End Play

[davetheacguy]

I just finished putting an engine back together. But this engine has some end play ? crank is moving in and out ? I tried moving the fly wheel closer to bearing no help. I rechecked bearing to make sure bearing were the correct thickness, okay there ? Any ideas ? I've built many engines over the years, this is something new ?
Thanks dave B

 

[Ray Sametz]

If it has a brass collet, sometimes they ware down on the back side.

 

[davetheacguy]

If it has a brass collet, sometimes they ware down on the back side.

Roger That ! I'll try another ferrel .

 

[Geraghty]

All the motors I know of lock up crank position on the front bearing.....
The crank end play is locked up tight on the front bearing...
If you are feeling end play after everything is tightened up you are feeling the slop in the front bearing itself...

 

[Rick Doane]

Mr. Rod is correct. Nominal end play from my database is between .0025 and .0035 inches, both directions, assuming there is no preload. No motor leaves my shop without end play after assuring the crankshaft is in the correct position.

 

[K F Wheeler]

Anyone know where I can get steel collets for Picco Blackhead P45's?
Been told some of them had the brass collets. And that was why they had a problem with the rods.

 

[David Bryant]

All the motors I know of lock up crank position on the front bearing.....
The crank end play is locked up tight on the front bearing...
If you are feeling end play after everything is tightened up you are feeling the slop in the front bearing itself...

both, my vintage Picco P67/80 and Rossi R65/80 engines, lock the crankshaft to the inner (larger) & front bearing

 

[Geraghty]

both, my vintage Picco P67/80 and Rossi R65/80 engines, lock the crankshaft to the inner (larger) & front bearing

If it was locking up on the inner bearing the motor would not turn over......Look real hard at it again.....

 

[SayMikey]

Anyone know where I can get steel collets for Picco Blackhead P45's?
Been told some of them had the brass collets. And that was why they had a problem with the rods.

Try Joe Warren I think he just had some made

 

[Mark Bullard]

Anyone know where I can get steel collets for Picco Blackhead P45's?
Been told some of them had the brass collets. And that was why they had a problem with the rods.

"?" Why would brass make problems with the rod?

 

[SayMikey]

Mark the Blackhead Picco motors had junk cones causing the crank to push on the rods over time. Mike Hallam I believe found this issue I changed all my cones to the ones he had made and it solved the problem.

 

[dwilfong]

The CMB engines lock the crank to the front bearing with the space that is the crank case seal.

 

[David Bryant]

If it was locking up on the inner bearing the motor would not turn over......Look real hard at it again.....

we're referring to the main crankshaft journal having a pressed fit into the inner bearing, correct?

 

[Rod Fonda]

I had a similar problem with a loose front bearing in the housing that would float the crank away from conrod about .010" taking up the bit of clearance in rear bearing,but go back under thrust,,I even tried machining a shim to pack the rear bearing to distribute the thrust load between bearings but it got fiddly and just replaced the front housing,,a flywheel/collet that is not locking the crank to front bearing will float the crank back towards conrod as some have mentioned

 

[K F Wheeler]

Still looking for steel collets for Picco Blackhead P45's... Need Two. Won't try to run them without the steel collets!
fedup7843@gmail 810-333-9828
Thanks. Ken Wheeler

 

[Brad Christy]

we're referring to the main crankshaft journal having a pressed fit into the inner bearing, correct?

David,

No. The front (small) bearing should NOT need pressed onto the front (smaller) diameter of the crank. This should be a slip fit. The flywheel cone should lock onto the inner race of the bearing when you tighten your flywheel nut/collet on the crank. At this point, the only end play you should have would be that which the front bearing is allowing, which shouldn't be more than a thousandth or two. If you are getting more than that, then I'd suggest that either the bearing is junk or the flywheel cone is clamping onto the crank diameter and not the inner race of the bearing.

FWIW... Under ideal conditions, the rear (big) bearing is merely along for the ride, to support the load of compression/combustion, and does nothing as far as controlling or affecting end play.

Thanks. Brad.
Titan Racing Components
BlackJack Hydros
Model Machine and Precision LLC

 

[DON MAHER]

Brad,
Please explain “the inner race of the flywheel “

 

[Brad Christy]

Brad,
Please explain “the inner race of the flywheel “

Don,

My bad. Corrected.

Thanks. Brad.
Titan Racing Components
BlackJack Hydros
Model Machine and Precision LLC

 

[David Bryant]

David,

No. The front (small) bearing should NOT need pressed onto the front (smaller) diameter of the crank. This should be a slip fit. The flywheel cone should lock onto the inner race of the bearing when you tighten your flywheel nut/collet on the crank. At this point, the only end play you should have would be that which the front bearing is allowing, which shouldn't be more than a thousandth or two. If you are getting more than that, then I'd suggest that either the bearing is junk or the flywheel cone is clamping onto the crank diameter and not the inner race of the bearing.

FWIW... Under ideal conditions, the rear (big) bearing is merely along for the ride, to support the load of compression/combustion, and does nothing as far as controlling or affecting end play.

Thanks. Brad.
Titan Racing Components
BlackJack Hydros
Model Machine and Precision LLC

I get it, thanks!

 

[Wasted wages]

David,

No. The front (small) bearing should NOT need pressed onto the front (smaller) diameter of the crank. This should be a slip fit. The flywheel cone should lock onto the inner race of the bearing when you tighten your flywheel nut/collet on the crank. At this point, the only end play you should have would be that which the front bearing is allowing, which shouldn't be more than a thousandth or two. If you are getting more than that, then I'd suggest that either the bearing is junk or the flywheel cone is clamping onto the crank diameter and not the inner race of the bearing.

FWIW... Under ideal conditions, the rear (big) bearing is merely along for the ride, to support the load of compression/combustion, and does nothing as far as controlling or affecting end play.

Thanks. Brad.
Titan Racing Components
BlackJack Hydros
Model Machine and Precision LLC

^^^ Listen to this guy.... he gets it !! ^^^

With both oiled bearings in the housing, the crank should just slip into the inner races of both bearings...by hand. Should drop right in with little effort.
The "step" on the crank should butt up against one side of the front inner race of the bearing and the flywheel cone up against the other side. Install the flywheel, torque it down and the crank should spin freely with very little end play.

Sometimes the cone will have a ridge where it butts up against the inner race of the bearing..
caused by slippage or spinning on the crank.
If it is not to bad it can be dressed with a file or trimmed up in a mill or lathe. It's kind of a one time thing though,, cut too much off and bad things will start to happen.