tree monkeys 2153 deluxe

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I'm definitely not Scott, but it escapes from the last place it can, right out of the exhaust port.

Trapped CR is when the piston just closes the exhaust port top edge on its way up & thus traps the charge down for "doing its business".

The other number is using the volume from the bottom dead to top dead centers piston travel positions for his calcs.

Great runner there Scott!

you are correct sir
and we don't have to worry about detonation until we get over 9-1 trapped
 
9-1 would be far more then the crank could handle.
I built a 440 head saw that had over 350lbs comp, killed the crank in just a few minutes
Have you tried removable inserts in the head,
Different compression, just pop the head off and put in desired insert.

I have a custom set like this on my sled, works great.
 

those look like nuts of stihl
 
View attachment 399784

the 371xp was introduced in 1996, I did this one in 96-97, I learned a lot from this cylinder.
It doesn't look like any squish work was done ........... quads with fingers .......... HUGE transfers

My head is spinning, I am trying to get what you are giving, but this reminds me of an episode of the twilight zone.................. unless it didn't work...... when you say you learned a lot, was it from this thing running like a champ, or a turd ?

Throw me some more scraps off your table please !!!!
 
It doesn't look like any squish work was done ........... quads with fingers .......... HUGE transfers

My head is spinning, I am trying to get what you are giving, but this reminds me of an episode of the twilight zone.................. unless it didn't work...... when you say you learned a lot, was it from this thing running like a champ, or a turd ?

Throw me some more scraps off your table please !!!!

this was a r&d cylinder before I figured out how to cut squish. it was fast, but no torque.
I would not call it a fail, it was a learning tool.
 
On a 357xp, I've heard people say with the high crankcase compression they are high RPM power but lack torque.
Could this be a good thing when hogging out transfers? If the pressure is there, why not get more volume through. When you're done maybe the velocity would end up near 346/2153 transfer velocity. This is why you stuff a crank in the first place, right?
Correct me if I'm wrong, just thoughts leaking out.
 

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