Aligning The Optispark
Aligning The Optispark Ok, so after at first just putting the pin in the cam gears when it felt like it was in and not checking TDC I tried putting it all together and starting it. Still no start, except this time instead of just cranking, it make extra noises like it was trying really hard to start and missed/backfired through the intake. So I read that I must make sure the pin went in the right way as it can be misplaced but there is only one true way it can go in for ignition.
Now, my dad helped me the second time around to find top dead center and we turned the crank by hand using the rocker arms as reference until the exhaust and intake valves on the no.1 cylinder were compressed. I had just the pin by itself in the cam gear where I thought it should have been, letting it turn until TDC was reached, and when we stopped its at 2 or 3 o'clock. Now did we do something wrong to find TDC, or if not, were should it be inserted so the teeth are in the right groove, because I have read people saying 6 o'clock and 9 o'clock, which is it?
Oh and can I start it without the waterpump installed for a few seconds to see iof I got it right this time?
Now, my dad helped me the second time around to find top dead center and we turned the crank by hand using the rocker arms as reference until the exhaust and intake valves on the no.1 cylinder were compressed. I had just the pin by itself in the cam gear where I thought it should have been, letting it turn until TDC was reached, and when we stopped its at 2 or 3 o'clock. Now did we do something wrong to find TDC, or if not, were should it be inserted so the teeth are in the right groove, because I have read people saying 6 o'clock and 9 o'clock, which is it?
Oh and can I start it without the waterpump installed for a few seconds to see iof I got it right this time?
Last edited by Marc3.4V6; Apr 9, 2009 at 09:15 PM.
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From: Decatur, TN (N-W of Athens)
It might be the wording, but how you described achieving TDC sounds like it could easily lead to not being on the correct TDC (edit: Because I know one of my "fans" will jump over this, TDC just equals piston at the top of it's stroke. Doesn't matter what stroke, it's still TDC. Hence "correct" being used.). You want the stroke that finishes the comrpession stroke, which is why it's easiest to pull the #1 spark plug and put your finger over the hole till a bunch of air gets pushed out. You'll know for sure you're on the compression and not the end of exhaust, because if you continue rotating it'll start creating a great suction 
That means no valves have opened (intake in the case of it being the exhaust) and you're on the correct stroke. While you can go off valve events, I prefer the idiot method to rule out any doubt. If we don't have any timing tab on our cars (haven't bothered to look, but I'd be surprised if we don't) then you'd actually want the crank hub's timing mark something closer to to 1 o'clock to 1:30.
Like Pork said, you can run it w/o the pump, but I'd recommend that the block at least have whatever coolant that was in it at time of removal, to be in it heh
That means no valves have opened (intake in the case of it being the exhaust) and you're on the correct stroke. While you can go off valve events, I prefer the idiot method to rule out any doubt. If we don't have any timing tab on our cars (haven't bothered to look, but I'd be surprised if we don't) then you'd actually want the crank hub's timing mark something closer to to 1 o'clock to 1:30.Like Pork said, you can run it w/o the pump, but I'd recommend that the block at least have whatever coolant that was in it at time of removal, to be in it heh
one quick question on this also, if i'm replacing opti's can i just take the one off and put the other on and just make sure the cam pin is in the correct slot on the opti so it seats completely correct? i dont have to worry about having it on a correct stroke or anything do i? I just wanna double check so i put this on perfect first time.
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From: Decatur, TN (N-W of Athens)
one quick question on this also, if i'm replacing opti's can i just take the one off and put the other on and just make sure the cam pin is in the correct slot on the opti so it seats completely correct? i dont have to worry about having it on a correct stroke or anything do i? I just wanna double check so i put this on perfect first time.
assuming the harmonic balancer hub has never been removed or (slipped) there is actually an arrow on the harmonic balancer itself and when it points at 12 o'clock you will be at TDC, you can then use the valve events to figure out what cylinder is at TDC you'll know its #1 when as your turning the arrow to the 12 o'clock position the intake valve on the #1 cylinder will just be closing
When installing an opti on a LT1 it doesn't matter one tiny bit what position the cam is in just as long as on splined shaft optis- they are mated and seated correctly. The shoebox pic above tells it all. There has been testimony of being able to incorrectly seat the opti so extra care needs to be given. From what I understand there should be absolutely no resistance when sliding the opti in place.
And on dowel pin optis- You make doubly sure you are aligned to the correct hole. It is rather difficult, if not impossible to seat the opti in the wrong hole, but I've read it has been done before by bolting the opti down before it was completely seated not realizing it was misaligned.
And on dowel pin optis- You make doubly sure you are aligned to the correct hole. It is rather difficult, if not impossible to seat the opti in the wrong hole, but I've read it has been done before by bolting the opti down before it was completely seated not realizing it was misaligned.
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