What is the basic timing belt replacement procedure?

[volvo 4 life]

I've been reading the D24 greenbook and trying to figure out what is absolutely necessary to change the timing belt on my D24. I would like to leave the rear belt alone if possible so the pump timing doesn't change because the car runs really good right now. Is it possible to change the front timing belt by marking the pulleys and belts and then checking the injection timing afterward with the dial indicator? I was thinking I could lock the injection pump with a pump lock pin, that way the cam and injection pump won't move while changing the belt. Does this sound like a reasonable method? I would check the injection timing afterward to make sure it is within specification.

[745 TurboGreasel]

If you are checking the timing afterward, you might save 5 minutes not adjusting it, but really all you accomplish is preventing yourself from locking the cam in the right spot, but it will cost you over an hour if you have to redo it.
Yes you can shove a new belt on, and it will probably run.
The timing you are trying to preserve won't be the same after. if you like it, but don't know what it is, check it before disassembly, and set it to that when you are done.

[ngoma]

Theoretically (actually more than theoretically, I lucked out doing similar when changing the waterpump) you should be able to:

1. Check the IP timing.
2. Change the timing belt.
3. Check the IP timing. If it is the exact same as before, you are good to go. If it has changed, you must check (and probably readjust) the cam timing, which necessitates resetting the IP timing.

Supposedly there are small differences in timing belt manufacturing tolerances, and differences in waterpump tightness before & after that can introduce enough variation to throw off the cam timing, and therefore, the IP timing.

IOW, you might get lucky, but will still need: 1) The cam timing tool, and; 2) IP timing tools, and be prepared to reset the timing (both) if necessary.

[volvo 4 life]

Ok, well then I guess I will just devote a day to the project and go through the steps of locking the cam and IP so it all comes out how it should. What is good setting for timing on an NA D24 for a little more power and better cold starts? It's a bit rough right now if it's under 40 degrees and the engine is very quiet, hardly any ignition knock at all.

[sonny]

How would you place the Cam Timing Tool, which you need to Change the Main Timing belt, without removing the Camshaft sprocket, where the InjectionPump belt runs on ?

You MUST Re-Time the Pump after Changing the Front Belt .
Anything else is not goot ...

Greetings

[volvo 4 life]

I am going to remove the rear pulley on the cam and put the lock plate in so it stays at TDC. I have a new rear belt so I will just change both belts while I'm there. Tools needed would be the crank lock tool, cam lock plate, lock pin for IP, dial indicator, dial holder, and pulley holding tool right? I don't quite understand how it's possible to torque the pulleys on the cam because it isn't keyed. How do you keep the cam from moving while torquing the pulleys down? Even if you hold the pulleys with the sprocket holder it would seem the cam would still slip while trying to torque the pulleys down, especially the rear since it requires around 70 ft lbs of torque.

[ngoma]

Originally Posted by sonny

How would you place the Cam Timing Tool, which you need to Change the Main Timing belt, without removing the Camshaft sprocket, where the InjectionPump belt runs on ?

You are correct. I have modified my step 3. above.

Originally Posted by sonny

You MUST Re-Time the Pump after Changing the Front Belt . Anything else is not goot ...

If you replace only the front timing belt without disturbing the cam pulleys (front and rear), and the IP timing retains the same setting as it did before the TB replacement, then we can say the relationship between crankshaft/camshaft/IP has remained the same.