Volvo 850R Timing Belt Question

jonslave · Post by **jonslave** » 03 Jun 2020, 15:37

Yet another one....

Lining things up again after a timing belt change over here.

Looks like my absolutely teeny tiny tick (almost non-existent, sheesh) in the crank pulley lines up properly with the pointer on the block with the cams this far out from the timing marks. (Could not get a clear pic of the crank with my phone and light source)

My questions are:

1. If I lined up the cam marks when I started and used a lock tool pressed into their teeth, how could this car have started and ran so well before I changed the belt?

2. Is there another way to confirm crank timing beyond that scary tiny tick?

3. If I'm sure this is right now, do I rotate the cam sprockets to match the crank alignment or vice-versa?

Thank you!

Post by **misha** » 03 Jun 2020, 16:04

I never used cam locking tool and never had cams or crank moved when replacing the timing belt.

Post by **erikv11** » 03 Jun 2020, 16:34

Cams always move when I do this job, well the exhaust cam does.

Your suspicions are correct, there's no way that is on the crank mark, that's too far out for it to run well. Keep looking; are you sure it's not there when the cam sprockets are lined up with the tick marks? Also there is a tick mark on the edge of the crank pulley, that you can use to help you find the teeny tiny mark. But you must go by the crank pulley mark.

Oh and (3) you become certain the crank is correct, then put the cams where they need to be. When the crank is on the timing mark the pistons are out of the way and the cams can be turned however they need to be, do whatever you want as long as the cams are set right before you move the crank again.

I need to run but here is some info from another MY, may be helpful: viewtopic.php?f=1&t=83534

jonslave · Post by **jonslave** » 03 Jun 2020, 17:05

Great info thank you. Just looked again with a high lumen flashlight and can confirm the mark lines up with the pulley in the photo cam position. Also confirmed with the mark on the balancer lining up with the mark on the block. Strange. I must have done something.

I can easily rotate the engine by hand, just curious, what is the maximum number of teeth the cams can be off before catastrophe?

Will take the belt off and line up cams. Do I need to find the tensioner pin again??

Thanks again.

Post by **erikv11** » 03 Jun 2020, 20:27

After you align the cams, you indeed have to remove and recompress the hydraulic tensioner and lock it with the pin before you can reassemble. Compress the tensioner slowly as per usual. If you can't find the pin, people often use a very small Allen key as a substitute.

Post by **misha** » 04 Jun 2020, 13:55

jonslave wrote: ↑03 Jun 2020, 17:05 ...just curious, what is the maximum number of teeth the cams can be off before catastrophe?

Up to 3...more than that is game over.