22RE Engine Half Rebuild

The 22RE engine in the 4Runner had a hard life. It was used to tow a 2000lbs. trailer for 60k. The original owner said he never went on hills, but that is still quite a bit of work. I drove it on and off-road until 115k.

There were several things that bothered me about the engine.

• Used quart of oil every 500-600 miles.
• Compression around 135-170psi.
• #1 plug was white hot, with broken insulator. Rest of the plugs were hot too, but not as bad.
• Lack of power, and lazy acceleration
• Runs very hot eventhough the temp. gauge shows it to be in the middle. Rubber hose were getting brittle due to the heat.
• Timing chain rattle at start-up that last for several seconds until you gun the engine.
• Hesitation during idling as if about to die, then catches on again.
• Whisle noise coming from the exhaust every now and then
• Poor gas mileage for 30" tires and 2.5" lift. 18mpg to 20mpg

Here are some of the things that I did to the engine before the engine refresh:

• New off-set oil seal in the front to cure the oil leak. Engine still use oil.
• Paid to have injectors cleaned using the injector cleaning machine. The idle got somewhat better, but still not as smooth as it can be.
• Removed all 4 sparkplugs, and poured transmission oil into each cylinder, then waited for an hour or so. Every now and then, I turned the cranks a little to work the rings. The was suppose to remove carbon deposit from the rings. Afterward, I had to drive around the block in the middle of the night because of the smoke coming out of the tail pipe. As I drove around the block twice the smoke lingered so thick that I could not see where I was going! This made the most improvement on the engine. Compression went from 130-140psi to 170-185psi. The truck seemed to have some more pickup during acceleration.

The truck had relatively low mileage, so I was going to leave the engine alone even though it was an irritant. One day coming back from work, the engine pinged while going up a sligth incline, and smoke came out of the tailpipe. Pulling the plugs, the #3 and #4 cylinder had oil on the plug while the #1 was white hot as usual. The compression was still 175-180psi, so that was quite good. It was burning oil, so I decided to do an engine teardown. I don't want to spend the money to do a rebuild. My job was not stable as the company was downsizing. Wife was pregnant, so spending two thousand for a rebuild engine was not an option. I just want spend a one or two hundred bucks to keep it in good running condition for another 100k or so before I pour in the money for a complete quality rebuild. Hopefully, economy would improve by then. Here is what I did and found.

