Pinging? Or a cracked manifold?

[JackFish]

I've been backing off my timing and removing vacuum in an effort to track down a pinging noise that I get on acceleration. To no avail.

There is a crack in the exhaust manifold, right around the choke stove area.

Could this be the source of the pinging-like noise?

 

[Bobscoupe]

Yes, it could be.

 

[fordconvert]

The crack could also be a lot worse than you think. A crack or leak around the choke stove means that the choke is drawing in exhaust. Exhaust will eat up the metal line, size the fitting on the choke housing, melt the choke stat, and plug he heck out of the vacuum port for the choke to the point it has to be drilled out not to mention keep the choke from working properly. I know this because that was what was wrong with my mustang when I bought it, it had a 'bad engine'. A new manifold, carb kit, and some used carb parts it was running fine.

I imagine it started out with a small crack. As the choke started to fail it started running rich. The rich exhaust sucked in fresh air and continued burning extra hot (sort of like a catalytic converter). Hot enough to melt that tube for the choke. You can just break off parts with your fingers.

 

[ludwig]

Somebody knew what was going on. They have been welding the crack on the underside. BTW, that is the typical condition of the the choke stove. Over all, the metal on a 40 year old cast manifold gets really brittle and punky sounding, especially at the high heat areas.

I just tapped and plugged the hole, top and bottom, until I got a set of headers. Then I bypassed the stock stove using an aftermarket choke stove to run the 1100. Ahh, that's much better.

 

[JackFish]

The flash negated any shadow that shows depth on this photo, but it looks like the badlands, about ready to crumble!
I started pulling everything apart yesterday.
Finally going to swap in my new head, manifold, cam, and timing chain. :mrgreen:
Here's a pic of the valve train @ 108,000 miles, if the odometer is to be believed:

Nice and clean, no sludge. On the inside, that is!!

 

[ludwig]

If you got the top end all nice and sweet, maybe you should go for an exhaust header too. 'Course, like most of us, you also hit the $$$ wall too.

Good luck with the assembly. Like you need it.

BTW, is that some Canadian high-volume carb warming spacer there?

 

[JackFish]

Got the head off, woo, was this one bad!

No headers for now, it's a fox-body, so I don't know what will fit.
And I have another manifold ready to go anyways.
That's just a stock EGR spacer. Those damn pipes are so hard to un-seize I took the head off with everything still attached.