Pranav catches the LT1 misfire zeka

[Pranav]

Great now I've caught the bug. Quick background:

-At NOLA in may, I would've sworn I had a tiny/faint miss above 4k RPMs. Then I dropped a valve and destroyed a piston.

-Pre-Hallet, new motor, 100% same ignition, fuel injectors were tested/cleaned, car seemed to dyno fine but high RPM looked a little janky on the dyno sheet; the dyno operator had goofed on hooking up the RPM pickup initially and the car still made the right numbers so we left it at that assuming it was the pickup

-At Hallet, after getting thru the wreck and rear end swap, I noticed I had the same miss from NOLA. Just enough to bug me but barely there. Went ahead and threw a new Delphi ICM on it. Made no difference

-Post hallet, took out all of the plug wires and checked them with an ohm meter; #3 was showing open/bad so I replaced it; all 8 plugs visually looked fine so I put them back in. Built a fresh opti and put it all back together. Also went thru and checked lifter preload. Some loosened a little, a couple tightened a little. Most were less than 1/8 with a couple being 3/8 turn from where it was originally.

Ran it on the dyno today and the operator could definitely feel that same miss, car was down 12-15ish HP and TQ and the high RPM graph looks jagged. AFR was solid at 12ish like it always is.

I need to double check, but I don't think I replaced the coil. How do I actually test a coil properly? I ohmed it before hallett and didn't find any conclusive results.

One other thing to consider; I left my digital dash on in the car over night so the battery was low before heading to the dyno. The dash is sensitive to voltage and will not turn on unless the battery has enough voltage, more than what is needed to start the engine; the battery was low enough to where the dash would not fire up with the engine off; it had to be running. At running idle it was high 13 on voltage and climbing after startup, right after the dyno pulls.

What else could it be? Going to try redyno on Monday with a charged battery and a fresh coil if I hadn't swapped it already, along with swapping/fixing anything else I may find this weekend.

[Supercharged111]

I went through hell with my car as you recall and I replaced everything but the knock sensor is what did it for me. I picked up around 20hp and my dynos magically smoothed out.

[marshall_mosty]

Check your mass air voltage and make sure it's not jumping around forcing the engine to chase itself. That is what it ended up being for me... I know mine is a Ford, but I think the LT1 uses a MAF...

[Sook]

Orange is spreading LT1 plague through the internet now! We tried to kill it with fire last week and it wouldn't die.

High RPM miss sounds like it could be the coil (plus they're cheap), may want to throw an ICM at it next. Any codes on the computer?

[Pranav]

No codes.

So far I've found the old coil ohms 2k-2.5kish more than a new one so I threw the new one in. Fuel trims seemed to add +2% but not looking at that too closely.

I just randomly yanked on the 2-wire coil connector and it would start to sputter and die as soon as I touched it. Pulled the backing/lock off the connector and one of the pins would just slide right out, not locked in place.

Could that have just been it? Still going down the list; I have 2-3 of everything and can keep throwing parts at it, would rather find the smoking gun. So far its been a bad plug wire; now I've found a weak coil and probably the coil connector.

[Sook]

I just randomly yanked on the 2-wire coil connector and it would start to sputter and die as soon as I touched it. Pulled the backing/lock off the connector and one of the pins would just slide right out, not locked in place.

I was having similar issues with the brand new coil connector on the new harness. Ended up cutting it off and replacing it with the original connector from the old harness. I hope that solves your problem.

[Pranav]

I hooked up my fancy opti signal analyzer and couldn't seem to find anything wrong with the opti signal at low RPM. I'll try it out on the dyno if I'm still having issues.

You guys need to check this stuff out:
http://www.1320electronics.com/OptisparkMonitor.html

Tomorrow morning I am replacing the coil connector and throwing on parts store plug wires, and keeping a parts store icm on hand for the dyno.

At this point my desire to get the car running right and tested in as minimal time possible outweighs my desire to find a smoking gun and not throw too many parts at it. If everything runs right on the dyno, I'll swap in ACDelco/Delphi parts and keep the house brand stuff as spares. I'll sell my other, used ICMs to you guys whenever you fry them at the track, since they all technically work.

