pro8cess

Please confirm and correct me if this is the right method to install a new timing belt to an engine in which the timing belt had broken off from.

I have a broken timing belt on my 88 toyota 3.0. I have a question about TDC and the cams on this engine since the timing belt broke It's more dificult to find TDC?

---To set up timing before installing belt---

1. Do I use a socket wrench (clockwise) on the nut in the center of the cam to adjust the timing marks on each individual cam to match the timing cover marks by hand? The cams don't appear to move when I move the crankshaft I believe this to be the timing belt has to be on to move the cams?
2. I then use a socket wrench clockwise to turn crankshaft to TDC (0)
3. Once L/R cams are alligned and Crank at TDC I can then start installing the new timing belt?

4. Once timing belt is set in place manually rotate crankshaft 2 revolutions(clockwise) to see if the timing marks are all still aligned and continue to put it back together.

**note: I really just need to know by rotating the cams with a socket wrench clockwise if this is the correct procedure. I've never dealt with a broken timing belt before.

Thanks again!

MudHippy

You should first mark(with a pen,paint,etc.)the timing belt at both the camshaft timing marks. Then, after rotating the crank x 2 and checking that all the timing marks line up. Keep rotating the crank untill the marks made on the belt come back around to where they were when you made them. They should end up being off by one tooth(on both sides)with the camshaft/crankshaft timing marks aligned. If not, repeat steps 1-4 untill they are. Then continue the process.

pro8cess

Thanks for the help I think I'm ready to start putting it all back together and find out if I'm on with the timing marks or off a tooth.

pb4ugotobed

Are you smoking crack man? You will be turning that motor over by hand for EVER until they happen to line back up perfect again.

There are marks on the cam gears that line up with the marks on the rear timing cover (metal one behind the cam gears), and the crank gear (that lines up with a mark behind it).

I'm only going to say this once, and anyone that wants to argue with me about it is purely just ignorant. There ARE marks on a Toyota timing belt, that coincide with these marks on the cam and crank gears. however, these marks are ONLY to make it a bit easier to set the timing belt up initially. Once it is installed, and set, those marks are completely irrelevant.

You DO want to rotate the engine around (crank will turn twice to turn the cams once) however, ignore any and all markings on the belt. you ONLY need to pay attention to the marks on the cam GEARS and crank GEAR themselves, to ensure that they line up with the set marks behind them. If they all line back up after one revolution, they'll line up after 2 or 5 or 10 revolutions. If they line up right the first time, put it back together. If your belt is off a tooth, it will be obvious when the marks on the gear don't come anywhere close to where they are supposed to.

And worst case, you screw it up, no harm done. Just like it didn't hurt the engine any when the belt broke. If the timing is off, it either won't run, or will run like ass. But it won't break anything.

camo31_10.50

PB4Ugotobed is correct...same thing i've always heard.

does it hurt to turn the motor over since it's not getting proper oil?

my motor is rebuilt, and has assembly lube on all the bearings...but what about the pistons? will it hurt since they are still DRY?

95blackToy

When I did mine. We did the timing as described byPB4Ugotobed.we also put a little glob of STP in each cylinder,just because of turning it and for waiting for it to get oil.also put some on the cams.

pb4ugotobed

no it's not going to hurt anything turning it over by hand. It is when you turn it over at about 5,000 revolutions per minute that you do damage

I am a tech at a Toyota dealer... and I blew up a LOT of the "cash for clunkers" vehicles. I will be the first to tell you, it takes a LOT to blow up a car. Without putting the solution in, you can hold an engine at the rev limiter with NO oil in the engine for quite some time before anything happens... Trust me, turning it over a couple times by hand, with assembly lube, without it, STP or not... it's not going to hurt anything at all.

camo31_10.50

that's reassuring PB!!! thanks alot!!!!!

thook

Make sure the crank is on the compression stroke when lined up at TDC. And, make sure the rotor's at 11 o'clock or on the #1 spark terminal when you install the distributor. Didn't see anyone mention it, so I thought I would.

pro8cess

Understand you a 110% pb4ugotobed Thank you

So I got the timing marks and oil pump and crank all aligned. Slipped the belt on and everything went smoothly. Put all the necessary stuff back together and cranked on the first try timing and everything seems to be right on (ran like it did before it broke) One noticeable difference though........From the timing belt area it sounds louder kind of like a whistle noise when accelerating is this just bveacause of th new belt! Did I tighten the belt too much? I'm kind of confused but it's running just fine should I worry........

