924Board.org

[gml]

In the process of overhauling my cooling system I'm doing my first timing belt replacement (1982 924 NA)

I lined up the valve cover needle with the mark on the top pulley before removing the old belt.

I had a hard time fitting the new belt on. The belt section was loose between the top pulley and the toothed part at the crankshaft. After even more finagling, I'm pretty sure I rotated the crankshaft while maneuvering the belt, and now the teeth on the belt aren't lined up anymore.

What do I do now? I suppose I have to find TDC manually (any helpful tips)? And more generally, how do you ensure that the crankshaft doesn't rotate when fitting the belt?

One last stupid question; the belt only goes around the top pulley, the crankshaft, and the tensioner right? I'm not missing anything?

Mod note: have Stickied this topic, seems like a good idea!
_________________
George

1982 924 NA 5-speed

[peterld]

It's easy peasy. And even better, as a normally aspirated, there is no chance of having hurt anything, as your motor is non interference.
Begin at the crank. Line up the notch in the crankshaft pulley with the pointer on the oil pump.
Now move to the cam and as before, line up the pointer on the cam cover with the dot on the Back of the camshaft pulley.
Fit the belt ensuring no slack between crank and cam and then finally tighten the adjusting idler pulley. You should be able to give the belt a half twist (NO more or less) at it's longest point, and you're good to go.
If you are unsure whether you really are at TDC, pull # 1 spark plug and insert a plastic/paper straw so that it is riding on top of the piston. Slowly turn the crankshaft pulley with the appropriate socket and bar, and you will notice the straw move up and down in the plug hole. At it's highest point is obviously TDC.
_________________
80/81 932/8 ROW

[924RACR]

Some added comments on the above... which is for sure solid.

It's worth verifying the crank position by looking for the alignment of the TDC mark on the flywheel, visible through a small port (maybe 3cm x 2cm) at the back of the block in the top of the bellhousing, pretty much directly under the ignition coil.

That said, there have been cases (though uncommon) where the flywheel has been removed then reinstalled incorrectly, not properly indexed - so the 100% guaranteed proof of lineup is the aforementioned method of removing the #1 spark plug and checking.

The other thing, the step "fit the belt ensuring no slack between crank and cam pulley." It should be obvious, but just in case... that's no slack on the side of the belt opposite the tensioner, so the tensioner takes up all the slack. I will usually lean on the crank pulley and rotate it slightly to take up every last bit of slack at this step, then recheck the marks before setting the tensioner.

As noted, especially with a non-interference NA motor, there's no risk of damage with this - but frankly since it should be less than 8 degrees and you're only nudging it by a hand on the pulley (NOT with a wrench!), you shouldn't be able to damage it anyway, just stop when you meet resistance.
_________________
Vaughan Scott
Webmeister
'79 924 #77 SCCA H Prod racecar
'82 931 Plat. Silver
#25 Hidari Firefly P2 sports prototype

[gml]

Thanks for the great info, both.

Looking at the shop manuals I realized I could check the flywheel markings for TDC on the crank. Quick question there, I find it very hard to read the markings due to surface corrosion, are the three markings +10, -0, -10?

I was using a wrench to rotate the crank pulley but it was very hard to make fine adjustments. Will try doing this by hand.

[Cedric]

I normally use the tdc mark on the front pulley, should be a notch there. But on an old scruffy wheel it can be hard, so maybe refresh it if you find it
_________________
1980 924 Turbo
www.instagram.com/garagecedric/

[924RACR]

One tooth on the cam pulley is about 8 degrees, from what I remember...

As Cedric said, you may need/want to clean off the flywheel markings to see better...
_________________
Vaughan Scott
Webmeister
'79 924 #77 SCCA H Prod racecar
'82 931 Plat. Silver
#25 Hidari Firefly P2 sports prototype

[Glemon]

[quote="gml"]Thanks for the great info, both.

Looking at the shop manuals I realized I could check the flywheel markings for TDC on the crank. Quick question there, I find it very hard to read the markings due to surface corrosion, are the three markings +10, -0, -10?

I was using a wrench to rotate the crank pulley but it was very hard to make fine adjustments. Will try doing this by hand.[/quote]

I have had trouble reading flywheel marks too. As far as fine adjustment, if you haven't already, take the sparkplugs out. It should make it easier to turn the crank.
_________________
88 924S
68 TR250
02 IS300

[djala]

I actually just bought a 924 last week. It's been sitting in a garage for 10 years, so the gas is bad and I'm assuming all the important rubber is bad, like the timing belt. I just replaced the belt and tensioner pulley today, which is kind of difficult to do alone.

I couldn't find any kind of mark on the crank, and I did accidentally move it when the belt was off, so I took out spark plug #1 and looked through with a borescope to find TDC. It might not be 100% exact TDC but it's pretty darn close. Used the dot on the back of the camshaft gear lined up with the mark there. Also used a marker to mark the crank for TDC for future reference.

Side note, emptied the fuel tank, and I have some cleaning to do

[PopUpProject]

What is the part number for the belt? I also just bought a 82 924 NA and need to replace all the rubber parts
_________________
Just trying my best to figure this out without total failure

Poppy the '82 924 Resurrection in Progress