I have a Weiand 7546...

I have been trying for an hour to insert the manifold plug for the water. I am using the 1/2" plugs provided by Summit. (Should I be using 3/8?) Out of the 4 that came in the pack, 3 have been trashed upon inserting only about 1/4 of the way. At first I was nice and was going to do a "test fit" etc etc. Then things got nasty. The plugs wouldn't fit, period. So I lightly rubbed the threads on a sanding surface, hoping to maybe clean up a miscue or something. Then, I took a wire brush wheel and "polished" the threads of the ports, but it hasn't helped. Then I got pissed and tried to force it, leaving a thread from the plug lodged in between threads of the ports.

Is it the poor casting quality of my Weiand or what? I am afraid I might have to go have my manifold tapped and rethreaded. Any guidance would be appreciated.

Are those Summit plugs aluminum?

Sounds like galling. It needs some kind of lubricant on the threads.

Try steel pipe plugs with some teflon paste as a sealer/lube.

1/2" pipe taps are available at Home Depot, Lowes etc for about $12.00 to clean up the manifold, but just don't chase the threads too deep.

Holes taped in aluminum intakes are usually tapped with a straight tap. Most of the taps you find end in "npt", stands for "pipe tapered". Ask for a tap ending in "nps" which stands for "pipe straight". Clean your threads with a straight tap then use brass pipe plugs. The brass doesn't have the electro-chemical reaction with aluminum that steel has. You can take brass plugs out years later generally with no galling. Since the plugs are tapered they wedge into the straight holes. The "pt" taps make tapered holes that allow plugs to go deeper into the holes and they're harder to seal. Try it, you'll like it.

Thanks droptop and jonn!

Now that you mention it, the plugs are tapered! That's kind of a stupid design if you ask me but oh well...

I didn't wanna damage anything further when I was mad, so I walked away and came back to it today. What a difference a positive attitude makes! The plug was still tough to get in on the driver's side but it finally went in after some minor "sanding." The hole where the heater core taps into is a different story, still going to require a minor rethreading. Ill take your advice Dyno Jonn and get the NPS tap.

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double post graemlins/clonk.gif