| TORQUE PLATE USE RECOMMENDATIONS |
Torque Plate Use Recommendations
While all engines would benefit, to realize an increase in performance and a decrease in oil consumption, the following list of engines should be finish honed with a torque plate to simulate the stress of the cylinder head when the engine is
assembled.
Manufacturer Displ. (L) (CID) Comments
GM 2.0L 121
2.5L 151
4.1L 252 V8 Aluminum Cadillac
4.9L 301
5.0L 305 Late model Chevrolet
5.7L 350 Oldsmobile
6.6L 400 Small block Chevrolet
6.6L 403 Oldsmobile
Ford 1.6L 98 Escort
1.9L 116 Escort
2.3L 140 OHC engine
5.0L 302 Late model engines
5.9L 360 *
6.4L 390 *
* While these are not thin wall blocks, durability and oil consumption is improved when a torque plate is used during remanufacture. It is not required to use a torque plate to prevent piston scuffing as we have noted to be necessary with the GM 2.0 and 2.5L engines.
The AERA Technical Committee |
| GENERAL MOTORS ENGINE IDENTIFICATION |
General Motors Engine Identification
General Motors is using 16 basic engine sizes or designs in its 1977 automobiles. These engines are manufactured by five car divisions. Most of them are interchanged among the various car divisions' cars. Before doing any service work on the engine, it must be identified.
The engine installed in a vehicle is identified by the fifth character in the vehicle identification number, which is visible through the lower left corner of the windshield.
Vin Code Letter Engine Size Source
A 231 - V6 (even firing) Buick
B 140 - 4 cylinder Chevrolet
C 231 - V6 Buick
D 250 - L6 Chevrolet
E 98 (1.6L) - 4 cylinder Chevrolet
F 260 - V8 Oldsmobile
G 350 - V8 (2 Bbl) Chevrolet
H 350 - V8 (2 Bbl) Buick
I 85 (1.4L) - 4 cylinder Chevrolet
J 350 - V8 (4 Bbl) Buick
K 403 - V8 Oldsmobile
L 350 - V8 Chevrolet
P 350 - V8 Pontiac
R 350 - V8 Oldsmobile
R 350 - V8 (EFI) (Seville) Cadillac
S 425 - V8 Cadillac
T 425 - V8 (EFI) Cadillac
U 305 - V8 Chevrolet
V 151 - 4 cylinder Pontiac
X 350 - V8 (Corvette only) Chevrolet
Y 301 - V8 Pontiac
Z 400 - V8 Pontiac
The AERA Technical Committee |
| RECOMMENDED BLOCKS FOR TORQUE PLATE HONING USAGE |
Recommended Blocks For
Torque Plate Honing Usage
Most engines will benefit somewhat from torque plate honing and realize an increase in performance, as well as a decrease in oil consumption. However, the following list of engines should be finish honed with a torque plate installed to simulate the stress of the cylinder head and bolts when the engine is assembled.
Manufacturer Disp. (L) (CID) Comments
GM 1.8L 112 L-4 OHV Chevrolet
2.0L 121 L-4 OHV Chevrolet
2.3L 138 Olds Quad 4 engine
2.5L 151 L-4 Pontiac
4.1L 252 V8 Aluminum Cadillac
4.5L 272 V8 Aluminum Cadillac
4.9L 300 V8 Aluminum Cadillac
4.9L 301 V8 Pontiac
5.0L 305 Late model Chevrolet
5.7L 350 Late model Chevrolet
5.7L 350 Oldsmobile
6.6L 400 Small block Chevrolet
6.6L 403 Oldsmobile
Ford 1.6L 98 Escort
1.9L 116 Escort
2.3L 140 OHC engine
5.0L 302 Late model engines
5.8L 351 Windsor engine
5.9L 360* FE Series
6.4L 390* FE Series
7.0L 429* Truck engine
7.5L 460* Truck engine
* While these are not thin wall blocks, durability and oil consumption is improved when a torque plate is used during remanufacturing.
