great421

iTrader: (1)

OK, so I'm going to replace my Opti this weekend (or at least remove the failed unit for return to Summit), but I have a stupid question regarding this half-baked cross between a full electronic ignition and a distributor.

Does the orientation of the rotor matter on install? In other words, given the old Opti's rotor was pointing say at 12 noon on disassembly, does the new rotor need to be in that same position?

I know the LT's have a camshaft and a crankshaft postion sensor and the Opit has two wheels (high res and low res - my low res has failed BTW), so like with a standard distributor is this orientation just as critical, or is it just a reference thing?

I only want to do this once! Thanks in advance (no pun intended)!

MIKE

BLACKSHARK

There is a spline on the sleve that will help you reinstall it. It only goes on one way.

PS.DONT FORCE IT!!!!!!!!!

Alex94TAGT

There was a post on this yesterday: https://ls1tech.com/forums/lt1-lt4-modifications/838629-optispark-installation-question.html

If the rotor was at 12:00 on disassembly, it will be reinstalled at the same position by default. This is not something you actively need to achieve -- since you have a 1996, you'll note that there are three 'slots' on the back of your optispark for the camshaft dowel pin to insert. The one with the small mark above it is the one you want to use, and theoretically, the dowel pin shouldn't fit into the other slots. Once this is aligned and fully installed, the rotor will be aligned correctly, exactly the way it was upon disassembly.

Actually, only 1996-1997 OBD2 LT1's have crankshaft positions sensors (1992-1995 OBD1 do not), and the Optispark only has one 'chopper wheel' with two rows of slots in it.

great421

iTrader: (1)

Blackshark / Alex -

Thanks for the info, I'm about to dive into the belly of the beast!

MrElectric03

iTrader: (71)

As said before...it only goes in one way. It has splines all the way aroung exept one spot, just dont force it and be sure its right. Good luck.

Revelation Z28

iTrader: (10)

what about the pre 96/95?

Alex94TAGT

Let's not confuse the matter. The OP has a 1996 vehicle, and as such, does not have a spline-driven optispark.

1995-1997 vehicles use the 'vented' optispark, which is driven directly by the camshaft dowel pin instead of the splined shaft to which you're referring. There are three slots on the back of his optispark, one of which has an indexing mark.

THAT's when you follow MrElectric's post!

On 1992-1994 vehicles, there's a short splined shaft affixed to the camshaft timing gear, which protrudes through the timing cover, and has two flattened teeth to serve as an index. Those flattened teeth mesh with the corresponding splined connection within the 1992-1994 optispark.

Revelation Z28

iTrader: (10)

so it only goes 1 way too?

Alex94TAGT

Yes, clockwise.

Yes! Yes, the damn optisparks only install one way, which is why I bothered mentioning the *indexing mechanisms* of both styles of optispark. If you don't index it correctly, you've installed it incorrectly. This is really, really simple.

I'm sorry, but these are the best photos I have on this computer:

1992-1994 Optispark drive (pictured here with the splined shaft inserted into optispark, flattened teeth only allow the shaft to install one way. Again, the shaft you see here is normally fixed to the cam gear, with the other end of the shaft protruding through the timing cover for the optispark):


1995-1997 Optispark Drive (three larger slots make room for cam gear bolts, elongated or otherwise 'marked' smaller slot accepts the dowel pin):


If you don't understand it at this point, your head has likely collapsed into a black hole, and you should consult a doctor immediately.

porksoda

iTrader: (39)

It does get better though!

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

Revelation Z28

iTrader: (10)

ive never had to take mine off yet thats why i ask.

i dont know if that last comment was directed at me or in general

Alex94TAGT

I was joking around with you, but the question you asked had been answered repeatedly. Have the courtesy to read the thread before you roll your eyes at me -- I'm only trying to help.

Revelation Z28

iTrader: (10)

well from the descriptions in other threads, they say that one is easier than the other. but they confuse which drive type they have.

Alex94TAGT

No worries -- neither are difficult. However, the 1992-1994 'spline-driven' versions might take 3 full minutes to pop on instead of 2.

It's just a matter of sticking your pinky into the optispark and turning the internal rotor assembly until you think it's aligned with the 'flattened' spline on the shaft protruding from the timing cover. Try lining it up and installing the optispark; if it doesn't sit flush, pull it off and rotate it a hair until it does.

Again, don't pull the optispark on with the bolts. It should sit perfectly flush on the timing cover without coercion. That's all that matters.

Boodyrider

iTrader: (2)

yeah, they are supposed to only go on one way... but the CRITICAL point is that either style, the mechanic MUST be sure it's lined up right, because either style, when installed wrong and with excess force applied, will not only not run right, but may also result in damaging/destroying the Opti, in which case said mechanic gets to buy another one, since not knowing what one is doing is not a warranty problem.

In particular, the later ones that use a dowel to like up are easy to screw up by a) putting the dowel in the wrong slot and cranking the oppti down anyway, or b) using a cam with a dowel pin that isnt long enough so that c) the dowel pin gets pushed back into the end of the cam when the Opti is tightened down.