I've never seen one like this... (Exh Manifold)

[DjS71]

Last post in my lackluster build thread, linked below.


I knew it had a leak, but... I was pretty amazed.

[Lee H]

Interesting, I've seen a few like that. Always wondered what caused it. Here's a picture from a pick a part last summer.

[Husker]

Thats wierd. Never seen anything like that.
Ron

[special-K]

I've had one blown out like that one,but not a hole. It looked like it exploded inside,ll bulged and fractured. It happened while descending from the North Rim of the Grande Canyon. Miles and miles of decelerating and braking. When I hit the gas at the bottom it sounded like an old tractor. I got down to Flagstaff and had headers put on. I actually wanted an original manifold because I had just had the exhaust custom made before leaving on the trip. Couldn't find one,so put headers on which required a dogleg cut and welded on my fresh new exhaust. This was in '89 and the truck had about 80k on it.

The other time was about 5 years ago. One manifold cracked all the way around where it collects (just below the hole in above picture) and just dropped the exhaust down with the lower part of the manifold attached. I used tie wire to hold it back up in place till I got home,then bought headers.

[Sammy]

Everyone I have seen cracked are always on the passenger side and in that area. Maybe just prone to cracking and this is the final outcome?

[special-K]

It's definitely fatigue,just the end of the life of that metal being one single piece

[70CHEVYBB]

A lean fuel mixture will dramaticly increase the exhaust tempatures. I'vwe seen the many times, but more on big blocks.

[DjS71]

Originally Posted by 70CHEVYBB

A lean fuel mixture will dramaticly increase the exhaust tempatures. I'vwe seen the many times, but more on big blocks.

That's what I was thinking, given the state of the carb when I rebuilt it.