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01-18-2024, 10:30 AM | #181 |
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Re: 47 V8 ignition mystery
What inside the distributor would cause only the same cyl. To misfire???
The rotor not getting spark to the cap prong or cap contact,,,if rotor to contact is to great it would probally fire intermintally,,,what would cause gap to change?? Possibility the bushings,shaft could be a little off!maybe one lobe on shaft cam could be worn down just enough to cause misfire,,,,,any of these things would cause only one cyl to misfire,that is assuming he has checked the wiring and caps ,plugs etc. which he say he has,,,,I say rebuild the distributor COMPLETELY,,,!!
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01-18-2024, 11:15 AM | #182 |
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Re: 47 V8 ignition mystery
You could just loosen the bolts in the manifold and slip a piece of metal under the carb to block off the heat riser.
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01-18-2024, 04:18 PM | #183 |
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Re: 47 V8 ignition mystery
I think maybe he has his HT wires mixed up
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01-18-2024, 04:34 PM | #184 |
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Re: 47 V8 ignition mystery
Think he said early in post that he put a timing light on # 6 wire and it was misfiring.
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01-18-2024, 05:37 PM | #185 |
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Re: 47 V8 ignition mystery
If you face a timing light at a TDC pully mark on say # 6 it wont match if the wire is in the wrong hole ,.
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01-18-2024, 10:29 PM | #186 | |
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Re: 47 V8 ignition mystery
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Quote:
Reading the timing light for each cylinder shows #6 missing the most followed by #3 some and #7 & 8 very rarely. This video shows the vacuum gauge at full idle, i.e. throttle closed completely, at highest and smoothest RPM by adjusting idle mixture screws. https://www.youtube.com/shorts/5UoexytEWQk Vacuum gauge moves down with acceleration and up with deceleration and is steady except at full idle.
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Prof. Henry (The Roaming Gnome) "It is good to have an end to journey toward; but it is the journey that matters, in the end.” *Ursula K. Le Guin in The Left Hand of Darkness Last edited by Old Henry; 01-18-2024 at 10:48 PM. |
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01-18-2024, 10:35 PM | #187 | |
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Re: 47 V8 ignition mystery
Quote:
The distributor is a Ford remanufactured sent to Michael at 3rd gen who just set the dwell that was off and replaced the condenser and sent it back.
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Prof. Henry (The Roaming Gnome) "It is good to have an end to journey toward; but it is the journey that matters, in the end.” *Ursula K. Le Guin in The Left Hand of Darkness Last edited by Old Henry; 01-18-2024 at 10:46 PM. |
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01-18-2024, 10:38 PM | #188 |
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Re: 47 V8 ignition mystery
Brian has also mentioned the heat riser but I don't understand what that has to do with the engine running rough. I would not want to run my car at below 0 temperatures without the heat risers.
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01-18-2024, 10:39 PM | #189 |
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Re: 47 V8 ignition mystery
The spark plug wires are all plugged in correctly. If any were swapped I think I'd get bad backfires.
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01-18-2024, 10:45 PM | #190 |
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Re: 47 V8 ignition mystery
Tonight I tested for vacuum leaks around the manifold and carb as follows:
Ran the engine at full idle speed (throttle plates totally closed). Squirted some starter fluid into the carb to make sure it would affect the RPMs. Removed the wiper vacuum hose and squirted starter fluid in there for the same reason. (Both changed the RPMs) Reconnected the wiper vacuum hose then sprayed the starter fluid all around the edges of the manifold, where the carburetor connects to it, and around the carburetor throttle shafts. No change in RPM by any of that. Would seem that I have no vacuum leaks causing the rough running. Other ideas?
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01-19-2024, 06:31 AM | #191 |
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Re: 47 V8 ignition mystery
>>>I've only got three weeks to solve this problem before I have to put Old Henry in a coma for two years while my wife and I go to serve voluntarily in the Philippines for two years.>>>Other ideas? >>
Only ~2 weeks now. Seems like time to wrap it up. Focus on preparing for the trip. Worry about the car when you get back and have more time. Meanwhile just keep running MMO. Maybe arrange for a friend to start & fast idle till it heats up every week or so while you're gone.. Last edited by Jack E/NJ; 01-19-2024 at 08:05 AM. |
01-19-2024, 08:30 AM | #192 |
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Re: 47 V8 ignition mystery
The engine vacuum is very low and erratic, should be 18-20 and steady.
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01-19-2024, 09:53 AM | #193 |
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Re: 47 V8 ignition mystery
So? What causes that and is it the cause of the engine running rough at all speeds? And, how to fix it?
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01-19-2024, 10:44 AM | #194 |
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Re: 47 V8 ignition mystery
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01-19-2024, 11:51 AM | #195 |
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Re: 47 V8 ignition mystery
Your vacuum leak test with starter fluid; you've checked the base of the carb area, but I don't see where you have checked where the manifold bolts to the block. The vacuum gauge certainly shows very low vacuum, which could well be indicative of a vacuum leak. Bear in mind, this vacuum leak could be internal; there can be a vacuum leak into the valley, or that heat riser could have cracked...I have experienced this.
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01-19-2024, 02:35 PM | #196 |
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Re: 47 V8 ignition mystery
Other than a bit of flutter, late valve timing seems closest. Maybe worn down cam gear teeth especially if fiber?
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01-19-2024, 02:57 PM | #197 |
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Re: 47 V8 ignition mystery
Broken valve spring ,Colet or guide retainer issue ,worn cam shaft ,
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01-19-2024, 03:10 PM | #198 |
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Re: 47 V8 ignition mystery
...or sticky valves might be late too as well as cause some vacuum fluttering?
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01-19-2024, 06:52 PM | #199 |
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Re: 47 V8 ignition mystery
Well, it looks like we have finally concluded that the rough running is nothing to do with anything exterior like ignition, carburetion, or external vacuum leaks. Everyone now seems to be suggesting that it is a problem within the engine itself requiring partial or complete disassembly. That I don't do and won't have done in the two weeks I have left of life as I know it.
So, I've put Old Henry into his coma for the next two years, unplugged the clock so it doesn't get another two year's wasted wear, removed the batteries from the outside and inside thermometers, disconnected the voltage booster, put fuel stabilizer into the gas tank and filled it up, gave him a nice hot bath, and topped up the oil. Might even consider putting it up on jack stands to save flattening the tires. My son lives close and will come monthly to run all vehicles while he's otherwise checking the property inside and out just like he did when we were in Hong Kong for 18 months a couple of years ago. Anything else to make Old Henry more comfortable in his coma?
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Prof. Henry (The Roaming Gnome) "It is good to have an end to journey toward; but it is the journey that matters, in the end.” *Ursula K. Le Guin in The Left Hand of Darkness Last edited by Old Henry; 01-19-2024 at 08:18 PM. |
01-19-2024, 07:14 PM | #200 |
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Re: 47 V8 ignition mystery
I wish you a safe and productive and rewarding trip .
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