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Old 03-02-2021, 04:18 PM   #11
Rj 2000 LS2
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Rj 2000 LS2 is just really niceRj 2000 LS2 is just really niceRj 2000 LS2 is just really niceRj 2000 LS2 is just really nice
Join Date: Sep 2018
Location: NE Wisconsin
Posts: 613

2000 L-Series 3.0L Sedan
Default Re: 2001 Saturn L300 (L81/3.0L V6) - Pre-Question for Head Gasket DIY Replacement

I believe the cams can literally only be installed in a certain position. They are keyed or something like that. But, if you watch the guy install the new timing belt, none of the cams are resting in the correction location and each must be spun to match the timing marks properly as the belt is threaded on that cam. In order to do this you must have the timing belt and crank locked into position at T.D.C. and route the timing belt in a counter clockwise direction, spinning each cam to the proper location and then clamp the timing belt to the cam to prevent it from spinning back to rest, which it would do. You will not believe how strong those valve springs are! It take some force to accomplish, then repeat with the next cam in a counter clockwise direction until all cams are locked to the belt using strong clamps and the belt is routed around the belt tensioner and it is roughly tightened to hold tension on the belt.

Now you remove all clamps and start to rotate the engine 360 degrees and check each cam to it's engine timing mark. Starting with the cam at 2pm position, adjust to the timing mark using the idler "cam" adjustment i.e. loosen the bolt and adjust the idler cam to zero the timing mark on the 2pm cam location. Tighten bolt and move to the next cam in a counterclockwise direction. Rotate 360 and verify the 2pm cam is dead nuts on time. Repeat timing procedure with each next idler.

It is important to recheck each cam timing mark after each rotation because any adjustment will affect all timing marks. It's a process you will only learn by doing it. It takes 8 or more rotations/adjustments of the engine to re-time the engine properly if you are lucky and nothing breaks loose! If it does, you have to start all over again. I think I had to rotate my engine 20 times or more to get it right nuts on.

Once complete, be sure to set the Belt Tensioner tension off the mechanical part's scale by about a 8th of inch. Lock the cams and belt locks before making any adjustments to the Belt Tensioner. If you loosen Belt Tensioner without first locking the cams and crank, everything will spin to rest severely de-tuning the entire engine! Setting it at the top of the mechanical part's scale is NOT enough tension for today's new belts. This is different that the manual but mechanics over time have learned more tension is needed on new belts.

NOTE: The marks on the timing belt are ONLY useful upon the immediate locating of the belt during first positioning of the belt. After one rotation of the engine, the timing belt marks are useless and you must rely on the CAM sprocket marks and the plastic housing timing marks for all adjustments. I noticed in your photo, you painted the side of the timing belt. When they said to paint the timing marks, they were referring to the Cam Sprocket Marks and the plastic housing marks, not the belt itself. Do not pay attention to the belt marks after the first rotation, during the timing procedure i.e. ignore the belt marks for this are ONLY useful when the belt is first installed around each pulley and idler.

Also, many belts are made for multiple engines and they are marked for both. So when you install the new timing belt, don't use the wrong belt mark for T.D.C.

Last point, don't listen to anyone who says the cam sprockets can be taken off the engine and the cam will remain stationary. It might or they might not. You'll know when they flop to rest because the valve will slam shut rather loudly.

IMPORTANT: If you have NO evidence of a leaking head... don't remove the heads! Oil does not leak from an engine head. Oil leaks from valve cover gaskets above the heads.
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