OutlawMike

No, the new belt should not make a whistling noise. I would try to figure that out. Maybe your upper timing belt cover is installed wrong and the belt is rubbing on it? Or the lower cover?

Mike

MudHippy

Nah, not a big fan of the crack. A little out of my price range. Besides, if I really needed to blow $20 every 3 minutes, I'd just go play some video poker.

You're right though, it would take forever to get them to line up PERFECTLY again. I just meant 'till the marks come back around to, near, where they were when the marks were placed on the belt. This will occur with EVERY full revolution of the TIMING BELT.

I know...it's not standard practice to do so. I was just trying to add my little "flair" to the procedure.

Why? Because if the belt was installed correctly, that's EXACTLY what you should see those marks do. The marks will travel one tooth further away from their original position with every revolution of the belt. Just as Toyota intended. If the belt did not behave this way it could cause excessive wear, as the belt would be continually engaging the same teeth on the crank and cam gears every time it completed a full revolution. And not engaging on "fresh"(different)teeth with every go round, as required.

I would think you'd be familiar with the concept, being a Toyota tech and all. Hmm...

Kinda hard to "over-tighten" the belt. It's likely that you'll need to replace the no.1 and/or the no.2 idler pulley(s). Most people don't, and that's what happens.

You could probably just ignore it and drive it another 60-80K miles, or so, as that's about the time you should replace the belt again anyway, and then replace 'em. But I wouldn't...

pb4ugotobed

I know the belt won't be on the same teeth revolution after revolution, which is why I said you'd be there forever turning the engine over until the marks lined back up again. Personally, once the belt is set, I'll turn it over a revolution to make sure the marks on the cam gears and crank gear line back up like they should, then I put it back together. I got more stuff to do than play with a timing belt all day. Once my gear marks line back up, I could care less what the belt lines up with. Timing belts pay a few hours labor, but honestly I'd rather do 3 or 4 camry accelerator pedal recalls, make more money, and do less work.

tried4x2signN

Forget the marks on the belt... It's the marks on the pulleys lining up to the match marks on the back of the timing belt dust cover you need to worry about.


And yes, whit dots help out a ton. Just like a white dot on a 22R crank pulley helps.

May need need it, but it dang sure helps...

pro8cess

After 2 revolutions from the crank bolt by hand it appears to line up perfectly on the cams and crank/oil pump. But first time around the belt kept being a tooth off after i adjusted/torqued the #2 idler. I then tightened #2 idler then put the spring on lined up the marks and lossened #2 idler with spring on got the belt tight and re-tightened #2 idler until belt was tight. I proceeded to do the revolutions with good marking results on the cams and crank/oil pump. Put it all back together and started right up (no need to even do timing with timing light)

Mostly I'm lookig to get info on how loud the belt is now. It seems to be much louder like I got turbo on or somthing now but all I did was replace the belt,water pump, idlers as the seals were clean of debri or oil. Do you think I got a bad Idler. The noise sounds loudest where the #1 idler is. It sucks to have to tear it all back apart just to adjust the belt if indeed the belt is just too tight. Can you tightedn the timing belt too much? and what is too little didnt want it slipping.
thanks

blake.nemitz

i want your job, sounds like a blast

MudHippy

Well, if you followed the procedure for installation to a T, then NO you can't over-tighten the timing belt. It's impossible.

