NotLawReview

After encountering some engine stumbling issues (described here: https://www.corvetteforum.com/forums...on-switch.html ), I was curious as to if anyone could help me with reading the old plugs?

I took 2 pictures of each plug, labeling them 1.1, 1.2, 2.1, etc.

Here are the pictures: http://imgur.com/a/hXpkX


Thanks!

tbrowne

How many miles were on the plugs when you changed them? The answer may in your first post, but it would be convenient to have the info readily available here. Also, did you change the wires along with the plugs? Some show signs of electrode wear, normal with high mileage, but I don't see anything abnormal on any of them.

NotLawReview

I honestly have no idea; the guy whom I bought the car from was curbstoning it and only had a mod list without any records or knowledge of when the work was done. Drives me crazy not knowing these things, much less not knowing the specs on the cam/etc.

I did indeed change the wires with the plugs as there was definitely some deterioration of the insulation of the wires.

Thanks!

tblu92

You really can get good plug readings on plugs with many miles on them--especially ona DD car--Idling and city driving tend to make them all look bad.
However as an old school tuner I do see one thing that I spotted
We always read plugs in 2 different ways
One is to read where on the center porcelain around the electrode the color begins--and how dark the color is---Can't see this in your photos but you want the color to be a light to medium brown color about 1/4" from the bottom seam
2nd On the ground strap--( I can see this on your photos) where the color change happens---
-Ideally you want the color change to happen on the "bend of the strap"
Can't see this on some photo but can on most---Yours change colors more on the flat of the strap towards the end----
The further the change happens towards the threads indicates "too much timing"
The further the change toward the end of the strap indicates "not enough timing"
Yours being closer towards the end to me means that your engine can use MORE timing---