Spark plug question

[Marian]

Novice question but you guys know I'm learning as I go. I bought some platinum spark plugs for the Monaco. From my research on the internet, platinum last longer than copper type but aren't as efficient. We all know that if it's on the internet it's the truth. Right? Hmm, that's why I have ya'll. Also, when setting the gap, is it the same for copper vs platinum?

 

[commando1]

Stay with the platinum. Efficiency? I think it's so negligible it's more theoretical than actual.

Yes, Gap stays the same. Enjoy the extra time you're not wasting changing plugs

 

[wihaltom]

I changed plugs in my 66 and went with platinum also.
The question I have is about the gap.
I gapped mine at .040 because I have an MSD electronic ignition.
Is this a good gap for an electronic ignition equipped engine?
When I put the Pertronix unit in my 67 Cougar, the instructions said to regap the plugs to .040.
I just figured to follow suit on the 300.
Any thoughts?

 

[saylor]

.035 is usual, but it seems like I read somewhere about MSD or pertronix or whatver throwing good spark at .040-.042...

 

[Big_John]

I ran my MSD ignition with .055" gap. That was what the tech at MSD recommended.

 

[wihaltom]

I ran my MSD ignition with .055" gap. That was what the tech at MSD recommended.

Man, .055 is a BIG gap, but if that's what they recommend, it must be okay. My '66 runs really good at .040 so I think I'll stick with that till I change plugs again.

 

[Furyos George]

Hi guys,
please note that if you are using a MSD ignition, it is recommended to use ONLY copper tip plugs. The platinum tips can melt and cause dieseling. Just do a google search on the topic.
In my small block I used to sidegap, index, and gap out to .50 and it used to run very well

 

[theos911]

I put Champions in my 318 Fury and I think they were .035.

 

[BillGrissom]

With a good electronic ignition (MSD or HEI), I would start with at least 0.055" gap. Problems will show up at low-speed with wide-open throttle, like climbing a steep hill or on a freeway on-ramp, since that is where you have max cylinder pressure where it is harder to throw a spark. If it misses there, reduce the gap. I had to do that in my 1996 2.4L and it cured the problem. That was a Chrysler TSB for the 2.4L Turbo engines (reduce gap to 0.050"). Of course, a turbo has even higher cylinder pressures.

 

[Big_John]

Man, .055 is a BIG gap, but if that's what they recommend, it must be okay. My '66 runs really good at .040 so I think I'll stick with that till I change plugs again.

It seemed big to me at the time, but the car (440 6bbl A12 Roadrunner) ran great with that gap.

 

[moper]

I always found even with the MSD instructions that something between .035 and .045 was about it. Beyond that and they lost a little "snap". Some factory ignitions run much more- up to .085".

 

[bluefury361]

Whenever I need to change plugs i've found NOS Champ J12Y on line for around $15.00 for a box of ten.

Just checked ......

http://www.ebay.com/itm/Champion-J-...faultDomain_0&hash=item27dc302302#ht_63wt_880