hot exhaust pipe and poor power

[Clem Clement]

The huckster we had been working on finally started. Lots of backfiring. The car has been sitting for 3 months with gas in the carb. We reset the timing using the Nurex special tool. After getting a fairly good hi idle, the exhaust pipe just aft of the exhaust manifold became cherry red. If we reduced the idle some the temp went down some. We retimed the engine to no avail. Also the motor had no power and a very slow acceleration. The radiator was fill.

It started poorly but idled OK.
We decided the carb, which had been rebuilt 2 years ago, had collected water and junk in it and removed the carb for rebuild which we will do later.

Any other ideas?

[jax55]

Carb may be part of the problem, sounds like it is running very lean. That would certainly cause lack of power and a too hot exhaust. Report back after the carb is rebuilt and how it runs now.

[Tom Wesenberg]

Late timing

[Russ/40]

Or more commonly called too retarded.

[edmondclinton]

Yup, too retarded.

[eagle]

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Sounds like timing but could possibly be intake leak.

[Brentwood Bob]

plugged exhaust, loose manifold.
bob

[Fred K-OR]

Due to the fact it was sitting for 3 months, mouse nest in the exhaust??? Just a WAG.

[George Miller]

Late timing

[heneste]

Is it possible that the car has a 'B' timing gear cover? If so, the timing pin may not be recessed in the block when the car is at top dead center.

[Quigley1930]

Late timing resulting from early beer

[Tinker]

Back firing through the exhaust is a typically a over fuel situation. Left over fuel igniting in the exhaust vs popping out the carb. Timing makes sense. But maybe not...

[fiddlybits]

Late timing. (Possibly too rich as well)
Cherry red because fuel still burning in manifold.
ignite sooner or less fuel to put flame back in cylinder.

[tbirdtbird]

late timing late timing late timing
classic case if there ever was one.

i have only heard of the Nurex method and never seen it. It obviously doesn't work.
Fix it before you warp the daylights out of the manifold and burn the valves

[redmodelt]

Generally I have found that a lean mixture and not advancing the timing makes the manifold glow red. An overly lean mixture does not have any extra gas to help cool the valves so all the mixture is burnt causing the manifold to glow.

[Big hammer]

Remove exhaust pipe/muffler/tail pipe---and see a two foot flame late timing

[Patrick L.]

Sounds like either a plugged exhaust or not enough ignition advance [ later timing].

[George Miller]

Late timing

[Purdy Swoft]

A classic case as Tbird says. Moved the points cam and introduced clockwise backlash. Points gap is probably also too close. I also think that the Nurex method slightly retards to help get by with V8 points .

[tbirdtbird]

Thank you, George for the emphasis!
Thanks Purdy for the Nurex tip. Why does nurex even exist? it is not needed.

This is a chance for everyone here to master an important lesson. This one you have to know. This is just as classic as it gets for late timing.

-The exhaust is NOT plugged
-A lean mixture runs hotter yes but you could NEVER lean it out enough to turn the exhaust manifold red (1100 degrees)...the engine would stall long before that could happen
-the engine has no power because the burn is so late it cannot do any useful work.
-The maximum cylinder pressure has to occur at about 10-15* after top center. In this case the max. pressure from the burn is occurring way later than that, prolly 25-30* ATC or later Problem is, the piston is so far down at that point that the volume of the combustion chamber has opened way up (the farther down the piston the greater the chamber volume, think about it), and the burn of the fuel is just dumping into a widely increasing space, and the fire just ends up going out the exhaust without actually doing anything.
-listen to your exhaust on this car right now. It will be much louder than a correctly timed motor
-fuel does NOT explode, contrary to popular belief It burns. An expanding flame front advances , raising pressure and pushing the piston down. In order to have the max pressure at about 10-15* after top center, the fire has to be lit early; it needs a head start. Thus we time a motor so that the spark actually occurs BEFORE top center
-try to get your head around this. A good mechanic does not need a timing light or timing marks, his ear tells him all he needs to know. Try to understand that timing is way more than a bunch of marks on a crank pulley, or for an A, more than just shoving a pin into a recess on a cam gear
-nearly every owner-tuned A that shows up here is timed late. Not as late as this case tho!!. I am surprised the engine will even run at all.
-no one knows timing and tuning better than the racers...just ask Pete or Jim B
-i once worked on a motor that had the cam installed 2 teeth off!!! Took forever to start the motor and then it ran like crap and exhaust turned cherry red in about 3 minutes.