Replaced the zincs on my engines today. I found teflon tape on the threads of the zincs in the heat exchangers. These are new exchnagers (OEM Crusader) that were put on in the spring befor my move to saltwater. Wouldn't those zincs have been installed at the factory? If so , what's up with the tape?
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Teflon tape
- Thread starter Gregory S
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I would take it off just to be safe.
Don't use teflon tape. It will insulate the connection. "Pipe dope" is a better choice. Same for plumbing for seacocks, thru hulls, etc if they are bonded. You don't want to have to bond each piece.
And - they say not to use teflon tape in a fuel system because pieces can break off and clog things. Again, pipe dope is a better choice.
And - they say not to use teflon tape in a fuel system because pieces can break off and clog things. Again, pipe dope is a better choice.
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Zincs are only effective when there is an electrical connection, so the use of Teflon tape is ... odd.
( Yes, Stephen, they would be easy to remove, but they would never work as intended! Imho. )
( Yes, Stephen, they would be easy to remove, but they would never work as intended! Imho. )
Most of the time with/without tape you will get continuity between the bolt and what its going into. If you don't believe it, pull out your ohm meter and check. Facts always outweigh opinions.
That said, most of the time the fitting won't leak without it, so your safer to just put them in without anything. When you do need to seal something 9 times out of 10, rector seal #5 will be a better product.
That said, most of the time the fitting won't leak without it, so your safer to just put them in without anything. When you do need to seal something 9 times out of 10, rector seal #5 will be a better product.
well, despite the tape, they seemed to be working. dissolved at a faster rate than the other zincs. I was always told not to use tape where electrical connection was needed like in oil pressure senders etc, but now I'm thinking it doesn't matter. But then, just because they dissolved, doesn't mean they were connected to anything and protecting the engine.???????
Capt. Bill1
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"Most of the time with/without tape you will get continuity between the bolt and what its going into. If you don't believe it, pull out your ohm meter and check. Facts always outweigh opinions."
+1 to that. Also if you want to use tape, just start the wrap a couple of threads back from the tip, as you should any time you use it, that way you know for a fact some of the threads are making direct contact with their counterparts on the cooler and making for a good electrical connection.
+1 to that. Also if you want to use tape, just start the wrap a couple of threads back from the tip, as you should any time you use it, that way you know for a fact some of the threads are making direct contact with their counterparts on the cooler and making for a good electrical connection.
It's tapered NPT thread, so tape should not be needed for good seal and it's use is counter to Crusader manual recommendation, so that is odd if it was that way from the factory. More likely if this was just a new cooling system the installer unscrewed the cap to make sure the pencil was in there and reinstalled, but still odd there is tape. Just take care to not overtighten the pencil anode cap. It's not that hard to split the brass H/Ex fitting or the brazing that holds it in place if you try to really firm it down until it stops . You might want to make sure that is not the case already to require tape, and that a metric thread pencil cap was not used .
boatcomfort
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Teflon tape is not for fuel lines. But there is teflon paste that's what is the best seal and keeps threads lubricated for easy removal. On Zinc pencils I notice that some (very few)manufacturers they coat the threads with some red stuff like some other fittings those don't need other dopes. But they cost a bit more. Why?? I can't answer.On my reply to Kida I had suggested teflon but sorry I should said teflon paste or pipe dope. No tape.
I've had 25 years as an a/c, refrigeration and commercial appliance tech and have much experience with both tape and paste. If you use the tape and start it - as suggested above - 1 or 2 threads from the end, you'll be fine for the 1st season. When you pull it out, tho', it'll leave little threads of tape stuck into the deeper threads. When you screw the new component in, it'll push those threads into the cavity and they can plug metered orifices. If you pull a component that was installed with tape, shine a light in there and take a look - you'll see those little teflon threads. You'll want to spend as much time and effort as is needed to get "all" of those teflon threads out. A tiny thread can cause a huge problem - usually at the worst possible time.
