By: Josh Carlson- 1/2004
Josh Carlson (aka Arbitrary Notion) is an active member of the 4x4Wire Bulletin Boards and it constantly looking for ways to get more power out of his 22R motor. His long list of engine modifications include a fresh motor with .030" over pistons, Engnbldr head, 38mm Weber carburetor, LC Engineering header, and LC Engineering exhaust. The next step in Josh's quest for power involved installing a new custom ground camshaft from Engnbldr. Expect to spend approximately five hours to complete the job. Parts necessary for the job include:
Tools necessary for the job include:
First, start marking and removing anything that would get in the way of removing the valve cover. Next, unhook the throttle cable and remove the four valve cover nuts. The grommets under those nuts may be difficult to remove. If so, use a screwdriver to pry them out. Don't worry about mangling the grommets as they will be replaced later. The valve cover should lift straight up off the head. If it does not, use a rubber dead blow hammer to loosen it. Note that the heater hoses can make removal of the valve cover difficult. They need not be removed, simply pushing them out of the way should suffice.
|Broken plastic timing chain guide shown above DOA guide.|
Before moving farther into this install, it is highly advisable to check the timing chain guides. When looking down the timing chain and there will be a plastic guide on either side (for 84+ models). Make sure they are not broken. If they are, stop! Get a timing chain kit from a reputable vendor such as Engnbldr, DOA Racing Engines, or LC Engineering and install the new guides at the same time as the camshaft. I recommend removing the head when replacing the timing chain and consider having the head resurfaced and a new gasket installed. Once the timing chain guides have been checked, drain the coolant. The coolant must be drained from both the radiator and the block. This is a very important step because if the coolant is not drained the head will float off the block and ruin the head gasket once the head bolts are removed. If you do not intend to remove the head, remove the spark plugs at this time. Doing so will prevent you from breaking the seal between the head and block if you manage to turn the engine whilst the head bolts are out
On carbureted models, loosen the fuel pump bolts so that there is room between the arm on the fuel pump and the cam that moves it. Next remove the adjusting bolt from the distributor. The distributor will simply pull out once the adjusting bolt is removed. Move the first cylinder to top dead center by using a 19mm (or 3/4ths) socket and a large beaker bar on the harmonic balancer bolt. Note to turn the balancer clockwise so as to not loosen the bolt. Keep turning until the mark on the balancer is in line with the 0 degree mark on the oil pump. The mark on the cam sprocket and the master link on the chain should also match up. Once everything is lined up, it is time to start removing bolts.
|Head bolt removal order.|
|Head bolt installation order.|
The first bolt to remove is on the camshaft sprocket. Note how the pieces come apart, as this will greatly ease reassembly. A screwdriver may be necessary to pry the sprocket off of the camshaft. Let the sprocket (with the chain still attached) gently rest on the timing guides and use a large breaker bar to start loosening the head bolts. Make sure to loosen them in the correct order, as noted in the photo to the left.
Alternate turning the head bolts one quarter of a turn each. Keep doing this until they are all loose, then remove them all. Try to keep them in the same order for reinstallation if possible. It is possible to remove all the head bolts (except the rear two) by leaving them in the head and lifting the rockers with the bolts still in the holes. Remember to clean out all of the head bolt holes as they need to be clean and dry in order to correctly reinstall and torque to spec. Note: It is a good idea to replace the head bolts whenever they are removed. Once again refer to a reputable dealer such as Engnbldr, DOA Racing Engines, or LC Engineering.
Once the rockers are removed, inspect the rocker arms and their adjusting screws, checking for an hourglass wear pattern. If it's very faint, it is possible to reuse the rocker arms. If there are dents or parts of the tip missing however, they should be replaced. A complete set of adjusting screws from your Toyota dealer costs around $25. After inspecting the rocker arms, move on to removing the cam journals. As with the head bolts, the cam journals should be loosened in small intervals to prevent them from becoming warped. Also, keep the bolts with the journals so as to return them to the exact location and orientation they had previously. Once all of the bolts and journals have been removed, the old camshaft will lift right out. Check for wear and cracks on the cam journals and replace any bad journals with new parts.
