TOYOTA 20R, 22R, & 22RE TECHNICAL INFO

 

03/15/06   Crank pulley bolt tool
10/22/07   Revised front crankshaft seals
11/08/10   Improved 22R/RE clutch  (Mark Sherman)
02/26/06   Permanent cure for loose headpipes
06/15/09   The 2xR timing chain
06/08/06   Installing a 2xR head with timing cover on
03/01/06   The 22R valvetrain illustrated  (Matt McFarlane)
??/??/00   Recommended rocker shafts  (Gary Meissner)


 


CRANK PULLEY BOLT TOOL
03/15/06

To hold the crankshaft while breaking loose or torquing the crank pulley bolt on a 22R engine, weld a handle comparable in length to your breaker bar and torque wrench (and with sturdy bracing) to a junkyard power steering pulley.  Bolt it to the main crank pulley in place of the original PS pulley.  If the engine is in a vehicle, let the handle bear against a frame rail as you tighten or loosen the pulley bolt.

Picture - 117k .jpg

 


REVISED FRONT CRANK SEAL
Revised 10/22/07

Pull the crank pulley off a 20R or 22R/RE engine and you are likely to find a groove worn in the pulley hub where the oil seal lip has been riding.  Instead of replacing the pulley or using a seal saver sleeve, consider using a narrow late-model oil seal.  The Toyota 90311-45014 front crank seal (as used on 1994 22R/RE pickups) measures 7 mm thick instead of the 11mm thickness of the older seals.  The Chicago Rawhide CR17758 seal is 9 mm thick, and other aftermarket narrow seals may be available.

Since the bore in the oil pump will accomodate a seal 11mm thick, you can vary the installed position of the 7mm seal within a 4mm range to insure that the lip of the seal does not ride on the groove.  Caution: Drive the seal at least deep enough to put it completely behind the chamfer on the front of the bore, or the resilience of the seal may cause it to extrude itself from the bore and cause a massive oil leak.
 


IMPROVED 22R/RE CLUTCH  (Mark Sherman)
(In the Old Celica Club, Mark is the unquestioned expert on Toyota parts)
Revised 11/08/10

"This is the Toyota-designed 'heavy duty replacement' clutch set utilizing both steel springs and rubber bushings in the discs, and it fits all 22Rx applications from 81-88 except the Turbos.  It will also fit 2WD trucks up through 95, replacing the later model truck clutches which only had springs in the discs.  This set produces a smooth engagement and a nice firm shift when in a hurry, and it does not chatter.

The 'heavy duty replacement' part numbers are:

31210-24020-84   Pressure plate
31250-35140-84   Clutch disc
Other clutch part numbers:
90363-12002-77   Pilot bearing
90363-40022-77   Throwout bearing, all 81-88
31230-35070-77   Throwout bearing, 89-95 2WD trucks"
Note: The parts specified above may not be available off-the-shelf but they can still be ordered.
 


PERMANENT CURE FOR LOOSE HEADPIPES
Revised 02/26/06

Even when new studs and nuts are installed and tightened to the recommended torque, the hardware clamping together the gasketed joint between the 22RE exhaust manifold and the headpipe will in time work loose and allow the joint to leak.  If you don't bother to check the security of the hardware periodically and simply wait until an exhaust leak becomes audible, you are at risk of having the gaskets burn through and the nuts or studs falling off.  The locking nuts are apparently one-time-use items and after they are retightened - or if they are removed and reinstalled - looseness will occur more frequently.

Discarding the locking nuts and double-nutting does no good, as that won't keep the studs from falling out.  Safety wiring would keep the hardware in place, but drilling the studs and installing the safety wire - and then removing and reinstalling it every time the joint is disturbed - would be tedious overkill.

For a simple, effective, and maintenance-friendly solution to this problem, cut a thin steel retainer as shown in the figures below for the 22RE (or to your own similar design for other manifold configurations) and install it as noted on the drawing.  The retainer is clamped between two nuts on each stud, so exhaust heat can't lengthen the studs enough to relieve the clamping force on the retainer.  The retainer cannot rotate in relation to the manifold because it is engaged with more than one stud.  The end result is that neither the nuts nor the studs can rotate in relation to the manifold, so the connection stays secure.
 

Drawing - 10k .gif
Photograph - 80k .jpg

 


THE 2xR TIMING CHAIN
(Another Toyota blunder)
Revised 06/14/09

If you have ever tried to check a 2xR timing chain for wear "by the book", you have probably been at least sorely perplexed.  At worst, you may have discarded a perfectly good chain.  From as early as 1980 to at least 1986, the official Toyota shop manual procedure for judging the condition of a 2xR timing chain - reproduced below - was blatantly wrong.  To compound the error, the procedure was faithfully copied by aftermarket book publishers Haynes and Bentley.  The problem is that even a new chain will measure more than 6 inches over 17 links.

