Timing belt lost marks recovery (assumed keyway on pulley)

[stuj]

Recently had a blocked PCV system that caused the inlet camshaft seal to blow out on the pulley side. Decided to change the timing belt at the same time.

Did all the usual timing belt change things marked the TDC and cam pulley marks, done this many times on other cars....But, didn't realise the inlet pulley wasn't fixed on a keyway! So lost the marks to set up properly.

After realising this I attempted to put the cam back to the correct position drove the car and there was little low end power, I made a few adjustments and the power improved somewhat but still not good.

Did some research and found the cam timing marks are on the back of the engine (gearbox end). To get access to the marks you have to remove the cover plug off the inlet valve shaft, this can be done by drilling a small hole in the cover and pulling out the plug (I re used the plug just put a small crew with silicone back in the hole). The exhaust cam timing mark is more difficult to get to, remove the engine torsion mount and crossmember and then removed the cam location transducer to expose the marks.

When I could see both marks I put the engine at TDC (can only be done reliably by removal of the main pulley) adjusted the timing marks to line up with the case. The inlet valve timing was out babout 5 degrees. The marks on the plastic cover are hopeless.

Put it all back together and the car runs well.

[AKAMick]

Using the Volvo cam locking device for the transmission end of the cams during seal replacement keeps everything in alignment, making marks of the Variable Cam timing pulleys in the rest and forward position prevents losing the timing when removing them, refitting them to correspond to the rest and forward marks you made keeps everything spot on.

[Astro14]

To put it simply: you did the job wrong, discovered your mistake, and got the cam timing pretty close after discovering the error. Right?

You have to use the locking tool, on the back side of the engine, to lock the cams, any time a cam pulley is removed. You can't loosen/tighten the pulley bolts without locking the cams, or you'll rotate a cam with NO WAY to keep track of the relative position/timing. None of the cam is visible when the pulley is in place, so you can't mark anything. The VVT hubs in particular cover everything, and you've got to rotate the hub to get the phase correct before the belt goes back on and the cam (which is invisible) has to stay in the proper position when that is done or the cam timing is all wrong.

Of course, you have to remove the cam pulley to replace the cam seal.

That locking (which requires removing things like the upper engine mount to gain access) is why a cam seal takes me several hours, instead of the 2 hours that a timing belt would take.

[stuj]

yes, when I realised I had lost the marks I tried to recover by trial an error, assuming the inlet valve could only be out by the angle of the slotted hole. But, the cam must have moved. Lucky I didn't bend any valves!

I don't have the alignment tool but a steel ruler and some scrap aluminium plate did the job, to line everything up. The timing mark on the crankshaft is obvious when you look at it but nothing like any of the manuals from Volvo.

This is a crap system in terms of maintenance, but I can see why Volvo did it this way to simplify manufacturing tolerances.

If I did this again I would buy the tool.

[sabbates]

Anyone have an Amazon link to the correct tool?

[Astro14]

This is the one that I used:

https://www.amazon.com/ABN-Camshaft-...TD9M09ZHMMZEQR

[2002V70XC]

I used the CTA one that FCP sells for $90 USD
https://www.fcpeuro.com/products/vol...gines-cta-2864
It was a great solid tool thats worth the investment.
The one that Astro linked is cheaper but i wouldn't buy that because of the review with the photos showing the tool got broken. Maybe that guy just got bad luck or the review could be coming from competitor who knows.

[Goldarlene]

So if I'm planning to do front and rear cam seals - do the rears first with the belt on? Then do the fronts with the tool locked in place?

[Xfingers]

Other members can correct me if I'm wrong, but I think the two rear cam seals (facing driver's side of engine compartment) need to be removed in order to attach the cam-locking tool. The rear exhaust cam seal can be replaced after the cam-locking tool is removed but the rear intake cam seal gets destroyed in the process. Both of the rear cam seals are pretty inexpensive so just have new ones on hand before you start the job. In other words, you have to remove the rear cam seals to do the front cam seals so do the rears LAST with the belt on.

[AKAMick]

I just recently did my 04 cam seals, the rears can remain in place while servicing the front seals, fitting the locking device does not interfere with the internal cam shaft rear seals, other years without the variable timing pulleys on both cams will need a replacement rear cover(not a seal) on the intake side as they don't have the timing sensors at the rear of the head, I used the cam locking tool that Astro recommended with no problems, this is a helpful video. https://www.youtube.com/watch?v=o4uLvH151-c