ajd0002

As I mentioned a few days ago, my belt broke. I've been reading various threads and most make reference to setting up the timing marks,crank marks etc with the old belt on. Obviously I've lost this capability, so when (if) I do it myself, do I line up crank at TDC, rotor in firing position for cylinder #1, and cam sprockets on their marks? I assume then I lock the flywheel and install the belt per instructions, set tension, and rotate the engine by hand twice to make sure nothing has slipped?
I was a bit confused with the 45 degree references, but from what I can learn this is to ensure no engine damage is done on rotating engine by hand after initial installation? My engine has been turned over a few times before I knew what was wrong, so does this still apply or is potential damage already done? Also, I wonder if an '81 has this mark on the crank as I haven't found it yet.
Thanks in advance.

Ed Ruiz

I believe your car has a non-interference engine. In other words, there won't be any valve to piston contact. The method you describe sounds correct.

The 45 degree setting is used on interference engines, since that's the only place where the crank can be rotated without causing valve damage. YMMV.

John.

My understanding is the 81 is an interference engine. You should replace the belt, then turn it over by hand and do a leak down check on the engine.

Ed Ruiz

Does your 81 require premium gas? Is its compression ratio less that 10:1? If the answer to both of these questions is "Yes", then it is likely that your car's engine is non-interference. YMMV.

BrianG

I believe that Ed meant that the 45 degree crankshaft position is the only position on a 32v engine where the CAM can be rotated without fear of having valves contact pistons. <img border="0" alt="[thumbsup]" title="" src="graemlins/bigok.gif" />

ajd0002

Thanks everyone......the question of interference or non interference comes up again!! I'll check my owners manual for gas requirement again, but i believe it is premium. In any case, I guess I'll know in about 2 weeks after the parts come in and the fun begins.

ajd0002

Ed, the compression ratio in the owners manual is listed as 9:1, and the fuel requirement is 91 RON/ 87 CLC for USA, (I've always used premiun, but 89 octane)
Non interference based on this, I guess/hope.

Ed Ruiz

Although I've not worked on an 81, I seem to recall a few folks who have, and they told me the timing belt broke, but the valves were not damaged. Maybe they were lucky or maybe the engine is non-interference. YMMV.