Piper Arrow IV Turbo Maintenance Manual page 152

B. Obtain a basic measurement from the top of the ring gear by measuring the width of the starter
ring gear plus the dimension from the forward machined surface of the ring gear to the forward
edge of the compressor drive belt. ( Refer to Figure 21-15.)
C. The check and adjustments of the compressor and/or alternator drive belts require diff e r e n t
procedures. Refer to the following appropriate instructions:
6. Compressor Belt Alignment: ( Refer to Figure 21-15.)
A. Place the straightedge against the right forward side of the ring gear and measure belt alignment at
compressor sheave (Point - B).
B. Measure belt alignment at the compressor idler pulley (Point - A). The belt misalignment at Point -
A should be half the misalignment of Point - B and the dimension at the top of the ring gear and in
the same direction fore and aft.
C. If at Point - A nominal misalignment is not within +/- .030 of an inch as obtained in Step B, add or
remove shims as required. Belt alignment should be made as close to nominal as shims will allow.
7. Alternator Belt Alignment: (Refer to Figure 21-15.)
A. With the alternator belt installed, align the idler pulley in the belt plane by adding or removing
shims, P/N 62833-82 as required. (Refer to Adjustment of Drive Belt Tension for belt tension
adjustment.)
ADJUSTMENT OF DRIVE BELT TENSION.
1. The adjustment of the York compressor and/or alternator drive belts installed on the PA-28RT-201 is
very important to obtain long belt life and proper component operation. (Refer to Parts Catalog for belt
numbers.) Adjust the belt tensions on PA-28RT-201 as follows:
A. Tighten the new compressor belt to 120 pounds span tension and the new alternator belt to 90-100
pounds span tension. When using the plastic type alternator belt, new belt tension is to be adjusted
to 65-70 pounds.
The higher tension specified for a new belt is to compensate for
the initial stretch that takes place as soon as it is operated. These
higher tension values should not be applied to belts which
previously have been used. See tensions noted below for used
belts.
B. Install the right front engine baffle and secure the side engine cowl latches, if previously removed.
C. Run the engine for a 15 minute period at 1200 RPM.
If the air conditioner is to be operated during ground servicing,
the test area should be clean and free of any loose objects lying
on the ramp. Only the service valve located on the evaporator
assembly should be used for testing.
D. Shut down engine and recheck the belt tensions. lf the compressor belt tension falls as low as 60
pounds reset to 80 pounds. If the alternator belt tension falls as low as 50 pounds retension to 70
pounds. The plastic type alternator belt should fall between 35-40 pounds.
E. This tension check should be made at every 100 hours or annual inspection whichever occurs first.
F. Check all idler and bracket bolts for safety and replace engine cowling.
PIPER AIRCRAFT
PA-28RT-201 / 201T
MAINTENANCE MANUAL
—NOTE—
— WARNING—
1G8
21-50-21
Page 21-33
Revised: July 13, 1983