Crankshaft end-play

[jspurl3]

I'm using how to rebuild a small-block ford manual by George Reid, and after I installed the crankshaft it says I need .004 to .008 inch end-play (front to back I guess).

I do not feel any slack front to back but I do not have a dial-indicator. So should i feel it? If so does that mean I need to sand down the main thrust bearings to get that play?

Thanks!

 

[broncnaz]

.004-.008will be hard to feel. If the crank turns freely I'd probably leave as is and not worry about it. if its boinding up then Id clearance it.

 

[Broncobowsher]

Agree, hard to feel that little. That is only a couple times the width of a human hair.
When you feel and see it move and it goes clunk at the end of travel, you have a wasted thrust bearing and more then likely a wasted bottom end.

I feeler gauge in the thrust bearing (with the crank thrust to one side to take all the clearance up) can be used to check the clearance.

If you are building the engine and it is a touch tight you can tap the crank forward and back witht he #3 bearing cap a little loose to settle the thrust bearing into place then torque it down. It can help alight the upper and lower bearing half and give even thrust loads to both the upper and lower bearings. I have seen this done and picked up a thou or so.

 

[jw0747]

if everything is tight and properly torqued to specs no need to worry. you're good.

 

[jspurl3]

Awesome thanks guys!

 

[bad 68]

Agree, If you are building the engine and it is a touch tight you can tap the crank forward and back with he #3 bearing cap a little loose to settle the thrust bearing into place then torque it down. It can help alight the upper and lower bearing half and give even thrust loads to both the upper and lower bearings. I have seen this done and picked up a thou or so.

X2
You should always do the step of smacking the crank with a block of wood and hammer or a dead blow hammer first backward then forward with the thrust bearing cap in place but loose not torqued. Then torque the cap and use a feeler gage to check end play.

 

[73azbronco]

Actually you use a pry bar and gently do this, I would avoid the smacking the end technique.

 

[bad 68]

I'm not talking a 5# hammer, small ballpeen. Single smack backward, smack forward, on center of crank, front and rear. Done.

 

[broncnaz]

The smacking thing is needed to seat the bearing as was stated usually a block of wood is used between the crank and hammer unless you have a rubber or brass mallet. the pry bar is used in the measuring process.

 

[73azbronco]

No, sorry, all my Factory Ford manuals specifically use the prybar to seat the thrust bearing, no smacking required.

In your defense, it used as an alternate method:

http://www.sporttruck.com/techarticles/0506st_ford_302_v8_engine_assembly/photo_22.html

but it's not specified in repair manuals anywhere.