3.0L and 3.4L rebuilding notes
As with most bi-metal motors, head gasket sealing can be a problem. The Toyota VZ is no exception to this rule. In fact, many shops would say that this engine is one of the more difficult ones to keep head gaskets properly sealed.
While the actual causes for sealing the head to block can be debated, there are several things that can be done to ensure long life for replacement head gaskets. Make sure that the deck on all blocks are surfaced. The firing ring between cylinders five and six tends to blow out and eventually eat away at the block.
If the block can not be decked and still remain within specifications, you should scrap the block. Use the best head gasket available. Replace all the head bolts, however, we are unaware of any aftermarket supplier currently making them available.
The head gasket failure rate seems to be an even tougher problem on the 3.4L. While a perforated core graphite head gasket is a good head gasket, it doesn’t seem tough enough to handle the 3.4L. We are aware of at least one aftermarket supplier that has a multi-layer steel (MLS) head gasket available for the 3.4L engine. However, we are unaware of an MLS gasket for the 3.0L.
Those we’ve interviewed who have used the MLS gasket say it effectively seals the 3.4L engine. We have also been told by several Toyota dealers that they have successfully used the MLS replacement head gasket to solve sealing problems on the 3.4L engine. Be careful when removing and installing camshafts, as the thrust flange on the camshafts are easily damaged. Gradually loosen the cam cap bolts one to two turns at a time, letting the valve spring pressure remain uniform across the camshaft. If one end is loosened all at once, valve spring pressure will allow the camshaft to rise unevenly, breaking the thrust flange.
Inspect for cracks and do not reinstall the cam if there are any doubts about the flange. Watch for stripped out threads on the cam caps and the seal retainers. Many times air impacts have been used and the threads have been damaged.
If cylinder head removal is done without motor removal, many times it will be difficult to remove the crossover pipe nuts. The two cylinder heads can be removed as one unit with the crossover attached; then remove the crossover pipe. To reinstall, install the right cylinder head and crossover together, then the left cylinder head.
Toyota and some other manufacturers utilize a ball bearing to cap off oil galleys instead of a pipe plug. These should always be removed to ensure that the oil galleys are cleaned of any contaminants.
To remove the ball, heat it cherry red with a TIG welder, then cool it with water; the ball will then fall out. Drive the other end out with a rod from the opposite end. To replace, use sealer and install new balls which are available from several different suppliers that sell standard balls for ball bearings. So far, the balls used have been standard sizes.
right now!
