| The following technical bulletins were published by AERA. |
| | LOOSE OIL PUMP PICKUP SCREENS | Loose Oil Pump Pickup Screen On
GM 2.8L (173 CID) Engines
Reuse of the oil pump pickup screen on GM 2.8L (173 CID) engines may result in low engine oil pressure and related problems.
The OE oil pump for this engine is manufactured out of aluminum whereas most aftermarket oil pumps are manufactured out of traditional cast iron. Removing the oil pump pickup screen, cleaning it and then reinstalling it in an aftermarket oil pump may result in a loose fit.
Apparently, the diameter of the opening that accepts the pickup screen in the aluminum pump is smaller than in the cast iron counterpart. This tight fit shrinks the diameter of the pickup screen, but is necessary because of the differing expansion rates between the aluminum oil pump housing and the steel pickup
screen. Reusing the same screen in a cast iron pump that does not require this much interference fit, and therefore features a slightly larger bore, may result in an undesirable loose fit of the screen. This could draw air into the lubricating oil system causing low oil pressure, valve train noise and lead to serious
engine damage.
The AERA Technical Committee recommends the replacement of all oil pump pickup screens as part of the remanufacturing process on light duty engines.
For additional information see AERA Bulletins: TB 680, TB 439 & SB 140
The AERA Technical Committee | | CYLINDER HEAD CRACKS | Cylinder Head Cracks On
1983-86 GM 2.0L (121 CID) Engines
AERA member machine shops have reported cracking of the cylinder
heads of 1983-86 GM 2.0L (121 CID) engines. Complaints of coolant in the engine oil may be a futher indication.
This engine joined the GM lineup in 1983 and featured a cast iron cylinder head assembly through the 1986 model year. The engine has been used in the J cars as well as S-10 pickup trucks. As of the 1987 model year the cylinder head is now manufactured out of aluminum.
Cracks have been noticed in the cast iron cylinder head near the valve spring seats at the top of the casting. Usually cracks develop across the #6 intake valve spring seat and continue across and behind the #4 and #5 exhaust valve spring seat. Magnetic particle inspection should be used to determine the
extent of the crack and what repairs, if any, may be performed.
A neglected cooling system may deteriorate the casting where a small amount of stress will induce cracks. Cracks may also be caused by engine freeze up, overheating, or disassembly of the engine without adequate cool down.
The AERA Technical Committee | | OIL LEAKS ON 1984-86 GM 2.8L ENGINES USED IN AMC | Oil Leaks On
1984-86 Chrysler (AMC) 2.8L (173 CID) Engines Used In Jeep
Applications
Chrysler (AMC) says there are three possible oil leak locations
on its 2.8L (173 CID) engines: the valve covers, intake manifold
and rear cradle area of the oil pan.
Replace leaking valve cover gaskets with AMC part #8983 503 179
or aftermarket equivalent. The seam where the intake manifold
and cylinder head mate must have a small amount of RTV sealer
applied to eliminate gaps or steps that will allow leaks. Gasket
over-crush is prevented by metal pins located on the side of each
bolt hole.
Intake manifolds usually leak at the rear manifold-to-block
mating surface. After removing the manifold and thoroughly
cleaning it, use a 3/16 (4.7mm) diameter spherical cutter
(Figure 1) to cut a 3/16 (4.7mm) wide groove that's 1/16
(3.1mm) to 1/8 (1.5mm) deep.
(Insert Illustration)
Fill the groove with RTV sealer when reinstalling the manifold
(Figure 2).
(Insert Illustration)
For 1984 engines, Chrysler (AMC) supplies an oil pan gasket kit
AMC part #8983 500 853 (or use an aftermarket equivalent), which
should be installed in place of the RTV sealer used at the
factory. It is important, however, to seal the rear cradle
corners with RTV sealant.
1985-86 engines should be closely inspected for deformed oil pans
(Figure 3). Replace deformed oil pans with AMC part #8953 001
840. Engines built after January 21, 1986 should not have
deformed oil pans.
(Insert Illustration)
The new, recommended method is to remove the stand-offs on the
oil pan rails (Figure 4) with a file or small hand-grinder. Use
AMC oil pan gasket kit #8983 500 853 or aftermarket equivalent.
(Insert Illustration)
The rear cradle seal is installed in the groove in the main cap
and a small amount of RTV is applied to the corners of the seal
where it contacts the block. Please note that once the stands
have been removed, RTV can no longer be used in place of the
gasket.
The AERA Technical Committee
August 1986 - SB 134
##END## | | VALVE SEAT INSTALLATION CAUTION | Valve Seat Installation Caution On
Chrysler 4.0L Engines
AERA members have reported coolant loss on Chrysler 4.0L engines used in the Jeep vehicles. This loss occurs shortly after cylinder head remanufacture and can vary in amounts.
