Air injection holes in Exhaust Manifold

[bpilati]

I was driving back home from visiting my parents when suddenly a lot of noise started coming from the engine bay. Sounded like something major had broken. So I came to a stop and turn off the engine. Got out the mini-Maglite and looked under the hood. Couldn't see anything obvious so I started the engine up, and sure enough it was still noisy. So I took a second look around and it was not coming from the valve area or block. Finally as I was mildly revving the engine I saw what was like a blue torch flame coming out of the exhaust manifold. One of the plugs used to replace the air injection tube had blown out. Imagine having a blue flame shooting right out of the exhaust port against the intake manifold. Does that sound dangerous to anyone? Guess when this happened. Well naturally it was 10:30 pm on a Sunday night. Well, it was a fine time to try to get help. I finally called a neighbor who came from an hour away to pick me up. Luckily I found out a friend at work had a car trailor, so he saved me a ton of money on towing. I haven't looked at it yet, but no doubt at least the intake will have to come off to make an on-engine repair. Hopefully it's repairable.

[EScanlon]

:cheeky: You mentioned ONE "of the plugS", so depending on whether it is one or two:

http://kalecoauto.com/index.php?main_page=product_info&cPath=1&products_id=8

http://kalecoauto.com/index.php?main_page=product_info&cPath=1&products_id=2

E

:cheeky:

[beandip]

you will need to remove the manifold, sorry . I just dug out my old 240 manifold to see how my PO plugged the holes. there are nuts showing on the face of the holes and they are welded closed. Many people have gone though the removal of the tubes . This is not really a necessary thing really doesn't effect the performance. With or without the tubes being there. Have the holes welded closed. If you live close to Portland Oregon you can have my manifold for free. Gary

[Arne]

I'm with beandip on this one - mostly. Since the manifold is cast iron, welding is difficult at best, even for an expert welder. I'd braze the holes up instead.

[Pop's Z]

Bryan, Here's what I did. I could not find a plug to fit the strange thread/taper in the exhaust manifold so I removed the air gallery and pulled the tubes out of the exhaust manifold, cut them off flush and replaced them( they seal like a flanged fitting inside the manifold). Then I cut the plugs off of the air gallery flush with the tops of the plugs and had them welded shut including the remainder of the tube. Problem solved and they don't leak and will not blow out. Good luck. Mike

[a7dz]

It is probably easiest to get the tubes out and screw plugs back into the holes. I am not going to remove the air tubes on mine unless they give me trouble. But, in your case you have to repair it some how. As bean dip stated it may be easier to get another manifold have it decked and then use it. Welding or brazing on the rusty fittings in there now will be a challenge to say the least. not to say I have not done so.

[Arne]

Yeah, but finding a usable '70-72 manifold is tough - I gave up. All the ones I found had the tube firmly rusted into the manifold, so there was no easy way to deal with them. And the '73 manifolds have EGR ports that need to be plugged, and that it hard to do as well.

Because of all this, I had resigned myself to using a header on the yellow car, even though that is probably unnescessary for a stock L24.

[bobc]

Try using brass plugs. The brass is softer than the steel, so this may help with the thread problems. I use to use brass plugs when I removed air galleries many years ago and used brass plugs that I purchased at the hardware store. Never had a problem with one coming out or leaking exhaust. The guy that taught me this trick said the brass expanded faster than the steel, so it made a very tight seal.

Hope this helps,

Bob

[fugetaboti]

When I bought my Z a while back, I wanted to clean things up, and removing the air tubes was one of the first things I did. I went about it all wrong when I used JB Weld to plug the holes. One by one, they would pop off during hard acceleration. I took the old fitting from the air tube and went to NAPA to have them match it up to some brass caps. I installed each one without removing anything from the engine. It can be difficult on some holes, but it is very possible with everything in place. I found it to be easier if the manifold was somewhat hot. If the manifold is cold, you'll have a very diffcult time installing the hard to reach holes. Hope this helps.

Rick

[Arne]

Yeah, brass plugs are probably the answer if the threads in the manifold ports are still good. The header that was on my parts car had smog tubes, and the plugs do appear to be brass. I do know that they sure don't want to come out now (header cold).