Troubleshooting red hot exhaust

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Model T Ford Forum: Forum 2017: Troubleshooting red hot exhaust
Top of pagePrevious messageNext messageBottom of page Link to this message  By Matthew Atchinson on Tuesday, June 06, 2017 - 05:22 pm:

I tried the suggestions of immediately knocking open the spark to 8-9 notches after starting and leaving it there. Went up and down the road, about 2 miles. Parked it and the garage and while not as cherry red as previously noted, I still managed to get a dull red glow from the back 2/3 of the exhaust manifold. What's the cause!? I'm wondering if maybe it's the fuel: I'm running 91 Octane ethanol free. Maybe a timing issue? Something with the spark plug gap maybe? OR, and I think this may be it, this motor never gets warm enough to read "optimum operating temp" on my Boyce Motometer. Maybe the fuel mix isn't vaporizing fast enough and I'm getting extra burn off in the exhaust? Or maybe there's a ton of crud in the exhaust catching fire. OR, this exhaust does have a slight leak on No.1 cylinder and maybe No.2, could that be causing it? Do any of these things sound like a likely culprit to my hot exhaust? I don't want to burn valves.....


Top of pagePrevious messageNext messageBottom of page Link to this message  By David Dufault on Tuesday, June 06, 2017 - 05:44 pm:

Just curious Matthew - why 91 Octane ?


Top of pagePrevious messageNext messageBottom of page Link to this message  By Tim Eckensviller - Thunder Bay, ON on Tuesday, June 06, 2017 - 05:47 pm:

Probably to avoid the ethanol. It's the same story up my way, the only way to get ethanol-free is with premium fuel and even then you have to shop around a bit.


Top of pagePrevious messageNext messageBottom of page Link to this message  By Chad Marchees _____Tax Capital, NY on Tuesday, June 06, 2017 - 05:53 pm:

Most likely two things Matt. Timing, or fuel mixture. If the fuel mixture seems to be right---typically from 1 - 1.5 turns from seated, then you most likely need to add more timing.

Even if you feel it has enough timing, it may need more. Try it and see.


Top of pagePrevious messageNext messageBottom of page Link to this message  By Matthew Atchinson on Tuesday, June 06, 2017 - 05:56 pm:

Yep, 91 is the only local ethanol free I can find. there may be a gas station 20 miles out that has 86/87 ethanol free.

I think the mixture should be OK. Right now I'm finding it starts easy when the needle is 1 1/4 turns out. I close it down to 1 1/8 and it seems to idle smooth there. I thought maybe it was too lean so I tried 1 1/2 but it didn't like it.


Top of pagePrevious messageNext messageBottom of page Link to this message  By Duey_C on Tuesday, June 06, 2017 - 06:16 pm:

8-9 notches is about half-way down right? And you have the stock ignition right?
Perhaps advance it some more on your next run and see then.
When cruising down the road, the lever/timing should be advanced farther than half-way.
I lifted this image from the forum after a search.

levers

Hope this might help.
Lotsa folks advance fully after starting and leave it. :-)

I'm blessed. I go to the left 3-1/2 miles or to the right 3-1/2 miles to get ethanol free fuel.

(Message edited by Duey_C on June 06, 2017)

(Message edited by Duey_C on June 06, 2017)


Top of pagePrevious messageNext messageBottom of page Link to this message  By Harold Schwendeman - Sumner,WA on Tuesday, June 06, 2017 - 06:52 pm:

Matthew - I think there is one other possibility, you could have a vacuum leak, which would also have the tendency to lean out the fuel/air mixture which could cause some or all cylinders to run hot,....FWIW,.....harold


Top of pagePrevious messageNext messageBottom of page Link to this message  By Matthew Atchinson on Tuesday, June 06, 2017 - 07:45 pm:

Harold, that could definitely be it. No.1 cylinder is having black soot build up around the edges where the exhaust runs into the block. I've been meaning to take the exhaust and intake totally off, cleaning them out, and putting the exhaust back in with those inserts.


