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Installing timing belt

Posted: August 4th, 2012, 2:50 pm
by WhiteFinish
Can I individually turn the crank and front/rear bank to get my timing belt correctly on ?

Don't know if it's necessary but I'm trying to reset my timing belt to rule out that my higher rpm misfire is due to bad set belt.

Re: Installing timing belt

Posted: August 4th, 2012, 3:15 pm
by Daninski
Ryan did a real good write up on making sure your TB in installed correctly. No time to fine it for you. Just Search timing belt and Ryan.

Re: Installing timing belt

Posted: August 4th, 2012, 3:33 pm
by RobMinhas
I believe this on eis the one Dan is referencing viewtopic.php?f=15&t=77978&start=15

Looks like White found it already so I'm not sure if that's the info he's looking for.

Re: Installing timing belt

Posted: August 4th, 2012, 4:30 pm
by Mooneggs
yes, you want to make sure all the timing marks are lined up. That's how you determine if the belt is on correctly. Check the online manual here for the procedure: http://www.mx-3.com/manuals/showimg.php ... B2-017.gif

Re: Installing timing belt

Posted: August 4th, 2012, 6:07 pm
by marcdh
Non interference so turn them all you want! We are lucky to have a brilliant workshop manual, it explains it very well. The only thing I do differently is use a manual timing belt tensioner.

Re: Installing timing belt

Posted: August 4th, 2012, 7:06 pm
by WhiteFinish
Great guys !

This is actually my first own timing belt :oops: :oops: Read a lot of times about it though haha
I'll get going with it tomorrow

Re: Installing timing belt

Posted: August 5th, 2012, 3:36 pm
by WhiteFinish
I tried to install the belt today and it f*... drives my crazy.

It kept misalligning and having a hard time to put the belt on.

Image

Image

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I started at the crank and put the belt on around the cam gears. The only bearing I took off is the one at the front head. I put this bearing back and squazed the belt around it.

This doesn't seem good.... (don't know what it is)
http://youtu.be/frs_xmE_XqM

A question regarding the manuel.
It says " rotate the crank 720 degrees after allignment, than recheck the mark"
How do you rotate the crank ? It's very hard to move it

Re: Installing timing belt

Posted: August 6th, 2012, 2:39 pm
by davmac
Temporarily put the crank pulley bolt back in and put a large ratchet on the crank pulley bolt and turn exactly 2x clockwise. Removing the spark plugs will make it much easier to turn, but I usually just slowly muscle the crank gear around with the sparks in. Use the mark on the crank gear and the engine block to measure the 2x around. If the belt is on correctly the timing marks will line up again. Note: Every 2 revolutions of the crank the marks on the cam gears and (obviously) the crank gear must line up with the marks on the cylinder head and engine block. The marks you put on the belt will not line up again.

I've replaced MX3 timing belts 3 times and found the best and easiest way is to leave the top idler pulley off (the one between the cam gears and under the top radiator hose) when installing the belt. I also start from the crank and go up and around the idler pulley and front cam gear first. Then do the same from the crank gear and around the tensioner pulley and back cam gear last. Hopefully you have the tensioner piston compressed and held in place by a small nail, drill bit or something - and only the top bolt of the tensioner attached to the engine block so you can swing it out of the way while installing the belt. Once the timing belt is on then install the top idler pulley by pressing down and holding in place while you start the threads of the bolt. Now you can check the install by rotating crank by hand 2x to check the timing marks and confirm the belt is installed correctly. The final step is to install the 2nd tensioner bolt and release the tensioner piston. Rotating the crank and timing belt by hand will not cause the belt to jump.

Re: Installing timing belt

Posted: August 6th, 2012, 2:47 pm
by davmac
Just quick note on the youtube - totally normal - you are just turning the cam shaft so that it is compressing and continuing past some of the valve springs making it seem to jump.

Re: Installing timing belt

Posted: August 6th, 2012, 3:02 pm
by WhiteFinish
davmac wrote:Temporarily put the crank pulley bolt back in and put a large ratchet on the crank pulley bolt and turn exactly 2x clockwise. Removing the spark plugs will make it much easier to turn, but I usually just slowly muscle the crank gear around with the sparks in. Use the mark on the crank gear and the engine block to measure the 2x around. If the belt is on correctly the timing marks will line up again. Note: Every 2 revolutions of the crank the marks on the cam gears and (obviously) the crank gear must line up with the marks on the cylinder head and engine block. The marks you put on the belt will not line up again.
Oooh... so when I do 2 revolutions it timing marks will line up again, but not the marks I made on the belt.
Why is this ? Should it be 4 revolutions before it lines up or i just won't?

davmac wrote: I've replaced MX3 timing belts 3 times and found the best and easiest way is to leave the top idler pulley off (the one between the cam gears and under the top radiator hose) when installing the belt. I also start from the crank and go up and around the idler pulley and front cam gear first. Then do the same from the crank gear and around the tensioner pulley and back cam gear last. Hopefully you have the tensioner piston compressed and held in place by a small nail, drill bit or something - and only the top bolt of the tensioner attached to the engine block so you can swing it out of the way while installing the belt. Once the timing belt is on then install the top idler pulley by pressing down and holding in place while you start the threads of the bolt. Now you can check the install by rotating crank by hand 2x to check the timing marks and confirm the belt is installed correctly. The final step is to install the 2nd tensioner bolt and release the tensioner piston. Rotating the crank and timing belt by hand will not cause the belt to jump.
What do you mean by the last sentenc? Final step to install the 2nd tensioner bolt ?
I thought the only thing to come off is the top idler pulley and timing belt tensioner.

Re: Installing timing belt

Posted: August 6th, 2012, 3:55 pm
by davmac
All I meant was that you don't have to install the tensioner completely before you manually turn the crank to check the belt.

Usually you pull the tensioner completely off the engine and compress the piston and hold it compressed with a hardened nail or small drill bit. Then re-install the compressed tensioner with only the top bolt so you can swing it out of the way while you install the timing belt. The tensioner pulley is still mounted just nothing pushing it against the timing belt. After you install the belt and check it then swing the tensioner into place, install and tighten both bolts and pull the pin that is holding the tensioner piston.

For practical purposes the marks you made on the belt will never line up again - at least not within a 2 - 4 turns of the crank pulley. I assume you made some marks on the belt according to the counts given by Ryan. That is great because if you managed to get the belt on and lined up with the marks on the crank and cam gears then when you check (2x turns of the crank) the cam gears should be lined up with the marks on the cylinder heads. All that matters is that every 2 turns of the crank the cam gears are hitting their marks = the crank and cams are in synch.

Re: Installing timing belt

Posted: August 7th, 2012, 4:47 pm
by WhiteFinish
Okey, i didn't realize it that the marks wouldn't line up.

Re: Installing timing belt

Posted: August 7th, 2012, 11:36 pm
by Ryan
Never heard of that confusion before, I'll go edit the post.

Glad you got it sorted out though :2thumbsup:

Re: Installing timing belt

Posted: August 8th, 2012, 1:11 pm
by WhiteFinish
Yep.... wasn't fool proof

And i proved it :oops:

Re: Installing timing belt

Posted: August 8th, 2012, 1:57 pm
by Ryan
Hey, you got the crank pully being kinda off.