What is the thread size of that small hole in the head near the exh port? Need to get six plugs to put in heads.

 

i just took the one of the old air injectors to the hardware store and they had plugs that were the same thread size. no idea though what the actual size was

 

m10 X 1.00
DIN 908 -Maryland Metrics has them

 

Joe,

On some thread I saw where a guy made his own (or had them made) out of long aluminum stock so the plug extended into the exhaust port. Then he milled it down flush to the port for nice smooth flow. I thought that was pretty slick, and shouldn't cost too much.

Win

 

I made plugs for mine. I tapped the hole all the way through, made aluminum plugs, and finished them smooth in the port. I also safety wired them (not shown in pic)

 

David,

Nice! That's the post I remember. What about using a TIG tack weld instead of safety wire?

Win

 

I can machine but I can't weld I guess I could have someone else do it or just weld up the hole. Of course it's hard to weld small, somewhat deep holes.

In hindsight, I wish I had welded up my original sparkplug hole and tapped it for 12mm like my second plug. That would have gained a little more compression.

 

Thanks. ...that's sweet on the flush machined ones, but mine are already on engine now.

 

Stephan has them or do a search. I ordered an extra one just in case I had one fall out at the track.....

You'll need hex heads as there isn't enough room for a socket.

 

Give us a call in the morning, we have the proper air injection plugs in stock that screw in with an allen.

 

I just installed a set of the IA plugs. Nice.

 

What, if any thread locker did you use?

 

I used red loctite but it's only good to 300 or 400F so I don't know that it's really doing any good. That's why I safety wired them. After the engine's been run a while, I imagine the exhaust soot will seal and lock the plugs in pretty well.