Balance chain procedure (two)

Balance chain/sprocket replacement

This write-up is Robert Kaplan's, verbatim. He sent nice pictures with it, but (with one exception) I was unable to include them because they didn't cross properly from his platform to mine. Many thanks to Robert for his efforts. The one exception picture dramatically illustrates the balance chain drive gear wear problem.

INTRODUCTION

I performed this procedure on a 1991 9000 Turbo. I decided to undertake this project after reading about catastrophic failures on 1991-1992 model year 9000's resulting from a failure of the balance chain crank sprocket. My experience validated this concern as the balance chain crank sprocket on my car was about 60% worn. My car had 155,000 miles at the time I did this project. Picture.

This is a fairly large undertaking. I had the benefit of time since I had my car stored in the garage for the winter. I don’t really have an estimate of how long it took to do this since I worked on it sporadically over the period of about a month. However, my best estimate is that the entire project could be completed in a couple of days of steady work by a decent amateur wrencher like myself.

GETTING STARTED

This project requires removal of the water pump. Removing, and particularly reinstalling, the water pump is a lot easier if the ac compressor is removed. I would at least consider getting the ac system discharged in cars already using r134a. Most shops that do a/c work will evacuate and recharge, when you are ready, for a reasonable fee. The reason professional assistance is required (beyond the environmental issues) is that a deep vacuum will be necessary before recharge. In cars using r12 (freon), which are model years 1992 and older, I would consider leaving the ac compressor in place.

Jack up the right front of the car.

Remove the wheel and both parts of the inner fender liner.

Remove the lower engine cover next to the inner fender liner and the center lower cover under the radiator.

Identify the water pump pulley and crack the four bolts on the front of the pulley (just loosen them).

The reason to do it now is to try to use the belt tension to hold the pulley still while you loosen the nuts.

The pulley may still slip on the belt, but try it anyway.

Drain the engine oil.

Remove the oil filter.

Drain the coolant by either unscrewing the drain cock using needle nose pliers, or removing the lower radiator hose. The drain cock is on the bottom of the radiator on the right side.

Remove the serpentine belt by depressing the tensioner.

I use a 24", 1/2" drive craftsman breaker bar with a 19mm socket.

Drop the socket down from above, push toward the back of the car with your right hand and slip the belt off the idler pulley with your left hand, then release the tensioner. Don’t worry about keeping the tensioner retracted using a special tool or other means because the tensioner assembly has to be removed.

Remove the pulley on the tensioner assembly. The tensioner pulley bolt has left-handed threads, so turn clockwise (pull forward) to get the pulley off.

Remove the idler pulley. The threads are normal on this one.

REMOVING THE CRANK PULLEY (HARMONIC BALANCER)

I call the “harmonic balancer” the crank pulley. Because that’s what it is. Since it’s hard to justify $300 for a pulley, the Saab Dealer calls it a “harmonic balancer.” They also call salespeople “client advisors.” But that’s a different tirade.

	The crank pulley is held on by a bolt with a 27mm head. Don’t be tempted by a 1-1/16th socket. Get the 27mm socket. [QUASI'S NOTE: A non-metric socket worked for me, but maybe that's because it was a 6 point rather than a 12 point.] If you have air tools, an impact wrench will zip that thing right off. If, like me, you have air tools, but your kids’ bedrooms are over the garage, and your only free time is late at night, the air tools don’t do you much good.
	Haynes says that in a car with a manual transmission, you can put the car in 4^th gear and that will hold the crankshaft in place enough to get the crank pulley bolt on and off. I haven’t tried it. [QUASI'S NOTE: There's so much rubber in the driveline that I doubt this would work.] The method I use is to jam the flywheel with a big screwdriver. Go over to the left (driver’s) side of the motor and look right below the large radiator hose running to the thermostat housing. Right below that hose, on top of the transmission, is a square opening. If you look carefully, you can see the teeth of the flywheel. Take a big screwdriver (flat blade) and insert the blade between the teeth. I found that starting from near the battery and angling down that way gets the best angle to grip the teeth.
	Now, use a breaker bar to remove the bolt. I use a 24" Craftsman bar that works fine. The crank pulley bolt MUST be torqued to 129 ft/lbs, so getting it loose can take some pulling. I have never had a problem sliding the pulley off after the bolt is removed. Supposedly you can use 2 screwdrivers to gently pry it loose if it’s a problem, but I have no experience with that.
	I understand that 1994 and newer cars don’t have the opening on top of the transmission. Which leaves the impact wrench or the 4^th gear method of jamming the flywheel. However, if your newer car is an automatic, you can remove the starter motor to jam the flywheel through that hole. Which may be a little easier said than done. And, of course, supposedly the better balance crankshaft sprocket started with 1993 or 1994. So may be you would not need to do this at all.
	[QUASI's NOTE: Many say you can put a socket and breaker bar on the bolt head with the breaker bar positioned near the ground, then crank the engine to break the bolt loose. Personally, I used the screwdriver-in-the-flywheel teeth method.]

