Squish choices help me decide
Thread Starter
|
Cruiser
Joined: Dec 2010
Posts: 102
Likes: 1
From: Canada
Squish choices help me decide
My 103 built is coming together. Just got my heads back from the porter, and my TW-555 cams should be in tomorrow..The chambers are set @ 82cc. I have two choices for head gaskets..The first will give me .030 squish and 9.59 corrected cr..The second will give me .035 and 9.49 corrected...do I push the envelope, or give myself a little room for the odd tank of poor gas...What would you do? 
Sponsor
Joined: Dec 2007
Posts: 12,084
Likes: 829
That cam needs to set at 10.5 cr, to be fully effective.
FuelMotoUSA, just tuned a 107", with our Stage II heads, 555 cam.
That was set at exactly 10.5 cr.
109 hp/127 ft/lbs, with OE t/body, and Rhinehart duals, and dyno chart is posted in the Touring section.
Those heads need to be surfaced more, and use the .030" gasket.
Scott
FuelMotoUSA, just tuned a 107", with our Stage II heads, 555 cam.
That was set at exactly 10.5 cr.
109 hp/127 ft/lbs, with OE t/body, and Rhinehart duals, and dyno chart is posted in the Touring section.
Those heads need to be surfaced more, and use the .030" gasket.
Scott
Road Warrior
Joined: Nov 2007
Posts: 1,984
Likes: 7
Tighter Squish can help with the fuel situation.
"Squishes" the mixture out of the edges and at about the point of ignition creates more turbulance. This can stop preignition and helps the flame burn better. Nice and tight.
This squish is not just,only, a compression issue. Its a good running issue.
"Squishes" the mixture out of the edges and at about the point of ignition creates more turbulance. This can stop preignition and helps the flame burn better. Nice and tight.
This squish is not just,only, a compression issue. Its a good running issue.
HDF Community Team
Joined: Jun 2006
Posts: 12,780
Likes: 2,609
From: san antonio
My calcs show that .030" and 82cc put your static at 10.4; pretty close to the 10.5 that Scott says that cam likes; .035 is going the wrong way. Moving away from the CR sweet spot for that cam and opening up the squish band.
Thread Starter
|
Cruiser
Joined: Dec 2010
Posts: 102
Likes: 1
From: Canada
My calculator comes out at 10.47, with the .030 squish..Its pretty close to 10.5 ? The Harley pistons have very small valve reliefs
Trending Topics
HDF Community Team
Joined: Jun 2006
Posts: 12,780
Likes: 2,609
From: san antonio
Don'tforget the singh grooves per Scott's suggestion; cheap insurance.
HD Forum Stories
The Best of Harley-Davidson for Lifelong Riders
6 Weirdest Harley-Davidsons Ever Sold to the Public
Verdad Gallardo
7 Times Harley-Davidson Chucked Tradition Out the Window
Verdad Gallardo
7 Surprising Harley-Davidson Products that Are Not Motorcycles
Verdad Gallardo
8 Best Harley-Davidson Motorcycles Ever
Pouria Savadkouei
10 Worst Harley-Davidson Motorcycles Ever
Pouria Savadkouei
Killer Custom's Jail Break Is The Breakout That Refused to Blend In
Verdad Gallardo
Crazy Bunderbike Build Looks Amazing, But Is It Impossible to Ride?
Verdad Gallardo
Harley-Davidson Reveals Super Cool Cafe Racer Concept
Verdad Gallardo
Engraved Rebellion: Inside Bundnerbike's Glam Rock II
Verdad Gallardo
Thread Starter
|
Cruiser
Joined: Dec 2010
Posts: 102
Likes: 1
From: Canada
I am just worried the singh groves will further put the compression in the wrong direction..I dont want to have the heads milled again (cost), and the compression releases are already in..Thanks for the replys