Checking 22R Timing Chain, Timing Sprocket and Overall Engine Condition With Engine Out of the Toyota Truck

[Speed]

Question---I have my truck's wrecking yard replacement Toyota 22R four-cylinder engine sitting in the driveway.  How can I check the condition of the timing chain, gears, sliders, tensioner without taking it apart to look? My Brother Dutch drove the donor truck onto a trailer, off the trailer at home, turned it around and parked it.  He said it sounded good and ran healthy, but it had an exhaust leak so he couldn't hear everything.  The speedometer was already gone, so I have NO idea how many miles.  It had been rolled so there was oil all over everything. The truck was an '85.  Any help would be very much appreciated.

 

Speed

[Moses Ludel]

Speed, I have a methodical approach to testing out-of-chassis or in-chassis stationary engines.  I've shared this in each of my books and many articles.  You and others should find it helpful. 

 

There are four "basics" to engine condition, and each needs attention.  Here's how I would test the Toyota 22R four-cylinder OHC engine on the ground:

 

1)  Compression or cylinder seal:  This can be tested on the ground with a cylinder leakdown tester and an air compressor.  Spark plugs removed, each piston must be brought to TDC on its compression stroke for an accurate read at the highest ring/cylinder wall wear point.  If you don't have a leakdown tester, I describe how to simulate one at the General Repairs forum.  The commercial testers have a gauge and the advantage of percentage leak readings.  A leakdown test confirms piston ring, valve, head gasket and castings seal.  Normal percentage of leak on a newer engine is 8%-10%.  An engine will "run" okay at 20% leak.  Beyond that, leak can affect manifold vacuum and the general engine performance.  Cylinder balance is always assumed to be within 10% on a compression test; on a leakdown test, I like to see no more than 5%-7% cylinder leakage variance.

 

2)  Oil pressure:  This is difficult to test in a static engine but can be done.  Using an oil pressure/priming tank, pressurize the engine's lubrication system to "normal" pressure.  See if the engine bearings will hold that pressure.  Since this 22R truck rolled over, be grateful it had carburetion and likely stalled.  EFI engines have been known to run with the engine on its side or even upside down if the rollover switch does not function, resulting in bearing damage or seizure.  If Brother Dutch did not hear any lower engine knocks, you may be okay...You'll know more when the engine is running.  The best check is to drop the oil pan and pull the main and rod caps one at a time.  Installing/rolling in new rod and main bearings is not a bad idea if the crankshaft is still round and mileage is somewhat high.  Cleaning the oil sump screen and inspecting or replacing the oil pump is not a bad idea, either!

 

3a)  Valve lift:  This can be easily checked on an OHC engine like the Toyota 22R.  Remove the valve cover and inspect the camshaft lobes and valve stem tips.  With valves adjusted properly, use a 6" steel ruler to measure valve lift and the closing height at each valve.  Compare the intake valves and the exhaust valves for lift.  This is a rough but reasonably accurate test and easy to do on an OHC engine.

 

3b)  Valve Timing:  This is your question.  Worn sprockets, chain and tensioner can retard valve timing.  To test this, again have the valve cover off.  Since there is a hydraulic chain tensioner, you will need oil pressure in the system to remove slack in the timing chain before checking the timing chain, guide and sprocket wear!  See my notes below before proceeding...With the chain tensioner pressurized, slowly rotate the crankshaft in the normal direction of rotation and just bring the TDC mark up to "0" without passing TDC.  Note the camshaft sprocket position.  Now slowly rotate the crankshaft in the opposite (reverse) direction until the sprocket just starts to move.  Note the degrees or distance the crank pulley has moved before the camshaft sprocket begins moving.  Now rotate the crankshaft back toward TDC to confirm that the camshaft sprocket will begin to move at approximately the TDC point.  I use a rough figure of 5/8" maximum pulley movement or slack/play on an 8" pulley to determine sprockets and chain wear.  This is measured at the crankshaft pulley's outer edge and the timing cover markers.  (On an engine without an overhead camshaft, the distributor rotor and crankshaft pulley can be a means for testing the timing chain wear.  I share this information at the General Repairs forum, too.)   Check the valve timing alignment points with the TDC mark.  This is also telling with regard to chain, guide and tensioner face wear.  When checking valve timing, always rotate the crankshaft in its normal direction of rotation and do not pass the TDC mark.  Retarded valve timing is a sure sign of sprocket wear, chain stretch and/or chain guide and tensioner wear.

