Time Belt Pulley Mark Accuracy...

[Capnemo]

Got my new timing belt on, first attempt the crankshaft turned, had to remove the belt (not easy) realign and install the belt again.

My question is, the camshaft timing marks may be ever so slightly off, as in 1 mm? I believe if one were misaligned it would have to be by a whole belt cog.
One cam mark seems 1mm. off from perfect, the other cam and crank are on the money. Should have looked when I removed the old belt. But it is nagging me.
But its off less than half a tooth so must be good.

I am using a 4" carpenters square backed up to the plate.

 

[samsquantch]

Had this happen on a 2.0T Subaru interference motor. Best advice I have is to count teeth before removing the old belt, install new belt exactly as before, then turn over by hand (correct direction) until you're satisfied. Subaru OEM belt had paint line off a mm or so, as you describe. Trust the teeth, paint is just a quick guide.

 

[Joelzy]

mine looked to be off by a mil or so but the line on the belt landed on the right valley so i went with it.

 

[Capnemo]

It wasn’t the paint, I was measuring the V notches in the pulleys with the notches in the sheet metal.

It’s all good, the beast fired right up and runs smoothly...

 

[thegipper]

I think sometimes everything lines up dead on and other's have reported that it is slightly off even though it is timed correctly. As long as you turn it over several times and it keeps lining up correctly, it's probably fine. Both of my engines I have done the timing belt on had the timing marks essentially line up perfectly.

Thankfully the 5VZFE is not an interference engine so worst case scenario is you have to take it back apart and fix the timing if you are off a tooth.

 

[Outrider]

I have run across this problem before, at least twice. I think it happened on my T4R, and I know it happened on my daughter's Protege5. I was pulling my hair out (what's left of it), scratching my head, and trying to figure out WTF was wrong. I ended up averaging things out, turning the crank a few times by hand, re-checking and trying to get everything to appear perfect, but it never did. I just got it as close as I could on all 3 marks, and said, "screw it". Turns out that I apparently got it right, because they both ran fine after that.

The other thing that I always do, and what was mentioned here, is to mark the old belt (and 3 pulleys) before taking it off. Then I mark the new belt the same way. If you do that, as well as getting the pulley marks in the right place, that's about the best that can be done.

 

[JohnMc]

I was just doing a cam belt on a closely related engine, the Camry/Highlander/etc 1MZFE. I initially put the belt on and lined everything up via the paint stripes. But... it just didn't look quite right. It wasn't *WAY* off, but it wasn't quite right. No warm fuzzy feeling.

So I relooked, repondered, and finally noticed that I had put the belt on backward. I guess 'front' is a bit of a vague concept in a transverse-engined car, but the wording on the belt should be readable facing the pulley/belt end of the engine (front on a 4Runner). Not to mention, ahem, there's also some printing with 'FR right next to an arrow pointing one way... I didn't initially pay attention to that).

Anyhow, took the belt off, turned it around, and lined it up again using the paint marks. And then all the timing marks were lined up properly.

Cams can be off a tooth. Or two. Or maybe even three, and the engine will run pretty well. The engine will act weirder the further off you get, though. Either no low-end torque and finally kicking in as the revs get higher, or vice versa.

 

[Capnemo]

I put my timing belt on backwards too, did not notice until it was on properly, PIA to remove and reinstall.

But I was going by the timing notches not the belt marks or paint dabs. It dawns on me if one of the notches was off 1mm that was still way less than the distance between fully teeth or belt cogs, so it musta been good to go.

 

[Adamdmc]

I'm tearing down my engine to replace the passenger side head because of the spark plug threads being stripped. When I set it at TDC before pulling the timing belt, I found that the cam gears were a full tooth past the notch when the crankshaft was set to zero. Do I put it back together like this, or do I set it according to book when I reassemble? I am installing a new timing belt while I'm already in there if that matters.

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[Dieselchessy]

As I recall one tooth is about 2 or 4 deg. Of timing on the cams. Some folks would set them 1 tooth advanced and claim better performance.

I set them at factory. Crank at zero with #1 at TDC, cams turned clockwise about 2 teeth, Belt on with marks lined up with pulley marks and arrows to the front. Then pull the pin on the tensioner and when it all comes tight all marks will be lined up.

If your doing this job on a rig you plan to keep for another 100k, then it’s good to pull the ac pump bracket and grind the backside a little so you have clearance to remove the back tensioner bolt with a ratchet. Makes the job a lot easier the next time.

 

[brillo_76]

I always set mine to factory spec. No reason to set the timing advanced. These arent high end spots cars.

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[TheDurk]

I always set mine to factory spec. No reason to set the timing advanced. These arent high end spots cars.

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Not just that, but the belt has absolutely nothing to do with IGNITION timing. It only controls VALVE timing, and I can conceive of no way to improve performance by going off-spec with valve timing in ANY vehicle. Ignition timing of the spark relative to piston position is controlled by the ECU based on direct reading of the Crank Position Sensor. You can't change it without doing electronic intervention.

