Hi all,
Starting to gather a few parts in readiness for a major service next month. Looking to replace the leads on my NBFL as part of the service and have seen mx5 parts selling 5mm, 8mm and 8.5mm leads.
Firstly, can someone let me know what the size refers to and secondly, what you would recommend installing?
Thanks!
I would suggest that HT leads are not a service item and i would recommend you leave the hopefully original Mazda items well alone unless there is a problem with the ones on your car?
Replacing excellent original Mazda items in boring black with inferior parts may well cause issue.
Standard leads are the way to go in my opinion but you don’t say whether the car is a 1.6 or 1.8 as leads are totally different.
If 1.6, 7mm Mazda leads x 4, 1.8 also has 7mm leads but only 2 and totally different spec.
7mm, etc relates to the width of the lead. You may assume that 8mm leads would be superior to 7mm but that most definitely is not always the case and I would argue from my experience seems to work the other way round. Leads function from new can be tested with resistance check. Inferior leads peform badly from new, allow water ingress and degrade quickly. A good set of original Mazda leads should really last at least 50k.
The ‘service’ aspect of original HT leads is checking for physical damage, perhaps check in the dark to ensure no shorting if misfire issue and with the four port coilpacks - all MK1, all MK2 and MK2.5 1.6 remove leads from coilpack to ensure no water ingress and associated corrosion.
Hi Rhino, thanks for the reply.
Car is a 1.8 53k miles.
I’ve had the car for a couple of weeks and the history is somewhat patchy haha so it’s going in for a full service, timing belt, water pump, aux belts etc, maybe brakes too, for piece of mind so thought it was a good time to change the HT leads and plugs as well. The car is a little rough on start up also so thinking it cant harm.
So you would reccomend sticking with 7mm leads?
Would be interesting to see what others have and if they have seen negative/improvements from running 8mm leads
I wouldln’t hesitate too much replacing an original Mazda part when it’s 20 years old - that said there’s little piece of mind to gain unless you’re seeing an ignition issue - do the checks as suggested and go from there. It’s common to replace the leads with the spark plugs and you’ll see many retailers bundle the two together. But if you’re not seeing a misfire or anything similar then I wouldn’t be in a rush my self.
Sorry can’t answer the question about size. Ordinarily a thicker wire supports a higher current.