Lifter re-ginding or turning - Page 2

**Dusk Blue Z** · #11 08-10-2016, 12:35 PM

The latest issue of Hot Rod Magazine has a tech article about cams and lifters, both curves and tapers. I have not read it yet, just a passing glance in yesterday's mail.
Mike

**Hotrodpaul** · #12 08-10-2016, 02:47 PM

Just checked some this morning. Results:

GM NOS - .0015" crown (100" R)

Crower Aftermarket - .0020" (62" R)

Used GM Solid - .0005" - .0008" crown

So it seems the claim of original GM at 120"R could be correct.

Next step is to program and try a re-cut.

Paul

L78steve · #13 08-10-2016, 05:19 PM

Just the (constant) load of the oil pump is enough to keep the cam pulled rearward in the block.

**SuperNovaSS** · #14 08-10-2016, 07:06 PM

This sounds like an awesome experiment. I'm excited to hear the results.

**kwhizz** · #15 08-10-2016, 07:13 PM

From the center (high point) to the outer lip there should be .0021 difference.........That is with a standard dia lifter.........don't think you can get the micro polish required by turning and polishing.......I'm sure GM uses some sort of a orbiting lapping procedure.....

Ken

**Hotrodpaul** · #16 08-10-2016, 07:35 PM

A .0021" difference in heights yields around a 60"R. It appears from the lifters I have seen the face is ground with some sort of orbital wheel while it is being swung on the radius, all while the lifter is rotating. I think a 60" radius would be a good place to start with this experiment.

I have read where it is recommended to polish the new lifter face with 600 grit paper to aid in break in.

The only unknown is the turned finish I will get with the carbide tooling and if polishing can give a finish comparable to the stock lifter.

Paul

**earntaz** · #17 08-10-2016, 08:30 PM

I think this is going to get interesting ... TAZ [img]<<GRAEMLIN_URL>>/dunno.gif[/img]

VintageMusclecar · #18 08-10-2016, 10:15 PM

<div class="ubbcode-block"><div class="ubbcode-header">Originally Posted By: L78steve</div><div class="ubbcode-body">Just the (constant) load of the oil pump is enough to keep the cam pulled rearward in the block. </div></div>

If that were the case there would be no need for a thrust plate or thrust button on an engine equipped with a roller cam.

L78steve · #19 08-11-2016, 02:10 PM

<div class="ubbcode-block"><div class="ubbcode-header">Originally Posted By: VintageMusclecar</div><div class="ubbcode-body"><div class="ubbcode-block"><div class="ubbcode-header">Originally Posted By: L78steve</div><div class="ubbcode-body">Just the (constant) load of the oil pump is enough to keep the cam pulled rearward in the block. </div></div>

If that were the case there would be no need for a thrust plate or thrust button on an engine equipped with a roller cam. </div></div>

Exactly. Unless there is a remote oil pump installed. Think about it the angle cut of the pump/Dist. drive gear will thrust the cam rearward.

If I'm wrong please tell me why.

**Hotrodpaul** · #20 08-11-2016, 02:32 PM

It may be that during extreme engine de-acceleration, such as a shift, that the cam may walk forward when using roller lifters, as the pump may be driving the cam during that very short period. I would think otherwise driving the oil pump would be enough to keep it in contact with the thrust face.

Paul