Plug readers please!

[jtb032295]

So here's a few pics.. 355, 3310 carb, timing set a 35* locked, 93 octane pump fuel, Autolite 26 plugs. Disregard #8 in the lineup pic, I had to change a plug after the heat and a junky used one was all I had.. The actual #8 plug is the one that is cut at the threads.

I've read that the "black oxide" finish plugs are not desirable for plug reading due to the lack of burn off around the base circle/threads.. I do plan to switch ASAP..

Thanks guys! Any input is appreciated!! I'm very new to plug reading but I'm trying to get a grasp on it.. I'll save someone a breath by saying I have been ALL OVER the internet reading about this topic lol

[FC-Pilot]

WOW, a 26 is a hot plug. If I have to use a cheap plug for a performance SBC I usually start with a 24. 25 is what comes in the chevy trucks that had marginal performance and low compression. What are the rest of your engine specs and what is the application?

Paul

[statsystems]

Get a plug that you can read the shell on first. But you already knew that.

Unless you have a stocker, that's a hot plug. Looks to me like you have it very fat at idle and mid throttle, to keep it from killing itself at WOT.

[user-612937456]

Get a plug that you can read the shell on first. But you already knew that.

Unless you have a stocker, that's a hot plug. Looks to me like you have it very fat at idle and mid throttle, to keep it from killing itself at WOT.

WoW how can you tell what it is its at idle or mid rpm?
Looks like 4 and 7 are a little lean others re marginally lean and 2 are just right are you using a dual plane? I would go 2-4 jet sizes up depends on whether its an open plenum or not as to which corner if its a dual plane make the leanest plugs just right and let the rest go mildly rich.

[BOOT]

Idle looks rich like said, wot bit lean.

What's your comp? I use 26 in a car but it's like barely 8:1

[englertracing]

wb o2 guage
and pyrometer

[statsystems]

Get a plug that you can read the shell on first. But you already knew that.

Unless you have a stocker, that's a hot plug. Looks to me like you have it very fat at idle and mid throttle, to keep it from killing itself at WOT.

WoW how can you tell what it is its at idle or mid rpm?
Looks like 4 and 7 are a little lean others re marginally lean and 2 are just right are you using a dual plane? I would go 2-4 jet sizes up depends on whether its an open plenum or not as to which corner if its a dual plane make the leanest plugs just right and let the rest go mildly rich.

The base of the ceramic has a fuel ring. That is WOT. As you move towards the other end you see idle and mid range. That's how I look at them. But you have to have a plug that you can read the shell. When the plug is hot it makes everything hard to do.

Many people use a plug that is too hot and jam a bunch of fuel through it to keep it out of detonation.

[jtb032295]

Well my comp is around 10:1 and I guess I should've started tuning with a colder plug.. From what I can tell with my magnifying scope, there is signs of slight detonation in the form of slightly peppered porcelain. No silver specs are present.

As far as the WOT fuel ring, how does it look? And what should I be looking for? I've heard a dark line, a tan line, 1/16", 1/8"? What is the correct thing to be looking for?

This IS a circle track motor, sorry for not mentioning that earlier guys..

I do plan on going 2 steps colder with the plugs.

[BOOT]

The problem with autolite is sometimes they look peppered out of the box, not that I'm saying you don't need to go 2-3 plugs colder! You may just have to mod your metering blocks to clean up that idle.

[jtb032295]

Plug comments are still welcomed! Any input is appreciated!

Also, I am switching to NGK plugs and I'm looking for a heat range recommendation.. Since Autolite has no way to compare heat ranges, what NGK heat range should I start with? My guess is 7's but I'm not sure..

Thanks guys!

[1972ho]

You can try this for a comparison but be aware I used it but the plugs that it had for me did not match the plugs that I had

[user-23911]

Timing set at 35 deg locked?
What does that mean?

So in lower revs it' s got too much timing so it detonates.
And makes the plugs look like it's detonating?

Why would someone want to lock the timing?
It doesn't make any sense.
First post.

[Amilcar]

Timing set at 35 deg locked?
What does that mean?

So in lower revs it' s got too much timing so it detonates.
And makes the plugs look like it's detonating?

Why would someone want to lock the timing?
It doesn't make any sense.
First post.

Be prepared to be shoot in the head after this...

[user-612937456]

Be prepared to be shoot in the head after this...

What else can you expect of the people from The land of the long white cloud LOL

[Zmechanic]

Slightly rich mixtures around the plug insulator nose can deposit some soot products very finely. If you look at it under magnification, it can look similar to peppering. Projected insulator plugs are worse about this. I've noticed on the AR133s I've used, the insulating ceramic actually appears to have a sparkly appearance if you catch the light right. It can make your heart skip a beat for a second if you catch that when you are working up your timing and mixture!

If you are doing WOT testing only, then I'd say your base fuel ring is right at the leanest I'd be comfortable with personally. I'd probably throw a jet sizes or two in it and see what it does.