Camshaft Bearings

(5) When diameter of bore at top of ring

proximately 4 inches long and slotted at 0.80

i n c h intervals 15 degrees to the horizontal to a

travel is more than 5.7610 inches after honing,

replace cylinder.

d e p t h of 0.12 inch from the bottom of the stone.

(6) Clean cylinder with a power brush

The stones are mounted to 1 / 16 inch thick cork

and hot (160F) soapy water. Dry thoroughly.

backing before mounting in the shell. This

design allows the stone to conform to the tapered

Lubricate cylinder bore to prevent rust.

e. Camshaft Bearings. Remove minor nicks,

section of the bore. The stones should be

m o u n t e d as per Micromatic Design No. 47415 -

burs, or scratches from camshaft bearing sur-

SA or equivalent. This number represents size

faces with crocus cloth dipped in dry-cleaning

7 / 16 x 1 / 2 x 4 stones mounted with cork

s o l v e n t or mineral spirits paint thinner. Replace

backing and slotted. This design will fit

cylinder assembly when camshaft bearing

surfaces are scored, galled, or deeply pitted, or

Micromatic stone holder No. 33960-5 and

Micromatic Model 5R-SFE-8 Blind End Tool.

w h e n they do not conform to limits specified in

overhaul standards (table 6-15).

(2) The surface finish should be devel-

oped in two stages. Rough hone the entire

f. Cylinder Exterior.

l e n g t h of the bore, using moderately heavy stone

(1) Cooling fins. Straighten bent fins as

near as possible to their original spacing.

pressure, until the ring ridge is removed and

entire bore has a cross hatch pattern. Finish hone

Replace cylinder assembly when more than one

using the same stones, with a very light pressure,

percent of barrel cooling fin area is broken.

f o r approximately 5 to 8 strokes. This operation

Replace cylinder assembly if head finis broken

will remove rough edges and fragmented metal

m o r e than half the depth of the fin or more than

left from the rough hone operation.

two inches long. A cylinder assembly can be

Note. The ring ridge may be removed using

used if it has not more than three acceptable

s h o r t stones and a short stroking action prior to

defects, or if no two of the defects are on adjacent

t h e full rough and finish hone cycle. Under no

fins. Repair damaged cylinder head fins as

described in (a) through (c), below, and in TB

circumstances are short cycle strokes to be

p e r f o r m e d after the full length strokes have been

9-2800-207-50.

completed.

(a) Use a fine mill file to remove sharp

corners of broken head fins.

(3) Honing oil should be principally

kerosene with a sulphurized base oil. Adequate

(b) Do not remove more metal than

n e c e s s a r y to produce a smoothly blended edge on

f i l t r a t i o n should be provided with both magnetic

the damaged fin.

a n d paper filters recommended. A suggested oil

is twenty-seven and one half (27-1 / 2) parts

( c ) Depth of any blended fin must not be

l e s s than 50 percent of its original depth, when

kerosene to twenty-two and one half (22-1 / 2

blended fin is less than 50 percent of original

parts Stuarts' Superkool base oil. This may be

depth, replace cylinder assembly.

purchased from the D. A. Stuart Oil Company,

8350 Military Avenue, Detroit, Michigan

(2) Studs and inserts. R e p l a c e d a m a g e d ,

b e n t , or stripped studs as described in paragraph

48204.)

6-4e and table 6-16. Replace defective helical-

(4) The hone angle should be 35 degrees

coil inserts as described in paragraph 6-5.

to horizontal (70 degrees included angle).

S p i n d l e speed should be 77 rpm, with a vertical

reciprocating rate of 43 cycles per minute.

6-71