Repair-It

Finally uploading pics of this.

There is no replacement interval for the timing belt on a 1UZ-FE unless it is used as a taxi or other situation where it idles a lot. In that case it is 60K. This car has 125K on it, so double the taxi interval mileage. There was quite a bit of other maintenance this car needed, including a major tune up, so we figured it would be a good time do just do everything all at once since most of the labor overlapped. Also it would make us feel better in case we were hammering on the car later.

In case you were wondering: 1 = first generation, UZ = engine family, F = DOHC, narrow valve angle head, E = electronic fuel injection.

Rock Auto sells a nice kit which includes a belt, a water pump, an idler pulley, a tensioner pulley, and a hydraulic tensioner. They actually have a few different brands, we went for the Gates. In thing engine, like other Japanese engines, the water pump is driven by the timing belt so they are generally replaced at the same time.

Lets start!

This engine is dirty.... Start at the top on the driver's side and remove the ignition wire covers. Also doing valve cover gaskets, so remove the PCV hose and the wire harness cover. You can see the missing valve cover bolt in this shot. Moving the cover also exposes the LH distributor and cam pulley. Yes, this engine has two distributors. For double the awesomeness. To remove the passenger side cover, remove the intake tube. This was a terrible job. In hind sight, if you remove the three bolts that hold in the air box you can lift it up and get the flexible rubber joint off much easier. You can then remove the radiator assembly. This includes the hydraulic (!) cooling fan and overflow bottle. The whole thing comes out as one piece, just disconnect all the hoses from the engine side, two brackets and lift. Make sure you drain the coolant first. I didn't get any shots of the removal, but it wasn't very exciting. You can free up some additional reaching room by removing the battery. After this you can remove the serpentine belt. The belt can be removed earlier, but its even easier with the radiator hoses out of the way. Also remove the serpentine idler pulley. Shot of some pulleys with no belt or hoses. Remove the alternator and loosen the A/C compressor (RH lower and LH lower respectively). Then remove both ignition coils. Next remove the two upper timing cover pieces. There is one on either side. They are held on with a few 10mm bolts. The LH one is a little bit of a pain as the distributor harness feeds through it and is hard to pull back through if the plug bracket is rusted to the plug. If you can get this small bracket off, this is not an issue. LH is driver's side and RH is passenger's side. You can see the water pump pulley now. The timing belt tensioner bolts straight up into the timing belt tensioner pulley on the RH side of the crank pulley. You can reuse these if you apply several hundred pounds of force to the piston to retract it and lock it in with an hex key. We had a new one so that wasn't an issue. Now is the fun part. To take the crank pulley bolt off, you need to hold the pulley stationary. This is normally done with a fancy Lexus/Toyota tool which utilizes two bolt holes in the crank pulley to attach a collar which you bolt a large handle too. I didn't have this, so a fashioned one out of wood and was going to use the weight of the car to pry against (this nut torques on at > 180 lb-ft). This didn't work. I split the wood before I got the nut to break free. You can buy the Lexus/Toyota tool for ~$165 in various places. This seemed expensive, so I ordered a mostly compatible one from eBay for much less. It just requires a large pipe which we have.

OEM Collar
http://www.toolsource.com/prod_medium/99091.jpg
OEM Handle
http://www.toolsource.com/prod_medium/97504a.jpg
Much cheaper eBay Special
http://www.ebay.com/itm/like/251439944179
I also ordered a cam pulley holder tool
http://www.ebay.com/itm/Auto-Car-Univer ... 1455192207

While waiting for the tools to show up, I figured it would be a good time to do the valve cover gaskets and spark tube seals. I pulled the ignition wires and distributor caps off both distributors as one assembly to simplify reinstallation later. The RH valve cover comes right off. You can see the internal gear drive for the exhaust cam here. Also remove the spark plugs. Use a pry bar to pull the old spark plug seals out and a seal installer to put the new ones in. Clean everything off before reinstalling. Clean and ready to reinstall the LH cover. You need to apply a small dab or RTV on each area where there is a metal joint on the cylinder head. There are eight spots in total. Two at each end of each camshaft including where the camshaft protrudes from the head to attach to the cam gear.

