Toyota Maintenance: Toyota 22R Timing Chain Replacement
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Author: Jim Brink, Technical Editor, July 2000
|22R with Valve Cover Removed|
Last month we reviewed D.O.A. Racing Engines timing chain kit that comes with their exclusive metal-backed timing chain guides. This month well address replacement of those timing components in a carburated 1986 22R engine.
Although this mechanical labor operation may seem like a daunting task, the home mechanic with even the simplest collection of tools can do it. No special tools are needed for this job, save for an assortment of metric wrenches and sockets and a timing light. Being armed with the Toyota factory service manual would be a big help as it outlines correct torque specifications for the various nuts, bolts, and other fasteners.
Before tearing into your engine, be sure that you have a basic understanding of the timing chain and how its related components work. This will be especially helpful in the reassembly process. If this is your first time doing engine work of this scope, take pictures, or better yet, follow the steps in the service manual. Follow up by taking notes or labeling bags for parts that are removed from the engine. Also, make sure that you have all the parts you will need to complete the job. In addition to the timing kit, you may consider replacing the following items:
Among the items listed above, I also suggest the following items be kept on hand:
You will ALWAYS want to change the engine oil and filter once the engine is all buttoned back up. Debris (old gaskets, dirt, etc.) and coolant will fall into the oil pan and you dont want to run that through the engine. If removal of the oil pan is done (see below) you will definitely want to change the oil and filter. Now is a great time to flush the cooling system and refill it with fresh coolant. If the condition of the radiator is suspect, pull it and have it checked by a local radiator shop.
There are several ways to go about replacing the timing chain components. One such way, and the one outlined in the Toyota service manual, is to remove the cylinder head and oil pan. While this is time consuming, it is the right way to do it. This method allows plenty of room to work on the timing chain and ensures a good seal between the head and the timing chain cover. The next way is to remove the timing chain cover and just the cover. In some cases, it may be necessary to remove the oil pan in addition to the cylinder head. If pieces of the original (plastic) timing chain guides have fallen into the oil pan, they will need to be removed to prevent blockage of the oil pump pick-up screen. Failure to do so could starve the engine for oilNot a good thing. Regardless of the method used, there are a few steps that need to be taken to begin this repair. Make sure you have a nice, clean area to work in and that you will have full access to both sides of the engine compartment. If the job is being performed on a 2WD truck, you may wish to jack it up and support it on jack stands.
|Remove the Mid or #3 Radiator Hose.|
If your truck is equipped with some sort of skid plate or splash pan, remove it for better accessibility to the underside of the engine. Drain the cooling system and disconnect the lower and mid (#3) radiator hoses. You may also want to remove the upper radiator hose to gain a bit more working room. While the coolant is draining, remove the cylinder head (valve) cover. Next, you can move on to the removal of the fan belts, fan and fan clutch, water pump pulley, and fan shroud. If your truck has power steering, you will need to remove the bracketry from the cylinder head and block, and set the pump aside. I personally like to tie it to the left inner fenderwell. Remove the upper alternator bracket from the timing cover (hold on to this bolt, it is one of the timing cover bolts) and move the alternator all the way over to the left side. You need not remove the alternator from its mounts or disconnect the electrical leads. If your truck has air conditioning, you will need to remove the compressor from the block and set it aside as well. There is no need to disconnect the lines from the air conditioning compressor. There is enough flexibility to move it aside.
|Breaker Bar Wedged Against Frame.||...From Another Angle.|
Next, and possibly the most difficult task, is removal of the crankshaft pulley. Due to its placement in the engine, it is very hard to get any type of air tool into this area to loosen the large bolt that attaches the pulley to the crankshaft. There is an easy trick to do this. Find a socket to fit the crank bolt (19MM) and place it on a long-handled breaker bar. Place the socket on the bolt as if it were going to be loosened. Next, wedge the bar against the top of the left-hand frame rail. Make sure the handle will not come in contact with the radiator! Disconnect and ground the ignition coil wire from the distributor, as you do not want the engine to start with the breaker bar attached to the crank bolt! Usually, one short hit of the ignition key is enough to break the bolt loose. At this point, the bolt can be loosened by hand. The crank pulley should slide right off of the snout of the crankshaft but a puller may have to be used in some circumstances.