Fortunately the dyno shop is a quick hop over from here, will try run it again Monday afternoon after work.

[BryanL]

Doubt it's your problem from Hallett but on the dyno don't rule out a weak/dead battery. I have had a few alternators go out while racing my ls1 and the first thing that happens is an upper rpm miss.

[Pranav]

Yeah I had it on a tender most of this weekend and the digital dash was having trouble turning on (needs higher voltage) until I got the car running. Flipping the ignition switch on it will intermittently not cycle the fuel pump.

I'm gonna test the battery tonight. I have a big arse boat battery I can swap in temporarily. It's funny because last year I had a battery start to get old and weak and not let the car start, but it still ran solid up top once I got it started.

When I swapped my plug wires yesterday, I found yet another bad plug wire. The theory of multiple bad plug wires beating up the coil also makes sense.

Prob won't dyno until tomorrow or Wednesday; they're booked up.

[ShadowBolt]

My battery is three years old and when I tried to start it up yesterday to drive it on the trailer I did not hear the fuel pump prime when turning on the key. Car would not start. Charged the battery for several hours and it started right up (fuel pump is priming). After backing the car and trailer in the barn I put the charger back on for three more hours. Battery shows 13.6 volts but only 62% charged. May be forced to purchase a new battery while at TWS I think it's on it's last leg.


JJ

[Pranav]

I used the battery tester and beat on the battery as much as I could; it tested perfectly fine.

Did some tests on the alternator, was solid at 14v and never got below 13.9v no matter what I did. I unhooked the battery while it was running and the voltage would jump around a little as expected but would still be around 14v.

However when I went to retest the coil and put it all back together, it wouldn't start again; To get to the coil I usually disconnect the IAT and MAF and pull the intake pipe. Turns out the one of the MAF wires was also a little loose; while running I could wiggle the MAF wire and the car would sputter and trip a MAF error code instantly. I tightened/taped the MAF wire down for now, got a new MAF connector coming in.

For as much as my engine harness has been on/off the car, over the past four years especially the MAF wire for restrictor plate swaps, I'm surprised I only have two connectors start to get loose on me.

Hopefully should finally get to dyno tomorrow and put this crap behind me.

[Tilton]

With as many times as you have been/are going to go to the dyno, you should just buy one.

[Pranav]

Ha! He charges me $55 each time unless I take a while and make adjustments; then it's $100.

Way better than paying the $600+ in fees and hotel only to still have a problem at the track...

[Pranav]

I give up.

It ran down on power but no misfires on the first pull, then would start to cut in/out once it warmed up. Swapped ICM on dyno and ran my opti signal analyzer, no dice. We can see it yanking back fuel or spark on the AFR chart, and the car runs hot (despite hugging 12:1 AFR).

I can throw more parts time and money at it, or jut sit this one out and look at longer term options for the car. I've amassed a sizable inventory of good, valuable LT1 parts including the clean/good motor that's in the car now, and am seriously thinking of just doing an ls 5.3 swap over thanksgiving break is the way to go.

Net loss financially is marginally more than what it will take to fix the car and actually run at TWS this weekend.

There's also the fact that I'm burned out and am starting to have problems dealing with the stress of having to hero the car back together before every race. NOLA was the only race where I didn't have to mess with the car, had a great time and placed well before I blew the motor. I've just barely finished catching up from the carnage of Hallett (rear end, alignment issues, body damage, trailer rebuild) and now I'm having to deal with this.

I've already missed three events this year for weddings and a funeral; I don't feel like TWS is a big loss for me this year, even if they do shut it down. There' still plenty of oil in that soil from my earlier motor blow ups there.

[dtanker65]

Sorry to hear it buddy. I have been head scratching about your problem.

Why did the motor swallow a valve? I keep thinking valve springs, maybe one busted coil? I had an engine that would float the valves at high rpm and it would break a valve spring every time.

