Bob's Studebaker Resource Website


R1 / R2 Cam Specifications

Jim Pepper - March 2016

Ref...

........No throttle response and no bottom end torque..... A 232 with an R1 cam Would be similar. You can have the stock cam reground adding a little more lift and duration but keep it conservative. The stock Studebaker 259/289 cam timing is well thought out. It could use some more lift. New valve springs will be needed. The small bore size of a 232 is a limiting factor on a 232. It limits valve size and breathing ability. I would do a general clean up of the ports and do a 3-angle valve job with a valve back cut. All modifications will be to promote low lift air flow. Surface the heads. A 259/289 intake will not fit. There are aftermarket aluminum 4 barrel intakes for sale occasionally on various sites. A larger 2 barrel carburetor from a later 259 or 289 might be your best bet. You may have to open up the throttle bores in the intake for this.

Here are the camshaft specifications for reference. You will notice that the R1 cam has similar specifications to the Chevy 350HP327 cam with less lift.

R1/R2
Camshaft Specifications
(Part # 1557663)

(Part # 1557663) Copies of the camshaft drawing (1557663) and the lobe profile drawing (1557662) are available for purchase from the Studebaker National Museum. Contact Andy Beckman if you are interested. Here are some particulars of the R1/2 cam;
Timing specifications at .020 lifter rise (considered valve seat to seat timing)

  • 260' duration @ .020 lifter rise or at .030 valve clearance (.020 X 1.5 rocker ratio = .030). (shop manual specification) .4295 gross valve lift minus the running clearance = .406 valve lift.
  • IVO - 17' BTDC
  • IVC - 63' ABDC
  • EVO - 56' BBDC
  • EVC - 24' ATDC
  • ICA - 113' ATDC
  • ECA - 106' BTDC
  • LDA - 109.5'
  • Valve overlap 41'
  • Based on above timing events, cam is retarded 3.5'

Other pertinent dimensions;

  • 53' clearance ramp from above timing points.
  • .53125 base circle radius.
  • .81762 cam centerline to lobe tip
  • .28637 lobe lift
  • 1.5 to 1 rocker arm ratio
  • 1.34887 base circle to lobe tip

These specifications can also be used to degree a cam during engine assembly.

The industry standard today is to measure cams at .050" lifter rise. Using these criteria, the R1/R2 cam specs out as follows:
Intake and Exhaust duration @ .050" lift is 223.6'

  • IVO - 1.4' BTDC (1.4' ATDC)
  • IVC - 44.6' ABDC
  • EVO - 37.6' BBDC
  • EVC - 5.6' ATDC

Stock 259/289
Camshaft Specifications
( Part # 534131)

Timing specifications at .020 lifter rise (considered valve seat to seat timing)

  • 245' duration @ .020 lifter rise or at .030 valve clearance (.020 X 1.5 rocker ratio = .030). (shop manual specification) ..359 gross valve lift minus the running clearance = .336 valve lift.
  • IVO - 11' BTDC
  • IVC - 54.5' ABDC
  • EVO - 51.5' BBDC
  • EVC - 14' ATDC
  • ICA - 111.8' ATDC
  • ECA - 108.8' BTDC
  • LDA - 110.3'
  • Valve overlap 25'
  • Based on above timing events, cam is retarded 1.5'

Assuming the ramp acceleration rate is similar for both camshafts, the duration for the stock camshaft at the industry standard.050 lifter rise is 208'.