Spark Plugs

Thunder Kiss · March 23, 2005, 02:27:57 PM

My car (early '86 with iron heads) is due for a new set of plugs.
There seems to be too much choice these days - platinum, iridium, multiple-electrodes, V-shaped electrodes, etc.

What does everyone use? Any recommendations?

TIPPA · March 23, 2005, 02:42:38 PM

I've tried pretty much all the plugs you've mentioned, thunder kiss. the platinum and iridium plugs are more for longer life. instead of having a 15,000km life theirs is more like 100,000kms. But you pay for it! As for the 'V' GROOVE and split electrode types, i've paid the small amount extra but have never noticed a power increase at all. and if there was, i certainly never felt it!
I just stick with my good old favourites NGK-R.

Vette Obsessed · March 23, 2005, 04:21:45 PM

I've never been big on platinum or iridium for the reasons TIPPA mentioned.

As for multiple electrodes and the like, from what I understand the spark will only "use" one of the electrodes when igniting anyway (I stand open to correction on this). I don't use them either.

I just use plain old "Champion Gold" plugs in my car - although everyone I have spoken to tells me NGK is better.

77CVT · March 23, 2005, 05:37:40 PM

QuoteI just stick with my good old favourites NGK-R.

Yep! I use Iridium's but I got 'em cheap. ;-) I have never liked Champion plugs - they never seem to last as well.

Stick with NGK and you'll be pleased.

86er · March 24, 2005, 06:00:06 PM

I don't like Champion plugs as they are a two piece pressed plug, problem being if the thread siezes up when you remove them you leave the threaded part still in the head which means removal of the head.
NGK are about the best for the price, the other plugs are good however unless your motor is highly modified you won't notice the difference

MJ355 · March 24, 2005, 06:20:09 PM

ive got a brand new set of mallaroy leads for sale to fit if u are interested

onya · March 24, 2005, 10:07:19 PM

I just fitted a new set of NGK and Splitfire leads and there is an improvement in idle and general driving.;27, I to have an 86 with iron heads. Most of the improvement came from the new leads.

77CVT · March 24, 2005, 10:42:58 PM

New leads can make a world of difference. I put a new set on my '85 and got an extra 5 mpg. 3 leads were crapped out. Best way to check is put a multimeter on each a\end and measure the resistance - anything over 8000 get new ones.

Top gun make an 8mm spiral core lead if you have trouble fitting 9mm into aftermarket lead seperators.

Thunder Kiss · March 25, 2005, 10:54:38 PM

Thanks for the replies, next question.
I pulled a plug and found it to be an NGK BPR6FS. NGKs web site states I should be using a UR5.
What's the difference? The car runs fine with BPR6FS.

86er · March 26, 2005, 12:11:06 PM

That's the heat range of the plug, depending on the type of driving you are doing will depend on the heat range of the plug
Hope onto NGK web site

Adam · March 27, 2005, 11:03:50 AM

Here's an interesting article on spark plugs:

http://www.silverbulletrx7.com/plugs/
(unfortunatly the article is targeted at, but not exclusive to- rotarys)

He compares a lot of hi performance plugs out there, as well as the more superior designs out there like the Brisk's (whom apparently have a power increase on the dyno in a piston engine):

and Torque master:

But if you go with the conventional design plugs theres prolly not a lot in it- the best thing to do is to index them.

Adam

77CVT · March 29, 2005, 01:57:41 PM

QuoteOriginally posted by Thunder Kiss
Thanks for the replies, next question.
I pulled a plug and found it to be an NGK BPR6FS. NGKs web site states I should be using a UR5.
What's the difference? The car runs fine with BPR6FS.

That plug should be fine. B is 14mm, P is projected tip, R is resistor type (all our cars should have these), 6 is a colder plug than the normal 5, FS is tapered seat.

I think I ran 5FS in my '85. It maybe different for an alloy head.

Explanation

Thunder Kiss · March 29, 2005, 08:07:13 PM

Thanks for the info, I ended getting another set of BPR6FS plugs but I might try 5's next time to see what difference it makes.

White Rider, I understand the theory of indexing but how do you actually get the electrode pointing the right way? A spacer of some kind? Also, do you think it's worth it in an almost standard road car?

77CVT · March 30, 2005, 08:57:00 AM

Quote... but how do you actually get the electrode pointing the right way? A spacer of some kind? Also, do you think it's worth it in an almost standard road car?

I do it on my cars (vettes). it is easier with the heads off (obviously) but with them on, make a mark with a marker pen where the electrode opening is and see what plugs end up pointing to the exhaust valve (or close to). I've found you'll get 5-6 in a good position but I got lucky with the last lot and got all 8 pointing in the general vicinity.

There are copper washers available to help indexing, but for the cost I don't feel it is worth it.

Spark Plugs

MJ355