Anyone seem marks like this on a camshaft?

[RustyRatRod]

Please explain, cause you guys are loosing me completely.

He is talking about the camshaft lobes. They are not flat. They are ground on a taper. That does two things. First, it contacts the lifters in such a way as to make them rotate in their bores. Since the lifter bottoms are not flat, but convex, that means the contact patch between the lifter and lobe is a small one and not in the center of the lifter. This is what promotes lifter rotation.

The second reason for the tapered lobes is to give the camshaft a "pushing action" towards the back of the block to keep the camshaft lobes in line with the lifters. Of course in a Mopar engine, the camshaft cannot go forward because of the thrust plate. Not all engines have thrust plates, though.

This was one advantage of the 440 6 Pack engine. Its camshaft was a low taper design, to help decrease friction. The lobes were not as tapered as a normal camshaft, as to induce a little more power from a little less friction. Same cam specs as the 375 HP 440, just ground on a low taper design.

 

[pomonamissel]

yes , rrr , thats what i'm talking about , some cams are grind angles are in one direction , so the cam gets pushed one way . and some grinders choose to put two opposing directions , for lifter rotation . two direction on the lubes tend to center the cam with very little thrust movement . but a single direction grind , pushes the cam up against the thrust stops . and can allow the cam to travel back n forth . some cam grinders put as much as 3-4 deg's of lobe angle for low rpm cams , for a good rotation at idle . and bank angle of the lifter bore can come into play also , not anyone had much to do with chevy's early 396 , lol . but it had a lifter bank angle issue on the drivers side , lifters never got a full rotation so they wore out lifters and cams , that clatering , tic , tac , tic lifters . those blocks required a cam grinder that knew his stuff . well and roller lifter cams are not angled lobed at all . to keep the twist out of the lift motion .

 

[MileHighDart]

He is talking about the camshaft lobes. They are not flat. They are ground on a taper. That does two things. First, it contacts the lifters in such a way as to make them rotate in their bores. Since the lifter bottoms are not flat, but convex, that means the contact patch between the lifter and lobe is a small one and not in the center of the lifter. This is what promotes lifter rotation.

The second reason for the tapered lobes is to give the camshaft a "pushing action" towards the back of the block to keep the camshaft lobes in line with the lifters. Of course in a Mopar engine, the camshaft cannot go forward because of the thrust plate. Not all engines have thrust plates, though.

This was one advantage of the 440 6 Pack engine. Its camshaft was a low taper design, to help decrease friction. The lobes were not as tapered as a normal camshaft, as to induce a little more power from a little less friction. Same cam specs as the 375 HP 440, just ground on a low taper design.

Ok, I get it now. But is there really anything I can do about cam end play when I install my new cam, lifters, and timing gear set? Do I install it all, and then check for end play? and do they make shims or something so this can be adjusted, or minimized?

 

[pomonamissel]

i understand that there are thrust end play shims , every timing gear set up is made with tolerances , so no magic one thickness shim that does the trick . it has to be installed , then end play measured for the slim thickness can be gauged , on an la motor that cam retainer plate hold the stick in . given my cam guy a call for the horse's mouth talking about how he handles end play on an la cam .

 

[RustyRatRod]

Ok, I get it now. But is there really anything I can do about cam end play when I install my new cam, lifters, and timing gear set? Do I install it all, and then check for end play? and do they make shims or something so this can be adjusted, or minimized?

No. They never give trouble in that area. The thrust plate keeps it from coming forward and the rear cam plug keeps it from going backward. The taper and lifters keep it in place while running. No worries.

 

[MileHighDart]

No. They never give trouble in that area. The thrust plate keeps it from coming forward and the rear cam plug keeps it from going backward. The taper and lifters keep it in place while running. No worries.

Cool, thanks

 

[pomonamissel]

just got off the phone with my cam grinder , he said , that a la cam should have been ground in two lobe angle to center the thrust of the lifters on the lobes . no shins on a stock set up . gear drive racey cams use thrust washers to keep the gearing working straight . so in your stock application just the retainer plate and the plug at the end of the cam main bore . so as rrr said '' no worries '' . just buy a good name cam . would be a great time for a custom grind cam . we're using a new style cam grind on this la 340 . 3-4 deg angle on the lobes and convex lifter faces for more rotation with todays oil .

 

[yellow rose]

just got off the phone with my cam grinder , he said , that a la cam should have been ground in two lobe angle to center the thrust of the lifters on the lobes . no shins on a stock set up . gear drive racey cams use thrust washers to keep the gearing working straight . so in your stock application just the retainer plate and the plug at the end of the cam main bore . so as rrr said '' no worries '' . just buy a good name cam . would be a great time for a custom grind cam . we're using a new style cam grind on this la 340 . 3-4 deg angle on the lobes and convex lifter faces for more rotation with todays oil .

View attachment 1714942549

Who is grinding that cam?

All performance engines have gear drives. My daily driver has a gear drive.

 

[pomonamissel]

red line racing cams , spiro jennings 408-313-0145 . here in san jose , ca .