Briggs & Stratton piston to bore clearance - Page 3
Close
Login to Your Account
Page 3 of 3 FirstFirst 123
Results 41 to 43 of 43
  1. #41
    Join Date
    Dec 2012
    Country
    AUSTRALIA
    Posts
    4,211
    Post Thanks / Like
    Likes (Given)
    20
    Likes (Received)
    1503

    Default

    Just about every small motor now has a nickasil bore,and wear is not an issue....They can be bored out,and a liner substituted ,if there is enough metal in the cylinder.....A friend of mine used to do that to install overbore kits in modern Triumph motorbikes......Seemd silly to me to wreck a nickasil bore to get a few extra cc s.......You can also get nickasil redone,but its not cheap.

  2. #42
    Join Date
    May 2007
    Location
    California
    Posts
    313
    Post Thanks / Like
    Likes (Given)
    43
    Likes (Received)
    57

    Default

    A forged piston will have more clearance than a cast piston, but they will both fit in the same hole. The reason is the clearance is built into the piston.

    Pistons are cam ground on the skirt as they warm up the skirt grows in the direction of the wrist pin. The skirt is also tapered the diameter at the tip of the skirt will be larger than up near the oil ring. The proper way to measure a piston diameter is 90 degrees to the wrist pin at a height equal to the center of the wrist pin.

    Skirt taper, clearance, and cam grind will vary by piston design so it's best not to second guess the manufacturer. A .020" piston will fit a bore .020" over standard. Also make sure you have the correct standard diameter, A sales brochure may say it's a 3" bore but the service manual may say 3.001" bore so make sure you have the proper standard size before sizing the hole.

  3. #43
    Join Date
    Mar 2005
    Location
    Kansas
    Posts
    8,518
    Post Thanks / Like
    Likes (Given)
    587
    Likes (Received)
    4265

    Default

    Quote Originally Posted by gappmast View Post
    Question, how do you measure a piston. I know with a micrometer but where do you measure it.
    Check the piston diameter at the centerline of the pin hole, 90 degrees to the pin.


Bookmarks

Posting Permissions

  • You may not post new threads
  • You may not post replies
  • You may not post attachments
  • You may not edit your posts
  •