The focus of this article will be the timing belt replacement on a 2001 Lexus GS 300 with the in-line six-cylinder 2JZ-GE engine with VVT-i (Toyota’s variable valve timing). Nothing can spoil the resale value of a high-dollar car more than an engine failure. Due to the complexities of the valve timing and internal engine clearances, these engines will most likely bend valves if the belt fails, or if the belt is installed incorrectly.

1. Timing Belt Replacement
2. 2jz Timing Belt Replacement

For these reasons, I would recommend that you read through this article and the service manual description for this job very carefully before starting this repair. There are also differences between models on this platform that can impact the way certain components are removed. WHEN TO REPLACE Recommended replacement intervals for timing belts are all over the map these days. Depending on which tech manual or tech assistance site you access, you can get widely varying mileage and time suggestions.

My advice is to look closely at the accessory belts, note any cracking or evidence of replacement, and then factor in the use of the car and its maintenance history. Cars that are driven primarily in hot, dry climates will probably benefit from earlier replacement than those living in more moderate conditions. Due to the possibility of engine damage if the belt breaks or jumps time, I would not recommend waiting beyond six years or 90,000 miles, which is the OE-recommended interval for this engine.

A quick scan through service bulletins, tech assistance requests and first-hand experience with this repair leads me to advise that extra care be taken on this repair. Ensure that every step is done correctly, and the proper tools and procedures are used to prevent comebacks, driveability complaints or difficulties in completing this service. FIRST STEPS Because of the interference possibilities, I suggest removing the ignition key and hiding it so the engine does not get cranked by mistake while the belt is off. The job is easier if it is on a hoist and the lower engine covers are removed. Drain the coolant and remove the fan shrouds. The various models and yearly changes to this series of cars make an initial inspection worthwhile after checking a repair information source.

To prevent the possibility of damage, I would recommend removing the radiator and fan just to provide more working space ( see Photo 1). Without removal of the radiator and shroud, space to remove the crankshaft pulley bolt is pretty much non-existent. (On SC 300 models, the battery and battery box will also need to be removed.) The serpentine belt tensioner may turn either direction depending on model, and the pulley mounting bolt will have threads of one direction or the other, depending on the adjusting rotation of the tensioner.

Remove or loosen the brackets for the external accessories (alternator, power steering pump and A/C compressor) as needed to allow removal of the lower front engine cover. Depending on the year, model and body type, some accessories and their brackets are removed or can be left in place to save repair time. The two upper timing belt covers can now be removed to allow the setting up of the engine for disassembly.

Toyota designates these covers as cover 3 (the large piece with VVT-i on it) which looks like the front of a large valve cover, and cover 2, the center part of the front engine cover. If you haven’t already done so, remove the serpentine belt tensioner. Using a suitable tool to hold the crankshaft damper, loosen but don’t remove, the bolt and pulley at this time. ENGINE SETUP In order to get the engine in the correct position for removing the timing belt, the tension on the variable timing must be removed to allow the engine to be at actual TDC.

Turn the crankshaft clockwise to align the main timing mark ( see Photo 2) on the damper with the “O” mark on the number 1 timing cover (lower part of front cover). There are two marks on the crankshaft pulley and two marks on each of the camshaft sprockets. The main crankshaft timing mark is 60 degrees counterclockwise from the sub-timing mark. The main camshaft timing marks are 30 degrees counterclockwise from the sub-timing marks. Note the location of the camshaft timing marks at this point. On this engine, I recommend that the marks be painted (preferably with different paint colors) to more easily reference the proper marks and locations ( see Photo 3), with the hard-to-see marks on the number 4 timing cover (inner timing belt cover, see Photos 4a and 4b). Obviously, if the camshaft marks are not anywhere close, turn the engine another revolution clockwise and start the alignment process again.

Once the main timing marks are located and aligned, turn the crankshaft counterclockwise to align the sub-timing marks ( see Photo 5) with the same reference points used for the main timing marks. At this point, if you were planning on reusing the timing belt for some unusual reason, put an arrow on it to indicate the direction of travel. You could also paint reference marks on the belt to speed reinstallation. While again holding the crankshaft pulley, remove the retaining bolt. A pulley puller may be necessary to remove the pulley without moving the crankshaft. Then remove the lower number 1 timing cover ( see Photo 6). Loosen the tensioner (damper) bolts evenly and take the tension off the belt.

Remove the outer belt guide (concave side goes out), and the little finger retainer that restricts movement of the belt away from the crank sprocket at the lower right side (5 o’clock position). Then remove the belt after marking the belt and sprocket, if you’re reusing the belt. INSPECTION As with all timing belt replacement procedures, inspect for damage to or from the belt, oil leaks or mechanical problems (loose parts) that would shorten the life of the replacement belt. Also, inspect the old belt for cracks, uneven wear, oil or coolant saturation, or impact wear from the guides or foreign objects that might have made their way into the covers. Inspect the tensioner damper for oil leakage that would reduce the tension that it applies. A small amount of oil may be present at the seal, but nothing more than a little seepage is acceptable.

