'90 2.4 oil pump replacement

[royster]

Since you have access to the left-side balance shaft from the engine bottom, you might do well to put the B belt cog in place and tighten it. Holding the balance shaft from below allows you to tighten the shaft’s nut without clamping (and possibly damaging) its gear teeth. Be sure to put the flange back properly, and I remind you of the “photographic” image left on the flange face. The crankshaft flange is important, as it keeps the two belts in their own corrals. (Check your manual for an exploded view of the parts to assure you have them in the right order). So we need to put the crankshaft B belt cog on, and there you pay attention to the flange timing mark positioning...but it can only go on one way, so have some confidence. Set the balance shaft gear to its timing position, get the belt tensioner on, and the belt. Get the belt teeth into the crankshaft gear teeth, and pull the belt so there is tension going up from the right-hand side to the shaft gear. Watch that sneaky crankshaft gear so it doesn't move from your pulling on it. Holding the shaft gear, engage the teeth, then loop the slack part of the belt above the tensioner. Tighten the tensioner according to the manual’s instructions. Make sure the 2 timing marks...the shaft gear and the crankshaft...are still perfectly aligned after the tensioner is tightened. If not, loosen the tensioner and work them until they are. The tensioner is pressed against the belt "finger tight", according to the manual. It does not need a lot of tension...it's only turning the balance shaft...and too tight of a tension will cause Feng Shui issues with your wife and second cousin, according to Lilian Too, but only in the Year Of The Tiger.

Check your manual's photos for timing positions, and I have also provided one for you below.

Once the B belt is installed, we’re ready for rock ‘n roll.

NIT-PICKY DETAIL: Trim any gasket material from the oil pump gasket that might be hanging down along the oil pan surface of the block. I used a single-edge razor blade to insure that the block bottom and oil pump bottom had a smooth transition, keeping the oil pan facing nice and flat all the way way around.

After coating the engine block side of oil pan gasket with silicone sealer, smear it real good with your finger; the inside-the-pan-side of the bolt holes is the most important: we want to keep oil in the pan. Sealing the outer edges only allows oil to possibly seep up and down the bolts. Be careful not to block bolt holes...that can haunt you later.
The photo below shows the important area to coat with sealer highlighted in orange.
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Reinstall the oil pan, getting a bolt on one of the corners to hold it. (Hold the pan in place so it doesn't sag or drop down from that one bolt). That frees your hand up to get another bolt in, to hold an opposite corner. Get the rest of the bolts in place, all of them finger tight. Work the bolts from the center, outward, in increments of ¼ turns until tight, then torque to specifications. (In all honesty, after tightening all the bolts equally with 1/4 turns, I just tightened mine good n' snug, but not too hard). Make sure you put the drain plug back in.

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In the photo below, engine block timing marks are highlighted in red, and pulley/gear marks are in green.
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SETTING THE TIMING BELT

This area of repair is notorious for errors, myself included. One of the reasons for these errors is that the instructions are not crystal clear in any manual: a collective of information got me to the point of knowing how to do it right, and I pass this along to you. By suggestion, I took photos for clarity. Take the time to study them so you’ll KNOW.

Taking the time to read this information, and checking out a video or two is well worth the time spent. It isn’t an impossible task to take off the timing covers…again…after removing the pulleys…again…but if you do this right, from the very start, you won’t have to repeat the operation.

BradMPH provided a good instructional video HERE.

With everything torqued to specifications, check around for some of the small details: go ahead and connect the oil pressure sending unit’s wire. The pressure relief valve is back in and tight, yes? The oil pump shaft and balance shaft can turn freely, yes? Okay, then.

The next step is to install the B belt. That’s the small one that goes on the left balance shaft.
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The only thing the manual doesn’t talk about is HOW to get the balance shaft nut tightened. I started this post with a tip on that. This is how I did it, and it worked for me.

Remember that the only reason for this B belt and tensioner is to turn that balance shaft: it serves no other purpose. But without it, your engine will shake like a dog shitting tacks. The balance shafts are to counter-balance the vibrations the engine naturally makes.

Your crank pulley should be at #1 TDC, as you left it. As well, the cam gear should be close to TDC, too. Remember your timing marks on the cylinder head, because this is one of the errors guys make: using the top of the cylinder head instead of the actual timing mark, slightly below the top.
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With the flange properly placed, get the next timing cog on the crank, and note that the timing marks are all in places you can clearly see.

Put the nut back on the right-hand silent shaft, finger tight. Get your screwdriver into that “secret hole” and see if it can be inserted all the way, or if the shaft is blocking it. Turn the oil pump gear-shaft (use the unbolted gear if you have to) to its timing position. If the screwdriver won’t go in the hole, turn the oil pump gear another full turn, and then you should have it. Leave the screwdriver in the hole in order to tighten the shaft nut to torque specifications.

The oil pump kit likely has an “o” ring for the little cap that covers the silent shaft nut. I remind you of this photograph.
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Replace the oil seal “o” ring, and dab a bit of oil or assembly oil on it, then screw the little door into place. Tap it with your nail-set or center punch clockwise until it feels solid. Good riddance to THAT frikkin’ detail.