Perkins 4.107 Heat Exchanger Plumbing Problem

[v40163]

Hello all,

I have just finished installing a newly rebuilt Perkins 4.107 engine into my sailboat. The engine has an expansion tank across the top front of the engine. The heat exchanger hangs off the bottom of the expansion tank.

I believe that I have connected the hoses incorrectly as I am not getting any raw water into the mixing elbow.

As originally installed the fresh water flowed from the expansion tank into the exhaust manifold, then from the exhaust manifold into the heat exchanger. As I wasn't sure which connections were which I poured water into each of the ports and observed where the water came out. HOWEVER, I WASN'T SMART ENOUGH TO WRITE IT DOWN!!!

Due to lack of availability of Perkins hoses I chose to remove the heat exchanger from the expansion tank and rotate it approximately 180 degrees in order to facilitate connection of most of the other hoses. I fabricated a hose that runs between the exhaust manifold outlet and the heat exchanger inlet (at the top of the heat exchanger). I am 100% certain that this hose is properly connected.

There are three additional ports that are all around the bottom of the heat exchanger. Two of them come straight out from the heat exchanger while the third comes out and makes a 90 degree turn UP.

I connected the input from the raw water pump into one of the two ports that comes straight out. The second port that comes straight out I hooked up to the inlet of the engine oil cooler. The third port (the one that makes a 90 degree turn UP) I connected to the fresh water inlet on the side of the engine block.

What have I done wrong? I have attached a couple of pictures. The first picture shows three of the four connections. In the picture the exhaust manifold outlet (the one that doesn't go to the expansion tank) goes to the upper heat exchanger port via the home-built quad 90 degree hose that goes out of the picture and then reappears in front of the heat exchanger.

Of the two lower hoses that can be seen in the picture at the bottom of the heat exchanger the upper one goes to (actually comes from) the raw water pump outlet, while the lower one goes to the engine oil cooler (out of the picture).

The last hose (that cannot be seen in the first picture) is attached to the 90 degree port coming out of the heat exchanger and goes over to the fresh water inlet in the engine block. It can be seen in the second picture and is next to the raw water pump.

I hope someone can help me. I really don't want to have to remove the expansion tank or heat exchanger and do the "water pour" thing again.

Update: It appears that my pictures did not arrive with the post. I will supply them if someone can tell me how.

Thanks in advance,
Ray Russell
Valiant 40 #163
Enshalla

[h the boat]

Hi there, you will need to disconnect the installation and check the ports again. I know this may sound tedious, but it may be the only way. Firstly the main heat exchanger must have four connection points not three as you describe. two are for raw or sea water, the other two are for fresh water. You describe changing the relative position of the heat exchanger and header tank, the missing connection point to the heat exchanger may be where it bolts on to the header tank.. The correct circuit configuration is as follows. sea water in from sea cock,to sea water pump, out to oil cooler, out from oil cooler, in to end of heat exchanger, out of heat exchanger, in to exhaust bend injection point...The fresh water circuit is as follows, OUT of top of thermostat housing, to top or upper connection of header tank, lower connection or your third heat exchanger connection to one end of exhaust manifold water jacket, other end of exhaust manifold jacket to fresh water pump on front end of engine block . It dosent matter which way round the connection to the exhaust cooling jacket is made, but it is very important to establish the correct connections on the heat exchanger.. You may have to unbolt the end of the unit to establish which are the correct ports. The sea water must flow through the small tubes, not around them. It wont matter how long the hoses are, as long as they are well supported, you may be able to use rigid metal pipe for some of it, but remember stainless or bronze. Aluminium is no good for salt water, but may be used with care on the fresh water side. If its still not very clear, you can PM me for more info. h the boat..

[v40163]

Thank you for your reply. However, I did describe four ports--(Port #1), one at the top of the heat exchanger which is connected to the exhaust manifold output.

The other three are at the bottom of the heat exchanger-two that come straight out from the heat exchanger and one that comes out and turns 90 degrees upward.

One of the two ports that come straight out (port #2) receives raw water from the pump while the other port that comes straight (port #3) out is connected to the input of the engine oil cooler.

I connected the port that turns 90 degrees upward (port #4) to the fresh water inlet port on the side of the engine block.

But I was not aware that the raw water must run through the tubes as opposed to around them. I do plan to unhook the hoses and verify the installation.

Thanks again for taking the time to reply.

And I finally figured out how to post pics. I included two--one that shows three of the connections and one that shows the fourth (90 degree) connection.

Ray R

[CaptMack007]

this is an old post but if you or anyone needs this info...
here is what and where those connections go...that generic reply from h the boat was no help to your specific question...
On the vertical heat exchanger;
the bottommost straight is seawater in from the seawater pump out.
the straight right above it is freshwater from the starter motor side of the engine.
the 90 degree is seawater out. Leaving the H exchanger ( i send that water through two remote mounted oil coolers and then it dumps into the exhaust pipe.
the top fitting is freshwater connects to the bottom of the two hose fittings on the exhaust manifold.
the top of the header tank (its not an "expansion tank" thats a little plastic bottle that the radiator cap connects to with a little hose) attaches to the top hose pipe on the exhaust manifold.

