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kycat2007
07-24-2007, 01:24 PM
I had some problems with the plastic and brass petcocks on the LT1 in my Maristar. I tried to loosen them and they just cracked out. Well I had to get the plastic out so I torched the plastic and scratched out the remaining debris. I then bought some 1/2 inch pipe thread plugs and installed them. Well I put on the tef tape but I am having some leak issues. Someone told me to use the tape and some pipe dope. Is this the solution to this problem? Do you think I am going to have to retap these holes if it doesn't work? any suggestions appreciated.

kycat2007
07-24-2007, 06:36 PM
bump...............

east tx skier
07-24-2007, 06:40 PM
The LT1 must have a different setup. I replaced all my engine drains, petcocks and otherwise with brass plugs. A little teflon tape and they don't appear to leak. I think you lost me with the "plastic" part.

JimN
07-24-2007, 08:08 PM
If you want to use the two hose setup that connects in the middle, that makes life a whole lot easier. That way, you never need to worry about the fittings on the manifolds being a problem because you never need to remove them. Otherwise, use brass pipe fittings and pipe dope or more wraps of Teflon tape.

kycat2007
07-24-2007, 10:12 PM
I have used lots of tape but still leaking. I threaded them the opposite way of the thread. I am going to try the dope to see how that works next.

thanks

JimN
07-24-2007, 10:29 PM
You want to use NPT fittings. The threaded part is tapered and usually pretty self-sealing.

WTRSK1R
07-24-2007, 10:31 PM
Pipe threads are tapered, so the farther you turn it in, the larger the plug or pipe becomes. This is different than normal threads on a bolt. Technically, the teflon tape or pipe dope is really there to help it from siezing so that you can remove it the next time, not to seal a leak. :twocents:

You might want to see if you can just tighten it a small amount further.


Then again, maybe the pipe dope will take care of it too since it will fill any voids as you are turning the plug in.

WTRSK1R
07-24-2007, 10:31 PM
You want to use NPT fittings. The threaded part is tapered and usually pretty self-sealing.

Beat me to it.

JimN
07-24-2007, 10:42 PM
What I didn't type before I posted is that the NPT fitting doesn't need to be cranked too tightly. Only a couple of things can ha[[en if it's cranked too much- the brass thread will shear and/or the cast iron will crack.

kycat2007
07-25-2007, 12:14 AM
I have barely put it in and then tightened it more but the leak is still there. When it got to the poaint that I could not see the hex head of the plug I figured I was screwed. After lots of tape it still is leaking but not as much as it was spraying in the beginning.