"Connect to Engine" instructions

[Angela]

I am replacing the heat exchanger for my not-too-old Westerbeke 15 KW genny (at the 900? hour mark). I bought a Westerbeke replacment H/E, this time in cupernickel (I think the original was not cupernickel - at least there are no such marking on it like there are on the new one), and the replacement H/E has a stud on it with instructions to "connect to engine." The orignal H/E had no such stud or instructions. So, am I really supposed to connect this to the engine, and if so, to where? Thanks for any advice you can give me.

I'm replacing the hoses, etc., since I have all this apart...a "while you're in there" thing.

[geofish]

Could it be for a grounding strap or cable?
If the exchanger is mounted with rubber strips and connected to the engine with hose, this stud may be there so you are bonded with the rest of engine with a strap or wire, especially if it really looks out of place in regards to the mounting method.

CUni (copper nickle) is good stuff and not cheap huh?

Good Luck!
Geo

[Angela]

It is held on to the engine by metal staps, combined to make one, but one at each end, i.e. four pieces combined to make a total of 2 supporting straps/clamps. I'm just not sure where to "connect to" the engine that the instructions want me to run some sort of grounding wire. I'm pretty good at engine work where I just cleanup, replace, or refurbish what was there, but when a new instruction comes along that tells me to do something that wasn't there originally, I'm not sure where to go, and as in this case, I don't know where to run the wire between the H/E and the engine.

Maybe in my application, the "connect to engine" doesn't apply, but I'd like confirmation from the folks smarter than me, and in this respect, is most of you. Admittedly, electricity of any kind, unless I am Just copying what was there, is a challenge for me.

[rsmith]

maybe they found out it wasnt getting bonded properly thru the mounts. What happened to your first one?

[REBrueckner]

Does the new heat exchanger have a pencil zinc of its own?? That's about the only cathodic protection that will help much. Pencil zincs elsewhere in the genny are almost entirely isolated from your heat exchanger by small feed hoses, rubber impellers, and so forth.

If you want to connect per the instructions, all they mean is to ground it somewhere on the generator....any exterior bolt on the generator will do that conducts to the generator bonding via metal.

[Boatnut]

It sounds like a ground connection. Straps are not usualy the best ground connection. You could connect the wire to the same connection the battery negative is connected to.

[Angela]

Thanks for the advice. The first one which is the original one, wore out, meaning something inside corroded to the point that the saltwater and coolant mixed and the coolant left out the exhaust. Then, it was just being cooled entirely by salt water. So, I've got some flushing to do as I clean this up.

Yes, it does have it's own pencil zinc - both the old one and new one have that. Will that "connect to engine" wire do anything to help the zinc fight off electrolysis and corrosion, or is it just a grounding wire so you don't get shocked by some chance?

[geofish]

Both!

[REBrueckner]

"You could connect the wire to the same connection the battery negative is connected to."

no. A bonding wire should never be connected that way. The entire bonding system shoud be kept distinct and separate from dc ground and ac ground and ONLY ever connected at a single point.

edit: while the prior statement is correct, a generator likely does not have it's own bonding connection....so connecting the wire between the gen and H/E is the almost the same as connecting it from the H/E to the negative terminal. Marginally better to connect the H/E wire to the nearest conducting (metal) point on the generator.

" Will that "connect to engine" wire do anything to help the zinc fight off electrolysis and corrosion, or is it just a grounding wire so you don't get shocked by some chance? "

The former...but it won't really help.....if there are good metals in the new heat exchanger it will last forever; if not, no amount of cathodic protection will help much. But I'd keep the pencil zinc maintained anyway.

My old Onan H/E had IRON ends and a copper core...an awful combination. Yet when I took it apart all that was wrong was the tubes were blocked with some kind of iron oxide (solid rust growth)...cleaned it out by breaking off the rust and it's still ok now at 39 years old. I never even knew there was a pencil zinc in that thing until I disassembled it....so I replaced it. Some stuff just works and other stuff doesn't.

[rsmith]

Hatt tied the bonds to the engines and generators and by default to the batt grounds, been that way on my boat for 44 years. Most people do not use the pencil zinks as they turn to mush and plug the tiny tubes in the exchanger. If the gen is tied to the bond system the zinks tied to the bonding system should protect the gen.
I dont know what OHNO you had but my 1967 MDJB and MDJC both ends are bronze and the cores copper.