question about timing and mufflers ??

[rddaves54]

I had to take my truck back to muffler shop today to have it checked out and the gaskets were burned out where they connect to exhaust manifolds. He told me the timing was off and running hot. He said that because of that the gaskets burned away and the galvanized pipe had the galvanize burn off as well up near the manifolds. It has been two months the pipes have been on.

Has anyone ever heard of that?

I set timing today at 8% and the RPMs at 600. It seems to be running better. When I took air breather off the top of carburetor it was black would timing cause this or do I need to adjust the carbs?

[GREASEMONKEY72]

i dont think ive ever heard of that before

[cdowns]

if a motor is running lean and not timed right ,i've seen manifolds and exhaust pipes golow cherry red

you say carbs tuned?? does that mean you're running multicab setup?

[Sinister]

If your timing is retarded, exhaust will run hot.

[GREASEMONKEY72]

that is true if its to lean it will run hot

[rddaves54]

No, only one carb but I was not sure what made top of carb black.

That means it was getting too much fuel right?

[GREASEMONKEY72]

what part of the carb is black?

the top outside or inside under the choke plate?

[Hubscrub]

Originally Posted by rddaves54

No, only one carb but I was not sure what made top of carb black.

That means it was getting too much fuel right?

lean is its not getting enough fuel, to much fuel is called running rich

[rddaves54]

the top outside of carb and around on the inside of the air breather holder.

[Rreemo]

I've seen one run lean enough to burn powder coating off of header primaries, so I'm sure it's possible. I would look to set your timing with full advance (30-32 degrees at around 2800-3000 rpm) instead of just setting it at base.

What ignition are you running, how does the truck seem to drive, do you hear in pinging (rattling), what carb is on it?

[Hubscrub]

Originally Posted by Hubscrub

lean is its not getting enough fuel, to much fuel is called running rich

sorry, i might have misunderstood you, i don't want to sound like a smart butt, i think i see now you was talking about the black on the carb, has it backfired through the carb? it has turned my air cleaner underside black when my truck has done it

[rddaves54]

I am running Pertronix ignition kit (1181) ignition and the truck today after timing and RPMs adjustment seem to be running great and smooth. Yes, it had back fired a few times a few weeks ago but has not since then.

“I would look to set your timing with full advance (30-32 degrees at around 2800-3000 rpm) instead of just setting it at base.”

Does this mean to run engine to 2800-300RPM and set the timing to 30-32 degree? And is this done while vacuum is unplug or plugged?

What would that do or help. Like I said it is running good today I was concerned because it has a old quadrejet 4bbl on it and I did not rebuild and I heard that I should not as they are hard to rebuild.

So I wanted to run it until I could do something with it. I have not adjusted anything on carb and did not want to unless I needed. That is why I asked about the black on carb but now I know the back fired caused it. Tail pipes are not black so the fuel is not too rich ,(I guess).

[rddaves54]

I had the gaskets replaced at muffler shop and he put the left pipe too close and I cannot shift into anything but reverse and drive it will not move down the pipe stop linkage. I had single exhaust but this should not have been a problem right? I am taking back tomorrow to get it move so I can shift (automatic).

I was reading posts and saw “mandrel bent” what kind of bend is this and how is it different from muffler shop bends?

[Tkmadone]

Sinister is correct, retarded timing causes unburned gas to continue burning as it is going out the exhaust, which heats it up considerably.

The lean thing is a misconception. At stoichiometric mixture, meaning there is the perfect amount of gasoline to burn all the oxygen in the cylinder, it burns hottest. Any richer or leaner it will be cooler than that.

At very high power settings, like going up a long hill, it can be beneficial to run a little rich to keep things cool. At cruise, where power is low, you can run quite lean with no ill effects.