Spuds Porting and Tuning Thread

[spudulike]

My Stihl Red Eye 066 - for those that have been following my progress - it was acquired after the coil went bad, the flywheel is keyed completely different from standard, I tried re-keying it and damn near blew the thing up - far too much advance.

 

I then applied a bit of science taking pictures of the dual key flywheel, drawing lines over the keys and measuring the angle. I recently had an 064 in and managed to measure off the difference it had on the keyway to my standard flywheel and bingo - 52* as I had on the images so filed out a big key, fitted a new key in the crank and used JB weld to form a new keyway.

 

I ended up bang on the 54* I wanted - that is standard + 2* advance - it will kick like a mule once the compression is up but should be bang on as far as ignition timing goes.

 

Next job is to machine the base and pop up piston - there is a big fat base on this cylinder so will see if we can get 0.75mm pop up and then adjust the ports and transfers!

[wyk]

Gonna fit a 36" bar to it and show it off on youtube?

[burrell_]

A 30inch bar maybe mate on 3ft wood spud will that do and we will vid my 660 to see the difference

[D A Tree Surgeons]

Question

When you port a saw do you reduce the squish as standard

or leave it because of the power gains in your porting:confused1:

i know you need to do the exhaust mod because more gases need to leave:001_huh:

im really enjoying this thread

also ive got an old 026 and i fancy having a play, would i gain much if i reduce sqiush? im gonna have ago at brasing on an old exhaust this weekend

[burrell_]

U can't really do much with the squish until

U start playing around with pop up positions

Most saws are set to the right squish from new

Spud will explain it alot better when he is. On line

[D A Tree Surgeons]

U can't really do much with the squish until

U start playing around with pop up positions

Most saws are set to the right squish from new

Spud will explain it alot better when he is. On line

 

Thanks burrell

this thread really is getting like the DARK ARTS

[burrell_]

I do call spud the dark lord :lol:

[D A Tree Surgeons]

I do call spud the dark lord :lol:

 

:laugh1:

[spudulike]

The squish band is set to stop the piston clouting the top of the cylinder but also controls detonation, the theory is to keep the combusting fuel on the centre part of the piston rather than the hot outer parts which will eventually melt and pit the top of the piston through compression and igntion advance.

 

Lowering the squish increases compression, increased compression gives more torque, a pop up and turned down base or squishband and base means even more compression and torque plus the upper port timing will stay the same if a pop up and base is done correctly.

 

If the compression is pretty healthy then the height of the exhaust port can be raised to raise the powerband without losing valuable compression.

 

If the height of the exhaust port is raised, the blowdown will be increased which will reduce the fuel charge in to the cylinder which will also require changing by raising the uppers.

 

Who said it was easy:001_rolleyes:

[D A Tree Surgeons]

The squish band is set to stop the piston clouting the top of the cylinder but also controls detonation, the theory is to keep the combusting fuel on the centre part of the piston rather than the hot outer parts which will eventually melt and pit the top of the piston through compression and igntion advance.

 

Lowering the squish increases compression, increased compression gives more torque, a pop up and turned down base or squishband and base means even more compression and torque plus the upper port timing will stay the same if a pop up and base is done correctly.

 

If the compression is pretty healthy then the height of the exhaust port can be raised to raise the powerband without losing valuable compression.

 

If the height of the exhaust port is raised, the blowdown will be increased which will reduce the fuel charge in to the cylinder which will also require changing by raising the uppers.

 

Who said it was easy:001_rolleyes:

 

I was with you for a little while then

then you lost me

i will try harder next time