Year end build

[drf256]

So Joe,

Did you ever epoxy the intake?

What do you think was responsible for the increase in total power?

More upper transfer area? Not enough case compression to push the charge out of the transfers early enough before raising and adding fingers? Fingers helping the flow on the AM uppers?

By adding fingers, all things being equal, you should have needed more BD to fill cylinder properly.

The way I see it is smaller case needs tighter smaller tunnels and transfers and should shift power curve up.

I’m just interested more in the “how” than the actual power number.

 

[drf256]

Here is a look at an OEM 272 jug vs. a meteor:
The OEM transfers blow much harder back toward the intake than the meteor. I will probably mock mine up with the meteor first and then modify & use the OEM jug.View attachment 361910View attachment 361911View attachment 361912View attachment 361913

Bingo. The unseen in AM vs OEM transfers.

 

[Red97]

So Joe,

Did you ever epoxy the intake?

What do you think was responsible for the increase in total power?

More upper transfer area? Not enough case compression to push the charge out of the transfers early enough before raising and adding fingers? Fingers helping the flow on the AM uppers?

By adding fingers, all things being equal, you should have needed more BD to fill cylinder properly.

The way I see it is smaller case needs tighter smaller tunnels and transfers and should shift power curve up.

I’m just interested more in the “how” than the actual power number.

I didn't epoxy the intake, altho if I build another, i may go that route, just to see.

The initial setup, was around 100,121,82 and made 6hp at 9500 minimal port work, on the stock carb. Was rather lethargic.

Swapping on just a 372 carb brought that up the 6.6 hp, but still limited with my tiny round to square intake boot. And dropped the peak rpm power closer to 9000.

Round 3, I threw the kitchen sink at it. After looking at how the large carb really helped low end, I knew I wanted to push the power mich higher in the rpm range. This 60cc clutch dosent need to lug down with 70cc type tq.

So, I raised everything up a touch. Ex to 97, transfers to 117 trying to push everything to peak around that 10.5k range. After a slight timing advance it really came alive right up in that range.

Wasn't really worried about case compression, as the 359 has no stuffers and is plenty open.

 

[drf256]

I didn't epoxy the intake, altho if I build another, i may go that route, just to see.

The initial setup, was around 100,121,82 and made 6hp at 9500 minimal port work, on the stock carb. Was rather lethargic.

Swapping on just a 372 carb brought that up the 6.6 hp, but still limited with my tiny round to square intake boot. And dropped the peak rpm power closer to 9000.

Round 3, I threw the kitchen sink at it. After looking at how the large carb really helped low end, I knew I wanted to push the power mich higher in the rpm range. This 60cc clutch dosent need to lug down with 70cc type tq.

So, I raised everything up a touch. Ex to 97, transfers to 117 trying to push everything to peak around that 10.5k range. After a slight timing advance it really came alive right up in that range.

Wasn't really worried about case compression, as the 359 has no stuffers and is plenty open.

Thanks for summarizing it for us Joe.

 

[Red97]

The motion picture version of this thread.

 

[Hundred Acre Wood]

Love the build. Tremendous output. But I want the 261 version of that.

 

[Maintenance Chief]

So question?, whats the deal with finger ports, why doesn't everybody use them? Are the unreliable with there results?

 

[huskihl]

So question?, whats the deal with finger ports, why doesn't everybody use them? Are the unreliable with there results?

Because half the guys think they work and half the guys think that if they help, the transfer ports aren’t big enough or timed right

 

[Stevetheboatguy]

So question?, whats the deal with finger ports, why doesn't everybody use them? Are the unreliable with there results?

Because half the guys think they work and half the guys think that if they help, the transfer ports aren’t big enough or timed right

And...... It's extremely easy to completely ruin a cylinder if you have a oops. Or even if you don't have a oops the plating can lift and then....... You srewedagain.......

But yeaahh....... @drf256 @Red97 make some nice finger ports.


Steven

 

[huskihl]

And...... It's extremely easy to completely ruin a cylinder if you have a oops. Or even if you don't have a oops the plating can lift and then....... You srewedagain.......

