Piston wash patterns

[usmcbuckwild]

I never found plug indexing did anything and not for lack of testing.
Your not wrong on the role of the piston ring.

I’m not arguing your point.

I was taught to index the plugs by my uncle. He was big i to racing back in the day and showed me how. He said back in the day when they cut down BBC and Hemi heads the plugs HAD to be indexed or the ground strap would kiss the piston. He clocked one side of his Chevelle engine, put the other side to torque spec and ran it for a couple months (motor was coming out to be freshened up). Showed me the difference in the piston tops when he pulled the heads; indexed had identical piston wash, non indexed hot hotspots and semi-even wash.

I do not have a series of pistons to lay out and take pictures of, but I would like to do a test of the indexing conundrum. We’ll see what the future brings.

 

[RI Chevy]

Would be an interesting test Curt.

 

[bwalker]

I’m not arguing your point.

I was taught to index the plugs by my uncle. He was big i to racing back in the day and showed me how. He said back in the day when they cut down BBC and Hemi heads the plugs HAD to be indexed or the ground strap would kiss the piston. He clocked one side of his Chevelle engine, put the other side to torque spec and ran it for a couple months (motor was coming out to be freshened up). Showed me the difference in the piston tops when he pulled the heads; indexed had identical piston wash, non indexed hot hotspots and semi-even wash.

I do not have a series of pistons to lay out and take pictures of, but I would like to do a test of the indexing conundrum. We’ll see what the future brings.

Might be different with four cycle V8's.

 

[HYPERSAWS]

About a year and a half 390 husqvarna

 

[RI Chevy]

Nice. Even.

 

[MG porting]

Nice. Even.

Agreed.

 

[Deets066]

Easy to see where the squish band is. Looks like short circuiting out the exhaust

 

[Deets066]

Cleaned up a touch

 

[Deets066]

Thoughts?

 

[Adirondackstihl]

View attachment 176213

Thoughts?

 

[Deets066]

Thanks Jer....

 

[Stump Shot]

View attachment 176213

Thoughts?

Angle of the dangle?

 

[huskyboy]

Would less muffler outlet help with short circuiting? I’m not a pro porter, just wondering.

 

[Deets066]

This was the easiest jug to grind on and keep even being a 2 piece head.

 

[Deets066]

Would less muffler outlet help with short circuiting? I’m not a pro porter, just wondering.

Too much?

 

[Deets066]

The exhaust port itself is very wide. 79-80 percent of bore

 

[MG porting]

View attachment 176219
Too much?

Give it some back pressure with that cover set up you're just wasting you're ear drums.lol.

 

[huskyboy]

View attachment 176219
Too much?

Be interesting to see if it still short circuited or not with a stock cover and side outlets instead?

 

[huskihl]

Backpressure is for pipes.


Lol

 

[Stump Shot]

I am not sure if you would totally mind some wasted fuel for racing, as long as it's performing the way you want to.