Fresh water coolant flow

[NormP]

Several years ago I rebuilt my 4-108. I also changed from the Paragon to a Borg Warner hydraulic transmission which requires an oil cooler. I bought a dual heat exchanger for the oil and transmission. When I plumbed it I first went through the oil heat exchanger and then the engine. Now I am having second thoughts, and I am thinking about going through the engine first. I haven't had much luck getting information on which way to go. Does anybody have insight on which way is best? I do know that the two fluids exchanging heat need to be flowing in opposite directions.

NormP
Portland OR

[eveningebb]

Norm,

I have a Westerbeke W40 with a Borg-Warner Velvet Drive transmission.  My raw water system runs with 3/4 hose:

1.  from the thru-hull inlet to the strainer,
2.  through the V-drive
3.  through the transmission oil cooler
4.  to the raw water pump
5.  then to the oil cooler mounted on the engine
6.  through the heat exchanger
7.  and then into the exhaust elbow.  

The transmission oil cooler was marked with a flow direction and the oil cooler is designed to be part of the raw water system, you can see the design on the engine cooling system schematics.  Good luck.

Dirk

[zaya]

Hi Norm,

could you please tell which borg warner transmission you used to replace the paragon. what did you have to do for that work ?

thank you

Phil

[NormP]

Hi Phil,

I installed a Borg Warner 71C. It is a 1:1 ratio. I talked to Walters Machine about it and they said using a reduction will overpower the Vdrive. It has been a while so I am trying to remember everything. You have to install a transmission oil cooler/heat exchanger with the raw water system. It is bigger and heavier than the Paragon. You will have to make more room below and it would not hurt to to add a mount for it (I didn't). It is longer so the jack shaft must be shortened. Not a big deal since it is adjustable (at least mine is). I seem to remember having to buy a new U joint coupling to match the bigger BW coupling. Finally consider the damping plate on the flywheel. Replace it with a new one that is designed for the BW. I replaced the damping plate with a new one for the Paragon. Don't do that.  The damping plate is crucial for reducing torsional vibration reduction at idle and no load conditions. The BW is a tight fit and will be hard to install and remove without cutting something away. I put mine on before installing the re-engine and have not had to remove it yet. I am deciding now whether or not to change the damping plate. If you remove the bell housing be careful of the shims on the bolts to the engine. They are there to align the mating surface to the transmission. The surface has to be flat and perpendicular to the shaft rotation by a pretty small amount. You may want to check it with a dial indicator. By the way the bolt pattern is all set for the 71C. The two bottom bolts are actually studs that allow the transmission to be slid onto the bell housing. As usual, alignment is very important. The U joint allows for quite a bit of angular slop, however axial alignment to the Vdrive is important. The Vdrive input can take some misalignment, check the specs from Walters. The Vdrive alignment to the shaft is the least forgiving. Just be sure that everything can be align within the specs. Walters has all of the alignment requirements. As you can see, it is not just a drop-in replacement. That is all I can remember, hope that helps.

NormP
Yashure
Portland OR

[Jim S]

Before replacing the Paragon, I would suggest attempting to adjust it.  It is not difficult to do the adjustment and it worked well on Phantom.  The details on how to adjust were in the original engine/transmission manual.  There are still places that will rebuild the transmission.   You just have to look around to find them.

[SV THIRD DAY]

And by the way, why did you replace the Paragon ?  (mine is slipping in reverse, so I'm considering replacing it).

Phil....mine was slipping also, then a 5 minute adjustment fixed the problem!  I would definitely look into it before shelling out the boat bucks for a new tranny if that is your only issue.