I know people have argued this but i just don't believe it. If the opti is driven by the cam and you now are advancing the cam 2 degrees you'd have to automatically pick up 2 degrees advance so you should tune to reflect that shouldn't you? Unless somehow the opti pin was also 2 degrees retarded too when they made it.

 

I know there are those who's cars run fine.

What I'll do is get the car up and running and see how the tune does. If something seems off with my track times I'll check with Bryan @ pcmforless and see what he has to say.

I have a spare PCM so it's no biggie.

 

The way I understand it, the Opti is timed to the cam, and this is fixed by the pin drive. What you are really doing by using the offset crank key is retarding (or advancing) the crank relative to the cam. I used an offset crank key to dial in my cam and it works just fine. Also, Bryan at PCMforless agreed that this is the way to do it.

 

If ya adv/retard the cam in an LT1 ya change the injector AND spark timing.
Ya will have to get the tables changed in the computer.
It is easier to get a cam that has the pin in the right place.
2* may not effect the old SOP meter but it DOES effect it. Go more than 2 and ya will see.

 

Right if you move the cam it will throw off the timing. Yes the valve timing will be correct but the computer needs to be compensated... just doesnt make sense any other way.

 

Just an update, my new LE3 checked in at 2.5-3 degrees advanced (out of several tries, constantly checking to make sure I was still at TDC). I dunno what to do at this point. Too much conflicting info about what adjustments affect the opti or not.

I guess since it's advanced I can leave it that way and let chain stretch get it closer to where it should be over time?

Is comp just that sloppy lately? Should I send it back?

 

Which degreeing kit did you end up going with? And what keys, do I need keys to adjust it? G's I need to learn alot real fast

-Dustin-

 

I didn't buy a kit, I picked up a comp 9" wheel, comp crank turning nut with a woodruff key purchased from a hardware store ground down to fit my front crank slot, comp "heads off" piston stop, and a dial indicator and mag base set from harbor frieght.

I have an offset crank key that I never ended up using, Mr. Gasket 2* key. I just didn't use it due to the tuning concerns.

 

So easier to just by the kit rather than try to find all that stuff?

-Dustin-

 

The kit doesn't have anything to spin the crank with a degree wheel attached, nor does it have a heads off piston stop. I did not think the kit was complete with what I wanted... the video would have been nice, but the process is pretty basic.

Find TDC using piston stop and degree wheel.

Once at TDC place modified lifter in bore on #1 intake lobe, place dial indicator in line with lifter.

Spin engine till dial indicator reads max lift from cam, zero out indicator. Spin engine back to about .100" lift, then spin forward to .050" before max lift, write down the reading, then continue spinning to .050" after max lift, note down reading. Add those two up, then divide by two for your ICL.

 

One fact is for sure, BOTH camps can not be correct. One knows what their talking about, one doesn't. I'm partial to bushing myself. Easier to incorporate!

 

Agreed, although I do have the offset key laying around, so i can do it.. god knows I have the tools at this point... it accomplishes the same in theory right?

Have you ever had any tuning issues, ie, have you ever addressed it?

 

I'd just adjust the cam with a crank key. Mine was off 3 degrees and adjusted it using a cam bushing/button. No tuning issues here, also i believe Grease said his was off like 4 degrees and he changed his. Then he went and put down 400+ rwhp with an 847 and Ai econoport heads. I mention the heads not to turn it into a who's better head porter i'm just saying that he didn't have "stage 2" heads. I'd say thats a good sign you can adjust the cam timing on LT1's.

 

I guess I'll pull the crank gear tonight and put the key in to see how it works out.

I'll check my findings again for the fifth time just in case as well.

 

Throw that bushing in to retard the cam a hair, especially if it leaves the cam at 1-.5° advanced, that's perfect.

Bret