If the belt breaks while driving with the valves hit the pistons?

 

I hear that this car is one of the easiest to do a timing belt change.....

 

The 740 is a non-interference engine. Go to www.stepbystepvolvo.com (though I haven't put up procedure for replacing 740 timing belt yet).

 

Replacing the timing belt is easy. Just make sure you're at TDC #1 firing when you slip old belt off and the new one on.

You'll need to remove the starter to gain access to the flywheel so you can jam it or have a helper jam it for you while you remove the bolt for the crank pulley.

Oh and as far as the tensioner goes, just loosen the big bolt in the middle of the tensioner wheel, give the old belt a squeeze which will compress the tensioner spring, then re-tighten the tensioner bolt with the spring compressed. This will allow you to remove and replace the timing belt without having to remove the tensioner.

Just a couple of tips I learned along the way. Hope they help you and good luck.

 

It is much easier to buy the crank pulley holder tool. IPD sells it for, I believe, $49 (used to be $40). You don't need two people to do the job and you won't cause possible damage to the flywheel.

Visit www.stepbystepvolvo.com, replacing timing belt for 740, for photo of crank pulley holder tool in use.

 

I have heard a lot of conflicting information about whether a B21 or a B23 is an interference engine or not.
My old Haynes manual said the B21 was not an interference motor, while the B23 was.
The Gates brochure indicates they are both interference engines. See here:

http://www.gates.com/brochure.cfm?br...cation_id=3487

If I were you, I'd just change it anyway because it's so easy to do and it's so cheap. To remove the crank bolt from a B23:

Get a long breaker bar with a socket that fits the crank bolt.
Wedge the breaker bar end against something while it's on the crank bolt.
Take the coil wire off to ensure it won't start up.
Crank over the engine with the starter just a touch and...VOILA! The starter does all the work.

No muss, no fuss. Works everytime. No assistant required. No broken flywheel teeth.
No busted kunckles.

Can be used to loosen most engines' crank bolts.
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