With the amazing help of the Milwaukee T Club, I made my maiden solo drive in my 1927 Tudor today. What a thrill. But all did not go well.
I pulled the choke, hit the starter, and the car started right up. It was awesome. I pulled it out of the garage and got up the courage to drive it around the block.
For 2/3 of the cul de sac, nothing but smooth driving. Engine was humming. I was ecstatic. I wasn't going too fast but I was focusing on my driving and not the car itself. That was great.
But then I started getting backfiring. I adjusted the throttle to ease the pull on the engine but I could tell the engine was struggling.
I got her home and opened the hood. The exhaust manifold was glowing (!) red, primarily in the half closest to the firewall. The glow stopped right at that big nut.
I take it that's bad. Any ideas what the problem could be?
I certainly did not lie seeing my engine glow in the dark, but I did make my first solo drive!
Either too lean of a mixture, or more likely, spark too retarded.
Any chance it's a coolant problem?
There's not any coolant in the exhaust manifold. The only way it can glow red is if the mixture is unburned, super rich. This typically happens when the spark is too retarded.
What do I do for a retarded spark? I've got new plugs on order, so aside from new plugs, what can I do?
What ignition system are you running? Assuming you're running a system with manual advance, here are some guidelines:
My '24 came to me with a Truefire ignition with manual advance set up to fire at 15 degrees after top dead center on #1 cylinder with the spark lever fully up.
For nearly all of my driving, I can leave the spark lever nearly full down. I do occassionally retard the lever to about 1/3 down if I'm starting off in low on an uphill slope. It is much harder to kill the engine when engaging the low band if the spark lever is retarded to about 1/3 down.
Some of your fuel mixture is burning after it gets into the exhaust manifold. You told us how the car started right up when you pulled the choke and hit the starter. However, you said nothing about advancing the spark lever or adjusting the fuel mixture. Those are the two most likely things which would make the engine to struggle. You didn't mention going up steep hills, so I would suspect you were on a fairly level area.
Be sure to push the spark lever all the way up before starting and pull it about 3/4 way down after it starts. If the timing has been set properly, that is the position to drive in. The fuel mixture as adjusted by turning the same rod you pulled for the choke. Turn clockwise to lean the mixture and counter clockwise to enrich the mixture. Set it where it runs the fastest and smoothest at a fast idle. Then after the engine warms up, check that adjustment again, you might lean it slightly to run the best.
If these things don't improve the performance of the engine, you might have burnt exhaust valves which would cause some of the burning fuel to go out into the exhaust manifold. Unfortunately, running retarded will cause the valves to be burnt or warped. To test for bad valves you will need to do a compression test. You need a compression gauge for that test. See other posts for compression test.
The reason the rear end of the manifold gets red hot is that all the exhaust from all the cylinders goes in that direction, so the effect is cumulative. The front of the manifold only gets hot from the first cylinder, and added to by the second, third and fourth. So the majority of gases will be burned in the rear of the manifold. The fuel should be combusted within the cylinder which will happen when the spark is advanced. Only hot gases should go out the exhaust.
Thanks Norm. Yes, I started the car with the spark up and lowered it about 2/3 down when driving. Previous owner marked the lever to where he ran the spark, so it's easy to hit the mark every time.
I was driving fairly slowly as a first time driver, so maybe 15 mph on very level road.
Mark, I'll try re-evaluating what I'm doing there. Thanks for the information, as well.
Mark, you have me confused, you said in above post
"I do occasionally retard the lever to about 1/3 down if I'm starting off in low on an uphill slope"
I thought retard is up and advance is down.
Sorry, I could have worded it better. Here's another attempt:
I start the car with the lever fully up. Once the engine starts, I walk over and pull the lever to the 1/3 down position and let the engine warm up at Idle.
I have to start off on an uphill slope after I back out of my driveway, so I start off in low with the lever 1/3 down. Once I'm moving at a good clip in low, I can pull the lever to nearly full down.
I normally do the rest of my driving with the lever nearly full down.
If for some reason during the drive I have to come to a stop on an uphill slope, I will push the lever back up to the 1/3 position before I start off in low gear, then pull the lever almost fully down once the car is moving again at a good clip in low.
Other folks' methods may vary.
Bah. Now I can't get her to start at all.
Lots of talk about the spark lever and still not much about adjusting the spray needle.
Running too lean will cause the manifold to glow. Unburnt fuel also cools the valves and manifold. Running too lean, all the fuel is burnt in combustion and none is left to cool on it's way out. Too rich make carbon and fowls the plugs.
Start the car, adjust the spark. At idle turn the fuel mixture (spray needle) in (clockwise) till the engine starts to run uneven then turn out (counter clockwise) till it smooths out.
If it still glows red, advance the spark and open the needle a smidgen more.
EVERY T is different and suggestions are ball park.
Backfiring at carb? Red hot exhaust. Both related to lean out of carb. With no start now I would look at fuel flow, carb setting, some issue with there.
Could be low gas, clogged fuel from sediment bulb to carb. Open carb drain below bowl and check for full flow into a drain pan. Carb float needle may be stuck so bowl isn't getting filled. Carb feed needle may need to also be backed out at carb adj Rich/Lean knob or rod to richen the air/fuel mixture.
Thanks Mark. I'll try that....once I can get her started again.
Hey, at least he made use of a good day to give it a try. The car has not been used in about 8 years, so there is probably varnish throughout the fuel system. He also has a vaporizer carburator that we will switch to an NH when all the parts come in. It is a very ice looking car.
It runs real when well it is idling and it is running in low.
How open do you have the carburetor adjustment? Most of us use about 1 to 1.25 turns to start. Then you can adjust a little from there to get smooth running. As mentioned, being too lean (too closed) can cause a heat problem. When closing the needle, don't force it, just to where it is snug, then open 1.25 turns from there.
It idles well when it is open 1 turn. It runs fine in low but spits ans sputters in high. We are going to replace all the wiring to rule that out. Sometimes Eido loses all electrical power, usually when his wife is looking. The tank is clean and the fuel filter has been removed. Problem is most likely the vaporizer carb.