Iridium-tipped sparkplugs, anyone tried 'em?

[Esprit]

Just forked out 100 quid (NZ) for a setfor the TR to try and cure a misfire that it's picked up of late. Replaced the points as well and so far the miss is still there (I'm slowly working my way back along the ignition system until I have it sorted). Supposedly they last a lot longer, self clean from carbon-fouling and give a more consistent, hotter spark over a longer gap than ocnventional plugs. Anyone used/reccommend them? Since the 7 is still running like the proverbial bag of spanners I've yet to see for myself. Can I look forward to better performance/longer plug life or have I just wasted my money and turned into a bolt-on boy? ......NOOOOOOOOOOOOO!

[davidd]

Adam (GTIR) bought a set for his Nissan, not sure if they sorted his problems out.
Have you tried a different set of HT leads ?

D.

[Esprit]

davidd..... yeah well I'm going to do the rest of the ignition system just so I know it's been done (Coil, leads, dizzy cap, rotor and condenser) although i NEED to do leads now as I managed to pull the end off one when I was mucking round with it (it might have been that in the first place) I'm also goig to have the carbs re-jetted as i think the proble,m might be that I'm still running the standard jets with a freer flowing inlet/exhaust setup.... in any case she's off the road for the next few weeks while I do 100+ hours at varsity

[Byff]

I only had a miss-fire once on my TR, found out it was the HT Leads (probably due to the battery coming loose, tipping over and spilling acid over them)

It didn't like running when the cylinder head gasket went on it aswell but i'll keep my fingers crossed its not that serious.

[pdv6]

A previous motor of mine used to intermittently run rough as a dog, especially in wet weather (so, that's pretty much all the time in the UK, then ) - eventually traced to the carbon HT leads cracking up internally.

[Esprit]

yeah well I've already shagged my leads so it's a new nice set of MSD leads as soon as i can pony up the cash. It's not a head gasket for sure, i know that much.... i build my engines strong

[gtir]

Iriduim plugs are overkill on most engines, where the standard NGK ones will do the job.
The only reason I got them is that I run high boost (1.2) and the NGK ones get a bit arsey.

I very much doubt that your problems will be fixed with new plugs, the HT leads usually are the culprit. Its not a complicated setup after all, no ECU's and what have you, so fiding the fault should be easy.

Maybe you have a piece of sheep in the air filter!

[Esprit]

gtir hehehe yeah, i knew there had to be a sheep joke in there somewhere!

Yeah well like said new leads and coil are definitely the next things to be done. I'm thinking it could be carbs too. The thing is she'll pull all the way to redline fine in first gear but wont get past 5,000RPM in 2nd 3rd 4th etc (6,500 redline).

I'm thinking if it's not dud ignition then it's leaning out at the high RPM. It's running K&N filters now instead of the airbox and the typical TR7 peashooter exhaust had been ditched in facour of a little freer breathing one (not a 6" nova exhaust either) and I think it just neds increased fuel to keep up. In about 8 weeks after uni I think I'll take her down to Swift's (the SU Carb specialists in NZ) and get them to have a looksee and see if they can weave any magic.