emptnest

I am upgrading my 93 (timing set and) opti spark to the 95+ vented version. Doing so requires that I change the timing cover to a 95+ model, and they are discontinued and difficult to find.

I have located a 96 version, but find that it is slightly different from the 95. The 96 uses a shorter hub (while the 95 uses the same long hub as my 93). The 96 also has a port for a Cylinder Position Sensor, which is not present in the 93 or 95.

So I would like to use the 96. Am I missing any other differences? Do I need a 96 hub to use the 96 cover? What other parts do I need for conversion to the 96 cover?

How do I handle the CPS - buy the sensor to plug the port and just leave it unwired??

LTxDave

The short hub accounts for the ring that mounts to the crank on the 96 for the crank sensor. It goes between the timing gear and hub. If you're not running the sensor, just use your old hub and everything will line up fine.

A crank sensor installed would plug the hole. I might have a dummy plug that will work if you want it. Will have to check this weekend.

emptnest

Excellent!! Thanks for the very helpful info.

Thanks also for offering the plug for the sensor port. Turns out that my seller for the cover says he has one too and will include it. So, I think I'm ok on that issue. If something happens I'll get back to you.

Thanks again, and Merry Christmas!

dizwiz24

Or you can leave the crank position sensor in there to block the hole if you have it (the used 96 timing cover i got from ebay had the position sensor in there). Thats what i did and it all fit my 93 crank just fine.

I too converted my 93 to gen 2 style - mainly because i wanted to use the cloyes version (adds a cam advance and cam retard keyway) of the lt4 extreme duty timing chain. I have stiff valve springs on my afr heads

Im not a fan of the electric water pump/dual roller setup like most people do...

emptnest

Assuming that my cam is stock and that I do not change it, can I still upgrade to the newer opti and extreme duty timing set?

Are modifications to the 93 cam or 96 timing cover required?

Car is mostly stock 1993 LT1.

STL94LT1

The Gen II vented opti is driven by a longer camshaft dowel pin. You will have to change your camshaft or somehow try to change the dowel pin in your original cam.

Kevova

You don't have to have a 95-96 Corvette cover. A 94-96 Fleetwood, Impala, Caprice, Roadmaster including wagons all used LT1 series. The full size car got vented optic first. 96 - 97 have a crank sensor which isn't necessary just to go "vented". Changing dowel is possible but you need to be careful installing it. With the timing gear off the soft plug in the back of the engine is the only thing keeping cam located toward front of engine. If you get carried away it is possible to knock cam back and cause soft plug to lose it seal.Requiring trans to be removed to replace it. Once old down is removed; I would install old cam gear on cam. Snug bolts then back off 1/4 turn The cam gear will keep cam in place and dowel aligned so it can be tapped in place.

emptnest

Thanks for that info. I'm glad to hear it's possible to change the dowel with the cam installed.

Is the cam drilled all the way through for the existing dowel, so you can just punch the dowel out the back side? Or do you have to pull the existing dowel?

What is the length of exposed new dowel (outside of the cam) necessary to properly mate and drive the new opti?

Kevova

Dowel can't be knock through it is a blind hole, it would have to be pulled out of cam. Dowel needs to be about a 1/4" longer than original, and should protrude out .620 out front cam.

STL94LT1

Pull the camshaft, install new camshaft with correct pin length. Will save you a HUGE headache!

mtwoolford

There might be another way to skin that particular cat.

Make sure the thrust plate is installed; grab that pesky little pin with a pair of vise grips and turn and yank till it comes out. Now take a proper sized bolt, and a washer, install the bolt and washer into the front of the cam so it locks the cam to the trust plate (so the cam doesn't shift to the rear and knock out the cam plug in the back of the block), get a new pin of the proper length and reinstall it (i.e. tap pin in with a hammer).

Or not; pull the cam as suggested, but then you'll probably begin thinkin' "may be time for a cam swap"; it never ends