Camshaft lead in ramp wear .. Never seen before

[dll67]

IMG_20160704_142353_821.jpg

Has anyone seen this type of wear? This cam has 175 miles on it.
I'm afraid I know and am desperate for other opinions.

[user-23911]

Mechanical roller?
Too soft?
Too much lash?

[dll67]

Solid roller .019/.020 lash Mike Jones cam and Morel .904 bushed lifters
I just had the lifters bored and bushed to .904

[dll67]

1.625 double springs 250# @2.00 installed height. Havent measured open pressure yet .. should be around 700#

[1989TransAm]

What oil are running?

[dll67]

Delo 400 for the wear additives .. 30wt

[ozmuscleowner]

I would have said its the lifter roller "skidding" prior to rolling over the nose from too much additives in the oil but the opposite side dents confuse me...unless the roller in the lifter is rocking and worn internally.

Good luck I'm definitely following this one

[Greenlight]

This may be a freak situation, but how much of the lifter protrudes BELOW the lifter bore when the lifter is on the base circle of the cam?

If the lifter protrudes too low, the high pressure angle tends to cause the lifter to stick/lock in the bore. Therefore, the load of the lifter against the cam lobe gets very high.

As the lifter rises, the pressure angle is reduced and even though the spring load is increasing, there is less side load at the cam/lifter interface.

[user-23911]

The roller is lifting off the lobe?

[dll67]

I would have said its the lifter roller "skidding" prior to rolling over the nose from too much additives in the oil but the opposite side dents confuse me...unless the roller in the lifter is rocking and worn internally.

Good luck I'm definitely following this one

The lifters were brand new with Mikes cam .. Morel 6143's .810 wheel bushings NO NEEDLES .904 diameter body

IMG_20160704_131736_490.jpg

All the wheels look perfect except this one on the right that looks like it ran over some garbage ... probably from the piston skirt next to it. There was smashed up needles in it from the needle bearing lifter that came apart before Mikes cam and bushed Morels. I obviously didnt spend enough time digging the shrapnel out of the skirts with magnifying glass and pic.

[dll67]

This may be a freak situation, but how much of the lifter protrudes BELOW the lifter bore when the lifter is on the base circle of the cam?

If the lifter protrudes too low, the high pressure angle tends to cause the lifter to stick/lock in the bore. Therefore, the load of the lifter against the cam lobe gets very high.

As the lifter rises, the pressure angle is reduced and even though the spring load is increasing, there is less side load at the cam/lifter interface.

I suppose its possible but the bronze bushings in the lifter bore stick about an 1/8" above the already extended bores in the Dart Big M block and the lifters are .300 longer than stock early BBC. As far as below the bores I think they are even with the base of the lifter bore.
Cam is 254/258 @.050" .424"/.424" Lobe Lift 1.7/1.75 rocker ratio 106 LSA 102 ICL .. switching to 1.7 on the intakes ... Just broke #1 intake thats how I found the cam problem. jesel 1.75 aluminum mohawk broke through the adjuster hole, adjuster out less than 2 turns .. bought used. Replacing with 8 new Jesel 1.7 solid body rockers

[user-23911]

Why so much lash?
I'd have expected 0.012 inch or maybe a bit less.

[dll67]

The roller is lifting off the lobe?

I thought maybe that as well but there is wheel pattern all the way around the base circle and lobe. Heads were new assemblies from Dart 900 miles ago then 150 miles ago I lost the needle bearing lifter. While I had the motor apart getting the lifter bores bored and bushed to .904 I had the heads gone through and the springs checked. 250#@2.00 installed height and just under 700# @ 1.200.
The 175 miles I had on it this time have all been easy tuning miles. Still trying to get the EFI tuning squared away. No pulls past 5500 no valve float not a single miss.


If you zoom into that picture I posted you can see the lifter hits on the left side of the lobe then it looks like pattern from the wheel turns toward the dent on the right side thats a little further ahead on the lobe. It looks like the roller could also be twisting?/bouncing?/skidding? after first contact with the lobe on the left before contacting again on the right. Also when I look close at a real low angle to the lobe I can see what looks like some blueing from heat on some of the lead in ramps that have heavier wear.

[ozmuscleowner]

I would have said its the lifter roller "skidding" prior to rolling over the nose from too much additives in the oil but the opposite side dents confuse me...unless the roller in the lifter is rocking and worn internally.

Good luck I'm definitely following this one

The lifters were brand new with Mikes cam .. Morel 6143's .810 wheel bushings NO NEEDLES .904 diameter body

IMG_20160704_131736_490.jpg

All the wheels look perfect except this one on the right that looks like it ran over some garbage ... probably from the piston skirt next to it. There was smashed up needles in it from the needle bearing lifter that came apart before Mikes cam and bushed Morels. I obviously didnt spend enough time digging the shrapnel out of the skirts with magnifying glass and pic.

Are they small flat spots on that lifter to the right side in picture that you posted?

[Greenlight]

This may be a freak situation, but how much of the lifter protrudes BELOW the lifter bore when the lifter is on the base circle of the cam?

If the lifter protrudes too low, the high pressure angle tends to cause the lifter to stick/lock in the bore. Therefore, the load of the lifter against the cam lobe gets very high.

As the lifter rises, the pressure angle is reduced and even though the spring load is increasing, there is less side load at the cam/lifter interface.

I suppose its possible but the bronze bushings in the lifter bore stick about an 1/8" above the already extended bores in the Dart Big M block and the lifters are .300 longer than stock early BBC. As far as below the bores I think they are even with the base of the lifter bore.
Cam is 254/258 @.050" .424"/.424" Lobe Lift 1.7/1.75 rocker ratio 106 LSA 102 ICL .. switching to 1.7 on the intakes ... Just broke #1 intake thats how I found the cam problem. jesel 1.75 aluminum mohawk broke through the adjuster hole, adjuster out less than 2 turns .. bought used. Replacing with 8 new Jesel 1.7 solid body rockers

Take a look at that particular bushing to make sure it extends to the bottom of the original lifter bore.