REMOVING THE TENSIONER ASSEMBLY

First remove the top bolt which goes through the tensioner strut.

There is a funny spacer that goes in here, don’t lose it.

Remove the bolt in the center of the tenioner assembly.

The arm that is attached to the top bolt is also attached here. Remove that arm.

Underneath the second bolt is a snap ring (“circlip” for you harmonic balancer types) on the post that the bolt screwed into. Remove this snap ring and the tensioner assembly pulls off the post.

Now look at the bracket that the top tensioner bolt screwed into. Remove this bracket by removing the two bolts holding it to the cylinder head.

Here's a picture of the tensioner.

REMOVING THE POWER STEERING PUMP AND BRACKET.

There are two hoses attached to the power steering pump.

Position a suitable bucket under the pump.

Remove the larger hose by undoing the hose clamp and pulling the hose off the back of the pump (ine was hard to get off).

The power steering fluid will drain out.

The other hose is the pressure hose and is secured by a 15mm or 16mm nut. Loosen the nut and the hose comes out of the pump.

I covered the ends of both of these hoses with fingers from rubber gloves to keep dirt from getting into them.

The bolts holding the power steering pump onto the bracket can be seen through the holes in the power steering pump pulley.

	There are 2 bolts with 10mm heads. Turn the pulley, look through the holes in the pulley, and you will see them.
	Remove these bolts and the power steering pump comes right out.

Now you have to remove the bracket.

The bracket is held in place by 4 bolts in the rear with 12mm heads and a bolt through the front with an 8mm allen head.

The 8mm allen head bolt is also the lower mounting bolt for the alternator. Take that one off first.

I have a ratchet attachment with an 8mm head, which makes this easy.

You can see the lower 2 bolts holding the power steering bracket on in the back. There are 2 you can’t see about 4" above each of these.

Remove these 4 bolts and you can pull the bracket out.

REMOVING THE ALTERNATOR

Don’t even try to remove the alternator without first removing both the power steering pump and the power steering pump mounting bracket.

DISCONNECT THE NEGATIVE BATTERY CABLE, then put a plastic cap over the negative terminal on the battery. The negative cable is the safest one to disconnect; disconnecting the positive cable first is bad practice, because if your wrench contacts the frame, very nasty sparks will fly.

Climb up onto the motor and look at the back of the alternator.

There’s a plastic cap covering the red cable going to the alternator. Remove the plastic cap.

Unscrew the 10mm nut under the cap.

Remove the washer and the wire from the post. Put the washer, nut and cap back on so you don’t lose them.

There is a small wire attached to the alternator near the big red wire. This one just slides off the post.

The alternator is held in place by 2 bolts with 8mm allen heads. You have already removed the lower bolt to get the steering pump bracket out. The upper bolt is the problem. It’s too close to the fender to get a ratchet on, so you have to use an 8mm allen wrench. The problem is that most 8mm allen wrenches aren’t long enough to get any real torque. What I did was to stick the end of the allen head wrench into the female end of a 3/8 inch extension bar and used that as a cheater bar. It worked well enough to get the bolt loose. Loosen this bolt out of the threads. You cannot pull the bolt all the way out, but this is ok. Supporting the alternator from underneath, move the alternator toward the back of the car and the top bolt will slide off the mounting bracket which is open at the end. Get ready, that bad boy is heavy. Draw the alternator out through the hole where the power steering pump used to be.

