ScaryFast

I put it back on after installing a new Optispark and the car is trying to start (it almost turned over once) but it seems like the starter is working too hard to get it to crank. It sometimes cranks for a second or two but then stumbles as if something's binding up. The battery is full so it's not running out of battery power.

Does the harmonic balancer pulley only go on one way, or can it be put on wrong? It doesn't appear to be rubbing on the opti unit, could it be rubbing on something else?

STL94LT1

The harmonic balancer hub will only go on so far, and bottom out against the lower timing gear. It wouldn't be stopping the car from starting.

JTHVETTE

I just put one on my LT1 project engine. The instruction that I had said to put #1 cyl. on TDC (compression stroke). Then put the pointer thats on the hub at 12 o'clock. To put the hub on, I started with a longer bolt than the stock hub bolt and pushed the hub as far as it would go with the longer bolt. I then replaced the longer bolt with the shorter bolt and finished pushing the hub until it stopped against the reluctor ring ('96-'97). Then I installed the hub with the pointer at 12 o'clock and installed bolts. I believe the hub will bolt up only in one position since the bolts will not line up with the hub but one way.
This is the only way to do this that I know of. There may be other ways, but I don't think this has anything to do with your starting problem.

JTHVETTE

Tom Piper

The three bolts that bolt the harmonic balancer to the hub on are not spaced evenly.
Therefore, it can only be bolted on the hub one way.

The stock hub does not have a keyway and can possibly be put on in any position.
But, according to the shop manual, you should put the hub on with the pointer pointing the same way as you took it off. Or, an "alternate" method is to put the hub on with the pointer pointing to the 12 o'clock position when number one cylinder is at TDC.

Since the pointer on my hub originally never pointed anywhere near 12 o'clock when #1 is at TDC, I have always put it back on the same way it was when I took it off. And, I have never had a problem.
I interpret the manual's "alternate" method as a good "standard" solution if you don't know what the original position was; but, not the best solution if you do know the original position (even if the original position was not at 12 o'clock).

Tom Piper

JTHVETTE

Tom,
May be this would indicate that the hub and balancer are balanced seperately so that they would work in any position? If the hub has to go back to it's original position, then what do you do when you get a new or used crank? The 12 o'clock position maybe just for timing purposes? I understand about your's being put back where it was originally. I've often questioned this setup. Why did GM not use the keyway that's already there in the first place?

???????
JTHVETTE

Tom Piper

I have done the same thing at least once a week.

Tom Piper

MSR

your starting problem actually sounds like a mistimed distributor. did the opti index properly and fully seat easily before even starting any of the bolts?

ScaryFast

Quick thing first (since this is what the post was originially about) - I did have the pulley on incorrectly. I wanted to be sure so I pulled it off and checked. There is an arrow on the pulley (which I'm sure you all knew) and my balancer itself has a mark (someone's been in there before - this may be my car's 4th opti). I lined them up and reattached.

But, to MSR's point, I think spark timing may be the problem! I had a friend listen to it trying to start and he immediately suggested timing as the culprit. When the pistons are on the compression stroke the motor is harder to rotate so the starter motor bogs down. I checked the manual to see how to adjust timing and it says the ECM does this and there is no adjustment. WTF?

I checked spark just to make sure and I have it on cylinder 1, 2, and 3. I didn't check them all due to time, but I assume I'm ok.

So how do I get the opti aligned? I spent 1/2 hour aligning the spindle into the crank and the opti. The check everyone mentions is that it should be flush against the block and it is (without forcing it). Could it still be misaligned? I'll remove it and realign it again just to make sure.

Additionally, I suppose my ECM could be firing incorrectly, any suggestions on how I might check that?

Strick

Please excuse me for suggesting something very simple that you probably already have done, but, recheck the plug wiring. It is easy to mess up the routing or get the wrong wire going to the wrong plug. No, there is no timing adjustment on the LT1. What else have you worked on during this project?

Redeasysport

Your just not havin much luck with you baby lately are you?
OK my ex-mechanic was able to install the opti out of position BELIEVE it. It had the same symptoms.The best way to get it in right is to take the spline out of the old one and insert it into position a couple of times to see what angle the keyed part is pointing to. It should slide very easily into place. Now set the opti to the same angle you just observed with the spline.Ease it up there and wiggle it left/right clockwise/counter clockwise till it slides in with a "pop" against the timing cover.It takes no pressure to install it at all when it is right and will be totally flush with the cover.

okies93

GM saved bu-koo bucks with eliminating the .35 key

okies93

sounds like timing is off, i would check the wires and make sure they are routed to the right plugs. sounds like opti is mounted right. do a follow up post to your findings.

ScaryFast

Gents, it appears that you were correct and the Opti was misaligned. I took it back apart and painstakingly set it up and reinstalled. The car now fires up and dies, just like it did last week...

Please move on to this thread as I have eliminated the Optispark as my problem.

http://forums.corvetteforum.com/show...18&forum_id=48

Thanks guys, you are all welcome to come by for the bash when my car starts.