Timing Belt Marks Keep Moving

zupta82 · Post by **zupta82** » 27 Jun 2019, 05:26

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Hello everyone, I have a 1997 850 and I can’ t keep the timing marks to stay put. I first aligned the marks on the crank and then the cam sprockets right on the money and lock the cams with my iPd tool.When I assembled all the new parts (idler,pump,tensioner), I then wrap the belt around everything and go to pull the pin on the tensioner and find that it keeps jumping about a tooth off when I go to rotate the crank. Should I align the crank and cams about a tooth off to compensate for the tensioner as it begins to re-extend after I pull the pins. This is driving me crazy, my bolts on the sprockets have not been touched . I have enclosed some pics

Post by **RickHaleParker** » 27 Jun 2019, 07:25

: C6357FA7-8D56-4D18-A159-E98E137AA401.jpeg (300.56 KiB) Viewed 2165 times

zupta82 · Post by **zupta82** » 27 Jun 2019, 08:06

I’m a little confused do you mean pry up on the roller tensioner arm thing and then pull the pin.

Post by **ZionXIX** » 27 Jun 2019, 08:27

When I changed my belt I had to compensate by moving one tooth in the opposite direction so it would all line up after I released the tensioner. It took me about 10 tries to get right. Just keep trying.

Post by **RickHaleParker** » 27 Jun 2019, 13:58

zupta82 wrote: 27 Jun 2019, 08:06 I’m a little confused do you mean pry up on the roller tensioner arm thing and then pull the pin.

I think you are not getting the belt tight going counter clockwise from crank, intake and exhaust, when you pull the pin that slack is taken up and that is why you are one tooth off.

I loop around the crankshaft, pull tight and loop around intake, then the exhaust, then push the belt over the tensioner, pull the pin. You got to keep the belt tight through the entire process.

callahanoffroad · Post by **callahanoffroad** » 27 Jun 2019, 14:03

RickHaleParker wrote: 27 Jun 2019, 13:58
zupta82 wrote: 27 Jun 2019, 08:06 I’m a little confused do you mean pry up on the roller tensioner arm thing and then pull the pin.
I think you are not getting the belt tight going counter clockwise from crank, intake and exhaust, when you pull the pin that slack is taken up and that is why you are one tooth off.

I loop around the crankshaft, pull tight and loop around intake, then the exhaust, then push the belt over the tensioner, pull the pin. You got to keep the belt tight through the entire process.

This is a really good tip

Post by **misha** » 27 Jun 2019, 16:22

You don't need cam locking tool at all.

Post by **erikv11** » 27 Jun 2019, 17:07

(1) cam locking tool is probably making things worse, see my suggestion (3) below which can not be done with a cam lock tool

(2) use the standard procedure: always start on the crankshaft then proceed from the right (install belt counterclockwise). Pull the belt tight over intake sprocket, then over exhaust sprocket, etc.

(3) BUT after everything is perfectly aligned and ready to go but before you start putting on the belt, cheat both of your cam sprockets about 1/2 of a tooth to the right (clockwise). This will greatly simplify keeping the belt tight as you traverse through the sequence. Be careful, the exhaust cam wants to jump due to cam lobe pressure, be patient you can get it to sit where you want it.

(4) check the marks when you are done, make sure you rotate a full cycle of the crank by hand and check them again.

You will find suggestion (3) to be super useful!

tardcart · Post by **tardcart** » 27 Jun 2019, 19:27

you show being half a tooth off which is not possible. are you turning clockwise to test alignment? (front of engine)

Post by **erikv11** » 27 Jun 2019, 20:11

Likely the angle of the pics is misleading. It's going to be off a whole tooth, and OP does say that in the first post.