If you can depress the push rod into the housing by hand, replace the tensioner. If the rod does not stick out of the body at least 8.0 to 8.8 mm, replace it. Make sure the tensioner pulley spins freely and that the retaining bolt is tight. Specifications call for Loctite on the retaining bolt and torquing to the proper specification. The pulley bracket should move freely; if not, make sure the spacer washer is in place between the bracket and the engine block on the retaining bolt.

Timing Belt Replacement

If the camshaft pulleys need to be removed for seal replacement, be aware that to remove the intake variable timing pulley, only the center bolt should be removed. Do not loosen the five bolts that hold the timing mechanism together.

If there is any sign of oil leakage at the variable timing sprocket (not the camshaft seal), then the variable timing pulley may need to be replaced. Variable valve timing codes may indicate leakage or other component failure. Service bulletins and tech assistance reports indicate that the crankshaft sprocket can be easily damaged, and cause timing and driveability problems and codes.

There are reports of even small scratches on the reluctor wheel causing problems as well as missing teeth. The standard procedure for hydraulic damper retraction is used to depress and pin the damper push rod in a vise or press. Make sure even and straight pressure are applied, and install a 1.5 mm hex wrench or pin to hold the pushrod in the retracted position. The engine should be cold by this time; if not, take a break until it is so the proper tension can be put on the new belt. BELT INSTALLATION The crankshaft shouldn’t have moved from its proper position, but double-check and adjust the timing mark alignment on the crank sprocket and the oil pump housing, if necessary ( see Photo 7). Make sure the front of the engine is clean and dry, and slide the new belt onto the crankshaft sprocket and over the idler/tensioner pulley.

If you are reusing an old belt, make sure that you have reinstalled it in the same position and direction. Install the little restrictor to hold the belt onto the crank sprocket.

Install the lower belt guide onto the crankshaft and install the number 1 timing cover. Install the crankshaft pulley and make sure that the crankshaft sub-timing mark is still aligned with the “O” on the cover. Install the pulley retaining bolt hand tight (do not move the crankshaft). Recheck the timing marks on the camshafts and adjust if necessary, remembering that the camshaft sub-timing marks should be the ones that are lined up with the marks on the number 4 cover (inner timing cover). Slide the timing belt onto the camshaft sprockets with slack on the tensioner side and no slack between the camshaft sprockets. Install the tensioner damper by alternately tightening the bolts after making sure the dust boot is in position.

Remove the hex wrench or pin from the tensioner body and allow a few minutes for the tensioner to stabilize pressure on the belt. After checking that all the proper timing marks are aligned, turn the engine over by hand, clockwise only, at least two full turns and recheck timing mark alignment. There should not be any restrictions, except the compression of the engine. If it wasn’t such a chore, having the spark plugs out makes this step easier and more conclusive that there is no valve-to-piston contact. If the timing marks are off, redo the procedure rather than take the chance that a mistake was made. Having the marks color-coded makes verifying proper timing easier.

Tighten the crankshaft pulley bolt to the proper torque and reinstall all removed accessories, covers, radiator and fans. Use a vacuum-type cooling system filler to prevent air locks and overheating (not good for a new belt).

FINISHING UP Even if you haven’t seen or serviced one of these cars yet, they are going to be around for a long time, like most Toyota products. Being prepared for routine maintenance and the peculiarities of the engine and drivetrain will put you ahead of the game when service opportunities come along. These Lexus models are superbly comfortable, extremely well made and performance is on par with the competition.

In '86 the Supra dropped its first name, and with the introduction of the fourth-generation model in late-'92, now shared about as many ties with the company's entry-level sport compact as it did with the brand's corny little Paseo. All of that was mostly because of the MKIV Supra's factory turbocharged 2JZ-GTE powerplant—an inline-six-cylinder engine so ready to make sobering sorts of horsepower that, even 23 years later, pro motorsports teams of all sorts still seek out the early '90s 3.0L just as they did decades prior. And for good reason. Few production engines before or since are capable of the sort of outlandish horsepower the 2JZ-GTE's good for with so few modifications. Here in the US, the 2JZ-GTE, which was a clean-sheet design, wholly independent of the preceding Supra's 7M-GTE, was available only in '93-'98 Supra Turbo models. In Japan the 2JZ-GTE was introduced in '91 underneath the Toyota Aristo's hood and survived within select Japanese Supras until it was curtains for the car altogether in '02.

The 2JZ-GTE's naturally aspirated and easier-to-find older sibling, the 2JZ-GE, is based upon the same short-block and nearly identical but higher-compression rotating assembly, but as far as Toyota's concerned, is only good for about 230 hp. You don't care about these. Stay away from them by not looking underneath the hoods of non-turbo, fourth-generation Supras as well as Lexus' IS300, GS300, and SC300.