REMOVING (AND REFITTING) THE WATER PUMP

I was able to remove my ac compressor since my system had conveniently discharged itself. I am sure removing and refitting the water pump is easier if the ac compressor is removed than it would be otherwise. If you can, remove the compressor and the compressor mounting bracket. The water pump is right below the ac compressor. If you don’t remove the ac compressor, then I would suggest getting a hand mirror so that you can see what’s going on down there.

The water pump is held onto the timing cover by three bolts. There is also a fourth bolt that is the lower bolt for the ac compressor mounting bracket, which screws into the top of the water pump. If your car is a turbo, there is a bolt with a 19mm head securing the turbo cooling line to the back of the water pump. In all cars, the water pump also connects directly to the block via a round connector. The last fixed connector is the metal pipe which runs across the back of the timing cover right above the oil pump. In addition, there are 2 rubber hoses connected to the pump.

First, unscrew the bolts holding the pulley onto the water pump and remove the pulley. I did not do it this way because I did not think to loosen the pulley bolts while the belt was still on. I was not able to remove the bolts without some tension on the pulley, but I really didn’t try that hard. Since I had removed the ac compressor, I was able to pull the water pump out with the pulley still on. It might be possible to loosen the water pump pulley bolts by just grabbing the pulley with one hand and loosening with a wrench in the other hand.

Disconnect the rubber hoses by loosening the hose clamps and pulling the hoses off. Next, if turbo, remove the 19mm bolt at the back of the water pump. One look at that bolt and you are going to groan. Yes, that bolt must come off even though seeing this bolt, and getting a wrench on it, are 2 different things. However, hopefully the 2 hours I spent trying to get at this bolt will save a lot of time and aggravation for others. Here’s how: Get a 3/8" extension bar of at least 18" in length. Attach a u-joint to the end of the extension and attach the 19mm socket to the u-joint. Get underneath the car. Starting from the opposite side of the exhaust, push the extension bar up toward the bolt staying as level with the bolt as you can. Basically, you run the extension directly below the air intake and the turbo to the back of the water pump. With your other hand, support the u-joint and push the socket on to the bolt. NOW remove the bolt.

Next remove the lower bolt for the ac compressor bracket. You may have already removed this if you removed the compressor and bracket. Note, when removing this that the wire for the oxygen sensor is attached here. Below the ac compressor bracket bolt are the top 2 mounting bolts for the water pump. Remove these 2 bolts. At the bottom of the water pump is the third mounting bolt. Remove this also.

Now pull the pump to your right to separate it from the metal hose running across the timing cover. Then pull the pump toward the right and down to pull it out of the block. As soon as the pump is free, it can be removed from the car. With the ac compressor in place, I am not sure if the pump can be removed from the front or if it has to go out through the right fender. If the ac compressor is removed, just pull the water pump up and out.

Look at the long tube on the back of the water pump to see if the connector is attached. If it’s not there, reach up to where the water pump goes into the block and pull the connector out.

If you are replacing the water pump, as I was, then you need to separate the 2 halves of the pump. The replacement is only for the front part. Unscrew the bolts holding the pump together and pull the back part off. Throughly clean the mating surface of the back part of the pump you will be re-using. I used a utility knife and then brake cleaner to get the old gasket off. The new pump comes with a new gasket and new o-rings. When reassembling the pump, I used Loctite 518 (anaerobic gasket maker) on both sides of the gasket because this is what Townsend recommended.

Next, turn your attention to the round connector. Remove the old o-rings and throughly clean this whole item. I again used brake cleaner to clean this inside and out. Fit the new o-rings and work petroleum jelly into them. Fit the large end of the connector into the end of the water pump. It’s a tight fit so tap it in with your hand.

When it comes time to reinstall, everything is the reverse of removal. However, pay attention when putting the back of the pump into the block that you don’t bang up the o-ring trying to figure out where the hole in the block is. If you crane your neck, you can see the hole from the side. Also, if you didn’t remove the ac compressor, note that the top of the pump mounting flange goes under the lower mounting bracket for the ac compressor. When reattaching the pulley, torque the nuts to 6 ft./lbs. I was able to do this holding the pulley in one hand and using a ratchet wrench with the other. I did not say that was easy.

