Is it possible to easily and reliably plug the air injection ports on 2.0l heads that have the ports? If there is a way, would it effect airflow?

It can be done in two different ways.

1. Cap the tubes,
2. Remove the tubes and plug the holes.
(or I guess if the heads are off, you could weld them shut)

Here is an old link that gives some information on this:
http://www.914world.com/bbs2/index.php?act...r,and,injection

Wow- amazing. thank you for the response. I hadn't even had this posted for 2 minutes before I got a response!!!

Greetings!

It has been a long time since my last post, but am back working on my '76 teener.

After pulling the air injection lines from my car, I have read a number of these posts to be able to effectively plug the ports. Capping seems to be the most popular and effective to preserve a future owner's ability to re-install the pump and lines.

I was on the McMaster Carr site and found acorn nuts in a variety of materials from brass to stainless and many metric sizes. Does anyone knows the actual thread size on top the injector pipe where the lines connected. I know the NPT stuff has been used, but a proper fitting cap with some muffler seal would seem to be the best long term solution.

Thanks in advance.

Tom

I thought I remembered that valve adjust screws fit. I have plenty of used valve adjust screws!

I know the valve adjust screws fit in the head, but I am thinking about the size of the threads on top of the air injector where the pipes fit on them.

Anyone?

Tom

I pulled one of my air injection tubes out and took it with me to Tacoma Screw and found some nice brass caps. I THINK they are 3/8 pipe threads. Anyway they fit well, don't leak, and look pretty good also. Like you, I wanted to make it easy for the next owner to go back to completely stock if desired or required. Tom

I pulled one of the injector tubes and took it to a specialty fastener place and they came with some odd ball british pipe thread size. Sold me some nice bolts for $6 each, but they fit perfectly. Sorry can't remember what exact size they were. Would definitely try for the correct size and not screw up the threads, just in case you ever want to reinstall the air injection. The PO used JB weld and some brass caps but he didn't seem to get them sealed very well so I switched out to the bolts.

I got mine years ago from performace products or tweeks. I think they were sold as 911 air injection plugs. Home depot does have the galvanized end caps that fit are pipe thread (for end of air injectors screwed into head).

pic

My first posted pics in answer above. here are a couple more.
Tom

I thought I'd share my experience with this. Car is a '76 2.0 California spec. I removed the air pump and the air injection manifold. I also removed one of the air injection nozzles to take to the hardware store. The thread on the "head end" of the nozzle is a M10-1.0. Its 50mm from the tip to the seat. The perfect bolt to replace the nozzle is a M10-1.0x50 socket head (allen).

I originally had planned to simply cap the the nozzles in-situ. However, they are definitely not 3/8 NPT as suggested in this thread. I was able to easily thread a M16-1.5 nut on the coupling end of the nozzle. I figured I wouldn't come up with a cap of that size easily, so I went the nozzle removal route and replaced with the bolt above.

Tom
83 911SC 3.4
76 914 2.0

The end of the nozzle is indeed M16. I bought some acorn nuts from Belmtric although I think my preferred method is replacing the nozzle with a bolt.