Resizing Chevrolet Vega Cylinders
NOTE: The tools and equipment necessary to perform the resizing process described below have been developed by Sunnen Products Co. AERA knows of no other Associate member manufacturing or marketing competitive tools or processes.
One of the mist significant features of the Chevrolet Vega Engine, Model 2300, is the use of an aluminum die-cast cylinder block that does not require a steel or cast iron liner in the cylinder bore. Pure particles of silicon, averaging about .001 in diameter, are dispersed throughout the aluminum alloy. To achieve the proper surface for ring and piston compatibility, the cylinders should be prepared in such a manner that the silicon particles protrude from the aluminum so the piston and rings contract only silicon. Because silicon is very hard, there will be very little wear in the cylinder bore. In fact, as far as the piston and rings are concerned, the cylinder wall is a silicon wall, and the aluminum's function is merely to hold the silicon particles.
If the cylinders become excessively scored or worn, they can be reconditioned with either automatic or manual honing equipment to accept oversize pistons. However, the usual sizing and finishing operation leaves a cylinder wall of silicon and aluminum --- the silicon does not protrude. Therefore, a special Conditioning operation is needed to remove aluminum from and between the
silicon particles so the silicon will protrude. This is the reason for the Conditioning operation which follows the honing operations, explained in detail in these instructions.
I. USING SUNNEN CK-10 AUTOMATIC CYLINDER RESIZING MACHINE.
A. GENERAL
Tooling (Sunnen Part Nos.):
CK-10 Automatic Cylinder Resizer w/
PF-1001 Filter
CK-3000 Hone Head
CK-50 Honing Oil
Master Holders Sets:CK-3035A
CK-3130A (for Felts only - do not use w/ honing stones)
Stone Sets: C30-A53
C30-J84
C30-C03-81
Felt Set: C30-F85
AN-30 Sunnen Silicon Compound
AN-35 Storage Box
Standard Cylinder I.D..........3.501
Cylinder Length................5-7/8
CK-10 Machine Settings for first three Honing Operations:
Stroke Scale..............2-3/4
Stroke Length Setting.....6-1/8
Top Overstroke............11/16
RPM.......................155
SPM.......................61
Feeding Setting...........(See Individual Steps)
Remove Alignment Guides for all operations.
B. HONING PROCEDURE
NOTE:Figures for Feed Dial Advance, Stock Removal Rates, and Surface Finishes are general information only, and are all approximate because of possible power line fluctuations and other variable conditions.
1. Roughing Operation to resize cylinders to any oversize desired.
a. Insert C30-A53 Honing Stones in Master Stoneholders and shorten Stones to 2-3/4 length by removing 3/4 from the stop (see Figure 1). Remove abrasive only, do not cut through Stoneholder.
b. Alter Main Guide as shown in Figure 2.
c. Set Feed Setting Number 3.
d. Hone to within .003 of finish size.
(1) Feed Dial Advance: 1 unit per .001 stock to be removed.
(2) Stock Removal Rate .....0029 per minute.
2. Finishing Operation
a. Insert C30-J84 Honing Stone in Master Stoneholders and shorten Stones to 2-3/4 length by removing 3/4 from the top (see Figure 1). remove abrasive only, do not cut through Stoneholder.
b. Set Feed Setting at Number 2.
c. Hone to within .0005 of finish size.
(1) Feed Dial Advance: 1 unit per .001 stock to be removed.
(2) Stock Removal Rate.......002 per minute.
(3) Surface Finish.......10-13 microinches.
3. Polishing Operation
a. Use C-30-C03-81 Honing Stone.
b. Feed Setting at Number 1.
c. Advance feed wheel very slowly until load meter indicates 30%, then hold feed handwheel while setting feed dial to 3.
(1) Honing machine will shut off after approximately 1 minute and 45 seconds of honing per cylinder. Hone longer to reach finished size if necessary.
(2) Surface Finish....2-3 microinches.
(3) Stock removal.....0005 to .0007 (to finished size)
4. Condition Operation
Standard Cylinder I.D. 3.501
Cylinder Length 5-7/8
CK-10 Machine Settings:
Stroke Scale 2-3/4
Stroke Length Setting 5-1/4
Top Overstroke 1/16
RPM 185
SPM 73
Feed Setting 2
a. Remove all abrasive left on cylinder surfaces from the previous operations by washing with filtered honing oil.
b. Install Sunnen C30-F85 Felts on CK-3130A Master Felt Holders and CK-3035A Master Stone Holders.
CAUTION: Be sure to replace Felts as required to avoid metal holders making contact with cylinder walls. One Felt may wear faster than others. Replace individual Felts as required -- they need not be replaced in full sets. Shim the Felts as you would stones or guide shoes when they become worn.
c. Saturate Felts in honing oil.
d. Mix Sunnen Silicon Compound thoroughly.
e. Coat Felts and entire surface of polished cylinder wall with Sunnen Silicon Compound.
f. Turn OFF CK-10 Honing Oil supply.
g. Condition first cylinder as follows: (1) With machine running, advance feed wheel until load meter reading reaches 30%.
(2) Set hand feed wheel to 10.
(3) The machine will shut off after approximately 2 minutes. The cylinder surface will have a dull matte finish (approximately 12-18 microinches). No significant stock removal.
h. Repeat Steps e and g for each cylinder.
i. Carefully clean block of all abrasive material and Silicon Compound prior to engine assembly.
NOTE: When not in use, the Felts should be stored in a clean container such as Sunnen AN-35 Storage Box to avoid contamination from foreign material or any abrasive particles.
