Model- 100202
Type - 0232-02
Code - 6807266
I am hoping to (once again) tap into the collective wisdom and experience on this wonderful forum on a challenge I am having...
This is an old 1968 Briggs 4 Hp, horizontal shaft, "flathead" I am restoring. When I took the engine into inventory I noticed it had a 5" length of 3/4" water pipe screwed into the engine exhaust port threaded hole. I want to remove the pipe so I can eventually install an OEM Briggs "hot dog" style screw in muffler. This section of pipe is REALLY frozen in the block! I have ran into this situation before and have always been able to (eventually) remove these sections of pipe or old screw-in mufflers.NO-Go on this one!
Here is what I have tried so far with no success whatsoever:
1. Soaking that area in "Evaporust" for over 24 hours.
2. Spraying the junction of the pipe and threads with WD-40, PB Blaster, and Gibbs Penetrant and using a lot of "tap-taps" with a hammer to help jar it loose.
3. The "melted wax" technique where you heat the area with a propane torch just enough to melt candle wax and let molten wax be drawn into the junction/threads.
With all of these techniques I use a big pipe wrench and try to unscrew it. All I have done is start flattening the pipe- the pipe has not budged one bit. I am afraid about putting any more force with the wrench, or using any more leverage as I do not want to bust a section out of the engine block in the process.
Is it time to really put the heat on the area with the propane torch? If so, do I heat the pipe or the area around the threaded boss on the engine block? If the latter, should I have concerns about melting the aluminum engine block? I am wondering if the different metals in contact with each other (iron pipe, aluminum block) have resulted in galvanic corrosion over time and caused the two to fuse together? Does anybody else have any ideas on how to get this section of pipe out?
Thank you in advance for any help!
Michael