REMOVING THE OIL PUMP

Looking at the front of the timing cover, the oil pump housing is bolted directly to the timing cover. On 91-93's, the oil pump cover is a large irregularly shaped cover held on with bolts. On later years, the pump cover is round and is held on (I think) with a snap ring. The crank position (knock) sensor is attached to the front of the oil pump housing with 2 torx screws (I believe they are T-25). Remove the sensor. I covered it with a finger from a rubber glove. Remove the wire for this sensor from the mounting bracket on the timing cover and let the sensor hang behind where the power steering pump used to be. Later model cars may not have this sensor.

Remove the 17mm nut from the bottom right corner of the oil pump housing. This is the oil pressure relief valve. Remove the spring and the little cup the spring fits into. You may have to stick your pinkie in to get the cup out. If getting the cup out is a big problem, try again after the pump is removed.

Remove the 12mm bolts securing the pump housing. Now remove the longer 13mm bolts. Pull the oil pump housing away slightly from the timing cover. Reach your hand behind the pump cover and pull the oil pump housing off the crankshaft, making sure that it all stays together.

Examine the back of the oil pump housing. Those 2 gears are the oil pump. Picture. Note that the outer gear has a small dot on it that you can see. Make sure, when you put it back together, that this dot is again facing you. You are supposed to keep the alignment of the gears the same when you put it back together. Meaning that the same teeth on the gear sprockets should interconnect at the same place. I am not sure I was totally successful doing this. If you are going to be replacing the main seal, you will have to remove the gears. Otherwise, I suppose you could just leave them in. Also, if the gears look at all questionable, it is a very good idea to replace them since weak gears may not be able to re-prime the pump when the engine is restarted.

REMOVING THE TIMING COVER

Now everything is removed except the metal hose running across the timing cover and the bracket holding wires to the side of the timing cover. Picture.

First remove the wire bracket by pulling the wires out and undoing the bolt.

Next, the metal hose has to be positioned above the timing cover and held in place while the cover is removed.

To do this, the bracket which holds the metal hose in position must be disconnected. This bracket is located on top of the thermostat housing, which is below the throttle body on the other side of the engine.  Look beneath the throttle body at the thermostat housing.   Picture. You will see 2 bolts with 10mm heads screwed into the thermostat cover. Remove these 2 bolts and you will free the bracket which holds the metal pipe. Note that the lower of the 2 bolts also has a ground wire attached. Don’t forget this wire on re-assembly.

After the metal bracket is freed, go back to the timing cover and pull the metal hose toward you and up. I secured the metal hose out             of the way with a plastic cable tie.

Remove all bolts remaining on the timing cover.

Since these bolts are all different lengths, I took a piece of cardboard and drew a picture of the timing cover with an “x” for each bolt. As I removed each bolt, I put it into the cardboard cutout.   This made keeping the bolts organized very easy. Picture.

Note that the metal plate for the serpentine belt tensioner post must be removed.

This is removed by removing the 40mm torx screw and 2 bolts.

Remove this plate and there is another bolt underneath.

After all the bolts are removed, you are supposed to be able to pull the timing cover off. I couldn’t. I pulled and pulled and pulled, and nothing. Finally, I got out the hammer and tapped it off. Actually, to get it going, I banged it pretty hard. On the left side (looking straight at the cover), I was able to hit the timing cover directly in the area where the power steering pump bracket attaches. On the right side, I stuck a large screwdriver on the top rear of the cover and hit the screwdriver with the hammer. Once the cover was separated enough to get fingers behind it, I was able to firmly, but gently, pull it off.

I have read that removing the timing cover is the point where you are most likely to damage the headgasket and, therefore, great care must be exercised in this phase of the task. However, the headgasket on my car seemed to survive banging the timing cover off with a hammer. Although I did bang the timing cover off, I did attempt to do it evenly, making sure that neither side was much further out than the other.

BALANCE CHAIN AND SPROCKETS

The balance chain system consists of a chain, four sprockets, one tensioner and two independent guide rails. There is also a third guide rail which is actually the outside edge of a timing chain guide. The sprockets include a crank sprocket, an “intake” sprocket, an “exhaust” sprocket and an “idler” sprocket. The intake and exhaust sprockets are attached to the respective intake and exhaust balance shafts. Picture (note the color code text on the picture page).

Before disassembling anything, examine the intake and exhaust sprockets. You will note that there is a groove on the edge of each sprocket which lines up with a groove on the balance shaft housing. There is also a raised mark on the balance shaft behind the sprocket which should be aligned with the groove on the sprocket. When the motor is at top dead center, these marks should all line up.