You can do the RH valve cover gasket without removing the throttle body, but removing it makes two of the bolts much easier to get to. Good thing too, as the throttle body was pretty dirty. After I got the tool, removal of the crank pulley was very easy. The hydraulic pump can also be removed from the front of the engine along with the lower timing cover. The cam pulleys and belt can come off now. You now get a full view of the water pump and both of the pulleys. If you look closely, you can see some seepage around the water pump pulley. Good thing all of this is being replaced. Again, good thing we were doing the timing belt, as there was substantial dry rot in the belt. Pull the thermostat housing off the top of the water pump, then remove the water pump. You can really see the coolant seepage here. New pump on. The FSM says to only put the belt around the crank pulley and add the hydraulic pump and lower timing cover first, but that is a pain. Put the belt and cam pulleys on before installing any other part. That way if you have an alignment issue, you don't have to remove the other parts to readjust. Once you are satisfied with the alignment, install the tensioner and remove the pin to apply tension. Add the lower timing cover and crank pulley. Rotate the engine two full rotations and see if the alignment marks line up. If so, install the hydraulic pump. If not, fix it then install the hydraulic pump. Also add the spark plugs back in. Now is a good time for new ones. Add the alternator, serpentine tensioner, distributors, rotors, and caps. Then add the upper timing covers and start running the ignition wires. This is a tedious process if you are using new wires as two cylinders on each side are driven by the distributor on the other side. The wires run through a channel along the front of the engine and clip to some small separators. Once this is done you are home free. Install the wire covers, the coils and the harness covers. I also needed to clean and reinstall the throttle body, as it was removed. Serpentine belt idler and belt, thermostat housing, radiator assembly, and battery. There is a coolant fill plug on the top of the thermostat housing that you use to fill the coolant. Add about 2.5 gallons here. It will also fill up the overflow bottle. Install any other stuff you removed or I forgot to mention here. Start it. Check for leaks. Turn on the heat to max in the cabin. Let the engine run with the coolant overflow cap off for a few minutes to work any other air out and top off as needed. I used Toyota long life coolant (red!) in this as that is what came out of it. Not sure when Toyota/Lexus switched over to long life coolant. Amusingly, this engine shares an oil filter with the Saturn.

When you are all done it should look like this. Since the plugs/wires/caps/rotors were changed, the off idle misfire that this had is gone. Also the engine is now super quiet. The old timing tensioner/idler pulleys seemed to be on their last legs with regards to bearing noise, so that was a nice bonus.

Now to fix all the other broken things and water leaks...

Some comments as I was reading and looking at the pics.

1) I didn't really think this through before but I guess all timing belt driven cams have the gears on the outside of the head, otherwise the belt would be soaked in oil...

2) Is it normal to have only 1 cam gear per head even on DOHC? Maybe that's how belt cars are? I think the VQ30DE has two gears (chain driven).

3) Plug wires were original....Sumitomo 1993. Sweet.

4) Probably too late but B12 Chemtool for cleaning that TB is what you want. Regular carb cleaner is nowhere near as good, depending on how baked on that gunk was.

5) That whole water pump design (and all the shit on the front of the engine) seems....like a lot of parts.

6) Not a whole lot of room in there....but with the radiator out I guess it was alright on the front. The sides are tight but with the plugs on the heads, I guess only the exhaust manifolds become a major PITA.

I probably had more thoughts but was interrupted several times...

Pretty much all of the F-head Toyota engines use a single gear where as the G-head engines pretty much all use two. Probably for packaging reasons.

So that's compact and light? I'd hate to see large and heavy.

I was waiting for the first "pushrods are superior" comment

I was thinking that the distributors are surprisingly old tech for a Lexus-exclusive engine like this. Distributorless was a thing since like 1984 (you'll never guess what I am referring to).

kevm14 wrote:So that's compact and light? I'd hate to see large and heavy.

Yeah, if a V8 had G-heads it would not fit in medium sized cars.

kevm14 wrote:I was thinking that the distributors are surprisingly old tech for a Lexus-exclusive engine like this. Distributorless was a thing since like 1984 (you'll never guess what I am referring to).

Toyota didn't put DIS in anything until the late 90's. This engine was first released in 1990. The dual distributors seem a little ridiculous but it was again probably for packaging reasons. Toyota usually drives the distributor off a camshaft and having a V8 distributor on only one side of the engine is not as symmetrical.

They could have done as Nissan did with the VQ35 in James' G35x and used dual TBs, dual MAFs and dual air intake boxes. For symmetry.