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2 3 1 V6 ENGINE V.I. CODE C
6A3-7
7. If valve stem has too much clearance in its guide, the
guide should be reamed to using a .003 and ,006" oversize
Reamer. See Fig. 6A3-14.
Fig.
6A3-15
Oversize Valve Identification
Fig.
6A3-14
Reaming Valve Guide
Oversize valve are identified by the oversize marking
stamped on the valve head.
The Parts Department stocks .006" oversize valves for
replacement purposes. See Fig. 6A3- 15.
8. True up valve seats to 45". Cutting a valve seat results
in lowering the valve spring pressure and increases the width
of the seat. The nominal width of the intake valve seat is
1/16". If the intake valve seat is over 5/64" wide after truing
up it should be narrowed to specified width by the use of 20"
and 70" stones. The nominal width of the exhaust valve seat
is 3/32". If the exhaust valve is over 7/64" wide after truing
it should be narrowed to the specified width. Use 20 degree
and 70 degree stones to narrow the valve seats to the specified
widths.
Improper hydraulic valve lifter operation may result if
valve and seat have been refinished enough to allow the end
of valve stem to raise approximately .05OW above normal
position. In this case it will be necessary to grind off end of
valve stem or replace parts.
9. Lightly lap the valves into seats with the fine grinding
compound. The refacing and reseating operations should
leave the refinished surfaces smooth and true so that a
minimum of lapping is required. Excessive lapping will
groove the valve face preventing a good seat when hot.
New valves should not be lapped under any condition
as the .0002"
-
.0015" aluminum alloy surface on the intakes
or the .0004" to .0015" nickel-plated surface on the exhausts
will be removed.
10. Test valves for concentricity with seats and for tight
seating. The usual test is to coat the valve face lightly with
Prussian blue, or equivalanet, and turn the valve against seat.
If the valve face is concentric with the valve stem a mark will
be made all around the face, while if the face is not concentric
with the stem, a mark will be made on only one side of the
face. Next, coat the valve seat lightly with Prussian blue, or
equivalent, Rotate the valve against the seat to determine if
the valve seat is concentric with the valve guide, and if the
valve is seating all the way around. Both of these tests are
necessary to prove that a proper seat is being obtained.
1 1. Remove any burrs from valve stem with a fine stone
and polish with crocus cloth.
12. Lubricate valve stems and guides with engine oil and
reinstall valves.
13. Install new intake valve seals.
Do not install exhaust valve guide seals.
a. Start valve seal carefully over valve stem. Push seal
down until it touches top of guide.
b. Use installation tool J 22509 to push seal over valve
guide until upper inside surface of seal touches top of guide.
COMPRESS SPRINGS ONLY ENOUGH TO
INSTALL KEEPERS. EXCESS COMPRESSION
CAN CAUSE SPRING RETAINER TO DAMAGE
VALVE SEAL.
14. All valve springs may be installed with either end up.
15. Reinstall valve spring, cap and cap retainer, using
same equipment used for removal.
16. Install cylinder head.
TIMING CHAIN COVER
Removal
1. Drain radiator.
2. Disconnect upper and lower radiator hose and heater
return hose at water pump.
3. Remove fan, fan pulleys and belt(s).
4. Remove fan driving pulley (crankshaft).
5. Disconnect fuel lines and remove fuel pump.
6. Remove Delcotron generator and brackets.
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