To remove the balance chain:

Remove the upper guide rail at the top of the chain by undoing the two bolts.

Remove the tensioner by removing the two bolts holding it in place.

Remove the sliding side rail against which the tensioner pushes, by sliding it off the post.

To remove the chain, you must now remove the idler sprocket which is the top right sprocket

Remove the bolt securing the sprocket.

The idler sprocket is a two piece item consisting of the sprocket and the shaft it rides on.

On my car the sprocket would slide on the shaft but the shaft did not want to pull off. The tension of the chain prevents removing it from the idler sprocket without also removing the idler sprocket shaft. Gentle pressure finally got the idler sprocket shaft loose. When it is loose, pull down and to the left and it should come free. Once it is removed the chain can be pulled out.

In theory, the balance chain crank sprocket simply pulls off the crankshaft. However, the drive dog for the oil pump rides on the crankshaft directly in front of the balance chain crank sprocket. I could not get the drive dog to budge. What I ended up doing was putting on work gloves and pulling out on the balance sprocket. With much effort, the drive dog finally moved a little. I then tapped it back to where it was with a hammer and screwdriver and pulled again. Eventually, the drive dog and sprocket came off the crankshaft. I think the problem was largely just the film of dirt on the surface of the crankshaft. I throughly cleaned the exposed portion of the crankshaft and the inside of the drive dog and was able to refit it without too much trouble.

Another thing to examine here is the ridge into which the cutouts in the crank sprockets fit. This ridge is actually a removable key. Make sure that this key is seated neatly in the groove on the crankshaft and that it fills the cutouts in the sprockets.

I did not find it necessary to remove the intake or exhaust sprockets. These sprockets and the idler sprocket appeared to be in very good condition and I decided not to replace them. The intake and exhaust sprockets would be tricky to get off because the bolts rotate with the sprocket (as opposed to the bolt on the idler sprocket, which does not). If I had needed to remove them, I probably would have wrapped the old chain around the sprocket, held it tight with vise-grips and then tried to get the bolt off. I suspect that refitting new sprockets would be even more of a challenge than removing the old sprockets because the intake and exhaust sprocket have to be torqued fairly tight, and the groove in the sprocket has to be aligned with the mark on the shaft.

My 91 came with metal guide rails. The guide rails seemed in good condition and I did not replace them. I understand that later model year cars have plastic guide rails. These are very cheap and should be replaced. The chain and tensioner should also be replaced as a matter of course.

To re-assemble:

The chain must be put on with the motor at Top Dead Center (TDC). This is essential so that the balance shafts will be timed with the motor.

First, slide the new crank sprocket on to the crankshaft.

Next, slide the oil drive dog back on the crankshaft.

Now take the crank pulley bolt (but not the pulley) and screw it into the end of the crankshaft. The bolt must be tightened enough so that the crankshaft can be turned in both directions.

You might have to jam the flywheel while tightening the pulley bolt.

Next, rotate the crankshaft by turning the crank pulley bolt. Look into the hole on top of the transmission where you jam the flywheel and watch for a series of numbers to appear on a metal strip next to the flywheel. A helper would really make this easy since you can’t turn the crankshaft and see in the hole on top of the transmission at the same time. What you need to do is to align the “0" with the perpendicular hash marks on the transmission casing. Try to get this exact. Picture.

Once the motor is at TDC, wrap the chain around the crank sprocket and the Intake sprocket.

Now drape the chain over the Exhaust sprocket.

Lift the chain off the Intake sprocket and turn the sprocket until the timing mark aligns with the timing mark on the housing.

Now do the same thing with the other sprocket.

Try to keep the slack in the chain on the right side.

Hold the idler sprocket and shaft together and fit the chain onto the idler sprocket with the shaft not in place.

Move the idler sprocket shaft assembly back into position and hold it there with your right hand.

Examine the intake and exhaust sprockets to make sure that the timing marks are still aligned.

Now pull on the left side of the chain to simulate the tensioner and see that the timing marks are still aligned. I put the sliding rail back on to get a better idea of the effect of the tensioner.

If they are not aligned, pull the idler sprocket/shaft down to create slack in the chain and try moving the chain around to get everything to line up. This took me a long time to get right.

When done, install the bolt for the idler sprocket and tighten.

