timing belt install

[roadboy]

hi, i recently just did my headgasket, i marked down the notches on the cam pulleys to the timing belt, after i reinstall everything i tried to install the timing belt.
i even made sure the intake side and in between the intake and exhaust cam pulleys were tight.

after i install everything and tightened the tensioner.
i give it a complete turn. and it jumps, not just a couple tooth. i would say at least half a turn.
any suggestions of what it could be? i at least tried again 4-5 times, same thing thats happening.
Thanks

 

[toyotanos]

Here's what I do with timing belts:
1- get the marks lined up and the belt installed
2- release the tensioner bolt so the spring can pull the belt tight(ish).
3- *important* put a wrench on te exhaust cam and rotate it counter-clockwise until the belt is tight on the intake gear-oil pump gear.
4- Tighten the tensioner bolt to spec.
5- try to rotate the exhaust gear clockwise to see if there is any play left in the belt. (there should be some, but very little)

 

[roadboy]

thanks, ill try tonight, i could understand if it was 1 or 2 teeth off but not at least 10 off.

 

[toyotanos]

no problem. If you are still having problems I might make a video to describe what I'm doing- this kind of 'turn this way, then that way' instructions can be hard to follow. Good luck though!

 

[roadboy]

Thanks, but I just had a mechanic told me whenever you spin the engine a one full revolution it dosent have to line up, but when you turn it again counter-clockwise it should line upm is this true? If that's the case everything lines up cause I can spin it back counter-clockwise and the notches on the cam pulley and the timing belt marks still line up

 

[toyotanos]

Both are true. The timing belt doesn't have a perfect number of teeth to always line up after turning, but you should be able to back it up and have them re-line up (otherwise that means the belt skipped a tooth)

 

[roadboy]

Yea, when I turned it back everything lined up, no tooth skipped and everythings tight. I guess everythings fine now, thanks toyanos

 

[CyFi6]

You shouldnt be turning anything backwards. With the crank pulley line up with the 0 mart on the timing cover, point the cams strait up and install belt, now rotate the crank clockwise a little bit and apply tension and tighten the tensioner down. Now when you turn the crank 2 times and line it back up at 0, the cams should both be pointing strait up.

 

[Poodles]

You shouldnt be turning anything backwards. With the crank pulley line up with the 0 mart on the timing cover, point the cams strait up and install belt, now rotate the crank clockwise a little bit and apply tension and tighten the tensioner down. Now when you turn the crank 2 times and line it back up at 0, the cams should both be pointing strait up.

Correct. Takes 2 full revolutions of the crank to equal one cam revolution. Line everything up, loosen the tensioner bolt and rotate the crankshaft 2 full revolutions (clockwise, if you go the other way you'll be putting tension on the timing belt on the opposite side, plus it will more than likely skip a tooth). If everything lines up, tighten the tensionor bolt (use the correct torque spec!).

 

[roadboy]

Thats what I'm doing but when I do 2 full revolution all notches line up but only the makrs on the TIMING BELT arnt lining up, when I retate it counterclockwise 2 full revolutions it then matches back with the notches with the timing belt marks, this is normal right?

 

[DearJimmy]

Correct. Takes 2 full revolutions of the crank to equal one cam revolution. Line everything up, loosen the tensioner bolt and rotate the crankshaft 2 full revolutions (clockwise, if you go the other way you'll be putting tension on the timing belt on the opposite side, plus it will more than likely skip a tooth). If everything lines up, tighten the tensionor bolt (use the correct torque spec!).

To add to the 2 revolutions...it is possible to line up all the dots and be 180 degrees out. At that point it won't start till you figure out what you did wrong. Maybe someone can tell how to be sure when things are being marked before removal?

 

[toyotanos]

That is normal.

Poodles/Cyfi- I like to rotate the exhaust cam backwards because I usually don't have the crank pulley reinstalled by then. It does the same thing as rotating the crank clockwise, but I feel it gives me more control over the belt slipping/skipping.

FYI- I also use clamps (spring clamps usually used for holing essays together) to hold the timing belt to the gears while I'm assembling. It helps a whole lot|!!

 

[jetjock]

...i give it a complete turn. ...

Edit: Wasn't quick enough.

 

[Poodles]

Thats what I'm doing but when I do 2 full revolution all notches line up but only the makrs on the TIMING BELT arnt lining up, when I retate it counterclockwise 2 full revolutions it then matches back with the notches with the timing belt marks, this is normal right?

Ignore the belt, look at the timing marks on the gears.

To add to the 2 revolutions...it is possible to line up all the dots and be 180 degrees out. At that point it won't start till you figure out what you did wrong. Maybe someone can tell how to be sure when things are being marked before removal?

No it is not possible to be 180 degrees out. It's a 4 stroke engine...

 

[jetjock]

Here's a thought: How about using the book, especially when having little understanding of how engines work...

 

[Poodles]

But life doesn't come with a manual, so we don't need one for anything else, right? :sarcasm:

 

[DearJimmy]

Maybe I used the wrong vocab by saying "180 out", but when I first installed my timing belt it wouldn't start. Since it turns twice to line up I think I had it aligned wrong where the valves were doing the opposite of what they should have been doing. Isn't that 180 degrees out?

 

[roadboy]

yea installed timing belt, no skipping of gears/teeth ect. just thought the timing belt marks are always suppose to line up with the notches every 2 revolutions.

 

[SC61 MK3]

set the crank at 0, line up the cam gears and put the belt on. marks on the belt do not matter just the cam and crank marks should line up every 2 complete crank turns, cams should be pointing directly down with one complete turn of the crank.

and again the marks on the belt do not matter

 

[roadboy]

yup, thats how it is now, thanks