Timing Belt Change

xk150 · Post by **xk150** » 28 Mar 2013, 08:40

Good Morning,

I have a 2004 C70 LPT with 103K miles and a 2004 XC90 with 95K miles... Am planning on doing the timing belt jobs on both vehicles in the near future...
My question... believe both have variable valve timing VVT... Is this something I need to be concerned about??? Form what I know about the job, must line up the cam's and cranks with timing marks... and be sure after new belt is installed the marks are still correct... Does VVT chagne this logic?

BTW... I did a 2002 C70 about 5 years ago with no apparent problems... and never could find the mark on the crank... just lined up the cams...

Also have read that cam locking devices do not work with VVT... is this correct.

FCP Groton has a good video on the timing belt job and it appears the car being worked on has VVT and no special mention was made to do anything different..

Thanks

Post by **chrism** » 28 Mar 2013, 11:57

If all you're replacing is the belt, then just get the crank and cams on their marks before removing the old belt. As long as all three sprockets are still on their marks after the new belt is installed, then the VVT will take care of itself.

However, if you seperate any one of the cam sprockets from its shaft (like if you are replacing a cam seal) then all bets are off and you will then have a cam alignment task to deal with.

Suggestion: BEFORE you remove the old belt, rotate the crankshaft clockwise until the cams are on their marks, then add your own mark on the crankshaft sprocket and engine casing with a sharpie. This method is often used as the crank sprocket alignment marks are kind of confusing. Also, it's not really necessary to remove the crank pulley. The plastic dirt guard that runs around the underside of the crank sprocket can be removed by unscrewing a couple small bolts, allowing you to work the new belt in there with a little twisting motion. The old belt can be removed by cutting it.

Post by **JRL** » 28 Mar 2013, 14:24

You don't just replace a belt so why bother with all that.
Yes you can use a cam lock, it's almost a necessity

xk150 · Post by **xk150** » 28 Mar 2013, 19:05

Sorry, should have mentioned will change water pump, tensioner etc when I'm into the project...
Have no intention removing the cam sprockets so should have no issues with the VVT...

I do have an impact wrench so removing the crank pulley should be easy... Is it worth doing or just work the new belt around the pulley after removing the plastic cover...

Thanks

Post by **JRL** » 29 Mar 2013, 12:39

YOU NEED TO LOCK THE CAMS

Japedo · Post by **Japedo** » 29 Mar 2013, 13:10

I built a cam locking tool today..... Nothing fancy but it should be ok!
I've done timeing belts without a can lock, but this should make it easier.

Japedo · Post by **Japedo** » 29 Mar 2013, 13:11

I built a cam locking tool today..... Nothing fancy but it should be ok!
I've done timeing belts without a cam lock, but this should make it easier.

Post by **chrism** » 29 Mar 2013, 17:00

If the crank sprocket is on its mark, the engine is NOT at TDC, but rather it's in a "safe" position where none of the pistons are at the top of their stroke. This means there is no chance of valve-to-piston contact and thus the cams can be independently rotated to your heart's content - not that there would be any reason to do that though.

I've recently done two belt and tensioner R&R's without locking the cams, with no ill effect. The video that FCP has on Youtube was done by someone that has obviously done it more than once and he doesn't lock the cams. Check it out.

xk150 · Post by **xk150** » 29 Mar 2013, 18:23

Thanks for all the great input...

When I did the job on my 2002 C70 HPT it was pretty straight forward and I didn't use a cam locking device but know it's good practice... Couple last minute questions.

1. Where can I purchase a cam locking device... Can't find the IDP verson on thier site any longer.

2. What exactly does the timing mark look like on crank gear... I am assuming it is betwen two teeth. Last time, I could not find the mark to save my soul.

Thanks

Post by **chrism** » 29 Mar 2013, 22:01

IPD cam locking tool:

http://www.ipdusa.com/products/5127/109 ... cking-tool

The crankshaft timing mark is somewhat vague. That's why some people (me included) paint there own mark before removing the old belt.

BTW - If you ever need to remove the cam sprockets, like when replacing the oil seals, you'll need an alignment tool like this one which holds the rear ends of the cams in proper alignment while you reattach the sprockets.

http://www.ebay.com/itm/Camshaft-Cylind ... ac&vxp=mtr