Iinstall the upper guide rail

Install the sliding side rail

Install the tensioner.

The new tensioner comes with a pin in the middle which holds the arm retracted. Don’t pull this pin until you are done. If you need to take the tensioner out to redo it, turn the arm of the tensioner 180 degrees and push it in. You can hold it in place by rotating the tensioner arm 180 degrees while retracted and reinserting the pin.

The last thing to do is to turn the crank pulley and make sure the timing marks on the sprocket retain their alignment.

REFITTING THE TIMING COVER

The next step is to refit the timing cover. Before doing anything, you must thoroughly clean the mating surfaces of the timing cover, block and sump. I used a full can of brake cleaner getting the oil residue off. Note that the timing cover fits onto posts in the block. On my car, the original grease was still there, but was dried out. The cover will not want to go back on if you don’t get rid of this grease.

Also, examine the head gasket. Mine had a little bit of abrasion on the bottom right side. I trimmed this off with a razor blade. The clearances are so tight refitting the timing cover, that lose material from the head gasket could bunch up and cause the timing cover not to go all the way on, or damage to the head gasket.

The last thing to take a good look at is the black o-ring in the oil sump surface. I read a post on the TSN about someone getting this bunched up putting the timing cover back on and subsequently losing oil pressure and the motor. This was not an issue on my car since it didn’t move at all.

The next step is to apply the sealant. However, before doing that, I tried a couple of dry runs figuring out how the timing cover fits back on. This proved to be very useful when I was ready to put it back on for real. I was also able to reassure myself that the sump o-ring would stay in place.

Apply a continuous bead of sealant around the entire mating surface of the timing cover. This includes the top and bottom of the timing cover.

The correct sealant is Loctite 518 (anaerobic gasket maker).

Apparently, you can use blue silicone on the sump surface, but I just decided to use 518 on the whole thing.

Loctite 518 might be hard to find, but it is available if you look.

Put the timing cover over the crankshaft and gently place it onto the sump. Gently push it into position. I used a lot of firm gentle pressure with a slight rocking right to left.

I got the cover completely on the left side, but could not push it all the way on to the right side. I tapped the right side gently with a hammer and it went into position.

Put the bolts back in and torque them down in a criss-cross pattern to try to get an even seal.

REFITTING THE OIL PUMP

This is a good opportunity to replace the oil pump o-ring and main seal. The main seal is not that hard to do as long as you note how deep the original seal was. Use a screwdriver to pry out the old seal. Use a tube (or socket) the same diameter as the outer edge of the main seal to pound the new one in. A plastic plumbing pipe extension piece can work nicely. [QUASI NOTE: I missed the proper depth when I put in a new seal. As a consequence, the new seal leaked for a month or so, but it did seal effectively after it had some time to wear in.]

The o-ring for the oil pump is another story. If you have one of the early 2.3's like mine, the o-ring is about the diameter of a cake plate and fits into zig-zagged groves on the back of the oil-pump cover. Plan on an hour to get that sucker in well enough to get the pump cover back into position. The problem is that o-ring is so big and the grooves are so erratic that as soon as you get it in on one side, it pops out somewhere else. It does actually fit even though you will surely think you were sold the wrong part. Try to avoid throwing the oil pump cover across the garage as I am sure it would be expensive to replace. [QUASI NOTE: Maybe something like Vaseline or axel grease would help to keep the o-ring in place.]

REFITTING THE REST

The rest is basically just the reverse of removal. Remember (I didn’t) that the alternator has to go in before the power steering pump bracket. Also, the top bolt for the alternator is the one with the washer. Make sure that the oxygen sensor cord is correctly secured.

Don’t forget the following basic things:

1. Re-install the engine oil drain plug and fit a new oil filter.

2. Re-install the radiator drain plug.

3. Refill with engine oil, steering fluid and coolant.

You are supposed to prime the oil pump before restarting the car. The way to do this is to crank with the DI cassette disconnected until the oil light goes out. I just cranked for about 10 seconds. If you start the car and the oil light does not go out, shut down right away. You may have a weak oil pump unable to re-prime.

The power steering pump may be noisy at first because there will be air in the system. I have found that turning the wheel from full lock to full lock a few times will cure this. Also, it takes a while for the air to bleed out of the cooling system so keep an eye on the coolant level