elisowski

What timing chain options are there for a 94.

On a 95, you can use a roller chain set up for an OE roller cam because the opti is driven off of the cam dowel pin.

A 94 differs in that the opti is driven by a small diameter (7/16" ? ) splined shaft connecting the cam sprocket to the opti.

In order to convert to this system, you have to swap the timing chain cover and opti to 95s and buy a harness extension to connect the opti.

Also, I believe you need to add a reluctor ring to the crank to pick up the crank position.

I would like the adjustability of the roller chain and I don't want to deal with all the slack in the stock set-up.

I know that Thunder racing offers a larger pulley for the crank to remove some of the slack. But, I believe a bigger pulley on the crank would slow the cam sprocket pulley. No?

What have other people done?

snakeatinZ

Good post. I need to know this as well!!!
Steve

elisowski

Administrator,

Please send this to advanced tech.

Thanks,

Ed

94 NO TOP Z

You pretty much have it right. Other than the crank reluctor is not required for any LT1 although it did come on '96 and up to detect mis-fires. It has nothing to do with the engine management.
Also, all LT1 upper cam sprockets have the extra gear to drive the factory water pump. If you go to a double roller you will have to go to the '95+ set-up as you decribed plus go to an electric water pump.

elisowski

That's what I was afraid of.

Any known problems with switching to the 95 opti.

I've read on Tbyrne motorsports store that in order to convert to the Extreme Duty GM timing for 95s that you need the following to convert to a 94:

vac harness part # 12554395
vac fitting part # 14082470
95 opti and 95 timing cover (which we knew)

I've also been told by a fellow convertee that you need a different harness extension to connect to the 95 opti.

Anybody know what the vac parts are?

snakeatinZ

Wow I am

shoebox

Here is what you need to swap to a vented opti. Make sure you read the part that says you have to swap the cam.

If you want to run the unvented opti, you basically are stuck with the stock type set, unless you want to spend big bucks for a Doug Rippie set that is about as much as doing a vented opti conversion.

94 NO TOP Z

If you go the '95 route buy the opti harness from Casper Electronics. The GM one is well over $100 now even at a discount price.

shoebox

...well, $84.27, anyway...

elisowski

It's all good when surrounded by GOOD people!

Thanks guys!