timing belt change
01-26-2004, 12:54 AM
#2
Big thirst, Sore Thumbs
Rennlist Member
Napoleon
Rennlist Member
Napoleon
Aint anyone going to help this guy.
It could run yes. Depending upon how much off you could bend valves. You don't want it one tooth off, but it doesn't really work that way. It's a matter of how closely the camshaft is in it's spin cycle to the Crankshaft.
Are you having issues, or is it just a general question?
It could run yes. Depending upon how much off you could bend valves. You don't want it one tooth off, but it doesn't really work that way. It's a matter of how closely the camshaft is in it's spin cycle to the Crankshaft.
Are you having issues, or is it just a general question?
01-26-2004, 02:15 AM
#4
Burning Brakes
Join Date: Nov 2001
Location: San Francisco Bay Area
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Yes it will run but it will run rough, are you getting ready to change it? If so there is a timing mark you can see directly on the bottom near the clutch bellhousing. Before you change the belt just crank the engine by hand and make sure the mark on the camshaft is aligned with the mark I mentioned above. Let us know, theres no doubt plenty of people know about the timing belt here. I've done the whole thing myself, I was very grateful I had this site.
01-26-2004, 12:42 PM
#5
Three Wheelin'
You need to be very careful in rotating the crank if the timing is off. These are interference engines and if the pistons and valves collide thousands of dollars perhaps $5K or more in damage will be done!
Ill add to the timing marks, there should be marks on the cam sprocket, and both balance shafts that line up with marks on the rear timing belt cover. I believe the exact location and type of mark depends on year and model of 924/944/951/968.
Also there is the TDC mark on the flywheel that should be visible from the top. I tried to find this on my 968 and could never see it. There are some other marks on the flywheel that you may be able to use to find TDC but they are likely to be model and flywheel specific. The method that I used and this only works with the belts still attached and very close if not exactly aligned was the remove the plugs and insert a long wooden dowel into the #1 clyinder then turn the crank with a ratchet. The dowel will come out to its peak twice, once at 180 degrees on the cam and then again at 0 degrees on the cam. The 0 degreed peak is TDC.
If your cam and crank are out of alignment they need to be professionally realigned before you continue.
These are pictures from the marks on my 968
Cam sprocket
Upper balance shaft
Lower balance shaft
Ill add to the timing marks, there should be marks on the cam sprocket, and both balance shafts that line up with marks on the rear timing belt cover. I believe the exact location and type of mark depends on year and model of 924/944/951/968.
Also there is the TDC mark on the flywheel that should be visible from the top. I tried to find this on my 968 and could never see it. There are some other marks on the flywheel that you may be able to use to find TDC but they are likely to be model and flywheel specific. The method that I used and this only works with the belts still attached and very close if not exactly aligned was the remove the plugs and insert a long wooden dowel into the #1 clyinder then turn the crank with a ratchet. The dowel will come out to its peak twice, once at 180 degrees on the cam and then again at 0 degrees on the cam. The 0 degreed peak is TDC.
If your cam and crank are out of alignment they need to be professionally realigned before you continue.
These are pictures from the marks on my 968
Cam sprocket
Upper balance shaft
Lower balance shaft
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01-27-2004, 10:17 PM
#9
Three Wheelin'
Where are you located? Perhaps another rennlister can stop by and give you a second opinion.
Would a compression test be a quick way to check those valves?
Would a compression test be a quick way to check those valves?
