How do my plugs look?
should I use less premix?


pulled my plugs off my
90 GXL, 84 k miles,
10 k miles on plug
nearly all hwy,
premixed 1 oz/gal to .5 oz/gal

before i pulled them, power lacked quite a bit, and idle was pretty rough, like every 2 seconds I missed once.

 

Nice clear pictures:

Tune is good.
Oil ash deposits are very minor.
One miss every 2 seconds - no worries.

The leading plugs are worn out.
The trailing plugs are half gone.

You might try BUR7EQP for leading. (Platinums for that longer lasting experience..)

 

This is too much oil ash (and a fuzzy pic.)

 

So that leads to the obvious question...what oil have you guys been using?

 

Those plugs look fine, just worn out.

I tend to go with 5k miles or so between plug changes. I'm sure I could push it a bit longer, but that's every 2nd oil change for me, and I don't like having to troubleshoot random issues, so I preemptively replace them.

-=Russ=-

 

Hell,

Mine look like that and I push mine to 12000 miles (every 4th oil change)....but sometimes that is hard to do. It all depends on how much city driving vs highway driving I do.

The last set lasted me 15000 miles because I was driving 96 miles one way to work for a month before moving. I racked up the highway miles and the plugs lasted longer.

Now, I live in the city and am constantly in stop/go traffic. I have about 7k miles on them I think I will be changing them next oil change.

 

I used castrol gtx (20w50 summer, 10w30 winter)
with sams club (coastal??) premix (this one smoked if I used anything more than 12 oz per fill,
now I am using penziol semi-syn 2-cycle (walmart), even with 18 oz I did not get smoke, but power lacked a bit
I already put in coppers, will try platinums next time

why is the #2 leading more worn that #1 leading plug?

 

Nice pics...finally!

Those spark plugs look perfectly fine for 10k miles.
They would need to be changed for optimum performance.


-Ted

 

It looks a *little* oily, but that could be the type of gas you're using locally.
Otherwise, they are still okay.


-Ted

 

premixing is new to me, I ran 91 or 94 octane and made sure the metering pump and lines wereclean and clear...never lost power or spoiled plugs. Is it recomended?

 

if you're not in a turbo 2 you need to lower the octane, it will cause incomplete combustion - 82 octane is ideal for a NA RX-7 due to the long combustion chamber shape. Octane is to prevent detonation, and you won't often have that in a normally aspirated (or even stock t2 s4) car.

Premixing on a stock car generally isn't recomended unless you just add a little extra in case the oil metering pump goes out. If you take out the oil metering pump, lines, and injectors you have to premix - people do this because premix burns more cleanly than regular motor oil and takes away one failure risk in the engine systems.