The 'E' Type Forum

Hi Guys
I've got an occasional misfire under heavy acceleration so it seemed like a good opportunity to work my way through the ignition first (will move on to fuel if it doesn't go away). I changed the plugs to champion N11YC from SNG but that didn't solve it. Have moved onto leads and have bought a lead set, but as an etype novice I didn't realise about the acorn caps and brass washers etc - I currently have push on silicon leads fitted by the previous owner, so assumed that's what I would get. I can order a new cap with the threaded connections (I need to order some rubber sleeves anyway as the SNG lead kit unhelpfully doesn't include them).
My question though is having only ever used one piece leads, how do I make the connections to the plug caps and the acorn caps. The plug caps look like they screw straight into the leads and I guess the sleeve holds them in place, but where / how does the brass washer with the split go? And how do I make the connection at the acorn cap end? Sorry if this is basic but got to start somewhere!
Many thanks!

Hopefully this helps? The brass screw simply screws into the end of the lead, into the conductor. Don’t forget to push the acorn plug on first!

Mine had a slight misfire on acceleration..... did everything on the ignition side, but it just got worse over time. Cylinder 3 would badly foul the plug.... it didn’t end well, and my S2 has just come back from its engine rebuild as the problem was a failed piston oil ring.

Hopefully yours is just a lead problem, although have a look at how your distributor is: it might me a problem with the vacuum advance sticking because of siezed weights.....

Paul

Hi Colin...misfire....can drive you mad trying to find them......on the low tension side check the actual wire connections into the spade terminals they can become loose...an easy way to eliminate most of the wireing is a temporary connection from battere to coil (put a fuse in).......it will bypass ignition switch etc....Steve

What sort of ignition system do you have? Is it an electronic module in the ditributor? Might be if the previous owner fitted silicone leads. If it is electronic, and your new leads aren't silicone, they could interfere with the signal. Mine did, and caused missing/cutout at high revs. Solved when carbon leads were replaced by silicone. Can also solve the problem I believe with special plug caps.

Hi Malcolm that sound a bit confusing.......silicone leads can have either a carbon core or a copper core......are you refering to PowerSpark who recomend useing Silicone/carbon core for electronic ignition...Steve
https://simonbbc.com/about-powerspark-8 ... -ht-leads/

Steve, It was simonbbc who recommended silicone leads to me, and I was using their powerspark system. I probably confused things saying "carbon", it was copper leads from SNG (new) that caused the interference. simonbbc sent me a silicone set, and problem instantly solved. Before then, I'd swapped coils, rotor arms, dizzie cap; everything was new and problem persisted until the silicone leads. They said the field set up, particularly if the leads are thin (the new ones from SNG were thinner than my original copper leads), set up a field that interferes with the "hall effect" of any of these types of systems. Me no nuthing, but the lead swap certainly worked!

Hi Chaps, thanks for the responses. Paul, my leads kit doesn't have the screws in your picture, just the brass washers. SNG dont show them either, any idea where to get them?
Malcolm - yes the previous owner has swapped it over to electronic ignition. I think on closer inspection the existing leads probably aren't silicon though as they feel quite stiff. Maybe normal copper but with push on connectors rather than the acorns. Are the acorn style leads and cap better than a standard push fit? If not i'll return the kit and try and source some standard leads, or take the push on ends off the existing set if that's possible, as I think my cap is fine. Sorry, so many questions!

Colin

Basically with electronic ignition you shouldn’t use copper core leads. You need a surpressed set (silicon etc) so they don’t upset the electronics. I’ve got pertronix on mine with modern leads that are surpressed but look original.

As for your question on the brass screws, mine came from SNG B’s and I recall came with the split washers... give them a call, they’re incredibly helpful and will sort you out.

Paul

Hi Paul, yes I have found them to be very helpful in the past. I'll call them on Monday. Thanks very much for your help.

Colin, the set I got from SNG didn't have the brass screws either. There is just a piece of extruding wire which you locate the hole in the brass washer over, then bend over. Screwing the acorns down then holds it firmly in place.
This is the set I didn't then use as it was copper and gave me the misfire.

Thanks Malcolm, I should have spoken to you guys first - lesson learned! I’ll speak to SNG on Monday and see if I can swap this set for suppressed ones.

Are you useing suppressed spark plugs.. Steve

Yes the Champion plugs are suppressed.

Ahh - champion plugs.
I think most recommend NGK but before you throw more money at this problem maybe you could check the resistance of each and compare.

I’m sure others will know more & better

Pesky misfires!

Just looked on the champion website.N11YC isn’t a resistor plug

Thanks Tim, I’ll change to NGK. I had read this on the N11YC page and assumed I was ok with them.
“Durable: Champion copper plus spark plugs are built to ISO and SAE standards for proven performance; Champion's patented SAC-9 semi-conductor resistor provides maximum EMI and RFI suppression”

Just my thoughts, as I say others more experienced than I may well advise different. Wouldn’t want you to go down a wrong route!

Good luck

Much appreciated Tim!

Still working through this post winter hibernation ( I know, I'm ashamed!) and come across this. As you can see ive got electronic ignition as mentioned earlier in the post, but does this earth wire still serve a purpose or is it redundant? There is hardly anything left of it in places, just a few bare strands. Thought it was worth a check!