Could the specification of 17 links be a simple typographical error?  (That surmise is supported by the maintenance manual for the twincam 2RZ-FE used in the Tacoma, which specifies 16 links.)  Sixteen links would be (16 x 3/8) - 1/4 or 5-3/4 inches*, and the 5.787-inch limit would then represent an elongation of about .64 percent.

* Although the specifications for a 2xR are primarily metric, the chain rollers are actually 1/4 inch in diameter and the links are 3/8 inch long.

A .64% limit on chain "stretch" may be reasonable for a street engine.  With a 96- or 98-link chain, 36 teeth on the cam sprocket and 18 teeth on the crank sprocket, about 34 links are in tension between the sprockets.  Lengthening those 34 links by .64% would retard the cam a bit more than 2 degrees, causing a noticeable but not drastic effect on engine performance.  Lengthening the entire chain loop by .64% would also add nearly 1/4 inch of slack, and that is probably about all that the hydraulic tensioner with its limited stroke can reliably accomodate, as illustrated here.

For optimum performance a very tight limit on chain "stretch" - perhaps a .1% limit, which translates to 5.756 inches (146.2 mm) measured over 16 links - would be more appropriate.  That would retard the cam less than half a degree and create slightly more than 1/32 inch additional slack in the chain, requiring only about 1/16 inch additional extension of the tensioner.

I do not know what chain elongation limit Toyota intended to convey, and I am NOT specifying a limit value or a particular number of links to measure.
IF YOU CHOOSE TO RE-INSTALL A USED CHAIN, YOU DO SO AT YOUR OWN RISK.


INSTALLING A 2xR HEAD WITH THE TIMING COVER ON
Revised 06/08/06

Rotate the cam so that the pin in the front hub is straight up.  Rotate the crankshaft to place the timing notch in the crank pulley at the zero mark on the oil pump.  (Pull up on the timing chain to remove the slack while rotating the crank.)

Arrange the cam sprocket in the upper loop of the timing chain so that with the sprocket pulled up to remove the chain slack, the index mark on the front face of the sprocket and the alignment hole or slot in the hub are both at the top and slightly toward the intake side of the engine.  Lower the sprocket onto the chain guides, rotating the sprocket to feed the chain slack to the intake side.

Set the head and the rocker assembly on the block.  Oil the head bolt threads and the undersurface of the bolt heads.

Install the head bolts and tighten them gradually and gently, in whatever sequence is required, to compress the valve springs and seat all of the rocker towers against the head.  Then torque the head bolts to 58 ft/lb.  (Consult a shop manual for the tightening sequence.)

To get the cam sprocket onto the nose of the cam, it will be necessary to apply upward tension to the timing chain.  Insert a round prybar or a large Phillips screwdriver through the center of the sprocket and into the threaded hole in the cam to pry the sprocket upward.  The chain tensioner may bind up and prevent the sprocket from moving up enough to slip onto the cam.  In that event, keep upward tension on the chain while rotating the crankshaft slightly counterclockwise to release the bind.

Once the sprocket is hung on the nose of the cam, align the sprocket hole or slot with the cam pin so that the sprocket can be seated flush against the cam drive hub.  Some cams have a hole in the outer circumference of the hub to accomodate a rod for rotating the cam.  If such a hole does not exist, align the sprocket with the cam by turning the crankshaft instead of the cam.

Verify the alignment:  Reset the crank to align the timing notch in the crank pulley with the zero mark on the oil pump.  The pin in the cam (visible through the cam sprocket) should be at 12:00 o'clock, with the index mark on the front face of the sprocket 1/2 tooth away from 12:00 toward the intake side of the engine.

Install the spacer or fuel pump cam, the distributor drive gear, and the cam sprocket bolt.  Torque the bolt to 58 ft/lb.  To hold the sprocket while you torque the bolt, insert a bar or hefty screwdriver through a hole in the sprocket on the exhaust side of the engine, so that the shank rests on the front of the head and the tip rests on the front cam cap next to the front rocker tower or, if possible, on the head in the gap between the two.  Do not use a valuable screwdriver as it will probably get bent.

Restore the crank and cam to zero (TDC on cylinder #1) and install the distributor.
 


THE 22R VALVETRAIN ILLUSTRATED  (Matt McFarlane)
Posted 03/01/06
 


RECOMMENDED ROCKER SHAFTS  (Gary Meissner)
Posted ??/??/00

"Use the LC Engineering Pro Rocker Shafts.  [They] are far more accurate in diameter, and the rockers fit snug around them with virtually zero clearance [and] could not be wobbled side to side like they can on stock shafts.  The wall thickness is over double [so the smaller bore] volume makes the oil pressure come up sooner.  The four oil holes per rocker are better placed to provide oiling to the rocker pivot [than] the fine slot in the stock shafts.  The chrome plating [is] mirror smooth and rock hard so they should last a good long time with virtually no wear to the rocker bores.  I would use them on any 2xR motor I ever build."

(L C Engineering is at www.lcengineering.com)