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Rebuilding The Toyota 3.0L V6
The Toyota VZ-series, 3.0L V6 engine was used in pickups, 4Runners and T100s. Toyota has built numerous six cylinder motors over the years, but all of them have been inline straight sixes.
By Dan Minick
In 1988 Toyota introduced its first V6. Most of the information that follows applies to the 3.0L version used in Toyota’s truck applications. The 3.4L is still fairly new to the aftermarket at this point.
3VZ-E 3.0L SOHC V6 ’88-’95
The 3VZ-E was also introduced for the 1988 model year on Toyota 4x4 pickups and the 4-Runner. Using the same basic design as the 2.5L (2VZ-FE) used in the Camry for that year, it featured a cast iron block and aluminum heads. It was also used on the full-size T100 pickup truck.
This version of Toyota’s V6 put out 145 hp at 4800 rpm and 180 ft. lbs. of torque at 3400 rpm. For the truck applications, two-valve heads with a single camshaft per head were employed. The cams still operated the valves via a bucket lifter and adjusting disc, but were of a larger diameter than other Toyota motors. These buckets and discs are unique to the 3VZ-E.
The crankshaft rod journal size was increased from 1.889" (on the 2VZFE) to 2.165" for the tougher applications that this motor was being used in. This motor was used through the 1994 model year on the T100, and in 1995 for the "small" pickup and 4-Runner.
This is a pretty good span of years for an application to cover, however, there is a difference in the number of bolt holes for the motor mount. Earlier ones had six, while later ones had four.
|In 1989 extra bosses were added to the upper part of the 3VZ-E 3.0L block. See four block photos above. The '89 and later blocks can be used on '88 applications.
The block is cast iron using a one-piece main cradle. (see photo below). In 1989, extra bosses were added to the upper part of the block. (see four photos above). The ’89 and later blocks can be used on ’88 applications.
In some early blocks from the ’88 model year, in the oil galley that is located in the valley below the freeze plugs, there have been several cases where cracks have been found. The galley can be repaired by sleeving the galley and drilling the oil holes, but the amount of time taken to do that probably is not cost effective.
The 3.0L uses a cast iron crankshaft that stayed the same for all years. There are steel 3.0L cranks that you may run across, but these are out of the twin-cam 3.0L car. Journal sizes are the same as the truck SOHC motor; the difference is the snout length of 2.75" for the truck and 2.50" for the car.
The cylinder heads are unique from left to right due to a spot for the distributor, although you can convert the heads by changing the caps and line boring the cylinder head. The early cylinder heads (’88 through ’90) had a smaller pilot hole for the distributor than the later ones which were 10mm.
To make a universal application, some shops have successfully machined the pilot holes to 10mm to fit later applications. This can be done without any problems if used on an earlier application with the smaller piloted distributor. The left and right camshafts did not change throughout the life span of the motor.
The belt tensioner used from ’88-’92 was a spring loaded tensioner (Toyota p/n 13505-65020). In 1993 the tensioner went to a hydraulic style (Toyota p/n 13505-65040) (see photo on page 38). To accommodate this change, the front of the right-hand cylinder head has a machined recess and a drilled and tapped hole. Earlier heads may be machined to be adapted if necessary.
The timing belt was also changed to accommodate the difference in the tensioner at the same time. If you are supplying water pumps, be aware of a couple of things to watch out for (see photo on page 39). Different applications had a bypass nipple while some did not.
The best bet is to have the customer identify which pump they have. From ’88-’92 the water pump must have a locator pin at one end for the spring on the timing tensioner. The 1993 and later water pumps did not have the pin. The pin can be knocked out on new and remanufactured water pumps that have the pin if it is not needed for the later applications.
5VZ-FE 3.4L DOHC V6
For 1995 on the T100, more power came from an increase in the bore size of the VZ V6. It was increased to 93.5mm, and had four valves per cylinder and twin cams per cylinder head. Now displacing 3.4 liters this motor put out 190 hp at 4800, and 220 ft. lbs. of torque at 3600 rpm.
This motor also became available on the ’95 Tacoma and the ’96 4-Runner. Even though it shared the same basic design as the other VZ V6s, it didn’t have many parts in common. Parts it did share with other VZs consisted of main bearings, thrust washers and freeze plugs.
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.
Customer complaints of oil consumption, even after a rebuild, can be from varnish and sludge build-up in the pcv area of the valve cover. A redesigned valve cover is available from Toyota to solve this particular problem.
While the 3.4L 5VZ-FE is still the V6 for Toyota’s light-duty truck applications, the Camry, ES300, Avalon and the new Sienna minivan are using a new V6 the MZ series. This motor features an aluminum block and was introduced in 1994.
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