4BT cooling upgrades input

[Shannon Ritzert]

I changed my plans on the new expansion tank install.  I had some questions, and wanted to make sure I am on the right track.  I need to get a few parts on order, and I am hoping to get everything on one ticket.  

 

 

 

 

Due to having very limited space under the motor covers on a Bertram 28, I decided to build motor boxes.  I want to mount the expansion tank and overflow bottle against the cabin wall as shown in the picture.  

 

I mocked up an engine in my shop, and mounted the expansion tank against the wall to simulate how this will be installed in the boat.  The height of the tank, and distance from the engine is all to specification on how it will be in the boat.

 

I want to run a 3/4 inch hose from the expansion tank, to the thermostat elbow as shown in the picture.  The nipple on the tank is 3/4 inch.

 

Can I then run a hose from the thermostat elbow to the exhaust cap as was original on the 4bt?  Francis Valerio did quite an extensive post on this project, and the pictures Rob Schepis posted shows this hose to go to a casting plug should be on the exhaust manifold.  I don’t see what difference it will make, as they end up in the same water jacket.  See pictures

 

I was going to vent the same as the picture rob posted on the exhaust cap, or vent on the elbow of the heat exchanger.  I have seen vents in both locations, and I assume picking the highest point to vent is the main objective.

 

I also read where Tony commented in Francis’  post that the return lines on the heat exchanger need only be 1/8 of an inch.  I was going to have those returns like the original 4bt (out of the exhaust cap elbow, and a location on the head)  I assume that 1/8 hose is plenty for these returns?

 

I am fallowing Tony’s Tips Cummins B-Series Coolant Plumbing, and the response I had from Tony a while back on upgrading the 4bt to 6bt cooling.  I am questioning the 1 inch line from the thermostat elbow to the exhaust manifold casting plug.  I wanted to get confirmation on this, and I wanted to see if I needed to change the turbo banjo to 1″ as described in this article as well.

 

Thanks guys!!

Topic

[Shannon Ritzert]

other line sizes?

I seen in another post where Tony said 1/8 to 3/16, and if you oversized, you would get air in the lines.  I see you just used barbs, and 3/16 hose, as opposed to flair fittings.  I would prefer barb over flares, so I don’t have to have hoses made. I did do the t-stats the year before last

On the 4bt with the original expansion tank, the tank just drops directly into the heat exchanger.  On the remote tank I will run a new 3/4″ line to the thermostat elbow like you are saying. 

Also on the 4bt there’s a 3/4 line that originally goes from the thermostat elbow to the top plate on the exhaust manifold.  On the 6bt that line is recommended to be 1″, and it dumps into the side of the exhaust manifold instead of the top plate.  Do you know if I can use the same plumbing as the 4bt? 

It was also recommended to increase the line size on the turbo, and the return line size from the turbo to the head to 1″  Do you know if I should do the same plumbing on my 4bt as the 6bt, or is this overkill for the 4bt?

[Patrick Mangum]

Vent Line Size

I just completed a similar remote expansion tank install in my 28 Carolina Classic with 6BTAs.  Much for the same reason, limited space in the engine room.  

When I talked to Tony about it, he recommended I use 3/16″ lines for the vents going from the various places on the engine back up to the tank.  I sourced some 3/16 fuel line and used that.   3/4″ main line going from the tank to the engine is correct.  It’s my understanding that the coolant in the vent lines by-passes the HX so if you have too much coolant by-pass you’ll overheat.  

While I was at it I went ahead and installed the 160 t-stats.  I’m happy I did this project, it really improved my engine room.  

I hope this helps.

[Shannon Ritzert]

Trying to upload pictures, sorry for the second post, pictures wouldn’t upload with the original post for some reason

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