LT1 is getting pretty ancient, it's a legendary mill like the 440 six pack. Seen many 440's around the boneyard?

I would not think twice about ebaying the LT1 stuff to and change to the current design motor. Sean has already done the engineering.

I have a friend swapping an LQ motor, I think, into his BMW. Iron block and aluminum heads I believe, he re-cammed it to get rid of the truck grind. Unmolested factory built long blocks are the way to go I think. I quizzed the local commercial rebuilder about their procedures for overhauling the new close tolerance engines and I'm not very confident about using one for racing. They reuse too many components that I would replace for a racing application.

The current production all aluminum LS Camaro engines are still too expensive on the used market. You might consider larger displacement than 5.3 and choke it down to CMC power for longevity.

I will not make TWS either, the car's not ready and I have to work. I wouldn't mind seeing a new a thread to talk about the Thunder group moving forward.

[Pranav]

Sorry to hear it buddy. I have been head scratching about your problem.

Why did the motor swallow a valve? I keep thinking valve springs, maybe one busted coil? I had an engine that would float the valves at high rpm and it would break a valve spring every time.

LT1 is getting pretty ancient, it's a legendary mill like the 440 six pack. Seen many 440's around the boneyard?

I would not think twice about ebaying the LT1 stuff to and change to the current design motor. Sean has already done the engineering.

I have a friend swapping an LQ motor, I think, into his BMW. Iron block and aluminum heads I believe, he re-cammed it to get rid of the truck grind. Unmolested factory built long blocks are the way to go I think. I quizzed the local commercial rebuilder about their procedures for overhauling the new close tolerance engines and I'm not very confident about using one for racing. They reuse too many components that I would replace for a racing application.

The current production all aluminum LS Camaro engines are still too expensive on the used market. You might consider larger displacement than 5.3 and choke it down to CMC power for longevity.

I will not make TWS either, the car's not ready and I have to work. I wouldn't mind seeing a new a thread to talk about the Thunder group moving forward.

The motor I blew at NOLA; no definite answer. I had a preceding issue with oil getting into the PCV and causing a misfire; I fixed it quickly. Car ran great for a day and a half then either the piston blew up and destroyed the valve while it was down, or the valve dropped and destroyed the piston. The carnage on that piston was insane, I need to find and upload the pics. All of the main/rod bearings still looked good however, including the one rod on the blown piston.

Fundamentally I don't have much of a beef with the LT1 mechanical hardware itself, but this ignition system is something that has given me trouble 3-4 times in the past 4 years and caused me a lot of stress each time. I just don't believe that this stuff is designed to hold up to what we put it thru and I'd like to do some research on what quick/easy fixes can be done to make it better.

As far as engine options and such, it's either the LS1 or the truck based 5.3 (aluminum or iron). I can't do custom stuff and restrict, that's ilegal.

The LT1 t56 to ls1 t56 conversion is documented and doable, might even turn a profit doing it since I possess two lt1 t56 input shafts.

The 5.3 swap is a lot of work that will add to my stress in the short term but likely fix thermal and weight issues I have with the car along with having a more reliable ignition system.

Now that I've calmed down a little bit since this morning, I can spend some time doing the research and seeing is making the switch is worth it, or sucking it up and fixing whatever is wrong with my LT1.

I'm on the fence either way but I think I'm done with TWS and this season. Total dumpster fire.

[Rob Liebbe]

"We can see it yanking back fuel or spark on the AFR chart, and the car runs hot"

I thought that was just a characteristic of an LT1. Back in the day, you couldn't win the first street race of a Mustang GT 5.0 v Cambird 5.7 LT1. But by the time you get to the third race and the LT1 got hot, the Mustang could win. The explanation I always heard was that the ignition would pull back when hot. May be urban myth, but the source was a very respectable powertrian engineer I worked with at Ford.

Plenty of LT1's have done well in CMC over the years. Recover, think about it, don't stress and maybe a solution will come to you.

