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Cranks for some 1996-2000 Hyundais were changed
Q I’ve heard that the cranks for some 1996-2000 Hyundais were changed. Any details?
A The AERA Technical Committee offers the following information on 1996-2000 Hyundai 1.8L and 2.0L engines. The flexplate/flywheel and crankshaft used in the Elantra and Tiburon car models have been revised.
The new crankshafts (p/n 23110-23710 for the 2.0L and p/n 23110-23510 for the 1.8L) were released July 8, 1999 and have the following dimensional changes.
1) The flywheel mounting flange (pilot) diameter has been reduced from 1.614˝ (41 mm) to 1.3780˝ (35 mm).
2) The flywheel mounting flange (pilot) height has been increased from .1575˝ (4 mm) to .2560˝ (6.5 mm).
3) The crankshaft rear flange thickness has been reduced from .8071˝ (20.5 mm) to .7087˝ (18 mm).
4) The crankshaft rear flange bolt hole depth has been reduced from .5315˝-.6496˝ (13.5 mm -16.5 mm) to .4528˝-.5512˝ (11.5 mm-14 mm).
NOTE: The new crankshafts are not interchangeable with the earlier ones. However, a crankshaft spacer (p/n 23112-23900) can be used with the new crankshafts to make them interchangeable with the older crankshafts.
The flywheel and flex plate assemblies have also been changed. The new flywheel and flex plate assemblies are not backward compatible with the older crankshaft. However, the older flywheel and flex plate can be used after installing a crankshaft spacer (p/n 23112-23900) on the new style crankshaft.
• The flywheel and flex plate assembly pilot bore diameter has been reduced from 1.6142˝ (41 mm) to 1.3780˝ (35 mm).
• The flywheel pilot bore depth has been increased from .1969˝ (5.0 mm) to .2953˝ (7.5 mm).
Each crankshaft and flywheel/flexplate combination requires specific mounting bolts. Tables 1 and 2 identify the different combinations for manual and automatic transaxles.
Q What’s the best way to pressure test Caterpillar C12 cylinder heads?
A The AERA Technical Committee offers the following information regarding pressure testing the cylinder head on 1996-2002 Caterpillar 12.0L C12 diesel engines. This engine uses a single in-line 6-cylinder head casting.
In order to properly pressure test these heads it is important to recognize that the coolant passages for each cylinder are not connected. When testing for leaks, each cylinder must be tested individually.
Some AERA shops have fabricated a thick plate that covers two cylinders at a time to allow them to check an individual cylinder with minimal set up time. This is also beneficial if only one injector sleeve has been replaced and testing it for leakage is being done.
The coolant flow of this engine has a detailed routing and is illustrated in Figure 3. It goes from the water pump through the oil cooler (5) into the supply manifold (7). The supply manifold, located in the spacer plate block, distributes coolant at each cylinder that flows around and cools the upper portion of the cylinder liner. At each cylinder coolant flow from the liner enters the cylinder head that is divided into single cylinder cooling sections. In the cylinder head, coolant flows up around the injector sleeve over the exhaust port and exits into the return manifold (6). The return manifold collects the coolant from each cylinder and directs the flow to the temperature regulator. Which, when in the closed position allows coolant flow through the regulator bypassing the radiator and then back to the water pump (4) for recirculation. When the regulator is open, coolant flow is directed through the radiator before it goes to the water pump.
Cooling is provided for only the portion of the cylinder liner above the seal in the spacer block. Coolant enters the spacer block at each cylinder through slits in the supply manifold (7). The supply manifold is an integral casting in the spacer block. The coolant flows around the circumference of the cylinder liner and into the cylinder head through a single drilled passage for each liner. The coolant flow is split at each liner so that 65 percent flows around the liner and the remainder bypasses the liner and flows directly to the cylinder head.