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Discussion Topic:
Low RPM/high load miss/'buck'
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len47merc |
12-29-2015 @ 8:24 AM
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Senior
Posts: 1168
Joined: Oct 2013
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Thanks for the heads-up on the PM Ken - fyi I replied.
Steve
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ken ct. |
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12-29-2015 @ 7:44 AM
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Senior
Posts: 1513
Joined: Jan 2010
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Steve check your PM's ken ct.
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ken ct. |
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12-29-2015 @ 6:02 AM
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Senior
Posts: 1513
Joined: Jan 2010
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Steve I would go through that dist and converet it to a crab style with new rotor,cap,rubber cap nipples, and clips and check points real good. I can do this for you very reasonable or send you the parts to diys if you want. Have done many in 25 yrs. Much simpeler setup.Use copper or steel cored wires. ken ct.
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40 Coupe |
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12-29-2015 @ 5:49 AM
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Senior
Posts: 1800
Joined: Oct 2009
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When you had the distributor set did you install new rotor and new inner distributor caps? The two parts have a maximum gap. As gaps (resistance) in the ignition system increase, the ignition coil has to work harder and produce higher voltage to jump the gaps. Once one part of the ignition circuit resistance becomes excessive miss-fires present themselves. How about the plug wires are they solid wire or higher desistance carbon? Replacing the plugs will decrease the resistance for a while but if the problem re-occurs shortly look elsewhere in the system. NAPA sells NGK plugs and can order them from the local warehouse overnight.
This message was edited by 40 Coupe on 12-29-15 @ 5:51 AM
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len47merc |
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12-29-2015 @ 5:26 AM
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Senior
Posts: 1168
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Pat - One would have thought I'd change the plug brand but given how clean and unscathed the business end of the plugs were, how positively and well they have performed for the last couple of years/3,500 miles, and the Autolites just happened to be on sale for $1.49 each locally when a new set of plugs was needed, I made the decision to give them one more chance. Had multiple plugs been found to be bad I would have gone with the RJ's based on Tom's experience and supereal's recommendation, but as only one was at issue I've given the Autolite's the benefit of the doubt for the time being and assumed the bad plug was a 'flier' that may have been dropped, etc.. I will report back on results.
While I run NGK's on most all my modern daily drivers I'd have a problem running anything beyond the Champion RJs or Autolite 216s on the '47 for no other reason than the principle of the thing. My gut tells me I'll be switching to the RJs in ~2017 (3,000+ miles) but hopefully my gut is wrong - usually it's not so suspect I'll be subconsciously and consciously monitoring every low rpm acceleration from now on.
Steve
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Pat's 52 |
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12-28-2015 @ 1:57 PM
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Member
Posts: 35
Joined: Oct 2009
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Steve, what new plugs did you go too? The Champion RJ's or the NGK's. I'm curious because I have the Autolite 216's in my 50. Thank you!
Pat
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len47merc |
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12-28-2015 @ 5:53 AM
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Senior
Posts: 1168
Joined: Oct 2013
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Tom - following-up - under load the seal between the porcelain and the base on the #2 cylinder Autolite 216 plug was bad fyi. I note also this particular plug with ~3,500 miles is two+ years old and as a result of the NC humidity exhibited a fairly obvious (and the most pronounced of all the plugs) rust stain on the porcelain around the top of the base as well. The car is kept in an very dry attached garage and never sees rain, but during extended wet periods here in NC the humidity shows itself on the plugs' bases. Not sure if that was the root cause or contributor, or if the plug was bad and just took a while to show itself, or if, as you suggest, the 216s just can't handle the heat and compression of the flatheads. New set continues to perform well btw.
Steve
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ken ct. |
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12-22-2015 @ 2:20 PM
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Senior
Posts: 1513
Joined: Jan 2010
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Tom O ,,check a motor cycle shop (not a Harley d. ) one. most jap bikes use all kinds of NGK's. ken ct.
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len47merc |
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12-22-2015 @ 9:56 AM
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Senior
Posts: 1168
Joined: Oct 2013
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Thanks Tom for sharing your experience here - that's very good feedback and info to have. Given my expectation surrounding the plugs was to realize 15K-20K miles minimum I really never expected them to be the root cause on this. Taking the old ones over to have them checked this afternoon - let you know what I find.
Good luck with your set of 216's - hopefully my experience thus far is just an isolated case.
Steve
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TomO |
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12-22-2015 @ 6:44 AM
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Senior
Posts: 7385
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I had Champion H10's that did not last very long before my engine developed a miss and then I switched to the 216's. I have about 1,500 miles on the ones in my Lincoln without a problem.
My 40 has Champion RJ-14-YC and I have about 6,000 miles on them. I changed to them because Supereal recommended them. They project a little further into the chamber than the Autolite 216 or the H10.
Another recommendation is the NGK # B-6L. I haven't tried them. No one around here carries them.
See if you can find someone with a spark plug tester and test the plugs. I suspect that they are dong the same as the Champion H10C did. The seal between the porcelain and the base was bad on 4 of the 8 H10C plugs that I had on my 40. Both the Autolite and Champion plugs are for "industrial" use and may not be up to handling the heat and compression of the flatheads. If that is the case, my Lincoln should show signs of problems this summer. It has a higher compression ratio than the flatheads.
Tom
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