World Formula bottom end

Adam Patro :) · Joined: 07 Apr 2008 Posts: 21

I am rebuilding my World Formula. New .010 piston, rod. I changed the bearing in the side cover. Do I need to adjust end play in the crank? How much should I have and how do I measure?
I put it back with the shims that were there for now.
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Tom ONeil · Joined: 20 Jan 2009 Posts: 72

.08 - .10 is not out of line. The clanking noise when shaking the block is cam - ignore it.
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Starman Racing
2011 National Champion - Outlaw 125 - T.Dowd
2010 Longhorn Outlaw 125 Champion - T.Dowd
2011 Lonestar Nationals 125 Champion - T.Dowd
2011 National Champion - Outlaw 250 - K. Engstrom

Chris Hatch · Joined: 02 Mar 2004 Posts: 405

too little is worse than too much. .008 - .012 is good. More than .20 too much. You also may want to "set" the crank prior too measuring by giving a decent "wack" to each end of the crank to make sure the bearings are all set in.

Tom ONeil · Joined: 20 Jan 2009 Posts: 72

Yep, a tap isn't bad idea to make sure all is well.

Briggs crank bearings are little weird - the flywheel side is pressed onto the crank and the PTO side is pressed into the sidecover.

It can be set by how deep the sidecover bearing is pressed in, but it takes patience. I dislike the shims because I believe it doesn't allow as much lubrication in as it could, so all mine are set this way. That's based on voodoo, err, personal preference. No facts, just me.

For ease of installation, wait until the sidecover is all the way on before installing the seal if possible. If not, use a small screwdriver or seal tool to guide it back into position if it wanders out.

If rules permit, a 1/16th shim on the PTO side on the cam can help keep thing centered. Polishing the ends of the cam isn't a bad idea either.

The sidecover should never be forced on. Line up the guide pins and see if the cam is lined up correctly. It may require a knife blade to hold the cam up to get it started. It will pop on with a satisfying 'thunk'. Torque the sidecover bolts evenly and it will never leak or have bolts back out.

It's not a bad idea to check it after a run or two- just grab the clutch and push/pull.
_________________
Starman Racing
2011 National Champion - Outlaw 125 - T.Dowd
2010 Longhorn Outlaw 125 Champion - T.Dowd
2011 Lonestar Nationals 125 Champion - T.Dowd
2011 National Champion - Outlaw 250 - K. Engstrom