Exhaust manifolds glowing red.
 

First start up after rebuild.
2,000 RPM break-in and noticed they were glowing. So I shut it off. I think the carburetor needs to be tuned because I can't get the RPM past 2,000 when WOT.
Just glad I was doing this in the evening outside my garage. I was able to notice the glow.

Re: Exhaust manifolds glowing red.
 

Lean mixture. In general, high idle speeds will give a lean mixture unless the choke is closed slightly during break-in. Closing the choke a little will cause the speed to increase. You just need to use something to hold it slightly closed at an optimum idle speed, since the automatic choke will be hot.

Re: Exhaust manifolds glowing red.
 

Timing too retarded will cause the same thing.. Spark fires late and the burn process hasn't completed when the exhaust valves open.

Re: Exhaust manifolds glowing red.
 

Vacuum leak too. Inspect above notes, and correct.

Re: Exhaust manifolds glowing red.
 

So I finished the cam break-in. All went well. The timing was off so now that's been adjusted. Except the rear main seal is dripping oil like crazy. So I drove the truck to the shop that rebuilt the motor. The shop is gonna keep the truck over the weekend to repair the oil leak. Once that's done, gonna flush the water and refill with coolant, slap the new cowl hood on, and enjoy.

Re: Exhaust manifolds glowing red.
 

so it was just the timing being off? Was it a significant amount?

Re: Exhaust manifolds glowing red.
 

Is that just because it leans out the mix, or some other factor?

Re: Exhaust manifolds glowing red.
 

Not sure if bad timing had anything to do with the glowing manifolds. Not sure what's a significant amount for the timing, but it was hard to start, idle was rough, the idle was almost like a drag car, very little power. Adjusted the distributor and the carburetor multiple times. Checked timing with a strobe. Got it to idle around 700. Now she purrs like a cat.

Re: Exhaust manifolds glowing red.
 

cool...thx for the update

Re: Exhaust manifolds glowing red.
 

Was just one part of one manifold glowing red? That could mean a problem only with that cylinder. Have to wonder what the spark plug, valve, and top of piston look like.

Let us know when you find the culprit.

Re: Exhaust manifolds glowing red.
 

A carb meters the fuel by "sensing/reading" the incoming flow of air. If there is air be introduced into the intake after the carb it will cause a lean condition because it is getting more air than the carb is calibrating for.

Re: Exhaust manifolds glowing red.
 

yep, just wasn't sure if there was some other effect

Re: Exhaust manifolds glowing red.
 

Gotcha' - Sorry, I didn't mean to be condescending :banghead:

Re: Exhaust manifolds glowing red.
 

no sweat

Re: Exhaust manifolds glowing red.
 

Not condescending at all. But a good explanation of a lean condition caused by a vacuum leak.