[h the boat]

Originally Posted by CaptMack007

this is an old post but if you or anyone needs this info...
here is what and where those connections go...that generic reply from h the boat was no help to your specific question...
On the vertical heat exchanger;
the bottommost straight is seawater in from the seawater pump out.
the straight right above it is freshwater from the starter motor side of the engine.
the 90 degree is seawater out. Leaving the H exchanger ( i send that water through two remote mounted oil coolers and then it dumps into the exhaust pipe.
the top fitting is freshwater connects to the bottom of the two hose fittings on the exhaust manifold.
the top of the header tank (its not an "expansion tank" thats a little plastic bottle that the radiator cap connects to with a little hose) attaches to the top hose pipe on the exhaust manifold.

With respect, Capt Mack I suggest you read the post again. Your miss leading descriptions (not all installations are as yours) and statement regarding the" Plastic bottle with tube attached leading to the radiator cap " You obviously do not know the purpose of this item or you would not have made the comment. It is there to catch the expanded volume of coolent when the engine is hot, and returns it under a clever vacuum arrangement to the system when the engine cools. Perhaps you have another name for a small tank that catches the expanded liquid... The originating question was well received and understood by the sender, and I have no intention of entering a discussion merely to swell your posts. h the boat.

[CaptMack007]

A small plastic or sometimes aluminum tank connected to the fill neck on a header tank or radiator is the expansion, or overflow tank and the big tank under the radiator cap is called the header tank. As a professional marine mechanic, that is what they are called.
What was clear from your post is that you didn't know what the hose ports on a 4.107 are specifically are for, and perhaps have never seen a 4.107 Perkins. Your suggestion that the guy take the system apart to figure things out was a poor one; he needed a mechanic that knows that specific motor to reply. Not a general and vague answer. You don't know what the connection are, and still don't.

[h the boat]

Originally Posted by h the boat

With respect, Capt Mack I suggest you read the post again. Your miss leading descriptions (not all installations are as yours) and statement regarding the" Plastic bottle with tube attached leading to the radiator cap " You obviously do not know the purpose of this item or you would not have made the comment. It is there to catch the expanded volume of coolent when the engine is hot, and returns it under a clever vacuum arrangement to the system when the engine cools. Perhaps you have another name for a small tank that catches the expanded liquid... The originating question was well received and understood by the sender, and I have no intention of entering a discussion merely to swell your posts. h the boat.

With respect Capt Mack, no I dont know everything, I have only been a qualified Marine Engineer for the last 59 years, not merely a mechanic. For your information, I was the consulting Engineer between Perkins and Bowman at the design and conception of the Perkins 4/99 and subsequently 4/108 as a marine application during 1957, probably before you were born. There are 3 Bowman and several other makes heat exchanger, fitted to various versions of the 4/108 series. they may look similar in construction, but patents were at that time seriously respected and no two exchangers of different manafacture are identical. The method I described is the only positive way to discover the correct porting arangements if it is not known for sure. I hope this will close the matter for good of everyone. h the boat.

[E39Traveler]

For anyone who has stumbled on this thread and is looking for the answer to the same question as the original poster, I am here to tell you that CapnMack007 has replied with the factually correct answer to the specific question of what the 4 ports on this specific heat exchanger installation connect to.

I am qualified to chip in on this conversation because...
1) I have had the exact same Perkins 4.107 cooling setup with the heat exchanger that bolts into the underside of the header tank installed in my boat for 45 years. I have taken this system apart and put it back together many times.
2) I am a professional marine mechanic with a marine repair business and a staff of employees doing this stuff day in a and day out.

I am sure that "h the boat" is a fine engineer and based on his statements is quite knowledgeable about Perkins 4.99, 4.107 and 4.108 marine diesels with Bowman heat exchangers. But this is not a Bowman system and, as he said, he does not know everything. In this case, his statement that the only way to determine which ports are which on the heat exchanger is to pour water through it is a very inefficient way to figure it out.

Follow CapnMack007's description of the four ports on this exchanger and you will be good to go.

Also, CapnMack007's definition of "header tank" vs. "expansion tank" is also the correct one. The metal tank bolted to the forward top end of the engine is the header tank. It has a pressure cap similar to a radiator on the top of it and the thermostat is located under the header tank. In this specific case, the heat exchanger is installed into the bottom of the header tank. The "expansion tank" or "overflow" is more commonly referred to as a "coolant recovery tank" in these parts. The coolant recovery tank is connected to the small tube at the neck of the header tank where the pressure cap is installed. The header tank is meant to be full of coolant. The coolant recovery tank is meant to allow for expansion and contraction and to enable bleeding air from the system without coolant going into the bilges so it is typically about 1/3 full of coolant when the engine is cold.

Note: the original poster has rotated his exchanger 180* on its long axis to make his hose routing easier and you can see this in his pictures. I don't recommend copying that.

Semi-Off Topic: the best engineers have mechanical experience. The best mechanics have engineering experience. "H the boat" sets himself up as the authority here because CapnMack007 is "merely a mechanic", but the poster didn't have an engineering question. This was a question for a mechanic and in the end, it was the mechanic who had the more relevant and accurate reply to the original post. You need someone to design you an engine? Call an engineer. You need someone to fix your engine? Call the mechanic. The engineer will have you chasing your tail and the mechanic will get you back out on the water.
I find it interesting that good mechanics do not assume that this makes them good engineers, but many engineers assume that the fact that they are engineers makes them good mechanics and it simply is not true. Mechanic and engineer; two related yet completely different skill sets.