Custom-made billet camshafts:

Custom-made billet camshafts:

A few questions, some interesting answers –

By Bertie S. Brown:

This International pull tractor camshaft measures approximately 44in long with 4 bearings, one at each end and two in the middle. John Deere uses 7 bearings measuring around 70mm in diameter.

This International pull tractor camshaft measures approximately 44in long with 4 bearings, one at each end and two in the middle. John Deere uses 7 bearings measuring around 70mm in diameter.

Most camshafts look indistinguishable from one another—even custom camshafts. “Not mine,” declares blown alcohol pulling tractor champion Mike Wilhite. “Mine are 2.5 inches in diameter.”

Wilhite, who runs an engine shop in Bardstown, KY, thirty miles south of Louisville, purchases a 12ft length of 2.5in case-hardened 8620 alloy steel or S7 tool steel bar stock. He then takes the long length of round bar to Russ Yoder at Erson Cams, who makes four camshafts from it. When finish-ground and heat treated, Wilhite installs the custom-made billet camshafts in the engines of his alcohol pulling-tractor customers.

BlueBlazes-EngineSix-cylinder inline engines adapted for pulling tractor competitions begin life as 200hp diesels revving to 1,500rpm, but when increased to 505ci (Light Super Stock) and converted to alcohol and assisted by three turbochargers they generate close to 4,000hp and 7,000rpm.

On the topic of pulling tractors, Yoder says, “We’ve made camshafts for 7.8 liter Ford diesels to an A22 International, from Cummins to Walkinshaw, Oliver to Massey Ferguson, Allis Chalmers to antique pulling tractors with engines originating from the 1920s.”

Why no shelf stock for the extreme categories?

Roller lobes ground on S7 tool steel. Grinding long camshafts like this from a round bar consumes around 8 hours of grinding time. Regrinding an existing core to change the profile takes around 3hr.

Roller lobes ground on S7 tool steel. Grinding long camshafts like this from a round bar consumes around 8 hours of grinding time. Regrinding an existing core to change its profile takes around 3hr.

“Its common practice for competition engine builders to increase cam bearing sizes, and our shelf-stock materials accommodate increases of up to 60mm for big-block Chevrolets and also big-block Fords and for some Hemi engines,” says Yoder. “But, beyond this it just isn’t practical to inventory cam cores of such diversity.” Hence, in this regard, Erson identifies the optimum grade of steel required, the customer brings them the appropriate round bar stock (some measuring 70mm), and they grind the camshaft.

“We’ve experienced good luck with 8620,” says Yoder. “It’s exceedingly tough and hard and durable.” But on vehicles with extreme engine power that have encountered cam lobe damage, he advises them to switch to S7 tool steel. “Though it’s three times more expensive than 8620,” he cautions, “its hardened boundary layer penetrates deeper than 8620.”

How are custom cams created and who determines the grind?

As you’d predict, Erson needs access to an original equipment camshaft in order to establish the lobe centers, as they have to be aligned with the lifter bores. The grind, however, is usually determined by Yoder and, on pulling tractors, is influenced by the number of turbochargers used (one or three), the fuel (alcohol or diesel), and engine displacement.

Blue Blazes“A lot of these tractor guys convert the engines from diesel to alcohol and run multiple turbochargers—they actually compress air from one turbo into another, which necessitates running over 100lbs of manifold boost. As a result their cylinder pressure is about as extreme as a top fuel car.”

BlueBlazes2Yoder continues, “Some of the 650ci Heavy Super Stock tractors produce 5,000-plus horsepower.” So the cylinder pressure is so high the exhaust valve has trouble opening, exerting excessive pressure on the exhaust lobes—that have to push the lifters up. “To survive, the cam lobes must demonstate 64C (Rockwell C scale) or harder, which is where the S7 tool steel camshaft has the advantage with its deeper hard surface. Its core, the center of the material, starts out at 16 points harder than the 8620.” Because its hard boundary layer is deeper, it succeeds in combating the high spring loads better.”

