With regards to Anti-freeze, I am aware of the need for the correct mix in late-model engines due to the correct heat for the sensors to operate the engine via the computers, but in my case, in normal every-day cars that I drive, 1972 Cadillac Eldorado and 1970 Ranchero, they get straight Water, from the tap, and have never had a problem with these, and all my other cars I have owned since 1964.

Heck, I even use Tap Water in my Batteries.

They say to use Distilled Water, but what I do is, put the container under the tap, pour in the water, let it sit for a minute till the water stops moving, and then it "di-still-ed" enough for me. We even drink the water that comes out of our taps down here.

Bruce."
 
"I just did a thorough investi

"I just did a thorough investigation of the Exhaust Manifolds, Intermediate Housing, and Upper Mount, and there is no such thing as a "Water Shutter" or "one-way" flap to stop any water from reverse-flowing into the Cylinders.

Is there anywhere else I should be concentrating on to find it?

Thanks,

Bruce."
 
"It appears I led you on a goo

"It appears I led you on a goose-chase there Bruce. I see no water shutters in the adapter housing of a 155. sorry about that.
I can't see for the life of me how seawater doesn't hydrolock your engine everytime you stop the boat...


Every stringer I have worked on has large spring loaded, rubberized plates in the intermediate housing adapter plate. Port side only on 4 cylinder, both sides on V6 and V8.
They're #42 in this pic, but it's a much later year than yours.
http://shop2.evinrude.com/Scripts/ImgServ.exe/convert?ilFN=E%3A\EmpartWeb\Data\41\983414\12.TIF&ilSC=100&ilIV=0&ilBR=0&ilIF=P&ilRE=8"
 
"That's okay Hy Stat,

I

"That's okay Hy Stat,

It got me going deeper and deeper into the guts of the matter, and now I am more conversant with the way it all works.

The Raw Water is supplied from two sources, at the "Y" Pipes on the rear of the Manifold Housing, and as this water pressure is supplied by the Water Pump in the Leg, there is no way that this water can go into the Cylinders as it cannot flow till the Engine actually starts, and by the time the water reaches the Manifold, the engine is firing, and the Exhaust Gas pressure will stop it from going the wrong way.

The only way I can imagine water getting into the engine is if the engine suddenly stops, as the boat is in the vertical position, with the bow downward, and by then, water ingestion via the Manifolds is going to be the least of one's concern. Water ingestion via the mouth is going to be of more concern, and hopefully the Life Vests are going to hold one up clear of the wet stuff.

Now I have to look for replacement Manifold Cooling Gaskets, and a 160 or 180 Degree Thermostat, as the one in place is a 130 Degree one.

Bruce."
 
"The Raw Water is supplied fro

"The Raw Water is supplied from two sources, at the "Y" Pipes on the rear of the Manifold Housing, and as this water pressure is supplied by the Water Pump in the Leg, there is no way that this water can go into the Cylinders as it cannot flow till the Engine actually starts, and by the time the water reaches the Manifold, the engine is firing, and the Exhaust Gas pressure will stop it from going the wrong way.
Bruce, there should be only one source.... and that is the single Raw Water pump.
First in line should be the H/E (although some older system vary), then the exhaust manifold(s)..... <u>(if not included in the closed system)</u>..... then the spent raw water goes on and out the exhaust system.

The only way I can imagine water getting into the engine is if the engine suddenly stops, as the boat is in the vertical position, with the bow downward, and by then, water ingestion via the Manifolds is going to be the least of one's concern.................
And this is what the exhaust "Flappers" are typically installed for!
Also note that engine idle RPM and camshaft profile play a role in this water reversion as well.


With regards to Anti-freeze, I am aware of the need for the correct mix in late-model engines due to .....................
IMO, you are doing yourself a disservice by not using E/G & h20 mixture..... regardless of year model.

