kwando

Looking for a place with good shipping prices as well.

reddahaydn

you guys are lucky...were looking around 2k to replace a timing belt over here in Australia. 5-7k for a full rebuilt (in a shop)
Very interesting thread! Some really good info!
Unfortunately for me it's due to bent conrods that I am here in the first place.

'86Owner

Good Info.

mickydeeez

did 60k service as well, valve cover gaskets,timing belt,water pump,all hoses and belts,with a tune up distributor cap,rotor,and spark plugs.After complete assembly,had some vacuum hoses crossed ran different when cold and poor freeway performance..corrected that issue.Now runs great except when cold still runs different kinda stumbles when accelerating.My problem is i went from 17 to 19mpg down to 14 to 16mpg ? Where do i start looking ?

tweeter79

My stock water pump didn't have a bypass nipple. So just to confirm I can still use one that has a bypass, I just have to cap it off?

This thread is great!! Thanks to all who contributed.

rworegon

Correct.

tweeter79

Thank you!! I tore into the truck yesterday fully expecting to change TB while I was changing water pump (Hadn't bought TB yet). TB looked great so I didn't bother changing it out. Has about 25k km's on it.

I managed to slide water pump out from behind the belt and new one went in just as easy. I put timing marks on the belt, then just rotated the crank about 2 degrees CCW and that gave me enough slack to work around the belt.

Thank you Yotatech!!!!! Bought my '95 pickup last fall and it's about to hit 350K km's, all stock

andrew1586

Got the belt on, rotate crank shaft 2 full revolutions, marks on belt are both 2 teeth off of cam gear marks. Should the marks still line exactly after 2 revolutions? Or because the gear ratios would the belt marks move? Loose belt? any help would be great. Read and read but no exact answer. also bought timing kit at o reilys, $150, and water pump at Napa special order $71 without oil cooler nipple. Thanks

scope103

No. In gearing, this is called a "hunting" ratio. It is designed this way to keep one part of the belt from always hitting the same spot on the sprockets.

nathanmyers

so basically what is happening is that there are a few to many teeth on the belt. this makes it not hit the same spot every revolution but if you were to turn it enough you would obviously get it in the correct spot again.

dsleggett

Never heard of that, and since the cam gears need to turn in an exact ratio with the crank it doesn't makes sense at all. If you turn the crank around enough to the get the timing belt marks back up to the cam pulleys they will exactly hit the marks again.

Just my 2 cents also: buy a 6$ oil pump seal BEFORE you start this job on a truck with 250K miles, then you can finish it late at night and not have to hit the parts store the next day.

Lining up all three timing marks the easy way: line up the crank properly and put the belt on, as you go up around the water pump to the driver's side cam pulley if it (cam pulley) is spot on the mark you won't be able to pull the belt tight enough to get it on without slack. So turn the cam pulley about 1 tooth clockwise, slide the belt on, then turn it back to the mark. This will take all slack out of that side. (All slack has to end up between passenger cam pulley and crank so that the tensioner can take the slack out). Now do the same on the passenger side cam pulley, turn clockwise one tooth, put belt on and turn back. Now your belt should be snug from crank and over both cam pulleys, put your tensioner on and it will tighten up the left side where all the slack is. I like to hold the belt in place with a couple clamps like in the photo so nothing slips before you get it tensioned.

Buy the tool shown in post #16, it's great for holding the cam pulleys and worked for the crank pulley bolt loosening also.

nathanmyers

you do this by changing the number of teeth on the belt. It doesn't effect the ratio at all. I'm also sure most of us here have turned the crank a few times when doing a timing belt change and found out that the lines don't match up when you turn it. At least not on the 3vze.

dsleggett

The number of teeth (belt length) from crank to driver's side pulley to passenger pulley is constant, all slack is on the other side. Maybe if you put the belt on backwards (L pulley mark on R pulley) it would be off after several rotations, but that doesn't make sense either because even with additional teeth on the slack side they are constant in number. The only way to move the marks would be to vary the number of teeth (length of belt) during rotation which of course cannot happen. The FSM says to line up the marks BEFORE removing the old belt if you are going to reuse it. Couldn't happen if it randomly moved around.

