CovKid wrote:I'm sorry Martin, but I can't support the cutting away of spark plug shrouds. Just replace the leads. Those shrouds are there for a reason. If you've ever had listen to interference on an FM radio from a vehicle close by without them, you'll understand why. Its very antisocial - to say the least
and infact illegal..... "Directive 72/245/EEC of 20 June 1972 on the approximation of the laws of the Member States relating to the suppression of radio interference produced by spark-ignition engines fitted to motor vehicles (3), as amended by Commission Directive 89/491/EEC (4), and in particular Article 4 thereof 'Electromagnetic compatibility' means the ability of a vehicle or component(s) or separate technical unit(s) to function satisfactorily in its electromagnetic environment without introducing intolerable electromagnetic disturbances to anything in that environment."
Ralph, interesting that you rubbish this remedy/diagnostic, based on your 35 year old plus experience of the 'Bad Old Days' when leads/rotor arms/connectors/plugs and caps were totally un-suppressed!!!
Yes...the metal shrouds only function is to reduce radio interference, but you talk as if these tin covers are 'COMPLETELY' responsible for doing this when (if you look at the system fitted to the T25) they are just one part out of several in the ignition system responsible for this function.
The fact is the rotor arm has built in suppression, the PIN connectors (lead ends) have built in suppression, the plug caps have built in suppression and this is the interesting part....the spark plugs (WR
7DC)..have built in suppression. Therefore, removing the shrouds has only a minimal effect. The other important point I would make is: back in the mid 80's NONE
of the spark plugs fitted at that time were suppressed but the spark plugs we use now ARE!
From memory the plugs being used were W7DC or W7CCO NOT SUPPRESSED...the plugs were use now WR7DC ARE! (R stands for resistor) So removing the shrouds may increase interference but this is count acted by the resistor/suppressor built in to the plug.
Yes this subject gets rolled out regularly because the metal shrouds can be an issue in allowing the high voltage to arc to ground before reaching the spark plug.
When I was a Volkswagen/Audi (VAG) technician back in the late 80's, removing the metal shrouds was an 'OFFICIAL' recommendation (from Volkswagen UK) and came about because of the number of vehicles (not just the T3) that were turning up at main dealerships with misfires. So please don't think I've just made this up!
My recommendation has always been to use the (cutting off the metal shrouds) as a 'DIAGNOSTIC' ...as in, if the misfire vanishes AFTER the shrouds are removed you could drive 'AS IS' or as I recommend, unscrew the original caps and fit screw on NGK Caps (which have the necessary suppression) for around £12 a set...much cheaper
than buying a new set of leads at £30 or £45.00 when the copper leads themselves are sound.
Illegal....lol...when you have 3 suppressors in there (with the metal shrouds removed)...its not like you are removing all the suppressors..which of course would be an issue.
I have been running with NGK plug caps on mine for the last 4 years....absolutely no radio interference to the cars audio or any TV or house radio for that matter....they DO NOT have tin shields.
Apologies to the original poster for these completely unrelated comments but when I see such miss-information being written it needed to be addressed.