I am currently doing the dreaded Timing Chains, Guides, and Chain Tensioners etc on my 1998 XJ8 3.2ltr.

I understand Bank 'A' and Bank 'B' sprockets need to be a 'half tooth' out (or out of phase), and that turning one of the sprockets through 180 degrees will change the phasing, I get all that no problem.

My question is: If rotating one of these crankshaft sprockets through 180 degrees moves it to 'half a tooth' out, how do you know which way round the first one goes onto the crankshaft in the first place? Putting it on the wrong way round, ie, 'half a tooth' out, would mean the valve timing will be off on both bank 'A' and bank 'B'?

There is information in the manual about making sure the sprockets are out of phase with each other yes, but nothing about which way round the first sprocket goes onto the crank? Any help would be appreciated.

 

The intake cam sprocket is loose on the cam until you tighten the bolt and that sets the correct cam timing. The lower sprockets have nothing to do with the final cam timing!!!!

bob

 

Thank you, I think I understand. Basically, when tightening the Cam it will 'time' itself with whatever the Crank sprocket is set to, so long as the cams and Crank are fixed with their respective locking devices. Yes, makes sense now.

 

The orientation would only matter if you did not loosen the cam gears and tried to maintain the timing. I elected to change my chains and tensioners, and as I did not want to aquire the cam timing tools, I did not loosen the cam sprocket, and relied on it being right from the factory.
By setting the crank in position, you can install one crank sprocket, add cam and chains and the flat should align with the head. If you get the sprocket wrong, the flat is just "slightly" not parallel.
Process worked as I had great success since this.

 

Hi dsetter, many thanks for your reply. I will be attempting to complete the job this coming weekend, and having had it confirmed that the Cam sprocket (being loosened to fit the secondary chain and tensioners) will align whatever the orientation of the crank sprocket, I feel a lot more confident.

As it turns out, I have the crank pin fitted to fix the engine from moving, the tool kit I hired (only £50 for virtually as long as I needed it) included the fixings to lock both Cams at the same time too. So, all necessary components are locked down so nothing will move, it shouldn't be a problem getting this right first time.

 

The crank sprockets only fit in one position and no matter what way around you mount them, they are correct.