1999 C70 Crank Shaft, Cam Shafts Synchronization

Post by **Kazthebassman** » 28 Sep 2013, 08:35

1999 Volvo C70 Cabriolet 2.4 L Turbo 90k miles
I started my C70 a few days ago. The engine light came on, acompanied by a scraping sound, from the right side of the engine. The engine seemed to be running fine. I noticed the timing belt had cut grooves through the timing belt cover. I quickly turned off the engine.

I removed the timing belt cover. I found the tension to be loose. The tensioner ball bearings were gone, leaving the belt with some slack.
I researched, the repair and ordered the kit with the water pump.

I removed the damper to see the crank timing mark. It was in alignment with with the oil pump mark, yet the cam sprockets were at the 7 o'clock position.

I am unsure of how to proceed at this point. Do I try to rotate the cams or crank alone to bring them to the marks ? It was running before. I did rotate the crank slightly to gain access to the damper bolts. While I moved the crank shaft, my assistant, observed the cams moving as well.

Any help or suggestions, as to how I can assure, proper crank to cams synchronization, would be greatly appreciated. Thanks, Kazthebassman

Post by **rspi** » 28 Sep 2013, 09:11

I would rotate the crank to see if the cams align with the cover, then double check the crank.

Can you tell us how many miles you think the tensioner had on it?

Post by **rspi** » 28 Sep 2013, 09:16

Oh, if for some reason the crank can't go around to get the cams aligned, put the crank back on its mark, then align the cams. When the crank is on its mark, the cams may be able to turn around 360°.

After everything is on mark, install a new or good used tensioner, and see if it starts and runs smooth without missing. If so, you are likely good. Replace all if the timing parts and keep moving.

Post by **Kazthebassman** » 28 Sep 2013, 09:58

I bought this car with 72k miles. It's at 90K now. It had an OEM Volvo tensioner. It may be the original. I believe the owner's manual stated 105k miles for belt/tensioner but I have heard other's say 70k is a safe mark.
Thanks for the info. I will try your suggestions and post results.

Post by **Kazthebassman** » 28 Sep 2013, 10:47

The crank wouldn't turn very much. I removed the belt. I moved the cam shafts, their marks, with the crank on it's mark. I put the belt back on, still with bad tensioner. The engine spins freely now. Thank you very much , rspi . I assume, the belt must have slipped at some time.
Moving on to the rest of the job. I hope all will be well.
I'll post a pic of this bad tensioner later. LESSON: Replace timing belt and tensioner well before 90k miles.

ManManOhMan · Post by **ManManOhMan** » 28 Sep 2013, 12:50

To get some clarity on this procedure because I'll be doing it in the next few days.
You position the crank, and then you can position the cams individually. I assume that if I am allowed to position the cams individually I would position them while going clockwise correct or not?

Post by **Kazthebassman** » 28 Sep 2013, 13:01

Clockwise is the direction I went. You should check alignment with the belt on. I believe, you should not have to move anything individually, unless the belt jumped or you moved one of the shafts without the belt on.

ManManOhMan · Post by **ManManOhMan** » 28 Sep 2013, 13:20

Thank you!!!

Post by **rspi** » 28 Sep 2013, 14:06

If you do NOT have VVT, I don't think it matters which way to turn the cams as long as they do not bind and stop.

It is a super rare chance that the car can jump time and be fine without valve damage. If the motor was running like you said, you can likely write a book to sell.

I've never done a mechanical tensioner on a Volvo but I've read about how to get it tight in the forum somewhere.

Post by **rspi** » 28 Sep 2013, 14:09

Oh, the belts have a time change recommendation as well. I usually don't leave those parts on past 10 years.