Author Topic: 24/2 Lister Coolant Manifold Leaking  (Read 3671 times)

Dave

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24/2 Lister Coolant Manifold Leaking
« on: April 09, 2011, 03:51:35 PM »
I bought a 24/2 back in 2005 and a 15KW head for a generator. I have been working on it ever since in my spare time. I started it up last weekend and I noticed some coolant dripping around the base of the manifold where it touches the engine as well as the hose barb king fittings that screw into the manifold. The threads were real loose and I thought the threads maybe BPT instead of NPT. According to the documentation I could find on it, the 1.25" pipe has the same TPI and should tighten up just like the BPT was NPT even though there is a 5 degree difference in thread angle.

The fitting was real loose in the threads and would not tighten and bottomed out. I put a lot of Teflon tape on it but it still leaks. I would think that if the pipe thread die was wore out, the threads would be shallower and irregular and the NPT pipe would not thread on. The threads look clean and sharp in the manifold. My first suggestion was to JB weld the hose barbs onto the manifold. I will probably try that since my other thought was to drill out the threads and try a 1.5" thread. I don't know if I have enough material around the perimeter of the manifold.

 I have questions.

            1) Is there some other thread standard other than NPT and BPT?
            2) Do they make hose barbs for this oddball thread?
            3) If I buy new manifolds, will they have the same problem?
            4) Does anybody sell coolant manifolds with good NPT threads?

Thank You for any help you can provide. I promise to have some pictures ready for my next post.

Dave
         

Tijean

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Re: 24/2 Lister Coolant Manifold Leaking
« Reply #1 on: April 09, 2011, 05:07:26 PM »
The flanges are threaded british straight pipe thread unlike  north american tapered pipe thread. A total abomination wherever I have encountered them. Lots of teflon tape on a npt nipple is a common fix but it does not make a mechanically strong connection. J&B weld (metal filled epoxy) is another gap filler for this. 1 1/4 npt would be the next larger standard size but as you suggest there likely will not be enough material. A tap that size is not in everyones tool box either. I would fab them from 1/2 carbon steel plate and either weld in female coupling halfs or a suitable sized barbed nipple.
Frank

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Thob

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Re: 24/2 Lister Coolant Manifold Leaking
« Reply #2 on: April 09, 2011, 06:05:20 PM »
I've had better success on leaking plumbing by using pipe dope instead of Teflon tape.  If you want to be able to take it apart again, you can get pipe dope at most big box hardware stores in the plumbing section.  I buy the white stuff with Teflon in it.  If you don't want to take it apart again, the clean it and use JB weld.
Witte 98RC Gas burner - Kubota D600 w/ST7.5KW head.
I'm not afraid to take anything apart.
I am sometimes afraid I'm not going to get it back together.

Dave

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Re: 24/2 Lister Coolant Manifold Leaking
« Reply #3 on: April 09, 2011, 11:36:34 PM »
I think I like the JB weld solution. Let's see where that goes...


Thanks Guys!

LowGear

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Re: 24/2 Lister Coolant Manifold Leaking
« Reply #4 on: April 10, 2011, 01:08:08 AM »
Of course JB Weld rules especially in this application.  I got a couple of cheapskie bio-diesel pumps and JB Welded proper pipe threads on them as I was concerned about cracking the cheap and crummy pump housing. 

The black stuff in the can seems heartier than the tube of white stuff to me.  The white stuff comes in at least two kinds.  One for metal only and then one rated for plastic as well.  Some folks use the tape and the dope together.

Casey
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bcf

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Re: 24/2 Lister Coolant Manifold Leaking
« Reply #5 on: April 24, 2011, 11:57:41 AM »
I used a rigid pipe threader with an ajustable die head to cut oversized threads to fit my lister.