I built cam bearings for a 280 this week. This is how we put on the rings, and so they are tight.
I squeeze the ends of the rings together so they hold the two halves, and hold the bearing in Key.
I also grind the inside of the ends of the rings to a 30 to 45 degree so the rings slide on with out digging into the cam bearing halves. The end clearance on the front cam bearing is not under .002, and not over .002-50. Bearing to shaft clearance is not under .002, and not over .002-25. The Lock bolts are built up with Brass, and are about a .001 thousandths fit, or just so the bolts go into the bearings hole no drag, and no back and forth movement.
Looks and sounds excellent. Are these unique to the 280 or just to those cams that require the later short cam bearing?
Yes Walt, the bearings we spun poured, and fit the 24-27 bearings to a Stipe cam.
Just a question for you Herm, isn't the front bearing meant to be around the other way so the chamfer allows clearance for the head of the push rod?
Never mind, just checked the service bible, yes, it should be around the other way.
The cut out always points to the rear of the cam shaft. Some cam bearings do not have the cut out, but they are shorter, and some were after market.
The Right side of the center bearing is the rear of the cam.
No Herm I'm talking about the front bearing not the centre one.
Never mind, just checked the service bible, yes, it should be around the other way. "END QUOTE"
Which cam bearing should be turned around the other way?
This one I've just pulled out of a 27 that was smacked by a rod, 30 degree chamfer facing the lobe, never come across the front bearing fitted any other way, even though the cam lifter more than likely does clear if reversed, but for no other reason it makes the cam bearing a lot easier to fit into the block.
The later style front cam bearings I've seen don't have a taper at either end. The later front cam lobes are wider so that the mushroom end of the push rod does not hit the bearing at all. If it did, a taper wouldn't solve the problem anyway. Rather, the end would have to be notched like the earlier bearings.
In Herm's photo it appears the front of the lobe was trimmed down and was babbitted to achieve a good fit between the lobe and the gear plate.
Whether or not it is tapered is of no consequence.
Yes, the early fronts, and late fronts were cut back and a thrust was poured on the front or all the cam bearings would have to be thrown away.
Then you can get the right end clearance on any cam shaft if new, used, or reground.
On a reground shaft, I always have the thrust, and mains ground.
On many early cam bearings, they can be cut to fit the newer shaft as long as the distance from the center hole to the rear of the bearing stays the same as the late fronts or the cam position will be off.
The only way that you can tell the difference is the rear of the front bearing won't have the notch.