Squish question

[bwalker]

I want as little squish as mechanically possible. The squish are isn't combusts son the smaller you make this area the more charge you burn.
Also when people talk about high compression saw motors they are talking about static compression. The compression ratio of a saw is quit low.

 

[bwalker]

And oil lowering octane isn't cut and dried. Some actually raise octane.
Octane is a measure of a fuels resistance to detonation which isn't the same phenomenon as pre ignition, although one can lead to the other.

 

[drf256]

Awright, I had to do it.

Squish now .0155

Freeport about .003

Rpm the same.

 

[paragonbuilder]

Does it feel stronger?


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[drf256]

Exhaust now 107 and transfers at 122+

 

[drf256]

 

[paragonbuilder]

View attachment 23543

Wow! Where's it tune at?


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[drf256]

Wow! Where's it tune at?


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It's at 15,800 now. It's getting a slick Canadian Farm Boy custom elbow to fit a Velocity stack and a meanie greenie. Mike picked up 400 rpm on his.

 

[smokey7]

Wow that's some big Rev numbers!!!! What a stock one like to tune to?

 

[drf256]

Wow that's some big Rev numbers!!!! What a stock one like to tune to?

Lol. I have no idea.

 

[Mastermind]

They run over 14,000 stock.

Did it gain anything from tightening the squish Al?

 

[bwalker]

Wow that's some big Rev numbers!!!! What a stock one like to tune to?

Mine likes 14800 with a muffler mod, gasket delete,timing advance and the choke disk ground down.
When it was stone stock it was so gutless the mods I have done are just about required. Not to mention they are free.

 

[bwalker]

I am not sure what the timing numbers are stock, but to me the 160 feels like a motor with too much exhaust timing and too small transfer port duct area.

 

[drf256]

They run over 14,000 stock.

Did it gain anything from tightening the squish Al?

Not sure Randy. Feels peppier, but may be in my head.

 

[drf256]

I am not sure what the timing numbers are stock, but to me the 160 feels like a motor with too much exhaust timing and too small transfer port duct area.

This is a particularly good factory jug. I've heard of exhausts as high as 95 stock.

This one was 99/124/68.5 gasketless.

With an 020 gasket and the .035 squish I was at 105/121.5/75, no Freeport.

Now with no gasket it's at 107/123/76 and I'm barely freeporting, like .002-3.

There's more info in this thread

http://opeforum.com/threads/my-buddy-daves-ms260-and-an-am-vs-oem-jug-comparison.2606/

And if it feels like a motor with too much exhaust duration and not enough transfer area, you're pretty much dead on accurate. That's why a 346 will generally outperform and 026.

 

[bwalker]

This is a particularly good factory jug. I've heard of exhausts as high as 95 stock.

This one was 99/124/68.5 gasketless.

With an 020 gasket and the .035 squish I was at 105/121.5/75, no Freeport.

Now with no gasket it's at 107/123/76 and I'm barely freeporting, like .002-3.

There's more info in this thread

http://opeforum.com/threads/my-buddy-daves-ms260-and-an-am-vs-oem-jug-comparison.2606/

And if it feels like a motor with too much exhaust duration and not enough transfer area, you're pretty much dead on accurate. That's why a 346 will generally outperform and 026.

What the exhaust duration for the stock 260?

 

[drf256]

What the exhaust duration for the stock 260?

162-170*

 

[jmssaws]

amazing job again al,brilliant!