HL 260 War Jug

[Chainsaw Jim]

So I'm trying to wrap part of my head around this whole compression thing that seems to have a few differing opinions or reported results.
I took two 5 cube saws and comp checked both to compare something. One maxes out at 240psi the other maxes out at 150psi. The 240psi saw consistently reached 90psi on every first pull while the 150psi saw consistently reached 95psi on every first pull. Same length pull rope and it seemed like each of the two turned over an equal number of times per pull.
Does this mean they have the same running compression?

 

[drf256]

Interesting observation Jim.

I think it means that they have around the same swept volume, so they will fill the dead space in the compressor line at the same rate. The lower comp saw should reach equilibrium before the higher comp saw. I'm talking outa my arse a bit, not really sure.

I would think that dynamic compression would need much more rpm to achieve itself than at starting rpm.

240 psi in a 5 cube don't sound fun to start.

 

[drf256]

Awe Sheet

About to drop jug. Found this

 

[Deets066]

Awe Sheet

About to drop jug. Found this

View attachment 57487

Is that before or after machining

 

[Basher]

Guess not!

 

[tickbitintn]

I cut the squish to where it was smoothed out a bit...Measured what I took out then "roughed" the cyl base to where I would be "in the ballpark"....





Well not quite.... Squish still about .028ish and about 1 mm of freeport... [emoji20]

Sent from my XT1254 using Tapatalk

 

[paragonbuilder]

Awe Sheet

About to drop jug. Found this

View attachment 57487

Jb?

 

[Deets066]

Jb?

Not on the ex.

 

[Onan18]

Awe Sheet

About to drop jug. Found this

View attachment 57487

"Freeport City" eh?

 

[drf256]

Got a lot of shít to load up.

Bear with me.

 

[Jughead]

Bare with me?hell i'm OCD spill it already!.lmao

 

[drf256]

The piston matched up well with OEM.

The pin bore to crown seemed even side to side. But I'm not sure now. What I thought was the bore could be the piston pin being off.

I can say I've never had this problem before and I've built a few of the model.

 

[drf256]

Cleaned threads up. Not great.

 

[drf256]

 

[drf256]

 

[Jughead]

Threads definately need cutting after casting.oh and that's one twisted piston.no way a wrist pin could be off that much.

 

[Deets066]

That sucks Al

 

[RI Chevy]

Looks like they need to go back to the drawing board.

 

[drf256]

Up now.

The piston is grinding against something in the bore. I'm not so sure it's bore taper, because it's not during the same degree of rotation. It can reach the top and then grind and bind up more on one side than the other. The skirts on the piston are a bit scratched up already.

I thought it was bore taper because the jug will actually slightly move around on the jug surface when only on with pins. The piston will move smoothly up and down. Then once you bolt it down, the rubbing starts and she binds up.

The exhaust port is much larger in height than an OEM one. The roof is about the same, but the floor is a lot lower-around .060. You're basically at the skirt bevel with no gasket with no mods at TDC. I generally take up to .050 off the base on this model without freeport.

The piston looked pretty good. Thicker than OEM in the skirts and on the money in diameter, overall height, crown to skirt and pin to crown measurements. One of the ring pins is out of the slug enough to be rubbing the bore. I have a flat cut OEM piston I may toss in it today for shíts and giggles. But the Freeport issues remain.

It's not going in the dumpster yet.

 

[Pincher]

I just can not wrap my head around how the piston can travel up a bore to within 5 deg of TDC and bind until 80 deg or so after. I am assuming deg wheel was indexed. If were not dealing with prototype/experimental parts I would be checking the connecting rod for straightness.