The tension spring that pulls on the #1 idler pulley causing for there to be any tension at all on the timing belt during installation, also controls how much tension the timing belt will/should have after installation. So, if you had the #1 idler pulley tension holding bolt, that prevents the movement of the #1 idler pulley on it's pivot, loose enough for the #1 idler pulley tension spring to be able to apply maximum timing belt tensioning force on the #1 idler pulley before you retightened it, then that's going to give you just the proper amount of tension on the timing belt. No more, no less. Unless you were, somehow, applying added tensioning force to the #1 idler pulley while you were retightening that bolt, then it wouldn't(in any way)be possible to over-tighten the timing belt during installation.

However, if you were to tighten down the #1 idler pulley tension holding bolt, that keeps the #1 idler pulley from moving on it's pivot, at a point when the #1 idler pulley tension spring wasn't applying it's maximum timing belt tensioning force to the #1 idler pulley, as in when the #1 idler pulley tension spring wasn't retracted as far as it could be, then that wouldn't allow the timing belt to be as tight as necessary. Trust me, this can happen.

In reality though, there's no specific(enough)procedure given to set the proper tension on the timing belt with these older, tension spring-driven type, timing belt tensioning systems for this engine. Meaning, I haven't been able to find this procedure described in full anywhere as of yet. But I have, through trial and error, discovered on my own how it's done correctly.

So here goes...

Correct timing belt tensioning with these older, tension spring-driven type, timing belt tensioning systems is accomplished by leaving the #1 idler pulley tension holding bolt just loose enough, so that the #1 idler pulley tension spring can pull freely(with very little or no resistance)on the #1 idler pulley. And then observing the #1 idler pulley while you're rotating the timing belt clockwise via the crankshaft. You'll be able to see the #1 idler pulley swing slightly to the left, and then to the right, on it's pivot point as you're doing so. You then want to tighten the #1 idler pulley tension holding bolt down, thusly holding the #1 idler pulley in it's current position, when it has swung as far to the right(you're right, engine's left)on it's pivot point as it will go. This should happen at, or around, the time when all timing marks are aligned. Being very careful at all times during this procedure to not let the timing belt skip over the teeth on the cam gears by preventing any, even the slightest, counter-clockwise movement of the crankshaft during it's rotations. Simple as that!

I still recommend checking for correct tension on the timing belt by doing as I stated previously in this thread. Which is an effective, if not the only, way of doing just that. And it's, in my view, a necessary step in timing belt installation with these older, tension spring-driven type, tensioning systems. I do this EVERY time I install a timing belt with such, as it is possible to achieve improper timing belt tensioning with them. Which is, without a shadow of a doubt, why Toyota later upgraded these engines to an entirely different, and totally fool-proof, timing belt tensioning mechanism and no longer uses these tension spring-driven type timing belt tensioning systems.
About the noise you're hearing, are you sure that you placed the timing belt guide on the crankshaft with the cupped side facing out? (It's the washer deally with all the holes that goes on after installing the timing belt and before installing the timing belt covers.)

pro8cess

Thank you Mudhippy!

Very well wrote and I was able to get into the timing belt cover and make some changes slight tensioner changes making sure I didnt apply to much extra tension to the idler. I had the spring apply the tension then made my coupe clockwise revolutions to see wht tension was like as well that my marks were on (which they were) I think I may have got it. It still sounds a little louder than I remember possibly could be a bad idler? But the idlers are new and spin freely. The timing belt guide is seated correctly as well. So for now I guess it works the noise seems to be a little less but you can still hear the belt in there as for before it was silent. So trial and error I guess we'll tell with time. It runs smoothly and appears to be all tensioned perfectly so it may just be a bad new idler hard to tell but after running it some miles the belt appears to be untouched in anyway and is running smoothly just the noise that has me boggled. BUt great write up very helpful!

stephens90yota

my timing belt broke last night, what are the chances that it messed up other stuff when it broke? and how would i go about checking?

James Woods

iTrader: (1)

Yeah that was fun, it seemed to me that the imports all took forever to go and the domestics went after a minute or two. The s-10's with the 4.3 that had aluminum oil pans all shot main and rod caps out of the oil pan, that was cool. I put a rebuilt 3.0 into a 89 pickup, the guy brought it back after blowing it up in the snow so I did it again and a month later I was blowing it up after he traded it in for "cash for clunkers" I was P.O.ed