Growing up doesn't have to suck

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Caddylack

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Cool AF! Do you have optispark issues with it? I've read it's a common issue with the LT1 motors. I've always liked the look of the SS rims on the wagons.
The optispark stuff is frequently discussed and rarely understood. I build my own optis, and they work great.

There are a few issues that one needs to be aware of:

The majority of the cheap optis on the market do not have loctite on the rotor screws. You absolutely cannot install one of these off the shelf, or it will come apart.

The genuine GM/Delco optis use a Mitsubishi optical sensor that is far superior to reproductions. You can transfer this sensor easily between units.

GM made the curious decision to put the opti directly underneath the weep hole of the water pump. Even so, this won't be an issue if your opti cap is sealed properly with grease! The other remedy is to tap the weep hole and screw in a barb so you can route the weeping down to the ground.

For those who are curious, the basic recipe for building a solid opti 4 da low is this:

Get a metal base with a good bearing that has minimal play.
Get a Mitsubishi sensor from a GM opti (your old one, one from the junkyard, etc.).
Order a cap & rotor (this is where you can cheap out if you want). Loctite the screws of the new rotor. Seal the edge of the cap with dielectric grease.

The above opti should last pretty much indefinitely.

Now, with all of that said, here is a fun fact: You don't even need the opti to run the engine.

If you use a "411" PCM (used with everything from TBI 350s to 4.3 V6s) then you can run 8 coils and just use the opti as a timing sensor, with no plug wires attached to it.

You also always have the option to use a conventional rear-mounted distributor, as the LT1 cams oddly still have the drive gear on them like a 1st gen SBC.

And, finally, if you want to spend money, there are kits like Torqhead that will allow you to convert to an LS-style ignition and PCM.
 

pwtr02ss

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The optispark stuff is frequently discussed and rarely understood. I build my own optis, and they work great.

There are a few issues that one needs to be aware of:

The majority of the cheap optis on the market do not have loctite on the rotor screws. You absolutely cannot install one of these off the shelf, or it will come apart.

The genuine GM/Delco optis use a Mitsubishi optical sensor that is far superior to reproductions. You can transfer this sensor easily between units.

GM made the curious decision to put the opti directly underneath the weep hole of the water pump. Even so, this won't be an issue if your opti cap is sealed properly with grease! The other remedy is to tap the weep hole and screw in a barb so you can route the weeping down to the ground.

For those who are curious, the basic recipe for building a solid opti 4 da low is this:

Get a metal base with a good bearing that has minimal play.
Get a Mitsubishi sensor from a GM opti (your old one, one from the junkyard, etc.).
Order a cap & rotor (this is where you can cheap out if you want). Loctite the screws of the new rotor. Seal the edge of the cap with dielectric grease.

The above opti should last pretty much indefinitely.

Now, with all of that said, here is a fun fact: You don't even need the opti to run the engine.

If you use a "411" PCM (used with everything from TBI 350s to 4.3 V6s) then you can run 8 coils and just use the opti as a timing sensor, with no plug wires attached to it.

You also always have the option to use a conventional rear-mounted distributor, as the LT1 cams oddly still have the drive gear on them like a 1st gen SBC.

And, finally, if you want to spend money, there are kits like Torqhead that will allow you to convert to an LS-style ignition and PCM.
Very informative post. I never really understood WHY the optisparks were such a problem. I avoided lt1s in the past for this reason alone. Thank you for the insite!
 
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iamdub

iamdub

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Oh... Kinda like mine? Excuse the stance, I was running (free) front tires that were actually a full inch taller than the 275s in the rear.

View attachment 390775

And then at the end of the day, mine does something that the Impalas can't do:

View attachment 390776

One of my local friends has a Duramax and 6L90E in his Roadmaster wagon.

Coool! Have a project thread for it? Like on another forum?
 
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iamdub

iamdub

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After spending far longer than I care to admit to find this post, do you have anymore pics? Mines bugging the shit out of me.

I didn't take any more pics of that. Whatcha wanna know?


Did you go with the one?
GM GENUINE 22834330

Si. Looks like it's only $9 higher now!
 

pwtr02ss

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I didn't take any more pics of that. Whatcha wanna know?




Si. Looks like it's only $9 higher now!
I'm not seeing how you got the headliner down far enough to get your hand in there. It looks like it's still pretty tight against the roof. Did you just take the ring around the sunroof off, a pillar, and visor? Does that trim around the sunroof just pop off?

Edit:sensor ordered. That buzzing is driving me nuts
 
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iamdub

iamdub

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I'm not seeing how you got the headliner down far enough to get your hand in there. It looks like it's still pretty tight against the roof. Did you just take the ring around the sunroof off, a pillar, and visor? Does that trim around the sunroof just pop off?

It's fairly rigid, so it'll hold itself up into position, just as it is in that pic, until it's pulled down. I removed the A- and B-pillar trims, the visor, the sunroof ring and the top portion of the door seal. You can easily flex the headliner panel down enough to reach the ~8" in to get at the aspirator. That sunroof trim is a minor pain. Best I recall, you flex it enough that you think you're gonna break it. Bow the lateral (left-to-right) sides since they're longer and will flex more to bring the sides and corners in enough to pop it out and back in to position.
 

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