1992 Toyota Camry Timing Belt

[tripplite]

Recently had to go to PepBoys (dont hang me for this as I already feel as I have made a mistake) to get an emergency replacement of the water pump on a 92 Camry 4 cylinder. Car had approximately 108K miles on it so asked for timing belt replacement.

I am not a mechanic by any means.

Got car back and it seemed to be OK but sluggish (i.e. pick up in acceleration was not what it was before). Brought it back and the mechanic showed me a couple of things 1)said slack in transmission cable was cause and 2) cracked air flow hose. Also he said he made some sort of adjustment to the timing. Showed me timing light and something about it being stable proving proper instatllation.

I notice the car is noiser than usual though it is more peppy. He did make some sort of adjustment to the ignition timing. I am not a mechanic but could he have altered the timing to compensate for improper installation of the belt? Can someone explain ignition timing versus valve timing to me? What damage might this cause, if any? Did I get a bad water pump? Getting noiser by the day seem like and this is about 200 miles after installation.

How can I check that installation was proper? Should I take it to another mechanic to get it double checked and what do I ask for?

[Daniel M. Dreifus]

Best idea is just to save up your money and have the job done right.
Learned years ago not to buy Pep Boys parts when the lifetime starter failed three times, and then the water pump excuse me for saying so puked its guts on the freeway. I was able to coast for about a quarter mile off the freeway, but had to pay for towing all the way back home. Water pump shaft was dangling loose in the housing - both seal and bearing were gone.
Yes. If the engine is not running right, the timing could be off, and yes there is a difference between valve timing and ignition timing and yes, you might be able to hide one by adjusting the other.
The timing belt controls the valve timing.
I always insist on genuine Toyota parts. They're made better and last longer than Pep Boys parts.
Anyway, since you asked, and I've done the work myself, the timing belt moves the water pump, oil pump, and camshaft. There are two idler pulleys, one stationary, and one that moves to put tension on the timing belt, that should also be checked when the timing belt cover is removed. They need to remove the pulleys and turn them by hand to check for quiet, smooth operation. When I did this on mine at 120,000 miles, they both made noise, but I was going by the advice of a mechanic in Texas who always replaces all the oil seals and bearings along with the water pump and timing belt, so I already had the new parts on hand. If you buy online, or shop the dealers, you can sometimes get substantial discounts on genuine parts.
So the timing belt turns the camshaft. You have double overhead camshafts. One is turned by the timing belt, and the second runs off a gear, meshing with the first.
There are four valves per cylinder, and no rocker arms. This makes for good engine breathing and efficiency, plus low reciprocating mass and low wear, and little need for periodic adjustment. But you have to get the timing belt installed just right. It is easy to be off by one tooth on the belt, and if you are, the engine won't run right. You will lose power because the valves aren't opening at the exact proper degree of engine rotation in relation to the piston movements.
Now at the other end of the camshaft, is the distributor which controls the ignition timing. Ignition timing, is when the spark plugs fire. Also very important, but different from when the valves open. What they share in common, is they are both tied into the camshaft. So if the timing belt isn't right, the distributor movement will also be off, but you can adjust the distributor by loosening one or two bolts on the outside of the engine and just turning the housing. Much easier than doing the timing belt all over again, because one of the engine braces has to be removed to reach the timing belt.
Point is, moving the ignition timing to mask a problem with the timing belt doesn't really solve the problem.
By the way, there is an oil sealing ring, around $2 for the part, that you can change at the base of the distributor and should probably be done at the same time.
Also a good idea to change the valve cover gasket and spark plug tube seals.
There's also a grommet for the PCV valve that should be changed, because it hardens and is easier to remove the fragments if it breaks in pieces, when the valve cover is off. When hardened, oil can seep from there also.
When you're changing the timing belt and water pump, should also probably be changing the spark plugs with factory platinum plugs and checking or replacing the spark plug wires, distributor cap, distributor "packing" the thin gasket under the cap that protects your electronics inside, and the rotor.
You're also supposed to change the gas cap gasket or just replace the cap.
Also supposed to check the sub frame mounting bolts.
Also, when you change the timing belt, since you have to remove them anyway, it's a good idea to replace the other belts for power steering and alternator.
Also a good idea to change the power steering fluid, transmission and brake fluid.
But, as I say, you could save up for these items to get them all done right.
To fix the timing belt adjustment you basically have to do everything all over again, except you're not using new parts.
Once the timing cover is removed (or upper half), you set the mark on the crankshaft to top dead center, then check to see that the mark on the camshaft sprocket is in exactly the right location with tension on the front of the timing belt.
There's another trick to installing the timing belt. You have to get the tension right. Assuming four cylinder, you should always replace the spring for the tensioner pulley with a new spring. I can't imagine you would still have the original, but there is an upgraded part. Also, the new spring probably has better tension than the heat aged old one, and they're cheap to buy. But you can't rely on that little spring to tension the belt. You need to pry hard on the pulley to fully tension the belt, then release that heavy pressure and let the spring hold the belt as you tighten down the tensioner pulley bolt.
There is a small indentation on the camshaft bearing that is visible through a tiny hole in the sprocket when everything is aligned correctly. You probably need a small mirror to see it, since the strut tower is in the way. I used a round tooth pick to insure it was pointing straight out. Like I said earlier, it is easy to be off by one tooth and the engine will still run, but won't run right. That would also cause the ignition timing from the distributor on the other end to be off - and you could adjust that, but when you put the timing right, you would have to adjust it back.

[Daniel M. Dreifus]

That part about "slack in the transmission cable" doesn't sound quite right either. There's supposed to be some slack. If you adjust the accelerator cable so that the butterfly valve is fully open when the gas pedal is pushed on the floor, the transmission cable adjustment should be right since there's less tension on that cable. There's also an iron stop like a small fishing weight on the transmission cable. IIRC, with the gas pedal on the floor, that marker on the cable should be at the end of the cable housing. (either that or it's the other way around and the marker is at the end of the housing at idle, but I think it is at full throttle)
The part about a cracked air hose sounds right though. That's not uncommon. With the four cylinder it won't affect engine operation because the MAP sensor is connected to the manifold, not the air tube, but cracks can let unfiltered air into the engine, so you should replace it.
As you've probably figured out by now, people messing and guessing with your car can sometimes cause more harm than good, but hopefully even the third rate Pep Boys water pump is an improvement over the one replaced on an emergency basis. But I stand by my original point, that once you're past the emergency, you should save up and get the job done right if you plan on continuing to drive that car.
Properly cared for, that engine and transaxle can last a long, long time.
Here's another thought. Dealers often have timing belt specials for $100. Might be less if they just need to check the belt is on the right tooth and double check the ignition timing. If Pep Boys adjusted it, you almost certainly need to change it back because installing a new timing belt should put it exactly back at the original factory setting with no other adjustment required.

[Daniel M. Dreifus]

One final thought.
If you're at 108,000 miles. All that servicing described earlier is due at 120,000 miles.
So if you have the dealer set the timing belt and distributor right, you've got 12,000 miles to save up for the other items, and the cheap water pump ought to last that long hopefully. :-?)