Don Terrill’s Speed-Talk

Just wondered if anyone is using a steel cam core for a flat tappet engine and using tool steel lifters and what durability are you seeing?
I am doing an engine for a spec class that must use a flat tappet lifter that is stock dia. for make of block used. No bigger.
The limit is a gasket size rule 1206 intake for GM. They are also limited to 2-3/16 restrictor in the stack. Injected alky. Seems that most guys are replacing cams 2-3 times a season from nose wear. Rocker ratios and style of rocker setup is optional. Most of the fast guys use about 180 seat 450 open but wear is an issue.Engines run anywhere from 7200-8200 rpm.Ti valves/retainers are a no no in this class.
Any thoughts if a steel cam/lifter combo would give more life in this case or just more cost to do the same job.
Thanks
Dave

Dave a customer of mine has a maropolus supler late engine with a steel cam and tool steel lifters,when he freshened it at 1700 laps per Bill he put a new cam and lifters in it.

Dave,

We have a class similar to that but uses 4412 style carbs and no wings. Springs are 150-450, rpm is up to 7200-7500, lift is .650-.675 with 1.7-1.8 ratios. We like to use the chevy 2.8 lifters like many use on the big blocks. I’m not really a EDM fan as most wear is a rotational problem. Nitrided cams and some coatings give us all year usage. Every once in a while someone washes the motor down with alky and we can get some wear. But this is what has worked for us. Many would use the Shubeck stuff before but it’s gone from the class now. Good luck,

Joe

If at 1700 laps a replacement was needed then a steel cam may save a mid season replacement but that said if the 2.8 style lifters are used is there much of a pressure drop from dumping oil all over the lobe? Are these a modified version of the stock lifter for a solid type cam application. I will have to contact PPPC and inquire about them as I guess they build them special.

We get them from Erson but I know Delta up in Tacoma has them. Where they get them I don't know at this time. Just about everything is Johnson or Delphi on the bodies. Had horrible failures on any Imported bodies on street stuff. Oil pressure is not a problem but then neither is wear for the most part. It sounds like your cams are similar to what we run. It's called Spec Sprint. No wing, bigger right rear tire, cast head and block, flat cams, no ti. Good luck,

Joe

Good luck is about it. We run wings here so that just keep the load on the parts and wears stuff out.

Dave
I assume this sprint class your running you run fuel pump off the rear of the cam and maybe the
waterpump off the front? With some of the deals I have been involed in with a cast/P55/lobe lok cams
I have seen them brake between the last to lobes...
Going with an 8620 steel core is a good choice. The biggest problem is finding a cam company that has
them rough in and harden for a tappet lobe. The cams we tested came from Cam Motion and was just told
a week or so ago that Bullett had some.

In our testing of the 8620 core it took a few trys before we got it to live.
This is what worked. Using a Ferrea Tool Steel Lifter out of the box no coating
8620 core rough in and heat treated correctly for your lobe.
Lobe taper .002 not over all but checking edge to edge.....
after finnish ground, cam must be nitrided (we used Winberg Cranks out of Denver CO)
Someone on another thread stated to use a coated lifter but I was told that will not work on
a nitrided cam. (I never tried it I was just told by a cam guy it would not work)
I would still break in with lite springs and good oil.....for a min. of 1 hour.....
We went 285/550 no issues..

Dave if you dont run anything off of the cam you should get away with a std type P55 I have
customers running them with 180-220/500 with a 1.7 or more ratio no problems..

Brian B
Dakota Parts Warehouse
The Ferrea Valve Guy
Now Stocking Hylomar
Ask about our Fast Setting Silicone
Sets up in about 15 min. really..................
877 235 2832

Brian B wrote:In our testing of the 8620 core it took a few trys before we got it to live.
This is what worked. Using a Ferrea Tool Steel Lifter out of the box no coating
8620 core rough in and heat treated correctly for your lobe.
Lobe taper .002 not over all but checking edge to edge.....
after finnish ground, cam must be nitrided (we used Winberg Cranks out of Denver CO)
Someone on another thread stated to use a coated lifter but I was told that will not work on
a nitrided cam. (I never tried it I was just told by a cam guy it would not work)
I would still break in with lite springs and good oil.....for a min. of 1 hour.....
We went 285/550 no issues..