|Distributor Electrical Connector.||Camshaft Sprocket Timing Marks and Timing Chain Index Links.|
Now, reinstall the crank bolt back into the crankshaft. You will need it to rotate the engine. Set the engine to top dead center (TDC). Align the keyway in the crankshaft so that it points up and the "dot" mark on the camshaft sprocket is at the 12 o clock position. If they do not line up the first time, rotate the engine through one 180-degree cycle and they should line up, assuming the reason this for this repair is not due to a broken chain. Remove the distributor cap and see that the rotor points to the #1 cylinder (approximately 11 o clock when viewing the distributor from the drivers side fender). Remove the 12-mm hex-head distributor hold-down bolt. Unplug the electrical connector at the distributor and pull the distributor out.
|Be Sure to Remove this Bolt at the Water Pump.||The Water By-Pass Tubes Bolt to the Back of the Timing Cover.|
It is now time to remove the timing chain cover. Remove the crank bolt. If the oil pan has not or will not be removed, the two forward-most oil pan bolts need to be removed as they thread into the timing cover. Next, remove the #1 water by-pass pipe from the passenger side of the engine and the heater outlet pipe from the drivers side. On 22RE-T engines, this is known as the #3 turbo water (cooling) pipe. There are 10 bolts that attach the timing cover to the block. One of these bolts passes through the water pump and has a 12-MM hex head (The other water pump bolts are 10-MM hex). Two of these bolts pass through the oil pump and one is threaded from the back-drivers side of the block, near the heater outlet pipe/engine oil dipstick area. One more bolt often overlooked secures the cylinder head to the timing cover. If the head was not removed, this bolt will be located below the camshaft drive gear, which is on the front of the camshaft. This bolt is usually hidden in a puddle of oil. Getting to this bolt requires removal of the distributor drive gear and the fuel pump cam (on carburated engines only). To do this, loosen the 19-MM hex-head bolt that threads into the camshaft. Try to keep track of where the timing cover bolts come out during removal. A good way to do this is to draw a diagram of the cover on a piece of cardboard. Upon the removal of each bolt, press it through the respective spot on the cardboard. This will make it much easier to reinstall the timing cover as there are several different bolt lengths used to hold it in place.
|The "Hidden" Bolt Under the Cam Drive Gear.||This is the Timing Cover Bolt Accessed From the Back Side of the Cover.|
As the timing cover has most likely been on the block for some time, it may not be easy to get off. In fact, it may put up quite a fight! First off, double check to see that all of the bolts have been removed, especially the two that I mentioned above and any associated with the air conditioning. A few raps with a rubber mallet may be required to break the cover loose. If the head is still on the engine, be careful not to damage the portion of the head gasket that seals the top of the timing cover. With the cover off, the timing components can be removed. Slip the oil pump drive spline from the crankshaft and set it aside. Remove the chain tensioner and guides. Slip the cam sprocket off of the face of the cam and the crank sprocket from the snout of the crank.
|Oil Pump O-Ring Seal.|
The fun is not over as the time has come to scrape gaskets! The engine block must be completely scraped and cleaned of all old gasket material to assure a leak-free seal. I like to stuff rags in the oil pan area, if it was not removed, to keep the old gasket pieces out. The timing cover will need to be cleaned of the old gaskets too. If the timing cover is greasy, it should be cleaned in some sort of solvent. If this is the case, I suggest removing both the water pump and oil pump from the timing cover. Most good timing chain kits, like the one sold by D.O.A. Racing Engines, come with a new water pump gasket and oil pump O-ring. Remove the old front crankshaft seal from the oil pump and replace it with the new one supplied in the timing kit. Consider replacing the water pump now if it is the original. Clean the forward (exposed) rail of the oil pan that is visible or clean the entire oil pan gasket surface if it was removed. Once the cover is clean, apply a thin bead of RTV to the cover and place the gaskets onto the cover. Apply RTV to the block side of the gaskets just prior to installing the cover back onto the engine.
|Index Marks on Chain and Sprocket.||Prying Out Old Crankshaft Oil Seal from the Oil Pump.|
Installation of the new timing components is the reverse of disassembly. Leaving the tensioner until last makes installing the chain a bit easier. The critical part of installing the chain is assuring that the camshaft and crankshaft are correctly timed together. Fortunately, most manufacturers of timing chain kits make this easy by clearly marking the chain and sprockets with timing marks. The chain will have bright links where it needs to be installed on the sprockets and the sprockets will have marks or dots where the chain needs to be placed, respectively. Due to the design of the timing components and the engine, the sprockets only fit one way on the crank and cam.