If exhaust valve seats are installed during cylinder head rebuild process, the counterbore tool may break into the coolant passages of the head. A valve seat counterbore as small as 1.500 outside diameter by .218 deep may create a through passage. Although each individual head casting may vary in casting thickness in this area, caution should be used in seat selection. Pressure
checking the head after seat installation is advised.
If a seat is installed into the number one cylinder, you may be able to see the newly created passage by looking through the thermostat housing opening at the very front of the head (see illustration).
The AERA Technical Committee | | HYDRO-CARBONS IN THE COOLING SYSTEM | Hydro-Carbons In The Cooling System
The AERA Technical Committee offers the following information on a quick check to verify if hydro-carbons are present in the cooling system. Hydro-carbons are a by-product of the internal combustion process of the engines that we work with.
Internal combustion by-products or hydro-carbon leakage into the cooling system can easily be checked by using an exhaust gas analyzer. Remove the filler cap of the radiator and put the analyzer pickup just over the top of the opening, being careful not to allow any coolant to enter the analyzer.
If the vehicle is equipped with an automatic transmission you can brake torque it for 3-4 seconds. This will raise the cylinder operating pressure, which flexes the cylinder head up, relaxing the head gasket. By doing this you might find a combustion leak that won't show up at idle speed light load condition.
Note: Multi layer steel (MLS) head gaskets require a very smooth finish, 30 RA maximum to seal properly. A cylinder head(s) that are not torqued properly or not replacing cylinder head bolts when required could contribute to this problem.
This test will show a leak in the combustion area including head, block and anything else that will let the combustion gases enter the cooling system.
The AERA Technical Committee | | BACKFIRE, KICK BACK, HARD OR NO START DURING CRANKING | Backfire, Kickback, Hard Or No Start During Crank/Start
For 1995-2000 GM 4.3, 5.0, 5.7 & 7.4L Engines
The AERA Technical Committee offers the following information on backfire, kickback, hard or no start during crank/start for 1995-2000 GM 4.3, 5.0, 5.7 & 7.4L engines. These engines are used in pickup trucks and sports utility vehicles.
Customers with this condition may have any of the combinations listed below. If the condition exists and you have a stored DTC code P0338 and it does not illuminate the service engine soon light, you must replace the crankshaft position sensor with Part #10456607.
* Backfire during crank/start.
* Kickback during crank/start.
* No start.
* Slow or hard crank/start.
* Grinding or unusual noises during Crank/start.
* Cracked or broken engine block at the starter boss.
* Broken starter drive housing.
* Broken starter ring gear on flywheel.
A condition may exist that allows the crankshaft position sensor to command 50 degrees of extra initial spark advance during crank/start position. This exposes the engine to higher than normal cylinder pressures, which may result in an inoperative condition.
The AERA Technical Committee | | DISENGAGED PUSHRODS ON AMC 4.2L ENGINES | Pushrod Problems On
1981-82 Chrysler (AMC & Jeep) 4.2L (258 CID) 6 Cyl. Engines
Pushrods in some 1981-82 Chrysler (AMC & Jeep) 4.2L (258 CID) 6 cyl. engines built prior to May, 1982, may disengage from the rocker arms causing noise, backfire or a miss.
To correct this problem, install a complete set of .070 longer replacement pushrods if any of the original parts become disengaged or bent.
The original pushrods are 9.640 to 9.660 long. (Part No.3227329)
Replacement pushrods are 9.710 to 9.730 long. (Part No.3242395)
NOTE: The original shorter pushrods (Part No. 3227329) are stillrecommended for use in 1980 and prior Chrysler (AMC & Jeep) 4.2L (258 CID) engines.
The AERA Technical Committee | | OIL PUMP DIFFERENCES | Oil Pump Differences On
1990-93 GM 3.1L Engines
The oil pump pickup screen and oil pump have been revised on 1990 and later GM 3.1L engines. The difference is in the diameter of the oil pump pickup screen tube and its mating bore. The original pump featured a 15.9mm tube while the current production pump uses a 19.0mm tube.
According to AERA sources, there are three different screens used with the current design oil pump. One screen fits Firebirds and Camaros (F-Body), another is for small trucks, and the balance use a screen with the part #10118622.
It is possible to use the current design oil pump and screen as a direct replacement for engines that were originally equipped with the smaller diameter assembly.
Original Current
Item 15.9mm Design 19.0mm Design
Description Part Number Part Number
Oil Pump 10146802 10116840
Pickup Screen 14092908 10118622
The AERA Technical Committee |
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