what's ron say?

[deepockets]

here's a pict of my wear pattern. I found no need to rotate the engine any more than a couple of revolutions to show you what I'm getting at. the lifter does rotate as you can see the way the lifter on the right has a curved line showing the rotation. my question hear is, does this look like the cam is going over the edge and going to be a disaster if I ran it. the cam is a comp cam xx lobe grind for the .875 lifter. the cams not that big, 256° @ .050 on int. and 262° @ .050 on the ex. .567 lift on int. and .585 on ex with 1.51 rockers. lobe lift is .378 on int and .390 on ex.  thanks for imput.

[firefighter3931]

Hey Don,

As long as the lifter rotates 360* when you're hand cranking it i wouldn't be worried. The XX lobe is pretty agressive but there are more agressive lobes out there that survive on the street. 

With the agressive .875 & .904 flat tappet lobes the lifter is riding close to the edge....it's a little un nerving to see at first in slow motion on the engine stand but in the real world it works fine. Just use good oil with lots of EP additives. I like Brad Penn 20/50 racing oil. I ran something very similar in my old 446 and it survived just fine on the street. That cam was an agressive Comp mechanical flat tappet grind with 260@.050 duration and .585 lift at the valve. 

That's going to be a great cam in a 500in street type build ! 


Ron

[deepockets]

hey ron, here's one more pict with the rocker arms installed with two rotations of the cam. the one on the right, I just dropped the lifter in and turned it right to left (the lifter that is) just a little to show the amount of contact surface there is at it's worst point.

[Challenger340]

Just some thoughts...
IMO, that "LOOKS".... a lot worse than it is ?

The xx .875 Cams are just standard taper designs as far as I know here ? aggressive lobes yes... but still std lobe "taper", which depending how "centered" the Lobes are to the lifter Bores "end to end" in the Block(NONE ever are anyways), it can account for looking at the "concerning" patterns you are seeing.

The problem is also compounded....which makes it look visually worse than it is..... by a lack of consistency in the machining alignment of the Lifter Bores in the Factory "stock" Blocks, which this looks to be ??

As anybody who has ever Degree'd #1 Cylinder when installing a Camshaft on a BB Mopar more than a few times, then later checked #6 it's running mate can attest... well.... lotsa bald spots from scratchín noggins !

Just one more thing to check... and without seeing the Engine/Cam installation here ?
Just check that there is not anything "goofy" going on up front with the Timing Chain and Gears ? What I'm getting at here.... is that the Camshaft as it turns in "mesh" with the Distributor Gear... "under load"... is pushed "backwards" to seat up against Block, with the Cam Gear taking that backward thrust.

No matter... I agree with what Ron said
as long as the Lifter is "Rotating", and you stay well under 300# Spring Pressure "over the nose" on Cam break-in, with plenty of Zinc in the Oil.... I can't see a problem ?
I would run it !

PS;
If you are still concerned... or wish to check further for more piece of mind, look at the "up" side on the Cam Lobe ramp itself.... a little tougher to see without having actually run the Cam yet.... but see if you can spot an upside down "J-hook" wear pattern starting to form on the Lobe itself from rotation.
The bottom of the "J" will be at the top of the lobe.... with the stick part of the "J" from one side of the Lobe at the top.... angling down toward the base circle moving towards the center.
if you can spot it.... and as long as the upside-down "J" is on the lobe.... not going off the lobe edge anywhere.... good to go.

Sorry for being long-winded... had a few beers last night... I got foggy brain today !