Heck, I even use Tap Water in my Batteries.
They say to use Distilled Water, but what I do is, put the container under the tap.........................
You may be missing the point....... tap water will shorten the life span of your batteries by introducing conductive properties and elements into the battery electrolyte.
This water must be PH neutral.
Allowing tap water to sit does not remove these elements! This should be Distilled Water!

How is the progress.... any new pictures?

."
 
"G'day Ricardo E,

Oops.

"G'day Ricardo E,

Oops....... I meant that at the moment, there are two sources of Raw Water going into the Exhaust Manifold Outlets. One each side from the fitting that the Raw Water initially passes through, on the back of the motor, and then another two pipes from the top of the Thermostat Housing, after the Raw Water has done its' job of cooling everything.

What I intend to do is do away with the side pipes on the rear housing, and plumb the Raw Water from this rear housing, to the H/E, then from the H/E Outlet, to the Rear Manifold Outlets via a 'Y' joint to equalise the water going to each side.

I am also going to convert the Thermostat and Housing to a simple Automotive type, as there will now be no need for the complicated setup as it is now.

This Engine/outdrive combination doesn't have Flapper Valves, and never has had, and there is no possible way of fitting any if I wanted to.

I am going to use Anti-freeze (E/G) in the Closed System, as I don't want any possibility of corrosion inside the various parts.

Pictures in the next posting.

Bruce.

PS. I was having a joke regards the 'Di-still-ed' water, but here, the water in our pipes is the purest in the world, and I have never had a problem with using it in batteries. Yes, I know Distilled Water is supposed to be used, but when I was in USA last year, I couldn't believe that your Supermarkets sold Distilled Water by the bottle. Never see that down here."
 
"Something tells me that you h

"Something tells me that you have a cooling system not quite of OMC design.
I have not been able to find it in the BRP catalog.
Square manifolds,and hoses going here and there.
The last of the 155 are listed in 1972, but that is normal even if the boat is a 73.
This is what it should look like:
295468.gif
"
 
"<[img]"http://www.marineengin

"
295476.jpg
Before being named 'Killing Time', in Auburn NY"">
Before being named 'Killing Time', in Auburn NY}
295477.jpg
Soon to be back on the Trailer"">
Soon to be back on the Trailer
295478.jpg
Just completed the Upholstery and Dash Panels"">
Just completed the Upholstery and Dash Panels
295479.jpg
Engine about to receive the Heads"">
Engine about to receive the Heads
295480.jpg
This is where the powerhouse fits"">
This is where the powerhouse fits
295481.jpg
Inside the Intermediate Housing."">
Inside the Intermediate Housing.

Bruce."
 
"G'day Morten,

Your Sch

"G'day Morten,

Your Schematics looks different to what is in my boat.

I believe that my boat was built by Chris Craft in 1973, as there is are 1973 Certification Tags on the Fuel Lines, and these have never been touched until I stripped it down and replaced the lines.

As you can see by the pictures I posted before, there are hoses going everywhere, and the Manifold Cooling consists of a 1 1/4" hose going into the front on one side, the water flows through the Manifold and out the rear, then across to the rear of the other side, via another 1 1/4" hose through the manifold, and out the front, and then out to the Exhaust Gas cooling via 3/4" hoses along with the Engine water.

Bruce."
 
"My connection speed to the BR

"My connection speed to the BRP site is close to down, nothing moves fast from Malaysia!
Anyway I'm a bit suspicious that someone has taken a car engine and thrown in.
The 'funny' cooling part at the rear of your intake manifold reminds me of the heater outlet???
Even the dished pistons indicates that, but I'm not too familiar with what they used at that time.
Do you have the history from start of this boat and engine?"
 
"G'day Morten,

From wha

"G'day Morten,

From what I saw when I pulled everything to pieces, the Exhaust Manifolds, and attached hardware are original.

As far as the engine goes, I cannot guarantee that it isn't an automotive one as I have never witnessed the insides of one of these Buick V6's, in the flesh, as this is the first one I have ever laid hands on, but I do know that the Water Pump has been replaced, as it is a different colour.

