(reground) cam went flat?

[Paul Workman]

Pete's comment about wiping a cam lobe sent a shiver up my spine - as I'm considering a regrind next year...

What I know about metallurgy you could stick in a thimble and it would still rattle around. So, it occurred to me that when a cam is reground, certainly the case hardening is removed and the surface hardening has to be redone or the opportunity to wipe a lobe comes to mind.

Well, Comp Cams provides an additive to replace the "good stuff" (zinc, etc) left out of today's oils - I buy it over the counter at "Winner's Circle" in Joliet. Having just replaced a "wiped" cam in my wife's 69 Vette I rather think it might be a good idea to start putting it in the Z, in addition to the AMO 10W-40 recommended by Marc, especially if running a reground cam to the rpm Pete does.

All that said, I'm reminded too of the advantages some claim by using tungsten disulphide (WS2) coatings on some parts. (More research in indicated, methinks.)

But, I leave the discussion of lubrication to the experts, except to say I don't see how adding the additive would hoit!

What say U?

P.

[Zr1 Destroyer]

Hmmmmm.....never had any problems with the Crower re-grounds.....wierd!?!?

[jonszr1]

i wonder who pete had do his reground cams ? what can one do to assure that a reground cam lives a long and uneventfull life ? is there a coating that would help here .?

[ALZR1]

Pete's comment about wiping a cam lobe sent a shiver up my spine - as I'm considering a regrind next year...

What I know about metallurgy you could stick in a thimble and it would still rattle around. So, it occurred to me that when a cam is reground, certainly the case hardening is removed and the surface hardening has to be redone or the opportunity to wipe a lobe comes to mind.





A few years I took A bad cam cause I was looking to regrind A set.I removed .010 to .15 off the every lobe even with about .100 removed the cam still rockwell 45c scale.So it's safe to say that it's not the regrinding of the camshafts.
As soon as my 441 is done which looks mighty sweet I should add.My regrinds are going in,along with alot of ZDDP.

AL.

[FU]

What size regrinds are you putting in the 441 Al ?

[ALZR1]

Originally Posted by FU2

What size regrinds are you putting in the 441 Al ?

239/440 intakes for now
224/430 exhaust

maybe in about A year i'll move to some big cams like yours Frank.



AL.

[tpepmeie]

Originally Posted by ALZR1

even with about .100 removed the cam still rockwell 45c scale.So it's safe to say that it's not the regrinding of the camshafts.
AL.

I had a stock lifter tested, and it showed 62, if I remember correctly. The key, as explained to me, is the depth of the hardening in the cams. I had a scrapped Jeal 470 billet cam that I sent off for testing. At the surface, it was compatible with the 62 of the lifters, however the hardness layer was exceptionally thin and the base metal was quite a bit softer. Any piece of metallic debris would break right through the surface layer and wipe out the lobe. At least that's how it was explained to me.

[Pete]

WTF.

Paul why did your wifes cam wipe out?

Now for all the smart guys out there that know it all.

Answer me this.

The last time i had my motor apart about 2 months ago i put 4 brand new GM lifters in the right side intake.(the side went bad)

Why only the new lifters went bad but my old 65k mile lifters are still good and i will be reusing them.

I've had my intake cams for over 2 years with no issues till lifter change.

Reason for changing lifters had a nosey one i had to hold 2k rpm for it to load up.

Two of the new lifters have started to show cracks the cam lobes look fine so basicly took out 3 out of 4 new lifters.

So please all you smart guys answer me the above question why they held up for 2 years but as soon as i put new lifters it breaks??



Pete

[jerrydirks]

I have a broken cam in 1992 ZR1, does anyone know of a custom cam grinder that has billets for custom grinding.

Jerry

[ALZR1]

Originally Posted by tpepmeie

I had a stock lifter tested, and it showed 62, if I remember correctly. The key, as explained to me, is the depth of the hardening in the cams. I had a scrapped Jeal 470 billet cam that I sent off for testing. At the surface, it was compatible with the 62 of the lifters, however the hardness layer was exceptionally thin and the base metal was quite a bit softer. Any piece of metallic debris would break right through the surface layer and wipe out the lobe. At least that's how it was explained to me.

Todd stock cams measure 55 to 56 rockwell and lifters measure anywhere
from 62 to 65 rockwell the difference being if you measuring on the outside
of the lifter or the inside of the lifter respectively.
If the cam was as hard as the lifter I think it would not last that long.That's why when you have billet cams made which measure around 62 rockwell the lifters need to be DLC'D (Diamond like coating) to make the
surface even harder.So the hardness of the cams and the lifter need to be
dissimiliar in order to work without failures,That's the idea is what was told to me.


AL.