Misfire

[coltom]

Should there be a ‘grommet’ thing holding the plug leads in the holder on the cam cover- see pic. My leads are loose in this holder and resting on the cam cover. It’s developed a misfire under acceleration and wonder if one or more lead is shorting as they’re not being held away from the engine.

[lancialulu]

Look at night! I see you have a 123. These produce a much hotter spark (especially if the correct coil is used) did the leads come with the kit?

[Wangler]

These leads should never be bunched together. That said, they shouldn't "leak" if they're good quality and in good condition.

I wonder if you might be getting an induced HT pulse due to the leads being bound together? At stated earlier, the spark is going to be more powerful with the 123 set-up if you have high power coil such as a Bosh Red. Anyway, get yourself the proper Lancia holder that attaches using a cam cover bolt.

[coltom]

These leads should never be bunched together. That said, they shouldn't "leak" if they're good quality and in good condition.

I wonder if you might be getting an induced HT pulse due to the leads being bound together? At stated earlier, the spark is going to be more powerful with the 123 set-up if you have high power coil such as a Bosh Red. Anyway, get yourself the proper Lancia holder that attaches using a cam cover bolt.

Do you mean the tube as in pic below (my car is series 1 Rallye)?

[waterman42]

Funnily enough I am about to fit some plug lead separators and other tweaks to avoid contact between leads and bits of earthed metal. A knowledgeable friend who was helping me out with my coolant leak issue spotted this and I'm taking his advice. Problem partly due to lead on no.1 which is the longest isn't quite long enough compared with the others, or in the alternative others are a tad too long. It came as a set so I'm wary of trying DIY length adjustment.

[Wangler]

These leads should never be bunched together. That said, they shouldn't "leak" if they're good quality and in good condition.

I wonder if you might be getting an induced HT pulse due to the leads being bound together? At stated earlier, the spark is going to be more powerful with the 123 set-up if you have high power coil such as a Bosh Red. Anyway, get yourself the proper Lancia holder that attaches using a cam cover bolt.

Do you mean the tube as in pic below (my car is series 1 Rallye)?

Don't know about the S1, but S2&3 uses one of these, with grommets:

[Beckerman67]

 In addition to previous answers, it would be worth checking and/or investing in a set of silicone leads.
 These are generally 8mm in diameter as opposed to 7mm for the standard PVC insulated.
 Quoting one supplier their silicone leads " have a temperature resistance from -60°C to +180°C and a breakdown strength of 40,000 volts."
 Their standard leads "have a temperature resistance from -40 ° C to + 85 ° C."

[fay66]

These leads should never be bunched together. That said, they shouldn't "leak" if they're good quality and in good condition.

I wonder if you might be getting an induced HT pulse due to the leads being bound together? At stated earlier, the spark is going to be more powerful with the 123 set-up if you have high power coil such as a Bosh Red. Anyway, get yourself the proper Lancia holder that attaches using a cam cover bolt.

.
Leads on S1 go through a tube all bunched together and this is held by a bracket, that is attached to the lower rear  cam cover holding screw.
Brian
8227

[nthomas1]

This is my S2, with the plug leads fed through the bracket attached to the cam cover.  I used cable ties to denote which cylinder each lead was for.  Of course you only need to label the first three, but the OCD side of me insisted on 4 cable ties on the fourth lead!

[coltom]

OK thanks everyone. I’ve found a rubber tube that may be suitable. I’ll separate the leads and feed through tube to hold them in place. Also-
- does someone know a source for silicon HT leads for a Series one?
- it looks as though my 123 ignition is using the original coil. Should it be using something beefier and, if so, what?

[Wangler]

OK thanks everyone. I’ve found a rubber tube that may be suitable. I’ll separate the leads and feed through tube to hold them in place. Also-
- does someone know a source for silicon HT leads for a Series one?
- it looks as though my 123 ignition is using the original coil. Should it be using something beefier and, if so, what?

A Bosch Red coil seems to be the favoured one. Works well on my S3, but there again so did the original Magneti Marelli.

[coltom]

Leads separated, cleaned and fed through appropriate rubber tube (bicycle handlebar grip with end cup of!). Looks much better. Will have to wait for dry weather to see if it runs any better.

[nistri]

I noted you are not using a standard distributor cap. By the way, the use of silicone leads has received mixed opinions, probably OK with strong electrical pulses from 123 but not ideal with standard ignition as silicone leads are said to have higher resistance.

[Wangler]

I noted you are not using a standard distributor cap. By the way, the use of silicone leads has received mixed opinions, probably OK with strong electrical pulses from 123 but not ideal with standard ignition as silicone leads are said to have higher resistance.

I think this is a good source of info.

Silicone is a great insulator, it isn't a conductor. So, unless I've misunderstood the above comment, silicone leads (with a suitable core) are the best available because of silicone's complete lack of conductivity.

https://blog.simonbbc.com/2022/10/14/what-are-ht-leads-what-do-they-do-in-my-classic-car/