TDC and OptiSpark Advice
 

I have done some researching regarding this but haven't found what I looking for, could you guys please provide some help/advice as I haven't found the answer in its entirety.

I am in the mix of replacing the harmonic balancer, optispark, I rotated the crank for some stupid reason (with the hub on) balancer off and opti off which I believe I messed up alignment between TDC and the opti to reinstall the opti. Previous owner installed a cam and the crank hub is in the wrong orientation I believe to compound this.

Pulled the 1 plug and put compression tester in and rotated the crank until I started seeing compression building then used the straw method to find what think is TDC. The cam dowel pin is at the 9 O'clock position. To double check the TDC would it be fair to say that the valves should be closed right?

If the above is all correct I can put it back together tomorrow aligning the opti cam pin dowel and pointing to 1 on the opti? http://shbox.com/1/opti_back.jpg

Maybe I'm over thinking all of this, any help or advice would be appreciated.

Richard

Re: TDC and OptiSpark Advice
 

The Opti has to be installed with the cam dowel pin in the correct hole. That's all the really matters. If it makes it easier, put the dot on the cam sprocket as 12:00 o'clock so #1 is at TDC. Then hold the slot on the Opti at the "1".

Courtesy of Shoebox

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

The damper is not a balancer, only a damper. Hub orientation doesn't matter. That's why the hub is not keyed to the crank, even though the crank has a slot for a key. But to put it back where the factory put it, there is a mark on the hub that you can set at 12:00 o'clock, with #1 or #6 at TDC.

Again from Shoebox

http://shbox.com/1/keyway2.jpg

http://shbox.com/1/cam_timing_ani.gif

Re: TDC and OptiSpark Advice
 

Since the car was running well prior, it would be fair to say that the opti installed as keyed all should be fine correct? I don't have the timing cover off to check the crankshaft gear as shown.

Thanks for the advise

Richard

Re: TDC and OptiSpark Advice
 

If the cam dowel pin is in the correct slot, it will run correctly. That can be tricky. If the Opti does not seat correctly, most likely it's not oriented correctly. Do not pull it down with the bolts. A lot of the installs go bad.

I added the animation which shows the dowel orientation vs. cylinder at TDC. Appears you had already responded before I posted the edit.

Re: TDC and OptiSpark Advice
 

Ok, I did a test fit with the opti and it goes in with no effort. The back of the steel plate of the opti sits against the cover nicely. My cam dowel sits at the 9 O'clock position, shoeboxes shows a hair higher than mine, not sure if that's due to the hot cam vs stock.

Richard

Re: TDC and OptiSpark Advice
 

Richard

As mentioned the only thing you need to be concerned with is getting the cam dowel pin in the right slot on the Opti. It does not matter what position the cam dowel is in terms of "oclock"

It also does not matter what orientation your Damper hub is on the crank. The Damper itself only bolts on one way

If # 1 is TDC both intake & exhaust valve are closed on #1 cyl

Re: TDC and OptiSpark Advice
 

Thank you both for the advice!