 

Note:  Unless there is oil pressure, the stationary timing chain and tensioner check will not be accurate on an engine that has a hydraulic, oil pressure actuated tensioner (engines like the earlier Toyota 18RC four-cylinder engine or the Toyota 20R, 22R and RE engines).  If you must test a stationary engine with a hydraulic chain tensioner like the Toyota 20R or 22R four-cylinder inline engines, try pressurizing the oil system with an oil priming tank.  Set priming tank pressure to at least normal engine operating pressure.

 

Additional Toyota 20R/22R and 22RE timing chain and sprocket concerns:  The 22R and 22RE are notorious for timing chain, chain guide and tensioner wear.  The single roller chain is most troublesome, and this includes your '85 engine.  The chain guides and tensioner surfaces wear out.  Look for deep grooving in the guides, try to inspect the tensioner surface if viewable.  Chain and sprocket wear is measureable.  The chain should not exceed 147mm or 5.877" spacing between 17 links when the chain is pulled taut.  This is impossible to measure with the engine assembled.  The tensioner is more apt to wear its contact face than fail hydraulically, although the symptomatic rattle at startup that disappears when oil pressure rises is the timing chain/guides and tensioner before the tensioner takes up slack.  Other measurements, including sprocket wear can be done, too.  I can furnish dimensions, though this can only be measured with a new chain as a reference.  Valve cover removed, look down the chain guides to inspect for wear.  The chain gets looser as the guide grooves deepen.

 

4)  Normal oil pressure:  This is dependent upon bearing clearances and general wear, including the oil pump.  On a stationary engine, oil pressure and bearing oil "bleed-off" could be tested with an oil priming tank set to normal oil pressure level or higher.  Steadily prime the lubrication system and try to hold that pressure within the system.  If there is rapid pressure bleed off, this could hint of excessive bearing clearances.  Slower bleed should be considered normal.  With pressure applied steadily from the tank, the engine bearings should hold some degree of pressure, although there will still be a continuous bleed-off at the valve train and the engine's lower end bearings. 

 

Trust this is all helpful to those buying or testing used engines and needing to know the engine's condition before installation in the chassis...

 

Moses

[Speed]

Thanks Moses;

   Here's my thinking on this particular engine. After having Dutch hear it run and drive it,I feel pretty comfortable that it'll run for a while without major issues. Before installation,I'm going to clean the engine and pull the valve cover,and look at the  guides from topside;if they look okay,I'll go with it as is and install the engine in my truck. If it makes bad sounds with the exhaust sealed up,I'll plan on going into it later,if not too bad. (Remembering my original timing chain,which I could clearly HEAR it rattle,but on opening it up,everything except the tensioner looked fine,I COULD easily have used the guides again,but since I had NEW ones...) Before installing the engine,if the guides appear overly worn,I'll probably just figure it for rings,bearings and a new double row timing set with the metal-backed guides,and probably an oil pump,and keep driving the leaker while I do this,THEN swap it. As much as I'd like to rebuild the original engine,with over 300K on it I suspect it'll need more than rings-n-bearings,plus it has a hole or two with buggered threads and possibly (probably?)a cracked timing cover,so I'd save THAT engine for an extensive going over later on. My big issue is that,to do a timing chain on this engine,it's highly recommended that I pull the cylinder head. (Trying to avoid that is what started this mess.) At that point,I might as well just do the rebuild and get it over with,so the break over point is pulling the head. If I can use it as is or make it relatively good short of that,I'll run it;if it takes anything more,it's overhaul time. Once the BroncWorth is operable and legal,I can spend more time on the 'yota and put more effort ($$) into doing it up right. A LOT of this depends on a lot of other factors,it truly is a matter of "making my choices on-the-run". It appears the "look down the timing case and see how it looks" method is pretty universally accepted,so I'll go with that.