 

[Dieselchessy]

Not just that, but the belt has absolutely nothing to do with IGNITION timing. It only controls VALVE timing, and I can conceive of no way to improve performance by going off-spec with valve timing in ANY vehicle. Ignition timing of the spark relative to piston position is controlled by the ECU based on direct reading of the Crank Position Sensor. You can't change it without doing electronic intervention.

You know they make VVT engines. Variable valve timing, to improve performance.
They also make all manner of adjustable cam pulleys for manually adjusting cam timing on performance engines.
So it would seem a static valve timing position would only be optimal in a range of rpm, and that changing it slightly could move that optimal range.

It seams an easy line of thinking that Toyota tunes these motors for emissions and drivability and not raw performance. Folks will do little tweaks that they think will help, like headers, cold air intakes, exhaust systems, Deck plate mods?, ect....

Saying adjusting valve timing won’t help any vehicle seems rather closed minded.

 

[brillo_76]

Not just that, but the belt has absolutely nothing to do with IGNITION timing. It only controls VALVE timing, and I can conceive of no way to improve performance by going off-spec with valve timing in ANY vehicle. Ignition timing of the spark relative to piston position is controlled by the ECU based on direct reading of the Crank Position Sensor. You can't change it without doing electronic intervention.

I didn't specify wither it was ignition or valve timing. I simply stated someone advanced timing as per the photos. Granted its great to explain the differences.

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[Soneill]

I'm tearing down my engine to replace the passenger side head because of the spark plug threads being stripped. When I set it at TDC before pulling the timing belt, I found that the cam gears were a full tooth past the notch when the crankshaft was set to zero. Do I put it back together like this, or do I set it according to book when I reassemble? I am installing a new timing belt while I'm already in there if that matters.

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Do not start it like that. Make sure the timing marks on the cam geard are lined up correctly. Spin the motor over by hand until the cam Mark's go around 2 to 3 times and make sure they still line back up. Other wise restart and recheck. I've done 3 of the 3rd gen timing belts and the marks are not always spot on but never that far off.

 

[TheDurk]

I'm tearing down my engine to replace the passenger side head because of the spark plug threads being stripped. When I set it at TDC before pulling the timing belt, I found that the cam gears were a full tooth past the notch when the crankshaft was set to zero. Do I put it back together like this, or do I set it according to book when I reassemble? I am installing a new timing belt while I'm already in there if that matters.

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I'd be careful relying on the crank pulley marks. One way that gap could occur is if the pulley is out of register on the key. There is only about 1/4" of key holding that pulley in register. If it slips a little bit, the only effect is on that mark. Better to check the hard mark on the sprocket with the pulley off.

Seems to me something is off here, and that's the most likely place.

 

[TheDurk]

You know they make VVT engines. Variable valve timing, to improve performance.
They also make all manner of adjustable cam pulleys for manually adjusting cam timing on performance engines.
So it would seem a static valve timing position would only be optimal in a range of rpm, and that changing it slightly could move that optimal range.

It seams an easy line of thinking that Toyota tunes these motors for emissions and drivability and not raw performance. Folks will do little tweaks that they think will help, like headers, cold air intakes, exhaust systems, Deck plate mods?, ect....

Saying adjusting valve timing won’t help any vehicle seems rather closed minded.

Fair point. I'll just say I can't imagine trying to improve performance on this engine by playing with static valve timing. You never know what people will cook up. Still VVT works because it changes with RPMs. Not the same thing.

 

[APhelps]

Not just that, but the belt has absolutely nothing to do with IGNITION timing. It only controls VALVE timing, and I can conceive of no way to improve performance by going off-spec with valve timing in ANY vehicle. Ignition timing of the spark relative to piston position is controlled by the ECU based on direct reading of the Crank Position Sensor. You can't change it without doing electronic intervention.

They literally make adjustable cam gears for performance cars.

 

[19963.4lsr5]

Do not worry about the 0 on the plastic cover. Worry about the mark and little V on the actual timing gear on the crank.

Advancing and retarding the cams move the power peek (both HP and Torque) up or down depending on if you advance or retard the cams.

My 93 ZX7R Ninja I roadraced in the mid 90’s had both cams centerlined at 108 degrees. I advanced the cams and split the centerline. Intake became 112 and exhaust became 110. It raised my power peek almost 1000 RPMs and I ended up with 120hp at the back wheel with a super sport valve job and the cams advanced. It took a few dyno days to come up with those numbers. Rob Muzzy said you’d never get more than 115hp out of a ZX7 engine. My guy in Somerville NJ thought outside the box and that bike with the super tall 1st gear would still run 10.80’s in 90 degree weather at Maple Grove in Reading PA. It was a super fun bike.


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[TheDurk]

Guys, I dialed it back. No need to pile on.