When I stripped the engine, and removed some of the blue paint, there is a Red colour underneath the Blue, but I put that down to it being some sort of protection prior to painting it Blue.

I am not sure what was the colour that Buicks used when these engines were in the cars, but pulling the engine down, it appeared for all intents and purposes to be original on the inside, as it had that "feel" about it.

Further, the Intermediate Housing hadn't been off the Leg, and the Intermediate Shaft didn't look to have been removed and the Ball Gear was so worn out, I think it was an original part.

The attached picture is from another Gull Wing Chris Craft that I found on the "Chris-Craft Gull-Wing Photo Gallery" site.

295519.jpg
1971 Gull Wing"">
1971 Chris Craft Gull Wing.

As can be seen, the Cooling hoses are virtually the same as mine.

Bruce."
 
"Interesting.
It might be ano

"Interesting.
It might be another option and that is that the engine has been marinized by Chris Craft.
I have found old inline 6 and V8, but no V6 as 'Chris Craft' engines. What is typical for them is the 'box' type manifolds while OMC used more like 'loaf type' and with the OMC casted at the side of the manifolds.
Sounds a bit strange that OMC should make this 'plumbing galore' that must be rather expensive when they already have a 'std' version.
That cooler-like 'splitter' you have where the raw water comes in from intermediate housing, I suspect might contain some valves/springs that directs cooling water out to the exhaust when thermostat is closed.Why it has a double entry (?), I do not know.It might be that one entry is for exhaust cooling and the other for engine supply, you have to take it apart to find out. Hopefully the internal parts are salt water resistant and operating?
In total it looks like similar to a closed circuit cooling, but without a heat-exchanger.
Had it not been for the low rated thermostat, I would have guessed it is a 'fresh water only' design."
 
"Very interesting indeed.

I

"Very interesting indeed.

It would be interesting to see if it was a Fresh-water only Marinisation. But, the way I see it, the Water Pump in the Leg supplies water to the engine, and the Exhaust Manifolds together, then the Engine's own Water Pump circulates it within the engine whilst the Thermostat is doing its' job of regulating the flow within the engine itself.

Yes, it is a Chris Craft Marinisation, as there are Chris Craft Identification Plates attached to the Exhaust Manifolds, stating the Engine size and Engine Number.

The "Cooler Splitter" does have constant flow to the Engine Water Pump, via a "T'd" fitting in the Exhaust Manifold to Engine Water Pump intake, and "Controlled" flow from the Splitter to the Manifold Outlets, as well as Full Flow from the top of the Thermostat Housing, back to the top of the Manifold ends at the "Y" Pipe.

I was thinking that the reason was to enable water-cooling of the Exhaust Gas whilst the engine was cold, and also when the Thermostat was open, plus an outlet for the rest of the cooling water from the Manifolds whilst the engine was warming up.

I haven't opened it up yet as I am wanting to see if anyone knew just what it did, and if there was a trick or anything, in case I messed it up. But, I will bight the bullet shortly, and hopefully surprise myself.

It took a lot of careful tapping to get the ends off the Manifolds when I decided to strip them down for internal sandblasting.

295523.jpg
Manifold Tag."">
Identification on Manifold

Bruce.

PS. Hope the water routing description isn't too hard to understand."
 
"By the way, suggest you move

"By the way, suggest you move further discussion to the Chris Craft board here at Marine Engine.
Click 'discussion board' on top, and you will find it scrolling down."
 
"I didn't think I was bein

"I didn't think I was being naughty as everything was centred around the OMC Stern Drive Unit that is attached to the engine which is in the Chris Craft Hull.

I now realise that the plaques were not clearly visible as they were covered with dust in the first photos.

But, I have asked questions on the Chris Craft board about the hull, so I have done the "Right thing" in the past.

Some things just overlap, and then continue on a tangent.

Any Chris Craft people looking in here?

Bruce."
 
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