Post Number: 95
|Posted on Monday, 30 March, 2020 - 00:28: |
Hello…not sure if I may post here regarding my SCIII where since a year is sporadically running on 7 cylinders…narrowed down to the A4, so exchange spark plug each time and runs normal for a few months however has happened now about four times…
(BTW don't drive it very often)
Felipe - have moved this post to the Silver Cloud and Bentley S section where it is more likely to get a response. David
Post Number: 108
|Posted on Monday, 30 March, 2020 - 13:13: |
Issue could well be related to a faulty lead or connection, mark the leads, remove the distributor cap and check condition of the cap internal contacts and clean them, check also for "tracking" or cracks in the cap. Check resistance of leads, from inside cap to plug connection, if "resistance leads" they should be approximately 1000 ohms per foot (300mm), if copper core leads the resistance should be no more than 1 ohm.
Trust that helps.
Post Number: 179
|Posted on Monday, 30 March, 2020 - 17:51: |
Is the plug oiling up? Does cleaning the plug make it work again?
I would install a hotter platinum or iridium plug in that cylinder if so, or simply do all of them, if it works fine after changing the plug it can’t be much else other than plug failure or oiling.
Is the car getting a good run when you use it?
Check the mixture also as plugs will soot up if too rich
Robert J. Sprauer
Post Number: 601
|Posted on Monday, 30 March, 2020 - 22:34: |
Replace the cap, visual inspection is not always reliable, check the leads under complete darkness for arcing. If you pull the lead on the mentioned cylinder, I'm sure you will see grey spots. Those are the arc witness marks.
Posted From: 22.214.171.124
|Posted on Monday, 30 March, 2020 - 19:59: |
Could the string and wax valve seals have failed?
There was an improved silicone rubber version available at service from December 1966.
(Message approved by david_gore)
Post Number: 97
|Posted on Monday, 06 April, 2020 - 05:08: |
Thank you for all suggestions, however will need to look up meaning on some...
My mechanic believes the plug is not sparking due to oil…next time will try cleaning plug rather than changing with new...
Have changed all plugs and when out has a good run…
Recently and before plug problem, all leads and cap changed plus points and condenser for complete tune-up…running smoothly...
Post Number: 383
|Posted on Monday, 06 April, 2020 - 05:21: |
Hi, have ya checked the dash Potts on the carburettor, if full of carbon piston can stick, lead to rough idle and oiled plugs. Worth a check.. easy to clean