Plugging air injection holes with solder

Last time I removed an air injection system from a v12, I plugged the holes “by the book” which involved tapping these plates for short bolts. The short bolts also had to have the threads ground off a portion. It was lots of work.

I’m feeling lazy. How about just pooling the holes up with plumbers solder?

Which holes? in the covers or in the manifold? Surely you mean manifold holes as you’d not create a seal plugging the covers.

If melted in, I’d worry about them melting out. And how would you ensure none drips out the bottom of the passage onto the valves?

Easier than grinding down bolts, just tap the manifold holes and screw in some grub screws.

Usually the passage is blocked by carbon deposits farther down than the tap needs to go and this catches the swarf. I put some grease in before tapping and then used a q-tip to remove the greasy swarf. The passage leads to above the exhaust valve so I didn’t want any to escape.

I bought the concrete studs from Home Depot recommended in Kirby’s book, I trimmed them shorter, dipped them in steel putty, and pounded them in. Only took me a couple of hours and no leaks. Probably not much more than soldering.

IMHO, solder is not a good choice.
I’ve done several of these.
Tap the hole 1/4-20, grease the tap first to hold the chips.
Use short allen-socket-screws to plug off the hole, screw them down flush
Reinstall the heavy tab-washer and nut
Done!

Agree. I have no numbers for exhaust temperatures and the flow temperatures for common solder. But, my sense is that at times
exhaust temperatures are high enough to “melt” solder.

I’ve used versions of “drill and tap” for Allen headed fasteners on at least three former critters. Neat and reliable.

Carl

i think i have been left out of things?

my heads and manifolds dont have any holes yuo speak about!!

Nobody likes the solder idea… so I guess even less would agree to JB weld! Tap and plug it is then. Set screws in aluminum seems like less work than tapping the plates, grinding bolt threads off, etc.

Thanks, John

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