Roller or flat tappet cams? shop won't guarantee flat tappet...

One of the machine shops i used had a tool that would cut a small grove in the lifter bore to make sure plenty of oil is getting on the cam lobe i thought it was cheap insurance. down side a loss of a lb or 2 of oil pressure at idle no big deal. Was told one way to make sure that the lifter with a little light oil would always plop down the lifter bore once started without being forced.

 

^^^^ Comp Cams offers a grooving tool.

 

Thanks. I was thinking of using grease, or maybe even chalk, so I could see the contact pattern. But if the lifter spins, that indicates all is good!
I do realize Nailheads weren't originally designed to incorporate rotating lifters, but I'm not going to get into that.

 

Once the engine is RUNNING, I verify that the lifters spin at a reasonable rate by painting a vertical stripe on the upper part of the pushrod, then viewing the spinning pushrod/stripe through a slot cut into a pair of Treasure Yard valve covers.

 

I'm sure if you want to see a pattern just use dry erase marker.......I use it on valve stems to check pattern. Even with the almost no pressure of a checking springs it patterns out. I'm sure the same would work on the lifter bottom.

 

I just checked the Comp cam that was ground last month for my 401.
Cam lobe dia is 0.002" larger on the rearward side vs the front, so 0.001" taper.
Checked the solid lifter faces with a straight edge, they all have a slight crown in the center. There are 2 I will take a closer look at, the crown looked off center.

I found a scary defect on the cam. One lobe has a sizable chunk of flash that wasn't ground away. Bet it would've destroyed the lifter. Saw another lobe with a much smaller defect.


Smaller one:

 

If you want to check the lifter crown more accurately, use a dial indicator with lifter on a flat plate or clamp the lifter in a precision machinist V-block on a flat place. You will be able to move the lifter and V-block around the dial indicator.
Mark the center of the lifter with a small tipped sharpy so you can run your indicator over it. Vet
Vet

 

Check out this YouTube video from Powell Machine. He demonstrates how to measure a lifter with a dial indicator.
Shows how bad these lifters are grind too. Vet

 

I just did all this with my 350, I used the EDM lifters, I put straight edge on lifter and saw the crown i used dial indicator on cam to see if it had some taper and got some there, I put cam in dry with lifters and put a sharpie mark on top of each lifter and spun the cam and looked to see how many times I had to spin the cam to make the lifter make a complete spin in the bore.
The ones that did not spin as fast I moved to another bore till they were all about the same and put back in box till I was ready to put together. If there was oil in the bore or on the lifter this friction would slow down the spin, this happened mostly at the back of the engine where some oil would still be dripping from the heads.

I also took out the inner spring while heads were on, I could take the spring out while piston was at TDC and I used a hooked tool that I stuck into the spark plug hole to hold valve as I used the spring compressor, used a magnet to grab the keepers. Now I did have to use air to put the springs back in as the valve would move down when compressing the spring. The valve seals in my engine would hold the valve some from dropping down when I took the springs out so that part was easy, putting back in I had to use the air to hold valve.

The last thing I did was use that Joe Gibbs break in oIl and used his regular oil after wards when I took the break in oil out.
The other thing I did was drive about 50 miles on the break in oil with the inner spring out keeping under 3500 rpm. I changed the filter after the 20 minute break in period at 2 grand to 2500 rpm drove the 50 miles and then put all back together and changed the oil to Gibbs zinc oil.
So far so good runs like mad faster than ever.

Mart let me borrow this fantastic tool he made as machinist and I got to say this thing is well.. look for yourself lol

 

Thanks for that.

I had a BBC that chipped the edge of the lifters on break-in. I never figured out why. Changed to a roller cam, upgraded under partial warranty by Lunati.

I bet the original cam had defects just like yours, which damaged the lifters. Not something I looked for at the time, and that cam went back to them as part of the roller-cam upgrade so I can't inspect it now.

 

Two years ago I used their 1405j lifters and the 284-88h cam because they didn't have the 212. Only problem is one of the lifter leaks down so it ticks at start up.