Perpetual Novice

Reviewing bentley before I do the job. it looks like I put on the locking bar, unbolt the gears, remove the locking bar, remove the gears.

So after I remove the locking bar what keeps the cam from rotating as I pull off the gear? Or do I not worry about it until reinstalling the gears?

silverd2

At TDC, the cams are "load balanced" and will not turn unless you use effort to move them.

I didn't use the cam locks or even loosen the cam gears when I did my belt...but that's a different thread entirely. Both ways work.

silverd2

P.S. I used most of the Bentley procedure, minus the gear removal and minus the lock carrier movement...plenty of space to work. Used the crank lock (really didn't need to...but did for peace of mind). Used paint mark method on gears (all 3) and old belt(transferred to new)to maintain correct timing.

Note: The belt slides off very easily with gears attached, since a tensioner on each side has been relieved. Getting the new one back on is a little tougher, but very possible when done properly.

Perpetual Novice

Gracias. I'm concerned that while tightening the puller on the gear I could accidentally turn the shaft..but I guess the old timing belt and the crank positioner prevent that.

silverd2

True...not as scary as you might think. The cams can actually turn several degrees before contact is made on pistons and turned back to TDC for final timing.

Not that I would consciously do it, but the cams turning to the point of contact, only under their own spring load, are not likely to have enough force to bend a valve...BUT, I would not say the same about turning the crank by hand, if cams were out of time.

Perpetual Novice

Done and except for a very scary start up (DO NOT forget to secure the fan ring before starting...you might need a change of pants if you don't.) she's humming along real nice.

The diamond-shaped washers (that the locking tool mates with) are keyed to the cam, so theres no real danger here. At one point the cams on the left bank clanged into a new position 30 degrees out But as soon as I got the cam locker on it pulled the cams back to TDC 5

Thanks for your help, and thanks to Bluauparts for the tool rental and detailed instructions.

silverd2

Yep, it takes just a little over 30 degrees before valves touch a piston...I've done that and turned it back...no harm at all.
In another discussion, I've recently learned that even hand turning the pulley past that will do no valve damage, as the hyrualic lifters absorb the force.
Real damage is only likely when a belt breaks with engine running...higher speed and full oil pressure.

Glad the job went well...congrats.

Sam