Re: Chasing Rough idle...compression?
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Plug wire leakage, quality or any other details or concerns about the physical plug wires themselves is NOT the issue here.
My recommendation to keep at least 1/2" distance between the plug wires has to do with a potential inductance that can happen in ANY ALL AND EVERY high voltage application automotive or otherwise. So my recommendation should in no way to be construed as any negative concerns about the plug wires themselves. It is ONLY a ROUTING issue of the plug wires that in some cases may cause problem crossfireing of spark plugs.
Posted on: 2011/5/26 9:48
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VAPOR LOCK demystified: See paragraph SEVEN of PMCC documentaion as listed in post #11 of the following thread:f
packardinfo.com/xoops/html/modules/newbb/viewtopic.php?topic_id=7245 |
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Re: Chasing Rough idle...compression?
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IIRC the manifolds are removed???? If so then check the valves, especialy the exh. valves for gum or deposits directly at the section of the stem that is in line with the top of the guide when the valve is closed or nearly closed.
Posted on: 2011/5/26 10:00
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VAPOR LOCK demystified: See paragraph SEVEN of PMCC documentaion as listed in post #11 of the following thread:f
packardinfo.com/xoops/html/modules/newbb/viewtopic.php?topic_id=7245 |
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Re: Chasing Rough idle...compression?
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If having plug wires close to each other may be a problem if teh wires are old, cracked and deteriorated. But from at least 1928 up on Eight,Eight Deluxe, V-12, Super 8 ,Six and 120 Packard manufactured these cars with the igniiton wires all running together and touching inside a metal "tube".
If wires shorting to each other, especially the cloth covered type, were a problem it would have shown up in the 20's, 30's and 40's. It didn't, plain and simple. I doubt that the collective wisdom and knowledge of all of us on this site comes anywhere near to that of the legion of engineers on East Grand Boulevard. and remember Packards were kknown for their smoothness. Witness the Toyota unintended acceleration incidents. There were few reported before the press got a hold of it, then for a short time it jumped a hundredfold. This is after the floormat probvlem was solved. Each and every incident investigated by all the agencies including NASA showed it was driver error. Downloading of the "black boxes" confirmed that. Twenty years prior the same thing happened with Audi, it turned out to be driver error. Now it's wires that touch and clothes pins on fuel lines to cure vapor lock. The closest terminology I can think of is mass hysteria
Posted on: 2011/5/26 10:50
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Re: Chasing Rough idle...compression?
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"Each and every incident investigated by all the agencies including NASA showed it was driver error. Downloading of the "black boxes" confirmed that."
It's true, it was usually elderly coming off a ramp or something and hitting the gas instead of the brake. Let's not forget, they couldv'e just shut the car off, but they never thought off that. The toyota wrong pedal crowd wasn't the brightest. Crossfire IS possible, and i'll put it in line to test if more plausible theories don't pan out. However, it's less likely in 1 6v low power ignition environment, and even less so in a setup that's identical to 10000 working other setups with wires the same way. I'll still give it a shot, but again, because it's free and easy to test. I'd really expect it to persist as the throttle is laid into on the highway also though, as voltage increases and rpms are raised and the engine becomes more sensitive. Manifold is on now, one is getting ready so it can be swapped. When they're off, if i haven't solved it, i'll look at the valves.
Posted on: 2011/5/26 11:44
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Re: Chasing Rough idle...compression?
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Packard was having problems of what was then called induction firing in their V-8s. The problem presented itself with #5 and #7 cylinders that fire sequentially on the LH bank. Odd numbered cylinders on the LH bank and even numbered one on the RH bank (Firing order: 1, 8, 4, 3, 6, 5, 7, and 2) Induction firing caused rough running engines as the current would be induced from #5 to #7 causing that cylinder to fire too soon. Packard recommended separating these two wires on the brackets so that they were on the outer notches of the brackets. In 1956 Packard introduced a revised and much wider spark plug wire bracket to deal with this problem. I am only aware of this problem in the V-8s and only with the two cylinders firing sequentially on the same bank.
(o{I}o)
Posted on: 2011/5/26 13:52
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We move toward
And make happen What occupies our mind... (W. Scherer) |
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Re: Chasing Rough idle...compression?
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High compression engines like the V8 are prone to that, as the spark has more difficulty jumping the spark plug gap due to the compression pressure and it may take, as tehy say, the path of least resistance.
I would have said that but my comments were limited to relatively low compression straight 8 engines as this forum is for post war straight engines. Thank you for mentioning it and pointing out my omission.
Posted on: 2011/5/26 14:15
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Re: Chasing Rough idle...compression?
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Quote:
Now it's wires that touch and clothes pins on fuel lines to cure vapor lock. The closest terminology I can think of is mass hysteria Fred I'm the last one to fall for snake oil remedies or believe in old wives tales but I must tell you that I am not the only person that has benefited from the old clothes pin fix. In the 60's my mothers 53 Cad would routinely vaporlock above roughly 5000 feet on a hot day. I'm not talking once or twice. It was so bad you could hardly use the car except on short trips the the local store and back. The clothes pins on the line between the fuel pump and the carburetor did prevent it. Never had any more vapor lock problems in fact when they sold the car a couple years later the gas line still looked like a clothes line. Note: the carb and fuel pump were replaced in an attempt to correct the problem. I wouldn't have believed it if I hadn't seen it with my own eyes. I know what you're thinking. The next thing is I'll tell you is crop circles are done by little green men from outer space.
Posted on: 2011/5/26 14:24
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Re: Chasing Rough idle...compression?
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Not saying you didn't see what you saw, but would like to understand the scientific reason for it working? Currently I don't see the correlation.
I could see if the clothespins were made of aluminum and acting as some kind of heat sink. Or wooden ones used as a spacer/insulation to isolate it away from something hot. But just not randomly stuck on a line like you were hanging laundry. I cant see what it could possibly do to affect the temperature of the line, or the fuel inside of it. Someone call the Mythbusters!
Posted on: 2011/5/26 14:51
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-BigKev
1954 Packard Clipper Deluxe Touring Sedan -> Registry | Project Blog 1937 Packard 115-C Convertible Coupe -> Registry | Project Blog |
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Re: Chasing Rough idle...compression?
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From post #34 above:
"...Packard manufactureds these cars with the igniiton wires all running together and touching inside a metal "tube"." Yes. And note that it ran thru a METAL tube but u forgot to mention that the metal tube was also grounded to the engine. Running wires thru a metal tube is only one way to prevent or bleed off any inductance. One other way is to wrap something like a 12 ga. wire around a plug wire for a half dozen turns or so and ground the other end to the engine. Jag V12 ca 1978 - 90 also ran plug wires thru a METAL TUBE GROUNDED TO THE ENGINE. However, i do not remeber if the plug wires thru any section tube were consecutive fireing or not. Doesn't matter. The tube bleeds off inductance. Compression ratio has no bearing on the electrical phenomenon.
Posted on: 2011/5/26 16:52
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VAPOR LOCK demystified: See paragraph SEVEN of PMCC documentaion as listed in post #11 of the following thread:f
packardinfo.com/xoops/html/modules/newbb/viewtopic.php?topic_id=7245 |
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