I plan to swap out the Opti in my '93 this year with the vented unit from a '95/'96. I have a '95/'96 Opti, a '95 timing cover, vented opti vacuum harness and vented opti wiring harness.

The cam is where I am a bit confused: Some say you have to go to the '95 - up cam, others say you can change the distributor drive dowel in the end of the cam to work with the newer opti.

Can anyone confirm that the pin on the end of the earlier LT1 cam can be changed out to drive the vented Opti distributor?

Thanks,

I think it's only the dowel...

I went with the Dynaspark... its ultimately cheaper cause you don't need the additional engine mods.

you would need to change the cam too.. it doesn't have the proper hole for the new style distributer. http://i164.photobucket.com/albums/u3/jdhawk93/sidebyside2.jpg

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Ahhh... crap...

I just took a look at the newer vented distributor and you are correct - it will not fit into the older style cam.

I could probably have the shaft turned down to fit the older cam but now we're getting a little crazy.

Well, I guess it's a good excuse to buy the LT4 hot cam, and roller rocker kit and change the timing chain too?

I actually have a complete delteq unit I bought a while ago. It has about 2,000 miles on it. I'm a little torn between which way to go - I like the idea of keeping the car visually stock. And if the water pump ever fails and unloads on the opti it will probably kill the optical sensor anyway? Then I'm right back to changing the opti again, so...

I've been torn on which route to take.

Thanks for the advice so far.

So - how big an undertaking is it to change the cam in a LT1 C4? Do you have to pull the engine up off it's mounts so the cam can clear? I could see this requiring the removal of the C-beam, all sorts of crap to get in there...

Or am I making it out to be more work than it is?

Thanks,

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Most guys get by lifting the motor a couple inches while still in the car, enough to clear the front crossmember.

last time i did a cam swap it took 8.5 hours but i was really hauling ass. its not that bad.. i may have a stock cam out of a 95 caprice kicking around. i don't know if i threw it out.. if i still have it i would let it go for the cost of shipping.

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Thanks for the offer I will let you know if I end up needing it.

I've gotta do a little more research before I decide how I want to proceed. I am pleased with the power from the car for my purposes (tooling to work, weekend drives) so, I don't know if I would really benefit from a hotter cam.

Either way thanks for the offer!

I don't know how the LT-1 varies from the L-98 in the way it sits in the car but we did a cam swap in my dad's 88 and got away with just some minor grinding on the crossmember. We didn't lift the engine. Some guys notch the crossmember but we didn't have to go that far either.

I'll be the devil's advocate here....with a happy hooker and engine hoist you can pull the engine install the cam degree it and have the car running in a mellow weekend....
I can do it in a single day.


Engine can come out intact..easy way to change plugs and wires too.
[IMG]http://i14.photobucket.com/albums/a342/aboatguy/pullenginewhole2.jpg[/IMG]

Mike

Thanks guys lots to consider. The weather has been fantastic (for Vermont) this "winter" so, I think I may get he car out of storage earlier than usual this spring and get started on all the projects I would like to get completed so I can drive the car this summer rather than work on it.

If I keep this car (which I see no reason for selling) I may buy a used LT1 and build it up on a stand, then swap it into the car when it's ready to go. That's the main reason I'm not too hot on getting into changing the cam this engine - and all the associated parts that go with it - I'd just assume keep this one going as cheap (and reliable) as I can for now. My current engine is very strong with no leaks at all.

decisions, decisions...

thanks again for all the help!

First off, sorry I missed the cam detail... whew...

2ndly, if you have a DelTeq, I would use it. The Opti is an old school mechanical distributor... slop and inaccuracies and all.

To be honest, if the waterpump blows, it will take the distributor side out a shit load faster than the optical side. The optical is marginally better shielded and what moisture that gets in will just fall through with little negative impact.

Whereas the moisture that gets on the opti will kill pluf wire terminals and once inside, lead to carbon tracing.

Over time, the bearings will get eaten to death, especially if coolant gets in there. Ethylene Glycol is not a friend of grease.

I have the LTCC, which uses 8 LS1 coils. The DelTeq uses 4 coils, each with 2 posts. This is the lost spark method of doing business. The DelTeq is based on the Northstar ignition system.

The precision of the spark control is impressive with these systems. It's also why GM went this way in the first place.

I asked Gordon Killebrew about the Opti once... "hell if I know" and he walked of... in short, he has no idea why the thought the Opti was a good idea.

I would do a new opti, pickle the hell out of it with RTV and then integrate with the DelTeq.

It will make doing tune ups tons easier and will make water related failures of the plug wires a thing of the past.

Remember, a big puddle can drown the opti! I got nailed way back in April 2002. Driving home from work in the gnarliest rain storm ever. Doing a whole 20mph, unable to see jack (if I had been on strang roads I would have parked it), I hit this puddle... a good 6" deep. The engine started to sputter immediately. I was able to floor it and keep it going, but it wasn't right until the next morning. It's so damned hard to reach the wires with WD40 when they are sooo buried.

It took about a year to manifest, but carbon tracing and such lead me to install the LTCC about 18 months later.

As an aside, that same storm damaged the lexan top!!! There was hail and the stones put these tiny stress cracks all throughout the top.

I really like the 2nd LT1 idea. It's the one that always works best for me. I would love to get an LT1 from an f-body, then get the block built for splayed caps, relieved and bored for a 383 and all the line boring stuff done for the bigger bearing crank. With all rotating masses internally balanced.

Then just take the time to build it...

Thanks for the thoughts Bogus. I've read through your thread and the more I think about it I think I will install the delteq unit. It's paid for, what the hell? I can make a nice cover out of dry carbon at work if I don't like the look of the coils on the valve cover.

The delteq is paid for. I'll spend the money somewhere else.

Thanks again for all the replies.

oh, I am sure you can make a really nice cover for the coil pack. IIRC, it has fittings for a screw on cover of some sort. If not, I am sure you can affix some kind of threaded shaft or what not with a good epoxy.

I vote no on the Delteq.

It's a good system, in fact I have one on my car. But it's defunct. In other words, no replacement parts available. At the very least, keep the all of the stock parts so you can go back to stock when your Delteq dies.

You may get many many happy years from it, or it may die in a week. If you're going through the hassle to change the system, do it once and forgettaboutit.

Hate to say it, but you know you could have vented the older style Opti.

MSD sells units for early & late optis

If your going to swap cams perhaps it's time for HotCam setup.

I still vote yes for the DelTeq... the coil packs are from GM, so a major part of the process is repairable.

On the other side, I have never heard of one fail.

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I've heard that Delteq is defunct. It seems the units go for around $200/$300 used so, I may keep an eye out and when a cheap used one comes up buy it for spares.

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I've seen the articles on venting the earlier Opti's.

I've also looked into all the Opti alternatives out there. after weeks of researching all the forums out there (Corvette, 3rd gen, etc) most are very hit or miss with anything other than a GM opti.

I've got a bit of time still before the car comes out of storage so, I'm still debating. I am leaning towards the Delteq though.