Top of pagePrevious messageNext messageBottom of page Link to this message  By Joe Andulics on Tuesday, June 06, 2017 - 08:34 pm:

Matthew, certainly not an expert, but I believe Harold is referring to a vacuum leak associated with the intake. The black soot around the exhaust shouldn't be an issue. A lean mixture would be my best guess. Good luck


Top of pagePrevious messageNext messageBottom of page Link to this message  By Harold Schwendeman - Sumner,WA on Tuesday, June 06, 2017 - 08:54 pm:

Joe,.....Yup! Intake of course. Thanks Joe,.......I guess I could have been more specific, huh? However, from what you've said Matthew, while you've spotted visible indication of an exhaust leak (black soot) between the exhaust manifold and the exhaust port, there would be no "VISIBLE" indication of a possible leak (which would be a vacuum leak) between the adjacent side of the intake manifold and the corresponding intake port. There is however, an easy test that you can conduct which would verify a vacuum leak between intake manifold and it's intake port. With the engine idling, squirt a bit of WD-40 around the areas where the intake manifold meets the engine block and intake ports. If there is a vacuum leak, the present vacuum and leak will suck in a bit of the WD-40 with each "squirt" and you will immediately hear the engine speed up a bit with each "squirt".
Hope this helps,......harold


Top of pagePrevious messageNext messageBottom of page Link to this message  By Harold Schwendeman - Sumner,WA on Tuesday, June 06, 2017 - 08:58 pm:

Matthew - By the way, don't do this WD-40 "test" with a red-hot manifold, or you could have a bit of a fire! Start the engine up from cold and do "the test" right away and you'll have no problem.


Top of pagePrevious messageNext messageBottom of page Link to this message  By Hal Davis-SE Georgia on Tuesday, June 06, 2017 - 09:00 pm:

If number one is sooty, it could mean you have an intake leak at 3 and 4, which would cause those two cylinders to be lean. Glowing exhaust is usually retarded timing or lean mixture. Pull the timing all the way down and see what happens. Spray the intake with starting fluid (or whatever) arould the 3-4 port and see if you detect a change.


Top of pagePrevious messageNext messageBottom of page Link to this message  By Hal Davis-SE Georgia on Tuesday, June 06, 2017 - 09:01 pm:

Oops, Harold beat me to it.


Top of pagePrevious messageNext messageBottom of page Link to this message  By Harold Schwendeman - Sumner,WA on Thursday, June 08, 2017 - 01:17 pm:

Matthew - Update?


Top of pagePrevious messageNext messageBottom of page Link to this message  By Lew Morrill on Friday, June 09, 2017 - 09:27 am:

For what it's worth and not to question the experienced T experts advice or analysis in this thread, my experience on other other gas engines seems to indicate that a rich mixture can create high exhaust temperatures because the excess fuel ends up burning in the exhaust. A lean mixture may raise combustion temperatures, but I have not experienced high exhaust temperatures with lean mixtures as combustion is more likely to be completed in the cylinder.

Agreed for sure that too little timing advance as noted by others can also create a lot of heat in the exhaust as the mixture charge again is not fully burned in the cylinder and continues burning in the exhaust.


Top of pagePrevious messageNext messageBottom of page Link to this message  By Steve Jelf, Parkerfield KS on Friday, June 09, 2017 - 11:13 am:

No doubt this will be considered heresy in some quarters, but I use the cheapest grade of fuel generally sold around here. That's E-10, which is labeled as 87 octane. So far I've detected no ill effects. That includes overheating. Since a recore of the radiator the runabout has not boiled, and I certainly haven't experienced a glowing manifold. I think your excessive heat comes from something other than the type of fuel.


Top of pagePrevious messageNext messageBottom of page Link to this message  By Mark Gregush Portland Oregon on Friday, June 09, 2017 - 11:58 am:

A weak/lean mixture can cause the manifold to glow. If the mixture is too lean then it is still hot as it leaves the cylinder. Part of the job of the unburnt fuels job is to cool the valve as it passes. Combustion is not instantaneous, that's why the spark is set to start the firing process before TDC after the engine is running. The correct setting will leave some unburnt fuel to cool as it passes out the cylinder.
If you are setting the spark timing correct, try bring the engine up to operating temp at your present setting, then opening the needle valve a little more and watch to see if the red fades.
I use an unlit propane torch to check around the intake for vacuum leaks.


Top of pagePrevious messageNext messageBottom of page Link to this message  By Mark Strange - Hillsboro, MO on Friday, June 09, 2017 - 12:20 pm:

I'm with Steve. Betsy runs fine on 87 Octane regular gas with ethanol. She has a 1924 engine with a standard high head and a Kingston L4 carb and stock manifolds. No overheating or any other ill effects. :-)


Top of pagePrevious messageNext messageBottom of page Link to this message  By John Codman on Friday, June 09, 2017 - 01:09 pm:

E-10 is OK, but it does soak up water, and SW Florida is very humid. I use 90 Octane Ethanol-free in my T. The T runs fine on it. Red exhaust pipes and manifolds (obviously) indicate excessive exhaust heat. This usually indicates a lean fuel/air mixture.


Top of pagePrevious messageNext messageBottom of page Link to this message  By Harold Schwendeman - Sumner,WA on Saturday, June 10, 2017 - 02:06 pm:

Matthew - (???)


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