I have never seen marks on a timing belt before (I've never changed this 3vze belt myself before), usually you just line up your crank and cam pulleys and stick the belt on, rotate a couple times to see that things still line up, and go. These marks are simply an aid and if you ignore them on the install and still get it timed right they will never line up, no big deal.

bmcghie

The marks don't RANDOMLY jump around... they continually move ahead or fall behind. Eventually, you will line them up again.

The "hunting" pattern refers to this action: Instead of lining up every rotation or every two cam rotations... the number of teeth on the belt is NOT an even multiple of the cam teeth... therefore it doesn't line up exactly nearly as often as you would expect. This helps prolong the life of the belt, as it helps distribute wear more evenly.

dsleggett

Thanks guys, I learn something new every day on this forum, that's why I love it!

nathanmyers

thanks for explaining this better then I could.

4rAndy

I recently installed a new TB. I had alot of trouble rotating the belt to check the marks because of compression? I removed all 6 spark plugs and there was still compression....but i got it lined up anyway. I need to know if all 3 markings need to line up after several revolutions...the 2 cam markings and the mark on the crankshaft. They all started out lined up but after a couple of revolutions the crankshaft mark is a tooth or 2 to the right of the raised mark, but the 2 marks on the cams are still lined up. Is this because of the 2:1 ratio or did the TB perhaps slip at some point? Is it those markings on the crank that have to line up or is it the mark on the crankshaft pulley that has to line up with the 0 on the little numbered thing next to it? Also is it ok to re-use the crankshaft bolt, and once i put it in should i use loctite?

eugenedbrooksiii

The marks need to line up when you install the belt. The number of teeth in a cam sprocket will be half the number of teeth in the crank sprocket in order to get the 2:1 ratio crank vs cams. I have not counted the number of teeth in the timing belt, but you can be sure that it is not an even multiple of the cam or crank sprocket tooth counts. Your later "alignment" of the marks on the belt may be with the cam and crank sprockets not properly aligned properly with the block, or may be with a tooth skip somewhere. It is hard to tell.

You pulled the spark plugs as you needed to. The remaining "compression" was the influence of the valve springs on cam lobes. In addition to possibly getting the timing belt wrong, this spring loading can make the adjustment of the belt tension unreliable. When I did this service on my 91 (which I recently replaced with a 2012 truck after 235,000 miles) I would use a light torque on the passenger side cam to take up any slop on the idler pulley when setting the belt tension. Once you get the belt in place and the tension set you can turn the engine backwards a little to check the marks again. Turning the engine round and round will not get you anywhere useful for checking marks, unless you want to do some math involving the number of teeth on the sprockets, the belt, and the off-sets relative to the block alignment marks.

In the 21 years I had my 91 truck, with the 5 or 6 times I had to replace the timing belt, I never replaced the crank bolt. I also never abused the crank bolt with an impact wrench. I made a special tool out of flat bar stock that bolted to the harmonic balancer and had a hole to get the socket through to the crank bolt. A breaker bar with a cheater pipe got it off and a torque wrench put it on (always using factory torque values). I always put a little anti-seize on the bolt threads.

nathanmyers

This was gone over in the above posts... The marks should not line up after several revolutions. It keeps a 2:1 ratio but the belt has a different number of teeth on each side between the cams and crank making it so it does not hit on the same tooth on the same part of the pulleys each time. This in theory makes the belt last longer. That's not to say that it didn't slip (that is possible but if the tensioner was on there is very unlikely) You can also reuse the crankshaft bolt. Also for the harmonic balancer I just hammered a piece of steel pipe so it was flat drilled 2 holes in it, bolted it to the balancer, put a cheater bar on that for some leverage and I used a wrench on the bolt and that's that. not as fancy as the toyota tool but worked. Just had to guess from experience on the torque values though. But that bolt is not supper critical on how tight it is as long as it doesn't come out. The solution above would probably be better though.

Hans Brost

There is a BDC and TDC with respect to the distributor/firing of the spark plug though isn't there?......or does it fire after both the intake and exhaust stroke?
i..e.. once at the top of every rotation (in which case you would be totally correct)?
z