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White Farm Equipment
Hopkins Minnesota 55343
A Subsidiary of WHITE MOTOR CORPORATION
208.

Serviceletter 
200-055-01
All Power Units
April 19, 1971
Subject: Improved Camshaft 20-0007763

We have available through our Parts Department, an improved camshaft, #20-0007763, which can be used to replace part #10A21831 and #10A30471.

The new camshaft #20-0007763, has a material change which will give longer life. The new shaft will be used in production, starting with July production of 425, 451 and 504 on diesel tractor engines, as well as the gas tractor versions.

We are using camshafts for different engines and applications with different valve timings and to avoid errors in the field when checking for correct valve timing, we list the following information.

When checking the valve timing with a dial indicator, proceed as follows: We will use camshaft #20-0007763 as an example.

  1. Allow engine to cool for 30 minutes if it has been in operation.

  2. Rotate engine until #1 piston is on the compression stroke and then on to the DC mark on the flywheel or crankshaft pulley.

  3. Set tappet clearance on #1 intake valve to exactly the clearance cold, as recommended in the respective operator's manual or on the data plate of the engine.

  4. Install dial indicator on cylinder head so that the indicator contacts the valve spring seat. Set dial at zero.

  5. Rotate engine one revolution to the 13° BTDC mark on flywheel or crankshaft pulley. The dial indicator should read  .003" to .006". Slight variations can be expected.

If using the feeler gauge method:

  1. Set the valve lash. .003 over our recommendation on #1 intake valve on the compression stroke, and then on to the DC mark.

  2. Rotate engine one revolution to the l3° BTDC marking. Will be zero or nearly so.

One degree less than the actual opening is used to compensate for any manufacturing tolerance that may exist.
208.

200-055-01

Camshafts, part #20-0007763, 10A21831 and 10A30471:

Intake opens14° BTDC

 Intake closes 34° ABDC
Exhaust opens 39° BBDC Exhaust closes 9° ATDC

Camshafts #10A19798, 10A19776, 10A30435:

Intake opens 20° BTDC

 Intake closes 40°ABDC
Exhaust opens 40°BBDC Exhaust closes 20°ATDC

Camshafts #10A24044:

Intake opens 9° BTDC

 Intake closes 39° ABDC
Exhaust opens 39° BBDC Exhaust closes 6° ATDC

Camshafts #10A9032:

Intake opens 4° BTDC

 Intake closes 38°ABDC
Exhaust opens 47° BBDC Exhaust closes 7° ATDC

Camshafts #10A25080

Intake opens 3° BTDC

 Intake closes 37° ABDC
Exhaust opens 53° BBDC Exhaust closes 7° ABDC

 

Camshaft lobe lift on # 10A30435, 10A19776 is .379+- .002.
Lobe lift on #20-0007763, 10A30471 and 10A21831 is .340 +- .002.
Love lift on #10A19798 is .377 +- .002
Love lift on #10A24044 is .379+- .002
Love lift on #10A9032 is .318 +- .002
Love lift on #10A25080 is .320 +- .002

Groove in rear camshaft journal for rocker arm lubricantion on # 10A9032, 10A19776, 10A19798 and 10A30435.

Hole in rear camshaft journal for rocker arm Lubrication on #10A21831, 10A30471 and 20-0007763 Groove in case or bearing.

#10A24044 has no hole or groove in rear journal.

When interchanging camshafts, caution must be exercised to avoid cam lobes striking the rods and that lobes are in proper relation to cam followers.

 
Jwv/j

TECHNICAL SERVICE DEPT.