Overseas derivatives of the 2JZ-GTE include the 1JZ-GTE—a destroked, 2.5L version of the familiar cast-iron longblock of which later versions featured variable intake cam phasing and a single turbo. Even the 2JZ-GTE was updated for the Japanese market in '97, when the engine received the same VVT-i treatment as the 1JZ-GTE with updated turbos.

But you don't live in Japan and, chances are, the engine you care about is the North American-bound 3.0L that makes more power and made you want the Japanese-made supercar since before you were old enough to reach the pedals on a Huffy. But you should; JDM engines are easier to source, less expensive, and just as capable despite some of their shortcomings, like smaller fuel injectors and cams. Toyota took cues from Nissan's circuit-owning RB series of engines when developing its 3.0L 2JZ platform. Like the RB26DETT, the 2JZ's inline configuration lends itself to a design that's naturally balanced. Unlike V-type engines, half of the block's rotating assembly doesn't get tossed around in opposite directions from one another.

Watch the 2JZ's mess of pistons and rods spin about and you'll notice its front three cylinders do the opposite of its rear. The even distribution of weight means the typical polar rocking motion you'll find in a V-6, for example, isn't there.

All you care about, though, is that the design means you can rev it higher longer, safer, and smoother than just about anything else. Being able to double power levels may not seem like something a simple engine's capable of, but that's sort of what make all of this possible. Looking for an engine capable of 700 or more horsepower without cracking open the bottom end? Build it out of heavier-duty cast-iron instead of aluminum, give it a solid deck to ward off cylinder movement, stuff in a forged crank, and tame the compression ratio with dish-shaped pistons just like Toyota did. A series of seven main caps keep the crank from shifting and under-piston oil squirters cool the rotating assembly and keep it lubricated at high RPMs. Toyota's people also carefully considered the engine's geometry, integrating the elusive square-shaped design where bore diameter and stroke length are one and the same. More than doubling the 2JZ-GTE's power output isn't hard, according the guys at FSR, but ditching the sequential turbo system for a larger, single compressor has got to happen first.

First, look for a turbo in the 64-80mm range accompanied by a higher-flowing external wastegate and ditch the side-mount intercooler for a front-mount unit with more surface area. Both GReddy and HKS offer upgrade kits that include everything you need to do just that. You'll also need a higher-flowing fuel pump, larger-diameter delivery lines, 1,000cc fuel injectors, and some sort of tunable ECU, like AEM's Infinity, for example. Aftermarket cams like those from Brian Crower will make getting to that 750hp mark a whole lot easier and are about the only thing you'll need to touch underneath the valve cover this side of stiffer valve springs to avoid potential valve float. The 2JZ-GTE's already proven itself worthy of belting out more than 2,000hp.

2jz Timing Belt Replacement

You'll need more than a 64mm turbo to get anywhere close, though, but it's less complicated than you think. Start with something in the 72mm range, and plan on bulking up the bottom end with forged pistons and rods as well as billet main caps. Larger-diameter head studs will keep the head from lifting off of the block. Even bigger cams and head porting have also got to be addressed here, and if you don't want to run out of fuel, look to 2,000cc injectors—12 of them if you're power goals are silly enough—along with a trio of fuel pumps, depending on how ridiculous and far away from that Celica lineage you want to get. The 2JZ-GTE translates into a seemingly conservative 320hp and 315 lb-ft of torque for North American-bound models, and there's a reason things seem so timid. Since '89, Japanese automakers have avoided expensive horsepower wars by capping production-car output in its homeland to 276hp. At least on paper.

This Gentlemen's Agreement has since been broken, but the once settled-upon but often-not followed terms meant engine's like Toyota's 2JZ-GTE left the production line with a whole lot of unsqueezed juice left in them. At the time, the agreement made a lot of sense for a country with a maximum speed limit of 62mph, but has since proven unrealistic for American car-buyers who who expect mom's minivan to make more power than a mid-'90s supercar. All this means to you is that turning 400hp out of the 2JZ-GTE with a few bolt-ons any numbskull could handle is easier than you think. Toyota's 2JZ-GTE gets all 320hp from a sequentially paired team of Hitachi turbos codeveloped by Toyota that aren't a whole lot different than the T3 turbo you once stuck on your Civic. Unlike parallel twin-turbo setups where two equally sized turbos huff the same amount of air at the same time, sequential layouts allow one turbo to do its job first and the other to join in at higher engine speeds. Often times a smaller turbo precedes a larger one, but with the 2JZ-GTE, equal-sized turbos sit at both ends.

The Supra was one of the first cars to prove that sequential turbocharging didn't have to be clunky and unreliable. Here, by 1,800 rpm the first turbo's already online. Stab the throttle, let the ECU, wastegate, and a couple of bypass valves do their jobs, and by 4,000 rpm, two turbos are spinning full-song.