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-   -   Analyze my Spark Plugs Please! (https://www.rx7club.com/2nd-generation-specific-1986-1992-17/analyze-my-spark-plugs-please-459960/)

Andrew. 09-04-05 03:33 PM

Analyze my Spark Plugs Please!
 
4 Attachment(s)
Unknown mileage on the plugs, I'm assuming ~3.5k miles since thats when the motor was built but the person that had it built might have not changed it, its been through 7 pulls on a dyno, been redlined and pushed, hasn't been tracked (yet) :D

Engine wise, specs are: aux bridge, ra rebuild kit, s5 manifolds, s5 tii secondaries. For ignition it has a jacobs fc1000, i'm throwing in some msd wires and I have some new 7's and 9's going in, the motor will be a street/track car, should I trade in my 7's for 9's or stick with stock setup? Thanks and heres the pics.

-Andrew

Go48 09-04-05 04:01 PM

They all look good except the one you have annotated Trailing Rear Rotor. The insulator on that on is a bit on the black side indicating that it wasn't completely burning the fuel-oil mixture. Could be that this plug was faulty or the coil-igniter or plug wire was not up to par.

The other plugs have that nice brownish deposit on the center insulators which is just what you want to see. BTW, I would bet that the plugs have been in this engine for considerably more than ~3.5K miles.

RotaryEvolution 09-04-05 04:17 PM

they look.... worn!

i hope you plan on changing them while they are out. aside from that they all look fine.

those plugs have a bit more than 3.5k miles on them. generally i reuse plugs in rebuilds as they take a fair amount of abuse for the first 1k then they should be changed shortly after depending on their original condition.

'89Vert 09-04-05 04:20 PM

Yah I would definately say those have been in there weeeellll more than 3.5k miles.

There is some debate whether or not to keep all stock 7's and 9's. With a bridgeport, you could probably stand to use all 9's and be just fine. I'm sure someone will disagree, but it seems that the extra spark couldn't hurt, considering your mods.

RETed 09-04-05 04:57 PM

They look perfectly fine.
The trailings look *slightly* richer than the fronts, but it's still not that big of a deal.

I believe the leadings are the two outside plugs in the pics? :)

You might be able to run all 9's, especially if you're running high in the RPM range constantly.


-Ted

fcturbo2 09-04-05 05:03 PM

Andrew...have you installed the K yet??.. I have a K and my plugs would look like that after i pull them out. I noticed after i replace mine with new ones from KRAGEN the car was easier to start. Im also running rich and premix..

Andrew. 09-04-05 06:40 PM

fcturbo2- Yeah the e6K is in man! Its been in for a while, we got to dyno it but ignition break up was across the board so i'm going to try to fix this up and put in some aftermarket grounds, the msd's and the ngk's. I bought my plugs from kragen 21.50 for all 4 With tax! not bad. Whats your aim man? I used to talk to you on it but it got deleted.
Ted- leadings are what were indicated, just double checked them :dunno:

-Andrew

fcturbo2 09-04-05 07:06 PM

myblackt2

Turbo II 09-04-05 07:21 PM

Ok, I'll try but it's hard to do over the innerweb.

The first plug appears to have a split personality it looks like...
The next one is a bit on the submissive side from the looks of it...
The one after that is being abused at home...
The last one is definitly manic depressive, just look at it.

Other than that, I think they will be fine, err look fine.

Andrew. 09-04-05 09:57 PM

So i put the new plugs in 7 and 9, new msd wires, also a new battery because the old one never held a charge and hit like .17 volts on the dmm and I had a 5 year warranty so I got a new one and...WOW this thing wasn't started for 2 weeks so i was expecting to wait a couple of seconds but no, instant start up and a nice consistant brap brap brap, throttle response felt alot better and I did notice a increase in acceleration, looks like that ignition box with those 2 things gave it a nice kick!

mr_vaughn 09-05-05 01:44 AM

what is your hp goal?
cause if above 250 go with 9 temp plugs all round.


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