Apply gear oil or assembly lube liberally to the new camshaft lobes and journals. Apply the lube to both sides of the journals and set the camshaft in it and turn the cam several times. You are now ready to install the journals and torque them to 14 ft/lbs. Turn the camshaft by hand, ensuring that it is sufficiently lubed and turns easily. Next lube the lobes of the camshaft by spinning them around and ensuring that they are completely coated. Note that the "nub" on the camshaft must be pointed straight up. Put the rockers back on top of the cam, noting the arrows on the rocker assembly that need to point towards the front of the engine. Finger tighten all of the head bolts, and then with a torque wrench tighten them a quarter of a turn at a time to fifty-eight foot-pounds. The head bolts must be tightened in a particular order, illustrated in the photo above.
|Reinstalling the cam sprocket.|
|Reinstall the distributor in the proper orientation.|
Once the head bolts are properly torqued, reinstall the cam sprocket. It will be a tight fit. Use a sturdy, long handled screwdriver to pry up on one of the upper holes on the cam sprocket. Make sure all the nubs on the cam sprocket are fitting together properly, as it is important that the sprocket is completely straight. Use a rubber mallet to level it out if necessary. Finally tighten the cam bolt once the sprocket is aligned. Once the cam bolt is torqued on, tighten the fuel pump (on carbureted models). Point the distributor towards twelve o'clock and press it into its spot. The rotor should turn itself so it is pointing directly at the vacuum advance. Tighten down the distributor-adjusting bolt with the rotor pointing at the vacuum advance. Make sure that everything is lubed properly and proceed to adjusting the valves.
Factory spec for adjusting the valves is .008 on the intake and .012 on the exhaust. It is best to use whatever spec the manufacturer provides. Make sure that the dot on the cam sprocket lines up with the master link and the timing mark is lined up exactly with 0 degrees. The valve adjustment procedure involves two parts. The first part consists of intake valves one and two, then exhaust valves one and three. The second part consists of intake valves three and four then exhaust valves two and four. Refer to the picture for the order. The first set is in red. The second set is in blue.
|Intake and exhaust valve adjustment.|
|Adjusting the rocker arms.|
Use a feeler gauge and insert it between the valve and the adjusting screw. If the feeler gauge does not fit into the gap, the adjusting screw needs to be loosened. If it fits loosely, the opposite is true. Use a 12 mm wrench to loosen the nut and a screwdriver to turn the adjuster before retightening the nut and checking the gap again. The goal is to achieve a medium drag, which consists of the feeler gauge sliding through snugly. Do this for the first set of valves and turn the harmonic balancer 360 degrees. This will move the first cylinder from the compression stroke to the exhaust stroke. Now do the same adjustments for the second set of valves. It is important to turn the engine a few times by hand to check for binding.
Once the valves have been properly adjusted, reinstall the valve cover. Apply a bead of RTV to the half-moon seals before installing. Next take the new rubber seal and fit it into the groove of the valve cover. Reinstall the valve cover and add the new grommets, tightening the nuts on top of them. There is not a factory torque spec on these nuts but the rubber part of the grommet needs to be flush with the metal ring. Now is time to reinstall any vacuum lines that were disconnected and inspect your work to ensure that no steps were missed. Fill up the radiator and replace the spark plugs and the engine should be ready to start.
To break-in a new camshaft, run the engine at 1800-2400 RPM for three sets of 15 minutes, making sure to adjust the timing during the first run. Try to vary the idle a little throughout the break-in process. After each run, let the engine cool down before starting the next set. After the first run, remove the valve cover and check the valves, as they will likely need to be readjusted when the engine is warm. If a loud tapping is present during the break-in, one of the valves may be too loose and will need to be tightened. Also re-torque the head bolts since most of them will change when heated up. Once the camshaft is properly broken in, you are ready to start enjoying your new engines new found power!