Advice on exhaust pipe connection

[tyssniffen]

So, I have a extension pipe connected into the exhaust Outlet and I noticed that it isn't threaded in very deep and I've got gas escaping at that connection point. I would love to hear advice on how to thread that thing more deeply or what sort of goop to put on the threads to close up the gap.

[broncodriver99]

How long of a pipe? The flanges on the engine should be threaded BSP thread. Aren't you in North America? Assuming the pipe is something you picked up locally it will be NPT. They are close but not the same. Certain sizes will only partially thread together. You can run BSP pipe and fittings which are available online. As far as goop the only things I can think of that would work are high temperature silicone/RTV or maybe furnace cement.

If it is just a short extension pipe I would just order a BSP threaded pipe online.

[tyssniffen]

It's about a 4-ft run

[AdeV]

Worst case scenario - use Exhaust Bandage (assuming it's available in the USA).

Just wrap the stuff over the top of the leak, rather than trying to fill the threads with anything.

To re-thread the pipe, you first need a pipe threader (tool hire places should do them) - but the likely sticking point will be getting hold of the right BSPT (British Standard Pipe Thread) taps/dies.... easy enough this side of the pond, less so I guess on yours.

If you've got a local British Auto specialist, they may also be able to help.

[dax021]

Not to nit pick, but I always thought BSPT was British Standard Pipe Tapered

[tyssniffen]

so, if I were talking to someone or renting a tapping kit, what would you all say are the specifications of the exhaust port?
1.5inch "British" tapered?     sorry, this is not an area I know about.

[broncodriver99]

There are two different BSP threads. BSPP which is a parallel thread(like a bolt) and BSPT which is a tapered thread(pipe fitting). The flanges on the engine should be BSPT. The issue is 1.5" BSPT is 11 threads per inch where 1.5" NPT is 11.5 threads per inch. So, after a couple of threads of engagement it takes up any slack in the thread form and binds. There is also a difference in thread pitch and form between BSPT and NPT. One cannot simply rethread  BSPT thread to NPT. You either need to have an adapter fitting(one end BSPT and the other NPT) or run the whole pipe system in BSPT.

You can also try old school pipe sealing cord/thread. Below is a link.

https://www.amazon.com/Loctite-442-35082

[broncodriver99]

Here are a couple of links to adapter fittings. Couple one of these with an NPT coupling or union and then run the rest of the system in NPT. As you can see they are a little expensive. You can probably find them cheaper elsewhere.

https://www.mcmaster.com/products/standard-pipe-fittings/standard-wall-steel-threaded-pipe-nipples-and-pipe-11/pipe-size~1-1-2/thread-type~bspt/

It's the bottom two that say BSPTxNPT.

[tyssniffen]

Here are a couple of links to adapter fittings. Couple one of these with an NPT coupling or union and then run the rest of the system in NPT. As you can see they are a little expensive. You can probably find them cheaper elsewhere.

https://www.mcmaster.com/products/standard-pipe-fittings/standard-wall-steel-threaded-pipe-nipples-and-pipe-11/pipe-size~1-1-2/thread-type~bspt/

It's the bottom two that say BSPTxNPT.

this is good stuff. I was just searching for such a thing.  yeah, pretty spendy. I'll go to a supply place, now that I understand the specs.   Thanks.

[ajaffa1]

Easiest answer is to take it to a blacksmith/welder and have him braze the joint. You won`t be able to dismantle it ever again but it won`t leak.

Bob

[t19]

I tried that with a piece from home depot.
Ended up taking off the cast piece and using a exhaust manifold part fron canadian tire.   Careful i had to grinfd off some width as it was pusing against the rod.