Babbitt thrust face locations

A

A Michigander

Junior Member
I have a question for all of you who have some experience with line boring a freshly poured Model A block. How do you locate the crankshaft in the block? Is there a dimension for the location of one of the thrust faces? I thought it had something to do with the face of the cam bearing boss but nothing makes sense to me. Any help would be greatly appreciated
 
I don't have the dimensions but I can tell you 2 of the methods.

There is a KRW tool, 2 parts, 1 is a gauge that fits in the bolt holes for the rear main, the other bolts to the pan rail, has a lever that can be swung out of the way when you are facing, it is set to the gauge --then the face of the bearing is machined so the lever can just swing down --

With a Kwik Way there are collars that fit on the bar in specially marked holes that a pointed setscrew locates, that system gauges off the face of the block at the rear of the center main.
If you look through Herms albums under Kohnke Rebabbitting there is a picture of the KRW gauge in use---
http://fordbarn.com/forum/album.php?albumid=1263
 
I install the cam shaft and measure from the timing gear to the front face. That always lines the crank gear up with the timing gear. Usually about 19.970"
 
My drawings show 1.4335-1.4345 from the center of the rear cap bolt hole to the rear babbitt thrust face. Should be the same for the block. Crank end play from the clearances is .004-.008. However, my understanding is that the line bore is indexed to the cam so as to get the crank center line the correct offset from the cylinder centerline. That is 3" laterallly from the cam center line, 4.154-4.156 radially from the cam centerline, to the crank centerline. The machinists here would know more about how to do it.
 
My Kwik Way instructions use 7 15/32" from the rear of the centermain saddle to the face of the finished thrust. Once this is done the rear of the thrust is machined to allow for .002-.004 clearance.
 
You must log in or register to reply here.
Back
Top