The AERA Technical Committee |
| THERMATIC OIL CONTROL VALVE |
Thermatic Oil Control Valve Caution On
1986-98 DDC 11.1 & 12.7L Series 60 Engines
The AERA Technical Committee offers the following information regarding a caution on the thermatic oil control valve used on 1986-98 DDC 11.1 & 12.7L Series 60 engines. Any thermatic oil control valve-equipped engine that has been overheated must have the control valve tested before placing the engine back in service. Failure to do so may allow subsequent overheating conditions.
Detroit Diesel Corporation has revised its test procedures for the thermatic oil control valve. Thermatic oil coolers became standard equipment on all 11.1L engine in 1996 and on 12.7L premium engines in 1998. Non-premium engines use cast iron pistons. Premium engines use a steel piston. The oil cooler requires a properly functioning thermatic oil control valve to operate the system effectively and prevent engine overheating.
The thermatic oil control valve operating temperature range is 220-237° F (104-114° C) and this valve must be tested whenever engine overheating occurs. To test the valve requires heating engine oil and observing the opening and closing values of the valve using a sensitive thermometer. Previously, a mixture of antifreeze and water was recommended to use and that procedure should no longer be used.
Caution: The flashpoint of oil is approximately 430° F (221° C), to not allow the oil used for testing to exceed 300° F (149° C). Make sure the valve is completely dry as any moisture may cause a violent reaction with the heated oil.
The AERA Technical Committee |
| WATER PUMP IDENTIFICATION |
Water Pump Identification On
1997-99 GM 5.7L VIN G Engines
The AERA Technical Committee offers the following information on water pump and pulley identification on 1997-99 GM 5.7L VIN G engines. The water pumps and pulleys during the above period underwent design changes that took place at various stages during production.
1997-98 water pumps have longer legs (the area used for attaching the water pump to the cylinder block) as shown in Figure 1. It also uses paper gaskets and a bolt on pump pulley assembly. The first design pump in 1999 has shorter legs, carrier type gaskets and a bolt on pump pulley. Second design pumps used in 1999, as shown in Figure 2, have the shorter legs, carrier type gaskets and a press-on type pulley. This pump design can be used on all model year LS1 aluminum engines.
When servicing the water pump, the appropriate model year kit should be used from GMSPO or aftermarket equivalent. The longer legged pump shown in Figure 1, will be phased out of service parts and the second design pump will supercede it. The 1999 first design pump is no longer available and the second design pump with the press-on pulley will be necessary for pump replacement. To determine which application takes what pump and gasket, refer to the chart below that GM has supplied.
Application Water Pump Water Pump Kit* Water Pump Gasket
1997-98 Y, 98 FLong Leg Pump 12369537 125568887, Paper Gasket
Bolt On Pulley
1999 F & Y Short Leg Pump 12456112 12559271, Carrier Gasket
Press On Pulley
* Pump Mounting Gasket is included in the Kit.
When replacing the water pump, it is important that the correct gasket is used. Use of an incorrect type gasket will cause misalignment of the serpentine belt on the water pump pulley and belt damage may occur.
The AERA Technical Committee |
| CONNECTING ROD IDENTIFICATION |
Connecting Rod Identification on
Caterpillar 3406 Engines
The AERA Technical Committee is supplying this chart to assist in identifying Caterpillar 3406 connecting rods used in different engine applications.
Connecting Rod A
Part #: 9Y6054 Forg #: 9Y6048
H/B *: 3.7868-3.7882 Pin Bore: 2.1654
Torque: 82-98 lbs.ft. + 90^
This rod was introduced in 1992 for 3406C truck engines and uses a large piston pin and simplified bolt.
Connecting Rod B
Part #: 7E5996 Forg #: 9Y6048
H/B: 3.7868-3.7882 Pin Bore: 1.9998
Torque: 82-98 lbs.ft. + 90^
This rod was phased-in in 1991 for all applications. It replaced Part # 8N1726 and uses the simplified bolt without the nut. It is fully interchangeable with Part # 9Y6400 and can be used within the same engine but torque differences must be adhered to.
