theory of x brand plug in certain makes

[HangFire]

I have two theories why some older vehicles may be better off with non-OEM plugs: Ethanol and waste spark.

The Ethanol gas thing is kind of obvious, it has a lower energy content and lower flame temperature than gasoline. That can be enough to push a pre-Ethanol vehicle to a different optimal heat range for the plugs.

While an older waste spark system might seem to be a natural fit for newer platinum plugs, sometimes the extra spark it creates a heat situation which causes these plugs to increase gap and burn out plugs very quickly. In these cases some folks have found old-school copper core plugs work better, and the replacement interval is not too different from burning out more expensive platinum plugs early.

 

[Oldmoparguy1]

Originally Posted By: Chris142
Don't put Bosch in a jeep.plenty of threads in the jeep forums about new Bosch plugs and cel's on along with misfires

Bosch plugs just don't work in my older Mopars.

 

[HerrStig]

Originally Posted By: HangFire
I have two theories why some older vehicles may be better off with non-OEM plugs: Ethanol and waste spark.

The Ethanol gas thing is kind of obvious, it has a lower energy content and lower flame temperature than gasoline. That can be enough to push a pre-Ethanol vehicle to a different optimal heat range for the plugs.

While an older waste spark system might seem to be a natural fit for newer platinum plugs, sometimes the extra spark it creates a heat situation which causes these plugs to increase gap and burn out plugs very quickly. In these cases some folks have found old-school copper core plugs work better, and the replacement interval is not too different from burning out more expensive platinum plugs early.
NGK has suggested one heatrange colder for their air cooled bikes on bleep alcohol infested gas. I couldn't find a set of platinum NGKs in the new heat range so put a set of "regular" ones in instead.
NGK knows plug technology. Why Bosch is hit or miss is beyond me.

 

[HerrStig]

Originally Posted By: hansj3
does anyone here subscribed to the theory that certain makes vehicle need certain brands of spark plug? Like chevys and ac delco, Asian cars and NGK, jeeps and champion?

I seem to prefer NGK v powers in everything, have themin my ssubsrus, jeeps, Honda...
SAAB used NGK as OEM in the 900 series.

 

[gonefishin]

AC Delco plugs is all I put in my Chevy Trailblazer.

For many years I only used Champions in my 3 cylinder 70HP Johnson outboard. Last year I decided to switch to NGK. I picked up 4 more MPH (GPS verified) than the Champions on the top-end. Once you find what an engine likes, stick with it.

 

[Jetronic]

Golden Lodge plugs work best in the older Alfa Romeos, up until the multi valve engines.

VERY unusual spark plug though.

 

[CBR.worm]

I've had bad luck w/ Bosch in a few situations, now NGK is my first choice regardless of the vehicle - assuming they have a suitable part. Most of the vehicles I work on are Japanese or German. In the past a number of Mitsubishi powered Chryslers - which I filed under the Japanese category.

On the bike front, my first few CBR's the inner cylinders were jetted differently than the outers.

 

[artificialist]

Originally Posted By: Trav
Originally Posted By: Leo99
Originally Posted By: earlyre
Originally Posted By: Leo99
I put Denso in my Toyotas. Never tried any other brand.

I changed the plugs in the vibe(2003 1zzfe) when my buddy first bought it, took out the OE plugs, put in NGK's. I think they were either the oe plugs, or the most highly recommended on the vibe forum i had joined.


I've heard NGKs are good. I forget if it was Honda or Toyota but I've read that the V6 engines sometimes have one bank of Denso plugs and the bank in NGK plugs from the factory.

Just beware the self-fulfilling prophecy.


I bought a brand new in the crate Honda CBR 1100, the 2 end plugs were NGK and the 2 middle ones were Denso. I ever found out why, they were the same heat range.

Is that a waste spark engine?
Sometimes waste spark engines would have platinum on the ground strap only for 1/2 of the plugs, then have platinum on the electrode side for the other 1/2 of the plugs.

This is also why some Toyota V6 engines had 3 NGK plugs and 3 Denso plugs.

Then, why you buy replacement plugs, you can't get the exact OE plugs, you instead typically get plugs that have both a platinum electrode and grounds strap.

 

[The Critic]

I try to put Denso Long Life Iridium in every vehicle I service.

If it is not available, then I go with either NGK Long Life Iridium or whatever the dealer sends me.