1500 emissions

[mylillooker]

I’ve got a 79 Midget (1500 engine). It’s got the Weber carb on it. It had been running fine but apparently has lost a plug that was in a hole in the exhaust manifold. Most likely part of the emissions equipment that's no longer there.

The hole is about 3/8 in round and the 3/8 NPT plug doesn’t fit. The threading in the hole seems to be thinner than the 3/8 NPT plug from the hardware store. It’s in an awkward place, which has made it more difficult because if I drive somewhere to have someone take a look at it it’s too hot to even see, much less touch.

I’m hoping that someone can tell me what was in it so I could have a reference point in my search to plug it. I’d even be happy with a suggestion as to what material could plug it and withstand the heat. As you could imagine, it sounds like a small tank!

It’s been sitting for a while, I’m out of ideas.

Oh yeah, the best I can offer is a crappy pic I took and a diagram from a catalog showing where the hole is approximately.

Mario

 

[Trevor Jessie]

Mario, you need somebody that has a spare lying around. You might check with ed@justbrits.com ... he may be in a helpful mood.

 

[jcatnite]

If I can get out during lunch today I'll look on my '76 and see if I can see what it might be.
JC

 

[sparkydave]

Hi Mario, I'm pretty sure that's where the EGR valve went. Earlier ones had it up on top between the intake manifold and the valve cover, but it seems to me it got moved to that location on later ones from pictures of other 1500s I've seen. I've heard of some folks just finding a bolt the right size to plug the EGR hole with, but I couldn't tell you what size that is.

-Dave

 

[jcatnite]

Mario,
I agree with Dave. That is where the EGR valve is on my '76. It isn't functional and I plan to remove it when I do my engine rebuild this winter. When you determine what will fit in there let us know. I had just considered welding mine up if I couldn't find a plug for it.
JC

 

[mylillooker]

Thanks to one and all. Once I figure out what size/type of threading it is, I'll let you know. Since the NPT (National Pipe Thread) wouldn't fit I'm trying to find a metric plumbing plug but haven't had any luck thus far. After that, I'm not sure which direction to go.

As usual, all suggestions are greatly appreciated.

Mario

 

[CrackMonkey]

If you can't find a plug, couldn't you JBWeld a coin over the opening? Or just fill it with JBWeld?

 

[adam70]

couldn't you just tap it to fit an NPT thread? or at the very least put a helicoil in it and use a smaller bolt. I've had problems like that on an old 81' porsche I had and did both methods when things came up "missing".

 

[Mark Jones]

It's fine threaded; UNF I believe. A normal fine threaded bolt, or the proper diameter of course, will fit.

 

[tortfeezor]

Mario, my friend, I have been where you are. I hunted high and low for such a plug for my '77 Midget (there's actually a thread on this forum from months ago about my misadventures). No luck.

I see someone has suggested JB Weld. Don't do it. If you read the JB Weld instructions, they say "not for use on really hot stuff like exhaust manifolds." In case you don't believe them, I can confirm that it's good advice.

If the suggestions from other posters don't work, you may have to do what I did -- buy a monza header.

 

[Trevor Jessie]

Tortfeezor, do you remember the sizes you tried that didn't work? Just to reduce Mario's efforts?