Lt1 coilpack conversion.

I mentioned this earlier, and searched and searched on carcraft but can't find it, anyone know any more information, or where to find it, about coverting an LT1 to a Cadillac Northstar coilpack system?

http://www.delteq.com/

Ugh $800 is right about what I bought that Roadmaster for. Here is where I wonder about all of these people saying, "You can pick up a 6.0 liter truck engine for forty three cents anywhere in the country," when just a coil controller swap is $800!

Ah, sounds like you've found Optispark = devil.

There is a bunch of stuff out there that will let you replace the optispark system.

Google the following stuff:

delteq LTCC dynaspark eficonnection.com

All 4 companies make parts or systems that will replace the opti on an LT1. I forget -- either delteq or LTCC is basically out of business today.........

From people I have talked to and teh intarwebz, either the Opti system is either grossly misunderstood or teh devil. I just look at the system and think we can do better -- having something that generates ignition sparks located just under/below the waterpump doesn't seem like the best idea.

FWIW I have an LT1 planned to motorvate my TVR when it is complete. I am planning on replacing the Opti.....when I get to that stage I'll make a decision to move forward with some sort of aftermarket system. If that day were today (and cost were no object) I think I would use a dynaspark optical trigger unit and use that to ignite some type of external coil(s) to get the spark to the cylinders. I think it is also possible to use just the opti part of the optispark and use that to trigger some sort of external coil(s).

Then there is also the thought of modding the LT1 intake to use a regular old time proven distributor......

Decisions, decisions..........................

Appleseed wrote: Ah, sounds like you've found Optispark = devil.

Grr. I really disagree. Blaming the optispark for failing is such a problem point for me.

Having spent insane amounts of time with the LT1, I think the Optispark is one of the finer setups. The optical part is ridiculously accurate and foolproof. The spark part is perfectly fine except for two things: 1) its proximity to a leak-prone water pump, and 2) that people expect berkeleying miracles from it an never service it. After 130k, I finally serviced mine with a new cap and rotor and it has been flawless.

How well do you think an HEI would perform at 130k?

My soap box...
1) people expect miracles from a cap and rotor - maybe because they have been absent from ignition class or because they don't like the idea of taking off the water pump and crank pulley to get to it. Trust me... on an LT1, the pump will fail 3 times before the opti does. 2) People go big bucks to bypass the "spark" part but keep the "opti" part... and they do it by replacing it with Northstar coils and a big-dollar aftermarket controller... one of the most failure-prone setups with an insane cost of coil replacement... all because they don't want to put a cap and rotor on their optispark???? I don't get it.

The optispark is quite honestly one of the greatest things since overhead valves (ok, not really, but its incredibly accurate) and people go nuts with Northstar junkyard parts and an aftermarket controller to bypass the secondary side when the problem is not the secondary side. Optisparks need servicing just like any cap and rotor. It also helps if the weep hole for the leak-prone water pump isn't located directly above the Optispark.

I modified my pumps with a vacuum nipple, a touch of JB weld, and a piece of vacuum line to route any water pump weepage away from the distributor. And, anyone who is running a non-vented Optispark needs simply to switch to the 96-up vented unit. The vent tubing for the intake is something like $18.78, and that is retail from the dealer.

The optispark kicks ass. Period. Blaming it for the water pump leaking coolant all over it is ridiculous, but it sure has lined the pockets of Delteq over the years.

In reply to Appleseed:

Not quite, I'm kicking around engine swap ideas for the Camaro again, and the biggest thing that kept me from getting one was the possible opti spark issues. I figured that the coilpack conversion would nip any future problems in the bud. I've always been interested in the LT1, mainly because of the reverse cooling.

BowtieBandit wrote: In reply to Appleseed: Not quite, I'm kicking around engine swap ideas for the Camaro again, and the biggest thing that kept me from getting one was the possible opti spark issues.

Having owned 5 LT1s and put an average of about 75k miles on each one, don't worry about the optispark. Seriously.

... and don't spend a penny on an aftermarket coil-on-plug setup that uses Northstar coils. Or... at least before you do that, price out what it costs to replace one of those coils and read up on how often they fail.