Sunnen AN-30 Silicon Compound is a carefully formulated substance and precautions should be taken to keep it free of any foreign matter. Keep lid tightly closed when not in use. Use only clean brushes and do not attempt to reclaim any of the Compound from Felts or cylinder walls after conditioning.
II. USING SUNNEN PORTABLE CYLINDER HONE
A. GENERAL
1. Tooling (Sunnen Part Nos.):
AN-111 or AN-110 Standard Cylinder Hone
AN-80 Quick Coupler
UN-60 Universal Honing Stand
(Do not put Stand in the aluminum cylinders as the walls may be marred. Use a scrap cylinder block or a bolt-on holder to hold Stand.) 5/8 Electric Drill, 350 RPM Stone Sets: MM33-J63
MM33-J85
MM33-C05
Felt Set: MM33-F05
AN-30 Sunnen Silicon Compound
AN-35 Storage Box
2. Flood cylinder with MAN-845 Honing Oil throughout each honing operation, using a continual spray pump or by applying continuously with an oil squirt can. Failure to use enough oil will result in stone loading and possible scoring of the cylinders. Do not use honing oil on the final conditioning step.
B. HONING PROCEDURE
NOTE:Figures for Stock Removal Rates, Stone Wear, and Surface Finishes are general information only, and are all approximate.
1. Roughing Operation
a. Hone to within .003 of finish size.
(1) Stone: MM33-J63.
(2) Stock Removal Rate.....0035 per minute.
(3) Stone Wear/Stock Removal ratio...1/1.
(4) Surface Finish......25-30 microinches.
2. Finishing Operations
a. Hone to within .001 of finish size.
(1) Stone: MM33-J85
(2) Stock Removal Rate.....002 per minute.
(3) Stone Wear/Stock Removal ratio..2/1.
(4) Surface Finish....15-20 microinches.
3. Polishing Operation
a. Hone to finish size.
(1) Wipe cylinder clean of any abrasive or foreign matter from preceding operations to avoid scouring or scratching cylinder wall.
(2) Stone: MM33-C05
(3) Keep cylinder hone feed pinion tight.
(4) Stock Removal Rate.....0007 per minute.
(5) Stone Wear/Stock Removal ratio....2/1.
(6) Surface Finish.....4-6 microinches.
4. Conditioning Operation
a. Saturate MM33-F05 Felts in honing oil.
b. Mix Sunnen Silicon Compound thoroughly.
c. Coat Felts and entire surface of polished cylinder wall heavily with the compound.
d. Condition first cylinder as follows:
(1) Tighten feed pinion wing wrench as tightly as you can with fingers.
III. Condition for 1-1/2 minutes, stroking the same as for honing. Using no honing oil - it will wash away the Silicon Compound.k Periodically tighten feed pinion. The cylinder surface will have a dull matte finish (approximately 12-18 (microinches). No significant stock removal.
a. Keep overstroke to a minimum during condition operation. Long overstriking tends to cause ends of Felts to wear faster; this may result in uneven conditioning.
CAUTION: Be sure to replace Felts as required to avoid metal holders making contact with cylinder walls.
f. Repeat steps c and d for each cylinder.
g. Carefully clean block of all abrasive material and Silicon Compound prior to engine assembly.
NOTE: When not in use, the Felts should be stored in a clean container such as Sunnen AN-35 Storage Box, to avoid contamination from foreign material
or any abrasive particles.
Sunnen AN-30 Silicon Compound is a carefully formulated substance and precautions should be taken to keep it free of any foreign matter. Keep lid tightly closed when not in use. Use only clean brushes and do not attempt to reclaim any of the Compound from Felts or cylinder walls after conditioning.
The AERA Technical Committee |
Pilot Bearing Installation For Crankshafts On
1970 GM (Oldsmobile) 5.7 & 7.5L (350 & 455 CID) Engines
Oldsmobile division of General Motors Corp. specifies that when a service crankshaft is installed in a 1970 5.7 & 7.5L (350 & 455 CID) engine equipped with a manual transmission, the pilot bearing should not be staked in place.
A snap ring, Part No. 9425556, should be used to retain the pilot bearing in the crankshaft as illustrated below:
The AERA Technical Committee |
Powdered Metal Camshaft Sprocket Introduction On
General Motors 2.3L Quad 4 Engines
General Motors has introduced a new camshaft sprocket in the later production 1992 2.3L Quad 4 Oldsmobile engine. The new sprocket is now made of a powdered metal material and previous sprockets were made of a ferrous type metal.
This composition change is one that is becoming prevalent in many engine components today, in both light and heavy duty divisions. Powdered metal components are considerably lighter and less expensive to manufacture. They are used primarily in components that are subjected to no torsional stress. Their wear properties when used in these unique situations are comparable to those of their predecessors, the heavier ferrous metals. They also have the distinct advantage of superior operation (in a compatible environment) over the once-used composite materials with non-ferrous metal timing components.
General Motors indicates that the updated gear is being used in vehicle applications distinct to the L cars and specifically to VIN Code A. This newly designed gear is the replacement for any earlier production vehicles in this classification and carries the GM Part #24570973. Along with the newly designed gear, the introduction of a new wrench, GM Part #J 39579 tool (replaces GM Part #J 36013), which is required for successful installation.
Both wrenches are used in the identical manner, as the appropriate procedure in the service manuals indicate (seeillustration).
AERA is aware of one aftermarket manufacturer supplying the tooling required to successfully change the old and new camshaft sprocket gears.
The AERA Technical Committee |
