Question about cam movement

[mecheng]

My friend was changing his timing belt on his 96 Turbo and his Cams moved from the 1 o-clock position to the 6 -oclock position when he was trying to get the belt back on. He was woried that maybe
the valve hit the piston.

I said to him: if it did, I doubt it would bend them as it would take quite the force to do so.
Correct?

Also, Does anybody know if the Volvo 5 cylinder engines allow you to move the camshafts as long as the crank is in the correct position (lined up with marks) without having any valve interference?

I helped him get everything put back together when he called me and the engine runs fine.

Thanks

[cn90]

The force on the valve spring is not strong enough to cause a bent valve.
Actually, when the cam sprocket moves, it moves because the spring pushes the lifter upward, so chances are the valves are in closed position when the sprocket lets go.

I just helped a friend doing his TB in his 2005 Toyota Sienna, the Rear cam sprocket moves all of sudden and shattered the mirror I had in my hand (I used mirror to verify timing mark). Lined everything back to factory marking, car runs fine.

Later, I looked it up online, many Toyota people have had this issue: sudden cam sprocket movement but nobody has had any issues with valve damage.

So ---> Nothing to worry about.

[Ozark Lee]

When the crankshaft is lined up to the timing mark you can spin both cams as much as you want to and the valves won't hit anything.

...Lee

[erikv11]

What Lee said; this is why the timing belt job instructions say to "put the crank on the mark" rather than "put the crank at TDC" or similar. The mark puts #1 just below TDC, and the rest of the cylinders well off of TDC, so that no interference is possible. Which also explains why tools like the IPD cam holder are for the most part unnecessary gimmicks (but I confess I have one ... it has other uses!).

[mecheng]

Brilliant, that's what I thought, the cs didn't move. I told him to drink his beer and relax, he kept worrying
I was skeptical about cam holders but they moved on me as well. A small 2x4 seems to do the trick

Thks

[rspi]