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Discussion Topic:
Ignition help, please...
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682bear |
02-27-2024 @ 12:48 PM
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Member
Posts: 27
Joined: May 2023
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This is an addition to my other thread 'Engine Running Rich'. I ended that thread by saying that I had sent my carburetor to Charlie for a rebuild. I got it back a couple of weeks ago, and finally found time to reinstall it today. The car runs much better... but still not good... I started pulling the spark plugs and testing the compression on all cylinders.... the compression is the same between all cylinders... no dead cylinders. However, I did discover that the back plug on the drivers side doesn't look like it has ever fired... A quick check proves it... it isn't firing at all... The distributor is a rebuilt diving helmet from Third Gen Automotive with less than three hours run time. The condenser was replaced at the same time. I'm guessing that I have a plug wire issue... Any information or advice on checking the wires would be appreciated... the issue would almost have to be where the wire connects to the distributor cap...? How would I go about testing that? How difficult is it to replace the wires? Thanks...! -Dave
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682bear |
02-27-2024 @ 12:49 PM
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Posts: 27
Joined: May 2023
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Sorry, I should have mentioned it is a 1940 Fordor with a 59A engine... -Dave
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carcrazy |
02-27-2024 @ 4:09 PM
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Senior
Posts: 1650
Joined: Oct 2009
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Inserting the #8 spark plug wire back into the distributor requires that you first remove the left hand (driver's side) distributor cap assembly from the distributor. Next remove the O-Ring that retains the outer cap to the inner cap so you can separate the two caps. The inner cap has four female terminals inside it. You want to insert the longest wire on the left side of the engine (black with yellow tracer) into the terminal hole marked with numbers 8 and 2. Make sure the wire is fully engaged into that terminal before joining the two caps back together and reinstalling the O-Ring. Note that there is a gasket that fits between the two caps. Place the cap assembly back on the distributor and retain it with the retainer bail (wire).
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kubes40 |
02-27-2024 @ 4:33 PM
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Senior
Posts: 3394
Joined: Oct 2009
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I might suggest you remove the tube and wires with the caps intact. Test for continuity between the terminal and the end of the wire. If the continuity is not good, then go ahead and tear that assembly apart and make darn certain each and every wire is firmly seated in the terminal plate. Carcrazy has offered good advice and from what you are sharing, the wire or the seating of the wire or the terminal plate are at fault.
Mike "Kube" Kubarth
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682bear |
02-28-2024 @ 11:04 AM
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Member
Posts: 27
Joined: May 2023
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Ok, I removed the driver side assembly intact per Kube and laid it out on the bench... I've shined the contacts on the inner cap up and cleaned the oxidation out of the spark plug clips on the wires. Using a digital multimeter, I'm getting 1.4 ohms on wire #8, 0.3 ohms on wire #7, 0.4 ohms on #6, and #5 is showing no continuity. On further inspection, I've realized that someone has replaced the connector on #5 (picture below)... the wire is protruding from the insulation inside the connector, but is not long enough to touch the connector. I'm assuming that, when installed onto the spark plug, the copper wire was held against the end of the plug. I carefully seperated the two halves of the cap... all four wires are still in position and are held tightly... I didn't try to remove them, I just pulled on each one enough to determine that it wasn't loose. I've read that these wires are supposed to be color coded with a tracer... as mentioned by Carcrazy... but these wires are all solid black and the plastic (or rubber) insulation on them has hardened enough to make them difficult to deal with. I think it's probably time to look at new wires... I would guess that they need to be a small diameter in order to work them through the steel tube they are routed in... 7mm maybe? Where is the best place to buy these to be sure of getting the correct diameter? Thanks- Dave
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carcrazy |
02-28-2024 @ 2:54 PM
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Senior
Posts: 1650
Joined: Oct 2009
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Many of the vendors report these wires as being "out of stock. One source that currently has them in stock is Dennis Carpenter. You can access his website under the Vendors section of this website. The part number for this wire set is 78-12259.
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682bear |
06-04-2024 @ 10:33 AM
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Member
Posts: 27
Joined: May 2023
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Ok... I'll need some advice on this... I've installed a new set of plug wires that I ordered from 3rd gen... double and triple checked that they are in the correct order... and checked all 8 wires for continuity from the distributor caps to the spark plug terminals... Everything looks good... mounted both sides back to the engine and cranked the car... It runs better... but still has a miss that got worse as the engine warmed up. I checked all 8 plugs for fire by holding a screwdriver to the head and moving the shank up to the plug terminals. I only managed to get a decent spark on three plugs. I shut it off, then pulled the plugs... #8 still doesn't look like it has ever fired (pic below)... WTH? I've double checked continuity between the cap and plug... it tests good. The distributor is a 3rd Gen rebuild with maybe an hour on it... the condenser was replaced at the same time. I still have the distributor that I took off... do I need to reinstall it and see what happens? Do I need to start looking at getting the coil rewound? Also, the engine at idle (@480 RPM) is showing a fluctuating 10-11 on the vacuum guage... and the idle mixture screws have no effect on how it runs... I assume that means a vacuum leak, but I can't seem to find where it might be... I've just had Charlie Schwendler rebuild the carb also. The frustrating thing is that it was running extremely well before installing new water pumps... and hasn't run well enough to drive since. I can't figure out what I scr*w*d up replacing the pumps! -Dave
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51504bat |
06-04-2024 @ 11:28 AM
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Member
Posts: 252
Joined: Apr 2020
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Don't assume that the new condenser you just installed isn't defective. And the problem isn't limited to flatheads. The condenser in the Buba converted Chevy distributor in my 8ba died. I replaced the one that came with the unit several years ago when I did a complete tune up. Luckily I saved the original Buba unit because the Standard brand unit failed just the other day. I reinstated the condenser that came with the distributor and all was well. But wait it gets worse. Being a slow learner I bought a new Standard brand condenser cause new is better, right? Well the new Hecho en Mexico unit died less than a week later as I was pulling into a swap meet. A buddy was selling NOS Standard ignition parts made in USA. Installed one of the condensers he had and problem fixed. Point is never assume an ignition part is good just because it's new.
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alanwoodieman |
06-04-2024 @ 7:44 PM
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Senior
Posts: 868
Joined: Oct 2009
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let me add something to look for--bad or dried up rotor buttons--with a steel shaft going thru the helmut dizzy rotor button I have had problems with the shaft shorting out the button. I always place two pieces of shrink tape-one on top of another on the shaft before putting the shaft thru the rotor button
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40 Coupe |
06-05-2024 @ 7:26 AM
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Senior
Posts: 1673
Joined: Oct 2009
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Plug wire resistance on #8 is too high. 1.4 Ohms seems low but it is about 4X the resistance of some others. You want to see about 0.3-0.4 Ohm. Solder the wires to the terminals. Have you checked the top of the distributor vacuum brake to see if the large hex is tight? You have to search for the vacuum leak. Best to do this at idle with the vacuum gauge on the wiper port of the intake manifold. Should have a steady approximate 20 reading. The carburetor idle mixture adjustment screws should make a big difference once you have the proper vacuum and all the plugs are working, the idle mixture will also effect vacuum. Swap the plug that is not firing to another cylinder. Engine cylinders are front to rear starting on the passenger side 1-2-3-4 then the drivers side 5-6-7-8 front to rear.
This message was edited by 40 Coupe on 6-5-24 @ 7:48 AM
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