Miata timing belt - is it off by a tooth?

The ratty Miata has been getting some maintenance over the winter.  I'm getting close to buttoning things up, but the timing belt has been problematic.  I've made a few attempt to get it lined up right, and it never works out perfectly.  I am wondering if I have it right, or if I have it off by a tooth on the intake side.

Here's the close up at the timing marks:

The intake seems off, but by less than a tooth, to me.

Farther back picture:

Exhaust cam pulley looks straight up, but the intake looks off a smidge, but again, maybe less than a tooth?  I counted the teeth between the timing marks at the top of the pulleys, and depending on how you count the one on the exhaust side where the timing mark is, I have either 19 (if the tooth where the mark is doesn't count) or 20 (if it does count).

Am I right in guessing the intake cam is off, and that it there is one tooth too many between the pulleys?  Or is there something else wrong?  Or is it just fine?

I think you need to rotate the exhaust pulley clockwise one tooth, or the intake pulley counterclockwise one tooth.

I keep squinting at both pictures and vaccilating. But I don't think it's 100% right.

It won't be dead on until you tension the belt, then there will be no question. Turn the crank 1 5/6 turns - you'll find an indicator on the front of the engine. Lock the tensioner pulley down. Then turn it the remaining 1/6 turn and alignment will be perfect.

I suspect you're going to find that intake cam has jumped by one tooth as it likes to do, but do the tension and you'll know for sure.

I have never counted teeth because if you tension the belt, you'll never have to.

If the intake cam jumps a tooth it's because you put all of the slack into the area between the cams.  This is the natural way to do it -- you put the belt around the crank pulley, between the idler and tensioner pulleys, around both cams and then meet at the top.  All the slack is up there, but when you tension it that pulls all of that slack onto the intake side, so it turns the intake pulley counter-clockwise.

When you take it off to redo it, try to have the belt relatively taut so that the slack ends up next to the tensioner.

In reply to Keith Tanner :

I already did that.  The photos are after the 1 5/6 turn, tension, then 2 1/16 turn.  Sounds like I need to pull it apart again.

In reply to b13990 :

I think the angle of the farther away picture is misleading.  The closeup is pretty much a straight shot, so I think the exhaust cam is straight up, but the intake cam is off.  Will try to fix it next time I get some garage time.

Yup. There's a little bit of tension on the intake cam from a valve spring at TDC, so it wants to jump over. 

Keith Tanner said:

Yup. There's a little bit of tension on the intake cam from a valve spring at TDC, so it wants to jump over. 

I’ve been using the FM tool to lock the cams together, but I suspect I’m not getting them locked together in the right configuration.

eastsideTim said:

Keith Tanner said:

Yup. There's a little bit of tension on the intake cam from a valve spring at TDC, so it wants to jump over. 

I’ve been using the FM tool to lock the cams together, but I suspect I’m not getting them locked together in the right configuration.

 

Honestly, I found the FM cam holder tool to only be good for keeping myself hydrated through the bottle cap remover function.  I tried and tried and tried to get it to hold the cams in place and I just couldn't make it work.  Now, it may have just been me not using it correctly, but I had zero success with getting the cams lined up until I set the cam tool aside.

wae said:

eastsideTim said:

Keith Tanner said:

Yup. There's a little bit of tension on the intake cam from a valve spring at TDC, so it wants to jump over. 

I’ve been using the FM tool to lock the cams together, but I suspect I’m not getting them locked together in the right configuration.

 

Honestly, I found the FM cam holder tool to only be good for keeping myself hydrated through the bottle cap remover function.  I tried and tried and tried to get it to hold the cams in place and I just couldn't make it work.  Now, it may have just been me not using it correctly, but I had zero success with getting the cams lined up until I set the cam tool aside.

I found I had to take into account that I couldn't pull the timing belt completely taught on the exhaust side, so it would move a bit.  It looks like I properly compensated for it moving a bit once the timing belt was on, but not the intake.

The way to use the tool is to put it in place before you remove the old belt, then the gears are locked together. We're working on a revision to the design that will be less prone to popping out sideways, but you can use a couple of zipties to keep the current design in place.

Keith Tanner said:

The way to use the tool is to put it in place before you remove the old belt, then the gears are locked together. We're working on a revision to the design that will be less prone to popping out sideways, but you can use a couple of zipties to keep the current design in place.

That would have been a good thing for me to do, and I saw it in the instructions...after I took the sprockets off.  That is definitely on me.

Keep in mind... if the crank pulley is off by one tooth, the cam will be off by half a tooth.  You can chase the cam pulley position all you want, but if the crank pulley is off by one, you'll always be off by half on the cam.

But yes... tension first.

I assume you mean that if the crank pulley is off TDC by one tooth. In which case, both cams will be off.

I have the FM tools as well but couldn't get the cam tool to stay put so this is what I do. 
 

Remove belt with engine on timing marks. 
Put new belt on cams and zip tie to hold in place. 
Run belt to crank. 
Recheck marks at cam and crank. 
Run belt through tensioner. 
rotate engine and double check timing marks. 
 