• One exhaust nut was loose. This must have made the whistle noise. Due to the loose nut, the exhaust manifold got warped. $40 for a sanding job fixed that. The leaking exhaust would have sucked air into the manifold. That could have thrown off the O2 sensor reading, and given the wrong mixture information to the engine computer.
• Rubber isolators on the injectors were badly deteriorated. Injectors looked fine. The deteriorated isolators probably caused air leakage. I sent them out to Cruzin Performance in Minnisota. That to info provided by Roger Brown's website.They were only 2% off of each other. After cleaning, they were 1% off. For $68 all together including shipping, they gave me new orings and rubber isolators for no extra charge. Those alone would have costed $36 at the dealer. This outfit is highly recommended! The deteriorated isolators could have caused the lean mixture for #1 cylinder, and maybe caused the hot condition.
• To my surprise, the infamouse guides were hardly worn at all. The driver side had no measurable wear. The passenger side had .002" of wear. Way below spec. I was going to replace them with another set of plastic guides. Metal ones were too expensive. Plus, if it ain't broken... When I put the new set of guides in, I noticed something. The old ones had lots of slop in the shoulder screw. You could feel the guides move when you wiggle them. The new ones due to tolerance, was compressed by the shoulder screw, and could not move. The new guides were just about .001" thicker than the length of the shoulder portion of the screw, so it could not move. The movement was probably there for CTE (Coeficient of Thermal Differential) difference between plastic and the metal engine when it heats up. If the guides could no move freely, then there could be lots of stress on the plastic. That could be the reason why guides fail. Is not from wear, but from CTE which cause fatigue failure. Anyway, base on the amount of wear so far, I am confident these guides will last another 100k miles.
• The wear on the tensioner was another story. There were deep grooves on the plastic rub piece of the tensioner. That had to be replaced.
• The piston came out with no problem. No need for a ridge reamer. There was quite a bit of carbon deposits. Soaking in WD40 per Roger Brown's web site worked wonders. I had a gallon can of WD40.
• The compression rings on the pistons were fine, but the oil control ring showed relaxation. The left ring is the replacement one. The right one is the original. Assume tension on ring is proportional to end gap, the original rings would have lost about a third of the tension. This could be the cause of oil usage during acceleration. Since I am only replacing the oil control rings, and not the compression rings, the walls of the cylinder should not need to be honed. There should not be much pressure on the oil control ring anyway, so there should not be need for breaking in. I was hesitant to replace the main compression ring due to the difficulty of breaking in chrome rings. Per enginbldr.com, moly and chrome rings are difficult to break-in. You should use cast iron ring if you are not boring out the cylinder. However, cast iron ring also wear faster than the chrome rings. For maximum durability, I figure, using the original rings should be the best way to go especially the compression is already 175psi.
• The cylinder looked great. There were specks of rust on the #3 cylinder. There was no ridge on the top. You could still see the hatch pattern on the wall. The cylinder are almost still new!
• The intake valves were fine, but the exhaust valve looked marginal. 4 new exhaust valves were put n. The seat looked fine, so I just lapped the valves in. There was almost no detectable movement of the valve in the guide. The guides were in great shape. Some Viton valve seals from Fel-Pro finished the valve job. The original seals were quite hard due to the high temperature.
• To cure the high temperature issue, I drilled a 3/32 hole on the thermostat. This is to allow hot coolant to pass thru the thermostat, and open the valve faster. I also found piece of foam blocking the lower quarter of the radiator blocking the air entrance below the bumper.. It was neatly cut and placed there. I don't think Toyota would have done such a thing. I move the foam lower so that it would not be blocking the radiator so much. That could have caused the high temperature in the engine compartment.
• Hylomar was used on all gasket surface on installation. This will make sure there is a good seal on all the mating surfaces, and also make it easier to clean up the gasket at the next repair.
• Torqued the intake and exhaust bolts, then waited an hour or so for gasket the settle, then re-torqued. The gasket compresses after the first half an hour. The bolts then becomes a little loose again.
• New water pump was put in. The original looked pretty good. From experiance, the alternators on Japaneese cars are pretty durable, but the water pump is the weak link.
• Adjusted the valves to .007" intake, and .011" exhaust cold. After first start-up, the valves were noisey, so I had to adjust them hot again to spec.
• Adjusted the throttle position sensor,TPS, per Roger Brown's site. When you adjust the throttle stop position, you pretty much have to adjust the TPS as well.

Results of the engine work:

• Used quart of oil every 500-600 miles.---->Now: estimated to use a quart every thousand miles.
• Compression around 135-170psi.---------> Now around 150-160psi.
• #1 plug was white hot, with broken insulator. Rest of the plugs were hot too, but not as bad.------> Plug color nice tan.
• Lack of power, and lazy acceleration-----> Now definitely more power. Now I could do 70mph up the same hill.
• Runs very hot eventhough the temp. gauge shows it to be in the middle. Rubber hose were getting brittle due to the heat.----> Appears to run cooler. That could be psychological though.
• Timing chain rattle at start-up that last for several seconds until you gun the engine.-------> Now: The tensioner must have been the problem. No more rattling sound at startup. Rattling came back slightly after several thousand miles. Oil was not changed for a long time. After an oil change, is fine now.
• Hesitation during idling as if about to die, then catches on again.-------> Now: Engine is very smooth running. No hesitation.
• Whisle noise coming from the exhaust every now and then----> Now: Aftet the engine work, exhaust nuts kept loosening. Finally, I used Stage-8 fasteners to solve the problem.
• Poor gas mileage for 30" tires and 2.5" lift. 21mpg average-----> Now: First run got 16.5mpg, second tank was 18mpg. Third tank was 19.9 mpg. Mileage got better as the computer learned. Highway/City driving is about 21mpg. City only driving is 16.5mpg. Not much change from before. Guess 21mpg is about as much as I can expect.