[TR] TR4 Engine Piston Installation

[Tony Drews]

New rings on honed liners add a fair amount of drag.  There are two 
things you want to be sure of:
1. Rod bearings are correctly sized and don't bind
2. Pistons are properly fitted to the liners

For #1, when two pistons are at the top and two at the bottom it 
should be pretty freely turning.  Once you are moving the pistons up 
and down it should be harder.  If it's still hard when the pistons 
are at top and bottom, you've got something wrong in the bearing area 
- either wrong sized bearings or the caps got mixed up.  Each rod cap 
is individual to that particular rod.
For #2, you need to measure the pistons and liners before 
assembly.  There should be 3 / 4 / 5 thousandths difference depending 
on what kind of pistons they are.  I believe this is normally 
measured 90 degrees from the wrist pin hole, but it's good to measure 
both directions.  Also, measure the liners at multiple points.

With all new stuff, it should take less than, say, 15 ft lbs to turn 
it over.  The force required will go up as you add cam and valvetrain, though.

- Tony Drews

At 06:29 PM 9/9/2008, Thomas Boggiano wrote:
>Hi All
>
>I installed the new pistons this evening in the new sleaves. All the rings
>gapped to .015 or .016
>When I put the Crank in eveything rotated nice an smoothly, As I put each
>piston in it got much harder to rotate everything, and after the last piston
>was installed it is now almost imposible to rotate anything. It really takes a
>lot of force to move a piston down or rotate the crank.
>
>On a new install how difficult should it be for all this to move? If I have to
>take it apart now would be a good time to do it.
>
>Thanks
>Tom
>_______________________________________________
>
>Support Team.Net  http://www.team.net/donate.html
>
>This list supported in part by the Vintage Triumph Register
>http://www.vtr.org
>
>
>Triumphs at autox.team.net
>http://autox.team.net/mailman/listinfo/triumphs
>
>You are subscribed as tony at tonydrews.com
>
>http://www.team.net/archive