Speed

[Moses Ludel]

That's a plan, Speed!

[Speed]

   I pulled the tappet cover off,and that engine's VERY clean inside,the mechanicals appear to be relatively new;it has a single row timing chain (the stock '81 has a double row-why the difference? Can the single row be as reliable as the double row,which lasted about 300,000 miles?),the chain guides show just a little wear. I'm more concerned about the tappets,where they slide on the cam lobes. While the cam lobes look new,the edges of the tappets that rub on the cam lobes appear to have "debris". It's the kind of thing you see when you apply a piece of metal the the bench grinder for a while. Makes me wonder if someone replaced the cam (or even rebuilt the engine?) but didn't "tune up" the tappet edges. not sure if it's worth taking it apart and applying a little filing to those edges or not. Another couple of weeks I'll have the BroncWorth tagged again,and I can start working on the Toyota. (Turns out it has developed more issues. Needs the engine swapped,rear brakes and axle seals,rear pinion seal,probably a wheel bearing on the left front,both Birfields replaced,all the front end seals replaced,at least one u-joint,but if I do one,I'll do 'em all,both E-brake cables and a set of shocks. Not needed but wanted badly is a Spartan Locker in each end,an A/C compressor and bracket for On Board Air,and a speedometer with a working odometer. (I'm also hearing a "knock" in the T/C in low range,maybe a chipped gear,but I think it'll live.)

   Speed

[Moses Ludel]

Lots of work in store yet, Speed! Make sure the cam lobes look okay...

There's controversy about Toyota's switch to a single row timing chain and lighter tensioner. We had an 18RC powered station wagon right after college days, the not so high miler succumbed to chain tensioner issues. I did the repair, including head removal and all, in the driveway carport. Toyota compensated for timing chain and tensioner shortfalls with the bulletproof 20R then apparently backtracked to the single row timing chain. My guess is the need to reduce valvetrain rotational mass on a light engine.

In any case, most 22R and RE engines made the 300K Club in the day. 300K with a single row chain gets lower odds than the double-row, though you're likely going to get considerably more miles out of that replacement used engine. One sure thing is the amount of work that you're doing, which in itself should extend the lifespan of the Toyota—you'll be working on it a good deal of time and not driving it! The transfer case noise is a bit disconcerting. Keep an ear open around that one...

Moses

[Speed]

It occurs to me that my T/C noise could be the loose Birfield telegraphing through drivetrain to the T/C. Another one of those things that make you go "HMmmmmmmm...."

   Oh-we now have a NEW problem. When I got this truck the brakes were rough,to say the least. I replaced both front calipers and the pads with new ones. all was fine until recently,when the rear brakes started dragging,due to axle seals oiling the brake shoes.  I cleaned 'em up real well with brake cleaner and backed the adjusters off about a turn,and all was well again.but,no-now the front brakes are doing it,I suspect from the steering knuckle seals leaking 90 wt. onto the rotors and pads. Maybe I should give up,but I can't make myself give in to the little monsters that keep giving me grief. As soon as I have the BroncWorth reliable enough to use,I can take the Toyota off the road and do all the  repairs needed to make IT reliable again,but even then,it'll be just an old rolled Toyota truck. (With CHARACTER!)

Speed

[Moses Ludel]

Speed...I do like the beam axle Toyota 4x4 pickups!  This was the trend setting truck of its era, a scaled down, proven Land Cruiser design that really shined.  That said, at the mileage on your gem, this is the kind of rebuilding and service work required...Keep the Toyota 300K Mile Club in mind!  These were the trucks that lived up to it.

Moses

[Speed]

"Keep the Toyota 300K Mile Club in mind!  These were the trucks that lived up to it."

   I'd love to do that,but I don't have any proof of its miles except what the original owner told me,and the fact that it looks like a candidate for the Million Mile Club.

Speed