Maybe this is wrong but it's worked for me. 

eastsideTim said:

Keith Tanner said:

The way to use the tool is to put it in place before you remove the old belt, then the gears are locked together. We're working on a revision to the design that will be less prone to popping out sideways, but you can use a couple of zipties to keep the current design in place.

That would have been a good thing for me to do, and I saw it in the instructions...after I took the sprockets off.  That is definitely on me.

Wait.  Instructions?  People...  read those? 

rustybugkiller said:

I have the FM tools as well but couldn't get the cam tool to stay put so this is what I do. 
 

Remove belt with engine on timing marks. 
Put new belt on cams and zip tie to hold in place. 
Run belt to crank. 
Recheck marks at cam and crank. 
Run belt through tensioner. 
rotate engine and double check timing marks. 
 

Maybe this is wrong but it's worked for me. 

Here's what I do. If you read my books, you'll find this same series.

Take everything apart, replace seals.
Lock the tensioner in the least tensioned position.
Set crank to TDC and cams to TDC position. 
Thread the belt around the bottom half.
Use a wrench on the flats on the intake cam to counteract the valve spring.
Thread the belt around the cam gears.
Tension. Check alignment by eyeballing the 12 o'clock marks.
Reassemble.

No zipties, no clamps, no worries.

I use a combination of adjustable wrenches, a big C-clamp and the FM tool with zip ties.

I lock the cams into position with the wrenches and clamp, then zip tie the FM tool into place. That way you can remove the pulleys together in order to change the seals, and then they can only go back in proper realtion to one another, and the cams.

You can make minor adjustments to the cam positions very easily with one hand on the two wrenches and then use your other hand to tighten the clamp.

Still having problems getting everything lined up right,  since I'm having to compensate for not being able to pull the exhaust side of the belt tight without turning the crankshaft, so if I put the pulleys on straight up, they are out of time when the belt goes fully on.

I'm also now seeing another issue - I don't know if it is all the tightening and loosening I've been doing, or if it was just on its last leg anyway, but I think the tensioner spring is getting weak.  On my last two attempts to put the belt on, it did not seem to pull the pulley out as far as it had in the past.

Debating on whether to keep trying, or just order a new spring, and wait until it comes in.  Engine has over 220K miles on it, so maybe the spring is just worn out.

Got it back to the point where the spring seems to be doing its job again, but I still cannot get the danged thing timed right.  Now, I think I've got the belt distance between the cam gears right, but they're both off by a tooth.   Every time I undo the tensioner, and try to adjust the belt by one tooth, then go through the checking process, its off by the same damn amount.  I think the belt is slipping by one tooth on the crank pulley every time I try to adjust its position on the exhaust cam pulley.

After being at this for an hour and a half, I'm taking a break for the night before I destroy something.  I really don't get this.  I've done timing belts on DOHC Neons, and on Subarus before.  This shouldn't be that hard.

In reply to Woody :

If you have the FM tool holding the pulleys, how do you open your adult beverage?

(As usual, I have nothing to useful to add.)

And thank you Keith, I saved your instructions even though I do not have a Miata.

In reply to eastsideTim :

I could probably come over Saturday morning if you'd like a hand

Keith Tanner said:

I assume you mean that if the crank pulley is off TDC by one tooth. In which case, both cams will be off.

Correct, by a half a tooth each.  If the crank pulley is off by a tooth, no amount of adjusting the cams will correct the situation.

I don't think I've ever done a Miata, but plenty of Mazdas.  IIRC, they put the tensioner on the "wrong" side, meaning you can have it perfect and then when you tension it, it does something funky and you have to start over.

Edit:  just checked... it's on the "right" side.

Well, if the crank pulley is off by a tooth you're just not paying attention. It has a big giant marker on it. There's no excuse for not having the crank at TDC.

Tim, don't try to get the whole belt on the pulley. Just get it about 1/4 of the way on, which gives you a little more wiggle room to get all the pulleys on. Then you push it on fully.

The only pulley that is trying to rotate is the intake cam. Everything else will stay where you put it. Just put a wrench on those big flats on the cam and horse it back where it belongs (or use the FM tool), then put your belt on. The intake cam is usually the last one I do so everything else is basically locked in place.

Are you locking the adjuster at max spring extension while you put this together? Makes life a little easier.

Just did this, but I did it in a wacky  way because I wasn't in my garage and didn't have my tools.  I digress.

I actually ran the belt over the exhaust sprocket first.  Get the belt tight/ taught coming up from the crank (properly around the idler pulley), get the sprocket lined up (i.e. with the dowel or "E" straight up at the top) get the belt on and zip tie the belt to the sprocket.   I'd use a ratchet on the cam nose to rotate it in to position and catch the teeth in the right spot.

From there it's really easy to do the same on the other side because the slack is all on the tensioner side.  Use a ratchet to rotate the cam with the dowel straight up again, slide the belt on. 

Goes really easy.  You can count the 19 teeth as a quick double check, they'll be "in between" the notches ( looking just like words between the quote marks), and once you rotate the belt a couple times it will all line up pretty.