Teflon paste will lubricate the threads, too, making the component easier to get out. You'll seldom see the old hard setting sealers anymore. Either tape or paste will be cut by the pressure of the threads and you'll have metal to metal contact and both will read OK on an ohmeter....always did for me anyway. I've tried it with no sealer, since - as mentioned above - it is a tapered thread and had uneven results. Sometimes it works, others not. The threads have to be perfect for that to work. Use the paste.
If a component is really in there tight, heat the end of it with a torch (not always possible or recommended) and get it as hot as possible. Heat only the component...then wait for it to cool off before putting pressure on it. The heat apparently "cooks" the sealer and often it'll come out more easily. If there's plenty of metal around it, heat the metal fast with a good torch and put pressure on it immediately, before the component heats up and expands. Often the housing will expand, allowing easier removal of the component. Every situation is different.
Tighten the component till it's good and snug - you don't have to put a cheater pipe on it and reef it to 500 lb/ft. Take it easy. If you do get a drip, tighten it a bit more. If it still leaks, pull it and re-coat it with paste and try again. Easy does it.
Many manufacturers of commercial kitchen equipment will void warranties if they find that someone has used teflon tape in their product. After a lot of experience with both, I rarely use teflon tape anymore.
Hope all this helps.
Lar.
Teflon paste will lubricate the threads, too, making the component easier to get out. You'll seldom see the old hard setting sealers anymore. Either tape or paste will be cut by the pressure of the threads and you'll have metal to metal contact and both will read OK on an ohmeter....always did for me anyway. I've tried it with no sealer, since - as mentioned above - it is a tapered thread and had uneven results. Sometimes it works, others not. The threads have to be perfect for that to work. Use the paste.
If a component is really in there tight, heat the end of it with a torch (not always possible or recommended) and get it as hot as possible. Heat only the component...then wait for it to cool off before putting pressure on it. The heat apparently "cooks" the sealer and often it'll come out more easily. If there's plenty of metal around it, heat the metal fast with a good torch and put pressure on it immediately, before the component heats up and expands. Often the housing will expand, allowing easier removal of the component. Every situation is different.
Tighten the component till it's good and snug - you don't have to put a cheater pipe on it and reef it to 500 lb/ft. Take it easy. If you do get a drip, tighten it a bit more. If it still leaks, pull it and re-coat it with paste and try again. Easy does it.
Many manufacturers of commercial kitchen equipment will void warranties if they find that someone has used teflon tape in their product. After a lot of experience with both, I rarely use teflon tape anymore.
Hope all this helps.
Lar.
I have never seen any leakage from around my HE pencil zincs and I don't use anything on them nor particularly crank them down. I guess I wouldn't be overly concerned if they did seep since that's just the raw water, other than that I might then be dripping salt water on the starter or the mount. Losing a few drops out of the raw side is not going to cause a cooling problem.
I also really wouldn't worry about bits of teflon tape getting into the HE since the passages are something like 3/16" wide. Those are just going to flush out.
I also really wouldn't worry about bits of teflon tape getting into the HE since the passages are something like 3/16" wide. Those are just going to flush out.
Any sealer is a good idea IMO to prevent any drips. It may not be necessary with new fittings because NPT distorts on tightening to form a seal but a small salt water drip can cause problems. I totally agree that Teflon tape should never be used in AC or fuel systems because of the small bits that plug stuff. It is OK for water pipe but I prefer dope.
No tape or pipe dope will insulate the fitting. The threads cut through anything for metal to metal contact. The pipe dope etc just seals the small spaces where threads may not. Use an ohm meter to verify conductivity if you are in doubt.
No tape or pipe dope will insulate the fitting. The threads cut through anything for metal to metal contact. The pipe dope etc just seals the small spaces where threads may not. Use an ohm meter to verify conductivity if you are in doubt.
I use Loctite 592 on all of my pipes and fuel lines. I believe this is called out on the Merc service manual as well. The biggest benefit of "stuff" in the threads is to decrease rotating friction so the flanks of the threads can be tightened enough to "seal" on them selves. Definately stay away from Teflon tape though in fuel lines.