On heat treating

The 8620 material is carburized while S7 tool steel is induction hardened; it does not absorb carbon. The process for tool steel camshafts involves an induction furnace and electric coils that bring the cams to the required temperature at which point they are quenched in alcohol.

On the other hand, the 8620 camshafts are placed in a carbon furnace that exposes them to a temperature of 1960 degrees for 40 hours.

When would you wish to change the profile and how would you know what profile to change it to?

Recently, Erson encountered a customer who had suffered multiple engine failures. Running blown alcohol, he mentioned he’d acquired a newly designed cylinder head and a camshaft made to match the head. But it turned out to be an expensive mismatch. Confused and dispirited, he came seeking help.

“We asked him if he knew the percentage of his flow figures, exhaust to intake,” recalls Yoder. “His answer immediately revealed the problem: his exhaust flowed 90% of his intake—which is wildly excessive.

“You have to trap the intake charge of alcohol in the cylinders,” insists Yoder; “you cannot allow it to be blown out the exhaust, as the engine will turn lean and destroy itself.

“Let’s say you’re running gasoline with the exhaust flowing 70 percent, you might consider adding 10 or 12 or 15 degrees more duration to the exhaust than the intake. But if you consider a blown alcohol engine that’s flowing 70 percent on the exhaust, we would typically suggest a standard straight-pattern cam or a reverse-pattern cam because the intake charge is under pressure; so on the overlap stroke, when both valves are open, this formula prevents premature ejection of the charge from the combustion chamber.

“As this camshaft was 4 degrees greater on the exhaust than the intake, we reduced its duration, making its intake period longer than the exhaust and reduced its lift capability by 0.050in. That fixed it!”


Erson Cams
Louisville Kentucky
Contact Russ Yoder


Mike Wilhite Motorsports
Bardstown, Kentucky
(502) 507-3352
Contact Mike Wilhite



  1. I’m looking for a custom grind 212/218 for my 2010 Ram 4.7 liter V8

  2. 1999 Dodge diesel 5.9?

    • Hi, Can you make a cam 289 299 222 232 510 534? If you can please advise how much. Thank you

      • John,
        Erson doesn’t have this profile, but they could make it. Feel free to give them a call. Best contact is Russ Yoder who can be reached at (502) 216-8804.

  3. Can you make one for a 3406 b model cat

  4. To Anthony, Jacob, and Robert:
    Call Erson Cams at 800-641-7920, and ask for John.
    If we can get a core, we can grind it.

  5. I’m in need of a custom camshaft for a 460 Ford that is stroked to 552cid. I need the 460 firing order changed to a FORD 351M/400/351W firing order. Can you do this?

  6. Rock,
    We can make you a roller camshaft with the altered firing order, either hydraulic or solid. We cannot make a flat tappet type for this.

  7. Hi,

    I’m looking for some performance camshafts for an Audi S4 3.0 supercharged. Can you help?

    • Sorry Darren, Erson Cams’ prowess lies in their domestic V8 cam core capacity but lack those required for your engine. It’s unusual to change the cams of a modern forced-induction engine until you reach significant power outputs because large gains are readily obtainable from increasing boost, larger intercooler, remapping, additional fuelling.

      Moore Good Ink

  8. Hello, I am in need of 4 camshafts for my 1990 Audi V8 Quattro. Would you be able to make some?

  9. Darren,
    For Erson to provide these camshafts, they would require cam cores specific to Audi’s technical particulars–bearing journals, lobe profiles, spacings etc. Unfortunately, they are not in possession of the cores or technical specifications.

  10. I have a 383 stroker engine and I’m replacing the distributor. The people at Summit Racing require information regarding the cam’s material (iron/steel) to match it with the correct distributor gear. The cam is an Erson e119845-47 hydraulic roller. Can you help?

    • From Erson’s Russ Yoder:

      The part number mentioned is a 2-piece core that should work fine with a stock OE distributor gear.
      Thanks Russ


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