ADJUSTING VALVES SAAB
8V
The valves on a 8V engine are adjusted by means of
different sized shims that go under the 'buckets' that the cam rides
on and on top of the valves. You first measure the clearances, then
remove the cam to access the current shims, measure the shims there
and then calculate the shim you need to get the correct tolerances.
You insert the correct shim. Make sure to check the new shim with a
micrometer before installing, they have been known to be mislabeled.
Then you reinstall the cam and recheck the clearances. See the 8V
head gasket section for details on removing the cam.
Checking the clearances is easy, adjusting them is a job.
To check them, turn the engine to TDC for nder. Since the distributor fits to the cam with an offset slot and driver, it must be in this position to remove the valve cover. Remove the valve cover. If the Allen screws holding it down are tight and seem like they will strip before loosening, give them a smack with a hammer. This usually loosens them up. I prefer to check each valve with the cam lobe for the valve I am checking turned straight up. Removing the plugs and using a bump starter on the starter eases this. You can turn the motor by raising one front wheel and engaging third on manuals and turning the tire to turn the motor. Use a paper and pen to record your readings for each valve as you measure them.
Look for .006-.012" for the intakes and .014-.020 for exhausts. If out of range, adjust to .08-.10" for intakes or .016-.18" for exhaust. Keep the buckets on the valve they came off of. Use a razor blade to remove any oil grunge build up on the old shims to get an accurate measurement of their thickness. Some shims wear where the valve stem hits them. These worn shims can give you trouble deciding on the correct replacement. Many times it takes more than one attempt to get all the valves right on the money. It does make a running difference when you do.
Valves too tight can burn or cause running problems, too loose noise, wear and running problems. You can get the cam out of time with the crank when removing the timing chain from the cam gear to remove the cam to change a shim and then destroy the motor. You can break the distributor or the cam when trying to remove/replace the valve cover. If you aren't equipped, don't have a set of feeler gauges and an accurate micrometer or dial caliper, and don't have a lot of engine experience, this is not a repair for you to undertake.