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I'm reinstalling my opti as the stock waterpump leaked all over it. (Car is a 94 trans am)

The old splined shaft was easy to slide in/out of the stock opti, the new opti the splined shaft is in there and not loose at all.

I got the splined shaft roughly lined up, and put it in, slide in no problems. I'm just wandering if it's possible to be 180 degrees out timing wise? (I know it will only go in at a certain degree, but does it matter if the motor was at TDC and firing for plug one?) I rotated the splined shaft a few times in the opti before putting it in.

Thanks!

CGrant

it matters.
Make sure your motor is tdc, you should have a mark on the crank, make sure that mark is up @ TDC
The opti also has a mark on it, if i remember correctly it has a 1 on it,
make sure the opti mark is pointing to 1 for tdc.

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So does it matter if it's firing for cyl 1 or not? How do I tell that?

CGrant

make sure that mark on the crank if up, tdc is cyl 1 (top dead center)

forgot to mention...go to autozone or the like and pick yourself up a how-to book.
Money well spent and gives you pictures so you get a better understanding of what were talking about.

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I know that with the mark 'up' on the crank it's at TDC-however that doesn't mean it's 'firing' for cyl 1 at that point right? It could be "180 degrees out"

(cyl 8 or whichever the other cyl is that's at TDC along with cyl 1)

I'm curious if it matters which cylinder is on it's compression stroke.

evilundisguised

The Opti is timed and driven by the cam, it doesn't matter what position the crank is in when you install it as long as you install it correctly.

What splined shaft is there on the Opti? The only one I know of is the one that drives the water pump (unless your '94 is drastically different than my '96)

Injuneer

94 is different than 96. 93/94 are the unvented Opti with a splined shaft, driven of splines in the cam sprocket. 95-97 use the vented Opti with the cam dowel pin driving the Opti.

As noted.... you do not need to have the engine at TDC. But you MUST insure that the "missing tooth" on the splined shaft is correctly indexed into the back of the Opti, and into the cam sprocket. If you do not visually verify, there is a good chance it will go together wrong. It has been done far too many times, by people who swore they had it aligned correctly, only to find it was "off".

Shoebox shows the way, as usual:

http://shbox.com/1/93-94_opti.jpg

http://shbox.com/1/opti_back.jpg

Shoe

CGrant

well i just learned something
I had no idea the 2 opti's were different on the (part that goes to cam)
CG

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Awesome thanks guys, I did a visual check and the opti slid in very easy. (I used the old dowel pin to roughly line the two up.)

I will do a test start and see how it goes!

Thanks!

Z28blake

Take off the valve cover and watch the rocker arms when #1 is firing the #1 intake valve should start to move. Than you know for sure #1 if firing and not # 6. But eveyone on here seems to think it doesn't matter.

maverickmk

it does not matter, the splined shaft is driven/connected directly to the camshaft and will only turn on the same index as the camshaft, so as long as you get the spline lined up correctly it will be on time correctly