But yeaahh....... @drf256 @Red97 make some nice finger ports.


Steven

It also tends to make them more high-strung. I’ve tried them maybe a dozen times and played with different opening times. Never did much for me. It’s different for others obviously

 

[Stevetheboatguy]

It also tends to make them more high-strung. I’ve tried them maybe a dozen times and played with different opening times. Never did much for me. It’s different for others obviously

I tip my hat to you guys. All the different recipes and formulas. It's truly impressive.


Steven

 

[Red97]

So question?, whats the deal with finger ports, why doesn't everybody use them? Are the unreliable with there results?

Lot of work for not much gain. They look cool and may possibly kind of help. Not really a worksaw thing. Mostly race/max effort type thing.

 

[Red97]

Had a chance to go out and cut.

 

[Red97]

Going to be building a couple more of these. Picked up some oem cylinders.

50, and 52mm



Small chamber on the 50mm


Large chamber 52mm

 

[huskihl]

Going to be building a couple more of these. Picked up some oem cylinders.

50, and 52mm

View attachment 362776

Small chamber on the 50mm
View attachment 362778

Large chamber 52mm
View attachment 362779

My 266-272 knowledge is minimal but the one you’re calling small might be the normal one. Or might be a 268xp. A 266 is much narrower yet from left to right. Believe they made 200psi stock

 

[Red97]

My 266-272 knowledge is minimal but the one you’re calling small might be the normal one. Or might be a 268xp. A 266 is much narrower yet from left to right. Believe they made 200psi stock

Want to say it was off a 268. I know nothing about these other than the bore size and they appear to be in great shape. Pretty excited about the 50mm, as I have a piston in mind that should work out awesome....

 

[Ketchup]

If I can get this hack pile to run, I’ve got a 670 jug that I want to put in a 2159. Small chamber just like the 266/8 but with a boot.


I tried to rush and get the saw together for the So-Cal G2G. Ended up setting myself back. Minor carnage, very rough grinding.




My Dolmar air filter came, and a cheapo 038 piston to replace the 064 slug. The 038 looks much better. The skirt is short enough to clear the case and the rings are lower.




@Red97, I really like the way your kill switch turned out. Where did you get it? I’ve got a stock switch bolted up right now but it doesn’t line up very well.

Also, your timing is 82/97/117? I was close to giving up on this jug, but I think I can get to that zone with the 038 piston. Current numbers are 78/98/114.

 

[Czed]

Going to be building a couple more of these. Picked up some oem cylinders.

50, and 52mm

View attachment 362776

Small chamber on the 50mm
View attachment 362778

Large chamber 52mm
View attachment 362779

If the 50mm intake is round like this
It's a 266
If it's kinda rectangular it's a 268
I may or may not have over 20-25 2 series

 

[davidwyby]

I was thinking the 60ccs were round and the 266 and up were rectangular. But my memory may fail me and not as much exp as you. I’ve been through both of mine, but it’s been a while.

 

[huskihl]

If I can get this hack pile to run, I’ve got a 670 jug that I want to put in a 2159. Small chamber just like the 266/8 but with a boot.
View attachment 363251

I tried to rush and get the saw together for the So-Cal G2G. Ended up setting myself back. Minor carnage, very rough grinding.

View attachment 363253
View attachment 363255

My Dolmar air filter came, and a cheapo 038 piston to replace the 064 slug. The 038 looks much better. The skirt is short enough to clear the case and the rings are lower.

View attachment 363252
View attachment 363258

@Red97, I really like the way your kill switch turned out. Where did you get it? I’ve got a stock switch bolted up right now but it doesn’t line up very well.

Also, your timing is 82/97/117? I was close to giving up on this jug, but I think I can get to that zone with the 038 piston. Current numbers are 78/98/114.

Just trying to help you out a little bit. You usually want to leave .100” above the ring pins. Much thinner than that and you don’t have enough heat sink left and the area around the pins will heat up and spit the pins out. I had it happen on a race 346 that I was building for myself. I had .070” above the pin. Probably saved yourself a cylinder by it failing early.