LT1 owners got some kind of hard on for the optispark not lasting for 3 million miles and they think its terrible., but when you have a water pump that drips coolant all over the cap, what do you expect.

Its like this.... Lets say you build a wonderful campfire and then start spraying it with a hose and the fire keeps going out... so you curse the fire pit, or the wood, or the quality of the flame. The problem isn't the fire, its the fact that you're spraying water on it. There are two solutions - either spend huge dollars on re-engineering the entire firepit (like buying a delteq kit) or to just stop berkeleying spraying water on the fire.

Seriously, a vented Opti along with a vacuum nipple in the pump's weep hole is a genius setup.

If you watch eBay you can get a replacement optispark for 60 that's what I did and if you use a roadmaster water pump it's about half the cost of camaro one just requires some fancy plumg of heater hoses. If the water pump comes off for any reason it gets changed. I will be incorporating the vacuum hose to the weep hole idea.

Curtis,

Thanks for the real world info. I think I will actually be going with the stock setup. I do appreciate it!!

@stan_d -- got any pics of the roadmaster water pump setup? I thought all LT1s used the same pump......

In all fairness, I'm spouting internet "knowledge." I've got 75,000 on mine without a hiccup. God knows how many miles were put on it by the cops.

orphancars wrote: Curtis, Thanks for the real world info. I think I will actually be going with the stock setup. I do appreciate it!! @stan_d -- got any pics of the roadmaster water pump setup? I thought all LT1s used the same pump......

same pump, different pipe fittings for the heater hoses pressed into different holes. go to your favorite online auto parts web site- i like www.napaonline or www.rockauto.com - and look up water pumps for a 94 Caprice, 94 Corvette, and 94 Camaro and you will see the differences.

when i had to put a water pump in the 94 Caprice i had a while back, i think the cost at the local Carquest was $65 after i brought the core back, and i think it took me about an hour to put it in- and most of that time was spent figuring out how to get the smog pump out of the way. the opti is right behind the pump, and comes out with only a few small bolts.

Just a word of caution if you replace an opti...

Putting the opti on is kinda like putting a torque converter in. You need to make sure it seats properly before putting the bolts on. Like when you put a torque converter in - if the converter hits the flywheel before you get the trans bolted up, its not right.

Line up the pin on the drive with the funky thing on the back of the opti and make sure you can seat the distributor on the cover the whole way by hand. Dont draw it in with the bolts or you'll tear up your new opti when you crank it.

See if Dal Slabaugh is still working at VanDevere Buick in Akron. He's a B-body lover and he gives us Impala SS guys super cheap parts.

Last I checked he had retired about 6 times and he's probably 134 years old, so he might be actually retired by now

Any pics of the water pump vacuum line mod? I have a vented opti on my new '95 Roadmaster. I'll try cleaning/brushing the cap and rotor first, because Challenge car budget. Though with 249k miles, it might just need replacing.

No pics. I'd go out and take a new photo, but I've replaced the pump since then and didn't do the mod this time. I just used a plastic vacuum nipple; the white barbed kind that is just a straight coupler. I mixed up some JBWeld (the steel epoxy) and used it to glue the nipple in place. Then I used a piece of 3/16" (I think) vacuum hose about 8" long and routed it down behind the opti so any weeping water would drop below it instead of on it.

Some guys drill and tap for 1/8" NPT and put a brass barb nipple in it, but the casting it pretty thin. That also will mean that there is a 1/4" of the threaded end sticking up into the housing raising the level of water in there before it drains.

Any other good tips for easy LT1 power? Is EGR and/or AIR system delete worth it? Easily swappable junkyard power parts? I know about the LT4 cams and 1.6 rockers so I have my eye out for a deal. May have already found a posi rear from another wagon.

Intake is good to about 450 hp. Iron heads actually flow better than the aluminum. The iron LT1 head flow such nice quality and quantity that GM copied it directly for the Vortec head. The aluminum LT1 head is still respectable, but its only about 20% better than TPI heads. Advanced Induction does amazing work with aluminum LT1 heads if you need more.