That's really strange, because if you take an 8620 cam that's been carborized to 60rc, and you then Nitride it, the hardness under the thin Nitride layer will drop to 40-42rc. I wouldn't think that was hard enough to keep the 550lb spring pressures from pushing through the thin Nitrided top layer.

CamKing wrote:

Brian B wrote:In our testing of the 8620 core it took a few trys before we got it to live.
This is what worked. Using a Ferrea Tool Steel Lifter out of the box no coating
8620 core rough in and heat treated correctly for your lobe.
Lobe taper .002 not over all but checking edge to edge.....
after finnish ground, cam must be nitrided (we used Winberg Cranks out of Denver CO)
Someone on another thread stated to use a coated lifter but I was told that will not work on
a nitrided cam. (I never tried it I was just told by a cam guy it would not work)
I would still break in with lite springs and good oil.....for a min. of 1 hour.....
We went 285/550 no issues..

That's really strange, because if you take an 8620 cam that's been carborized to 60rc, and you then Nitride it, the hardness under the thin Nitride layer will drop to 40-42rc. I wouldn't think that was hard enough to keep the 550lb spring pressures from pushing through the thin Nitrided top layer.

Mike I don't know how to respond to what your saying....I am just stating what I did that worked.....
Brian B
Dakota Parts Warehouse
The Ferrea Valve Guy
now Stocking Hylomar
ASK about our Fast Setting Silicone....
877 235 2832

Brian B wrote: Mike I don't know how to respond to what your saying....I am just stating what I did that worked.....
Brian B
Dakota Parts Warehouse
The Ferrea Valve Guy
now Stocking Hylomar
ASK about our Fast Setting Silicone....
877 235 2832

I believe you. It's just got me thinking, and maybe rethinking some things.

We make 8620 billet cams for flat tappet Cummins I6 engines, but we don't run a lot of spring pressure.
On SB chevy's, we just carborize the 8620 core to 62rc, and run coated lifters against it. Without the coating, the cam and lifters wouldn't last. I never tried Nitriding them after grinding, because it would knock the core hardness down so far.
You having success with a case hardness of only 40rc, has me thinking, so I'm going to try doing what you did, and I'm also going to try two other options I think would be better.

It would be good if I could save my customers the cost of coating the lifters.

CamKing wrote:

Brian B wrote: Mike I don't know how to respond to what your saying....I am just stating what I did that worked.....
Brian B
Dakota Parts Warehouse
The Ferrea Valve Guy
now Stocking Hylomar
ASK about our Fast Setting Silicone....
877 235 2832

I believe you. It's just got me thinking, and maybe rethinking some things.

We make 8620 billet cams for flat tappet Cummins I6 engines, but we don't run a lot of spring pressure.
On SB chevy's, we just carborize the 8620 core to 62rc, and run coated lifters against it. Without the coating, the cam and lifters wouldn't last. I never tried Nitriding them after grinding, because it would knock the core hardness down so far.
You having success with a case hardness of only 40rc, has me thinking, so I'm going to try doing what you did, and I'm also going to try two other options I think would be better.

It would be good if I could save my customers the cost of coating the lifters.

Mike, Does nitriding a P55 core have any effect on the core hardness?. I have heard you talk about the K15 core also. What is the difference between a K15 and P55 core and which one is the preferred core with you?

therealdynodan wrote: Mike, Does nitriding a P55 core have any effect on the core hardness?. I have heard you talk about the K15 core also. What is the difference between a K15 and P55 core and which one is the preferred core with you?

I know the nitriding effects the cast cores, but I'll have to ask the metalurgest to find out the numbers.
The P55 core is a little harder then the K15 core, but it also more prone to breaking.
For me, I stick with my version of the K15 core(machined between the lobes for correct spacing), because I have no problem with the cores lasting at least a full season, and I don't have to worry about a broken cam destroying my customer's engine.