|Oil Pump Drive Spline||Prepare Chain and Sprockets for Installation.|
Set-up the chain and sprockets for installation. The toothed end of the crank sprocket faces forward. Slip the new crankshaft sprocket with chain over the snout of the crank. Do the same at the camshaft. I like to tie the chain to the cam sprocket to make sure it stays in the correct position. Getting the cam sprocket onto the cam takes some effort, especially when using a kit with a pre-stretched chain like D.O.A.s kit. This is where the crank bolt comes in handy. Thread the crank bolt back into the crank and snug it down. While applying upward pressure on the cam sprocket, rotate the engine back and forth with a breaker bar on the crank nut. This will stretch the chain out a bit to get it over the front of the camshaft. With the cam sprocket on the cam, install the cam drive gear bolt temporarily to keep the sprocket from coming off. Install the guides and tensioner at this time. The long-sided tensioner goes on the drivers side of the engine. Install the oil pump drive spline onto the crankshaft. You dont want to forget this step! Before installing the timing cover, be sure all of the timing marks line up. If the water pump and/or oil pump were removed, reinstall them. Pour a little oil into the oil pump so that it will prime upon startup.
Apply a thin bead of the proper RTV to the oil pan. Some suggestions are Toyotas black FIPG (Formed-In-Place-Gasket) or Permatex Grey Import or black RTV. Apply RTV to where the cylinder head joins with the timing cover. Gently install the timing cover onto the engine. Be patient as the RTV on the oil pan and timing cover locating dowels on the face of the block will create some resistance. Also, the oil pump drive spline may not immediately engage into the oil pump. When the cover is flush with the block, the bolts can be installed. Torque the 8-MM (12-MM hex head) bolts to 9 ft-lb. and the 10-MM (14-MM hex head) bolts to 20 ft-lb.
Next up is reinstallation of the miscellaneous componentry such as the air conditioning, alternator, and power steering. Install the water tubes back into the timing cover. Place the water pump pulley on the water pump and install the fan, fan clutch and fan belt.
|Position Rotor at 12 O' Clock.|
To install the distributor, first make sure the engine is set to TDC. Place the distributor rotor in the 12 oclock position and install it into the cylinder head. When the distributor contacts the drive gear on the cam, it will rotate counter clockwise to the #1 firing position or TDC. The timing may not be exact, but it will be close enough to get the engine running. Plug in the electrical connector for the distributor. Install the bolt and snug it down and install the distributor cap.
|Crankshaft Timing Mark at "0" for TDC Setting.|
Install the crankshaft pulley and torque the large bolt to 116 ft.-lb. This can be accomplished with several methods. The key is to keep the crankshaft from turning while torquing the bolt. My personal favorite is to chock the wheels and place the transmission in the highest gear (4th or 5th) and the parking brake engaged. If the vehicle is 4WD, place the transfer case in 4-Lo. This will create the most resistance in the drivetrain. An alternate method is to use a chain or strap-type wrench to hold the crankshaft pulley in place while tightening the bolt to specification. Either way is effective and depends on personal preference and tool availability. Install the camshaft (valve) cover and any other parts removed from the engine. Tighten the fan belts and reattach any vacuum hoses and electrical connections that were disconnected. Change the engine oil and filter. Install the radiator (if removed) and radiator hoses. Fill the cooling system with the correct mixture of anti-freeze and water. Check once more that any items that were removed or disconnected are back in place. Remove any tools from the engine compartment.
|You May Wish to Replace the Distributor O-Ring if it is Leaking.|
Start the engine and allow it to reach operating temperature. Note any unusual sounds. Timing chain replacement is straightforward and provided the instructions in the service manual were followed, the engine should operate normally. Shut off the engine and check the fluid levels and inspect for leaks. Start the engine once more and set the ignition timing per the underhood emission decal. EFI-equipped trucks are set to 5-degrees BTDC with the EFI check connector shorted. Carburated trucks should be set to 0-degrees BTDC with the vacuum lines disconnected from the vacuum advance unit.
All that is left to do now is drive your Toyota another 100,000 trouble-free miles. Knowing the timing chain has been replaced means more piece of mind and hopefully many more years and miles down the road.