Blown Exhaust Gasket?

[Ayles]

Went for a short 15 mile cruise the other day and about a mile from my house the exhaust note changed dramatically.

The car was running beautifully and still starts right up and idles no problem.

The car has ARP hardware so I think its unlikely an exhaust stud is broken.

https://youtu.be/xLz0TCJdaY8

[Jack Stands]

Broken diluvar head stud (really hope I'm wrong on that)!

[OldSpool87]

I can't see what year car it is but that could also be a missing air injection plug.

[timmy2]

Originally Posted by OldSpool87

I can't see what year car it is but that could also be a missing air injection plug.

His sig shows an '82 so maybe.

[Ayles]

Interesting, i havent heard of that plug. The head studs are ARP, so I think that would be unlikely that one is broken. Can I see the plugs with an inspection mirror and a flashlight?

[OldSpool87]

If you have them they are visible and look like this:


My '82 does not have them and it looks like the first pic in this thread:
No air injection ports 1982SC





Sent from my iPhone using Tapatalk Pro

[DanielDudley]

Sometimes you have just got to get under there. If you have the original muffler, they do wear out. If you blow a hole out the bottom, it will be as you described.

[Ayles]

Went under the car yesterday afternoon. All of the plugs are in place/tight and everything is very clean/dry.

Also went through my engine documentation (build was done by Dick Elverude) and the car has raceware head studs and only about 450 miles. I have a B&B header system that may have cracked, found a few threads with that issue.

Looks like I will take the header off of the offending side to examine the gaskets and make the sure it hasn't cracked.

[OldSpool87]

Would soapy water trick work? Granted you'd have to start with cold engine and move quick.

[gerber28]

To find an exhaust leak on a cold motor I have a cut off air hose wrapped with foam to make a tight seal at the tailpipe. Turn down the air pressure to about 10 lbs and you can usually hear your leak. to pinpoint a hard to find location I use smoke from an incense stick.

[Ayles]

How about a blown out O2 sensor plug! Wish I would have noticed before dropping the header. But happy it appears to be a simple solution.

[DanielDudley]

Never would have guessed that one.

[OldSpool87]

Glad you found the culprit. Good news overall.