Connecting Rod C
Part #: 9Y6400 Forg #: 7E0034
H/B: 3.7868-3.7882 Pin Bore: 1.9998
Torque: 74-90 lbs.ft. + 120^
This rod is identical to connecting rod B except for the bolt. This rod uses the long through bolt and nut, and different torque.
Connecting Rod D
Part #: 8N1726 Forg #: 8N1727
H/B: 4.0743-4.0753 Pin Bore: 1.9998
Torque: 74-90 lbs.ft. + 120^
This first design rod is used only in narrow crankshaft applications. This rod also uses 9/16 bolts, while all others use 16mm bolts.
* H/B - Big end housing bore
The AERA TechnicalCommittee |
| CYL. HEAD HAIRLINE CRACKS AT INJECTION NOZZLE PORT |
Cylinder Head Cracks At Injection Nozzle Tip Port On
All Large Mack Diesel Engines
Laboratory tests have revealed that many cylinder heads are being replaced unnecessarily in large Mack diesel engines. Generally heat cracks in the deck at the nozzle tip port area between port and valve seats are not critical.
It is good practice to pressure test cylinder heads whenever repairs are being made for internal combustion engine coolant loss or when hairline cracks are evident as other work on the engines is performed.
Heads which pass pressure tests and are satisfactory for reconditioning and reuse can be modified to reduce hot spots in the heat concentration areas. This can be accomplished by blending the radius using fine abrasive stones and finishing with crocus cloth. New replacement heads should also be modified by rounding the edge of the hole to increase resistance to hairline cracks. See illustration.
In summary, do not replace cylinder heads unnecessarily. Pressure test for leaks and if found sound, recondition as required. All reconditioned or new heads should have the injection nozzle tip port and deck junction radius added to increase resistance to heat concentration hairline cracks.
The AERA Technical Committee |
| EXHAUST GUIDE CAUTION |
Exhaust Valve Guide Caution On
1965-98 GM Big Block Engines
The AERA Technical Committee offers the following caution for exhaust valve guides on 1965-98 GM big block Chevrolet engines. Through the many years of
use of these engines, GM has modified cylinder head castings numerous times. One of those modifications involves the method of repair considered for
exhaust valve guide service.
These engines' valve guides were not intended as a replacement item from GM. The guides were located into the head castings after the head was cast and
the exhaust guide is water cooled. The water-cooled guide also has two different size press fit diameters. Adding additional confusion to the matter,
they also switched the location of the larger diameter sometime in 1985.
Several types of concerns exist for terming exhaust guides unusable, including excessive wear or coolant leakage. Either a new OEM casting or an oversize stem diameter from GM serviced excessive valve guide wear or coolant leakage. To meet customer satisfaction however, aftermarket manufacturers have offered replacement valve guides for these engines. If the guide is leaking coolant around the outside or inside diameter, the entire guide may be replaced.
To determine which outside diameter guide you have and which direction to remove an exhaust valve guide, the following procedure is suggested:
Drive the guide no more than .250 (6.35 mm) toward the valve spring side of
the head and stop. Then, measure the newly exposed area of the guide
OD next to the spring pad.
If the measurement is .620 (15.748 mm), it is the first style guide. To remove this style guide, continue driving it toward the valve spring side of the head.
If the measurement is .616 (15.464 mm), it is the second style guide. To remove this style guide, you must drive it the opposite direction toward the combustion chamber side of the head.
Guide Diameter Direction
@ Spring Pad to Remove
After Moving .250 Valve Guide
.620 (15.748 mm) Valve Spring Side of the Head
.616 (15.464 mm) Combustion Chamber Side Head
Some AERA members report many years of successful valve guide repair by using conventional universal replacement guides, both thin wall liners and ?
outside diameters. That type of repair is made only when the water-cooled exhaust guides are not leaking.
The AERA Technical Committee |
