Max Valve Spring Pressure for Reground Camshaft

[mopowers]

For those of you with reground hydraulic roller cams on stock cast cores, what kind of spring pressures are you running - seat/open?

I'm considering having a stock roller LA cam core reground to 233/241, .544" w/ 1.6s. but was told not to go much more than 110lbs seat and 300lbs open for spring pressure because of the cast core. Doesn't that seem light for a hydraulic roller cam with those specs. It's a just a street motor and won't see crazy RPMs, so maybe it'll be fine.

 

[RustyRatRod]

Whatever your cam grinder says. There's really no difference between a new one or a regrind regarding that.

 

[GTX JOHN]

I have run as much as 140 on the seat on my street cars with
no issues for a number of years with a quality CWC cast iron
cam. I never use the new Chinese cams in anything. I would rather
regrind the cam when there is enough left on the lobe to do so.

However, I never let the cars sit idling for more than a minute or
two without shutting the engine down in any of my cars.

 

[Bewy]

Flat tappet core are 'cast' & they can handle much more than that. It is the barrel diameter, the section between the lobes, that takes the load [ & flexes if not big enough ].

 

[mopowers]

Whatever your cam grinder says. There's really no difference between a new one or a regrind regarding that.

That's what I thought too. The cam grinder said that original cores weren't made from the best materials though and that the springs he recommends are seemingly nothing more than a comp 901. That seems a pretty strange for the hyd roller I'm looking at considering all other cam makers are calling for something in the 120/355 range for similar grinds.

 

[RustyRatRod]

That's what I thought too. The cam grinder said that original cores weren't made from the best materials though and that the springs he recommends are seemingly nothing more than a comp 901. That seems a pretty strange for the hyd roller I'm looking at considering all other cam makers are calling for something in the 120/355 range for similar grinds.

Ken Heard at Oregon says the stock Chrysler cores were hardened almost slam to the center of the core. He said they have never ground through the hardness. I guess if you're getting into solid roller territory, it's best to go with a billet core anyway.

 

[mopowers]

Ken Heard at Oregon says the stock Chrysler cores were hardened almost slam to the center of the core. He said they have never ground through the hardness. I guess if you're getting into solid roller territory, it's best to go with a billet core anyway.

That's weird. He told me that regrind I wanted would definitely grind through any hardening, but since it's mostly on the base circle where spring pressure is lightest, it's not a huge problem. He also said the material itself is such that he wouldn't recommend running much more than 110 seat and 300 open pressures. Seems a light for a small hyd roller, but I guess we'll see.

 

[RustyRatRod]

That's weird. He told me that regrind I wanted would definitely grind through any hardening, but since it's mostly on the base circle where spring pressure is lightest, it's not a huge problem. He also said the material itself is such that he wouldn't recommend running much more than 110 seat and 300 open pressures. Seems a light for a small hyd roller, but I guess we'll see.

What kinda cam are we talkin about here? Roller? All I've ever discussed with him are slant 6 and early Hemi cores. Plus he also said that of other Chrysler V8 flat tappet cams.

 

[GTX JOHN]

If the cams are stamped "CWC" they are the quality
casting and you will have no issues except with some
of the cheap Chinese lifters that will be an issue = not the casting.

The old CWC castings are not getting any easier to find.

 

[mopowers]

What kinda cam are we talkin about here? Roller? All I've ever discussed with him are slant 6 and early Hemi cores. Plus he also said that of other Chrysler V8 flat tappet cams.

Yep, hydraulic roller. Maybe they don't have as deep of hardening because they use a roller tappet. Who knows?

If the cams are stamped "CWC" they are the quality
casting and you will have no issues except with some
of the cheap Chinese lifters that will be an issue = not the casting.

The old CWC castings are not getting any easier to find.

That's good to know. Definitely no CWC stamped on mine. I only saw an "8" lightly stamped on the back end and a few three digit numbers cast between a couple lobes. Thanks for the info.