So... great intake (you'll likely want a bigger TB for 375 hp and up), above average stock heads, pretty good compression. That means they respond pretty well to bolt-ons; headers, mild cam, etc. The first "wall" you'll hit is likely with the head ports. By that point you'll also likely want more compression.

There are some guys passing CA smog with 450 hp and very careful tuning in LT1s.

maschinenbau wrote: Is EGR and/or AIR system delete worth it? Easily swappable junkyard power parts?

As with any EGR vehicle, it makes zero affect on peak HP. EGR valves are only open during part-throttle cruise, so it won't hurt WOT and might save you a couple MPGs to keep it. AIR can be deleted in most LT1 cars legally due to a campaign by GM. The pumps failed frequently, and EPA determined that the AIR system was not required for it to pass. The correct way to do it is reflash the PCM to ignore the air system and then just pull the relay. But, again... it is an electric air pump that injects air downstream of the engine, so no power improvement from deleting it.

One somewhat controversial mod is a 160 thermostat. This requires a reflash to be effective. On a traditionally-cooled motor, the water in the block reaches the opening temperature (let's say 195) and opens and starts flowing water out to the radiator where its temp drops. On a reverse-cooled LT1, the water comes from the radiator TO the engine. That means the water in the block might be 220 before the stat opens at its advertised 195. Therefore, power can be had by switching to a 160 stat. If you are using the PCM to activate electric fans, it has to be reflashed for the fans to come on earlier, otherwise there will be some times that the water still gets just as hot in the radiator and nullifying any benefits. This mod WILL decrease MPGs considerably. A 160 stat can make more power on any engine, but it comes at the risk of oil not getting hot enough, gunked valves, and coked rings. In the LT1 its not a problem because the water in the block still gets plenty hot. I ran one for 80k before switching back. I wanted the 2 mpg more than I wanted the few hp.

Standard PCM tweaks can make 15 hp on an otherwise stock engine. There is too much fuel in the map to combat NOx and maintain a detonation tolerance for warranty CYA, so leaning out the fuel a bit typically gets 5-6 hp. For the same reasons, the ignition curve is a wee bit conservative. Adding a couple degrees will make another 8-9 hp, but it will require the use of 91 octane or better. Otherwise, there will be detonation (which is bad, m'kay) and also the knock sensors will just pull out any additional advance you put in the base program curve.

Also mixed reviews on the LT4 knock sensors (and the KS module in the PCM). Rumor has it that it is more able to distinguish detonation from things like additional noise from a larger cam, headers, roller rockers, etc. Some guys claim that the stock LT1 knock sensors get confused by aftermarket things which add noise to the block. I don't think its really an issue until you get pretty wild.

When you're ready for reflashing, contact Bryan Herter at pcmforless.net. Great guy, and he's done a handful of PCMs for me from mild to wild.

In reply to curtis73:

If I said that online I'm seeing about two at-the-wheel HP out of a 160F degree t-stat, would you think that's inline with what you know about these cars? Personally I'd probably grab a 185F job and maybe add my customary tiny hole to aid in burping.

Where's Opti at on this one? This thread should be right up his street.

Guys claim 8-10, but I think they're full of poop. I'd give it a solid 5 alone, more with fuel trim changes.

The important thing to note is that with regular cooling, water starts at the stat temp and goes down from there. With LT1 reverse cooling, it starts at the stat temp and goes up from there, so a 160 stat in an LT1 probably keeps the block 180-190 the same way a 190 stat would in a SBC.

But I'm a little weird... I would much rather have the oil health and couple extra MPGs of the higher temps. As long as nothing is overheating, keep it as hot as you can.

The other thing to note is; how much hp can you actually feel? 10? 20? 30? All the little stuff that gets 2 hp each might end up as a sizable investment for 15 hp that you'll never really feel.

curtis73 wrote: There are some guys passing CA smog with 450 hp and very careful tuning in LT1s.

do they go by the name Volkswagen?

and i remember hearing about lt1 guys using ls1 coils and pcm's to run there engines, made tuning much easier also.

but it depends on what you want to do with the car, for just a fun DD with maybe a few bolt ons i'd stick with the opti. if you want serious power i would look into the ls1 coils/pcm atleast as an option