hardness of GMs old solid flat tappets

[cv67]

Whats the general rockwell??hardness or hardening process of their old performance cams on cams/lifters?

Is anyone producing similar quality parts today?
Seems there is a big enough market for guys that still want them what am I missing?

[mag2555]

I don't know what hardness these items would test at.
But I do know that there old suff was made by Mellings tool which did things well!

I buddy who has now passed away use to work at a GM plant firing the motors over and doing a quick break in session and according to him the parts where good enough back then to have few if any failures when looked at ratio wise.
If your gonna need to run the new old stock Cam and Lifters with more then 280 psi of open spring pressure there is two ways to do it safely.

1) break in the Cam with just the outer springs.

2) send the Cam and lifters out to get Cryogenic treated.

[pdq67]

I want to say something like a Rc of 64, BUT I may be way off??

I will say that the two-piece lifter that has a stellite foot is HARD!!

They can be resurfaced and used again and again!

pdq67

[Barry_R]

Old GM lifters were made by Delphi (AC Delco...).
They were a unique design with a steel foot friction welded & attached to a cast iron body.
I do not believe anybody else has done that since they stopped making them sometime in the 1990s

[cgarb]

I noticed a lot of those GM lifters that I trash canned looked perfect on the bottom. I wondered about having them resurfaced and putting solid lifter guts in them. Probably not worth the time and effort.

[Geoff2]

I bought Melling lifters from Summit about 8 years ago that had the Stellite foot. They were for a Pontiac.

Also, here in Australia, we routinely re-face lifters because of the high cost of new lifters. We have done it for DECADES. They can be re-faced 2-3 times.
Soooooooo, if you are worried about the reliability of your NEW Chinese/Mexican FT lifters, get your old factory lifters re-faced........

[novadude]

When did they stop making the "hard-foot" lifters? I bought some Hyd FT Delphi lifters in the late 2000s (two sets, two different sources) that had the hardened "foot". Didn't know these were no longer available (or are we only talking solid lifters)?

[F-BIRD'88]

As far as I know you can still buy new GM hyd lifters with the steel alloy foot.
I believe they are in the GMPP catalog.

Before you get all wrapped up in all this including getting your SFT cam and lifters
"ICED" etc etc,
Consider this. A off th shelf solid street roller cam system with off the shelf standard solid roller lifters will make more power and more torque
and last longer than any all solid flat tappet setups custom or otherwise, HD "P" cam core or otherwise. Special hard foot lifter and or extra oiling hole and cryogenic heat treating and all.
These solid street roller cam systems are very reliable as they run with modest valve spring
pressures and the lifter and valve motions thus acting forces are moderate and easy on ALL the parts that matter.
Do not confuse with a full race, race only solid roller cams system intended for competition racing, that require very very high valve spring pressures.

By the time you are all done with a specialized solid flat tappet cam setup with all the goodies
Custom grind, special materials. cam core and treatments, oils and special break in methods and parts you will far exceed the total price of a off the shelf solid street roller cam and kit
and will have LESS power and torque and a shorter service life and will have spent more money.

[BrazilianZ28Camaro]

I want to say something like a Rc of 64, BUT I may be way off??

I will say that the two-piece lifter that has a stellite foot is HARD!!

They can be resurfaced and used again and again!

pdq67

With 20+ years of metalurgy and milling experience, I can tell you the cam core is far from 64 HRc. Even the hardened foot lifter might not be that hard.

I never measured the cam hardness but I'll guestimate around 40-44 HRc.

[pamotorman]

I tested some 20 years ago and the cams and lifters were around 55- 60 Rockwell C

[pdq67]

As far as I know you can still buy new GM hyd lifters with the steel alloy foot.
I believe they are in the GMPP catalog.

Before you get all wrapped up in all this including getting your SFT cam and lifters
"ICED" etc etc,
Consider this. A off th shelf solid street roller cam system with off the shelf standard solid roller lifters will make more power and more torque
and last longer than any all solid flat tappet setups custom or otherwise, HD "P" cam core or otherwise. Special hard foot lifter and or extra oiling hole and cryogenic heat treating and all.
These solid street roller cam systems are very reliable as they run with modest valve spring
pressures and the lifter and valve motions thus acting forces are moderate and easy on ALL the parts that matter.
Do not confuse with a full race, race only solid roller cams system intended for competition racing, that require very very high valve spring pressures.

By the time you are all done with a specialized solid flat tappet cam setup with all the goodies
Custom grind, special materials. cam core and treatments, oils and special break in methods and parts you will far exceed the total price of a off the shelf solid street roller cam and kit
and will have LESS power and torque and a shorter service life and will have spent more money.

OK,, post up some part numbers of these so-called, "solid street roller", cams that you mention!

And I assume that CC's great old 288AR BBC cam will be one of them.

And as for foot hardness, I never said that I really knew what they were.

pdq67

[F-BIRD'88]

Start with all the comp cam in catalog ex solid rollers and magnum solid rollers.

Then all the solid rollers in the howards catalog
that have .370" to .,390" lobe lift.

Same examples in Erson , Isky ,Crane, etc etc.
Thats a lot of affordable solid street rollers.

The specific cb 288AR-8 #11-700-9 cam is not really a "street roller"

but there is a comp Magnum cb280ar-10 #11-691-9
and a CB288Ar-10 #11-692-9 that are street rollers.

Don't forget the UDharold developed voodoo street solid rollers..
Ud harold also had a series of .3705" lobe lift + .3883" lobe lift + .3944" solid street
rollers you can get from howards and bullet and lunati.
Spme have reg catalog part numbrrs too.
.050" duration from 242 to 269.

All these "street roller" class of cams all will out perform
any all flat tappets including boutique custom grind.
Use relativly modest springs for long service life
and are affordable especially in kits form all said and done.

I have not even mentioned the extent of choices.

Best cost compare all in pricing against a solid flat cam with
all the optional bells and whistles and special oils etc included. Price comparable more power more torque
better longer service life even with standard solid rollrr lifters.

They are street marine endurance long life oriented designs
.

[F-BIRD'88]

If you are all paraniod about flat tappet cam wear, service life etc this is the way to go.

You will go faster and farther for equal or even LESs money
over the life of the car.

[F-BIRD'88]

Your buddy UDHarold was very up on designing cam lobes specificly for this purpose.

Look in the old Ultradyne catalog on the web archive
for various reg catalog cams he had for this purpose.
You can still get all these and more in same "sr" lobe class of camshaft
thru bullet, howards and lunati.

comp xe and magnum use similar lobe design for purpose
designs for their street rollrr stuff.
And they have more stuff beyond that.

[JodyB]

I think part of the answer to the original question is that the production gm sft cams were designed with marginal valvesprings and valvetrain in mind. Very non-agressive lobes that would rpm with cheap production parts.