[Mike S]

I read that the heat line on the ground strap should be at the bend. Mine is a little closer to the base. It runs great. Do you think I should take a tad of timing out. I forgot what I set it at but I think it was 38. E-heads with 12-1 compression.

Last night I ran 6.30 with a 1.340 60'

[Elarson]

Taking timing out will move the color closer to the base.
When we ran the Grocery Getter, the nitrous experts recommended tuning the timing to put the color at the bend. We beat up a lot of pistons following that advice. Then started retarding the timing and every bit that we took out made it faster and easier on pistons. When the pistons were happy, the color was at the base of the ground strap.

FWIW:
Eric

[Tom Vaught]

Originally Posted by Elarson

Taking timing out will move the color closer to the base.
When we ran the Grocery Getter, the nitrous experts recommended tuning the timing to put the color at the bend. We beat up a lot of pistons following that advice. Then started retarding the timing and every bit that we took out made it faster and easier on pistons. When the pistons were happy, the color was at the base of the ground strap.

FWIW:
Eric

I have seen a lot of engines killed by 1 degree too much timing and a lot of very fast engines (with happy pistons) when the timing was a lot less than what many thought it should be.

I have seen a several boosted engines make excellent power with less that 10 degrees of timing at max boost and max rpm.

Tom V.

[charlie66]

I would take 2 to 3 out .

[steve25]

If that color change over point was not made by just full throttle runs and then shutting the motor down then you need one step colder plug, but even if it was the heat range looks like it’s on the edge of too hot to me.

One things for sure buying and testing another set of plugs is a heck of a lot cheaper then the cost of pounded out rod bearings!

[johnta1]

The bend is for heat range of plug.

Timing is taken from the base of the bend. The whole circle of the flat part.

[grandville455]

Originally Posted by Elarson

Taking timing out will move the color closer to the base.
When we ran the Grocery Getter, the nitrous experts recommended tuning the timing to put the color at the bend. We beat up a lot of pistons following that advice. Then started retarding the timing and every bit that we took out made it faster and easier on pistons. When the pistons were happy, the color was at the base of the ground strap.

FWIW:
Eric

I thought less timing would move that mark more towards the tip and not the base? That's how i've always understood it atleast

[bluegoat65]

Nice looking plug. Maybe take out a couple degree. How does the fuel ring look down below...lol. Cut one apart and take a looksie.

[bluegoat65]

Originally Posted by grandville455

I thought less timing would move that mark more towards the tip and not the base? That's how i've always understood it atleast

x2 here

[Scott65]

As mentioned, I'd take a new 3923 and 3922(or NGK equivalent as I like them better) and make a clean run to check heat range. It looks a little hot. (if you get the same heat mark on a new plug) I'd make a guess(though an educated one) the 3922 will be appropriate in a 12:1 engine. Once the heat range is verified, timing by power numbers(appropriate fuel is assumed)

[steve25]

With night time runs the humidity usually soar’s and can make for your jetting looking fatter and allow you to run more timing then you could during mid day runs for example.

[racegto65]

Good info in this video from Steve Morris about reading plugs

https://www.facebook.com/watch/?ref=...59749171308412

[Elarson]

Originally Posted by grandville455

I thought less timing would move that mark more towards the tip and not the base? That's how i've always understood it atleast

Yes, you're correct. I said it backwards.
Retarding the timing reduces the temperature in the chamber and causes less cooking of the groundstrap; so the color band moves out toward the tip. The base of the strap sinks heat into the metal shell and stays cooler.

Grocery Getter ran best with almost no "blue" on the ground strap.

Sorry for the confusion...
Eric