[Fbody383]

Now that I've calmed down a little bit since this morning, I can spend some time doing the research and seeing is making the switch is worth it, or sucking it up and fixing whatever is wrong with my LT1.

I'm on the fence either way but I think I'm done with TWS and this season. Total dumpster fire.

I think you can find the LT1 issues way cheaper in the short run. IF you want to move toward a 5.3 in the long run, I think Sean's is a combo that seems to be working out, and you can put it together over time.

The motor in my car went bone dry when we dropped the radiator in January at Houston. I'm comfortable the LT1 works fine for what we do, though finding the gremlins, ahem, may depend on complexity.

Simplicate and add lightness. It's cheaper than the swap.

[mach1]

Put in a rule change request and get some coils on those.

http://www.delteq.com

[Fbody383]

Put in a rule change request to go back to stock brakes and 230/300 :cool:

[Sook]

having a more reliable ignition system.

Where do I get one of those?

[Fbody383]

Where do I get one of those? I think I've changed one ICM and one coil since 09.

But that's what running in the back does for you I guess.

[Alien]

Put in a rule change request and get some coils on those.

http://www.delteq.com

I've been trying to get a list of options to alleviate the opti issues. There's quite a few, some I think better (in CMC spirit) than others.

EFI Connections, LTCC Bailey Engr, Delteq, MSD, and Dynaspark.

I've been lucky and only had a rotor come off. Who here has had definitive Opti issues?

[AllZWay]

I've been trying to get a list of options to alleviate the opti issues. There's quite a few, some I think better (in CMC spirit) than others.

EFI Connections, LTCC Bailey Engr, Delteq, MSD, and Dynaspark.

I've been lucky and only had a rotor come off. Who here has had definitive Opti issues?

I replaced one Opti that finally gave up, but it was from an original 164k mile engine and a few years of racing before it failed.

Then I bought a Delco replacement, not junk from Autozone and it is still running on Craig's car.

The trick is not to get them wet and if you do, blow air through the vacuum hose to help dry it out and never buy a cheap opti.

http://jpmotorsports.biz/images/opti.gif

[39PitCrew]

EFI Connections, LTCC Bailey Engr, Delteq, MSD, and Dynaspark.

Who here has had definitive Opti issues?

While it isn't a CMC car, my 94 Vette is on it's 5th opti since the factory one failed at about 80K miles.
Put in an MSD, took out the MSD and sent back to them for repair.
Put the MSD back in, took out the MSD after another couple thousand miles because of
repeated no-run events. Put in an O'really opti, car is currently on 3rd one of those.
I've gotten too good at replacing it. Error code is always no lo/hi res timing signal.
Have checked connectors and chased some wiring. Have never been able to get it
to happen when I can connect a scan tool. So far the failure seems totally random.
Sometimes it drops out for a few seconds while driving (scary, by the way) while
other times is will fail for a day or two and then next time it starts right up and
runs fine for weeks. It always either runs fine or doesn't run at all (no timing = no fuel).
Frustrating. Sean and David can tell you how baffled and peeved I am about it.

[BryanL]

Sorry to hear about it Pranav. There was a reason why you won some NASA award last year I think.

Mechanically the LT is a great engine-clutches are a little suspect. But I am so glad I went with the LS due to all the gremlins with the LT and how hard it is to find the problem. I don't blame Pranav for throwing in the towel-I would have a long time ago. I'm all in favor of allowing the aftermarket solutions.

So anyone interested in buying a white LS 4th gen??? It's ready to take the podium with any halfway decent nut behind the wheel.

[AllZWay]

Pranav... Just throwing this out for something to check on power loss.

Over the years of the LT1 the knock sensor located in the block had a couple different variations for resistance. These are very specific to the PCM you are running.

I ran into this when I switched from a 93 engine that matched my PCM to a 95 engine I bought used. The engine was complete so I just dropped it and went, but I was down about 40hp. I think it did throw a code though about the knock sensor was how I found it.

It is a quick check though to pull it and see if the part number stamped on the part matches the year of your PCM.

[GlennCMC70]

Some pcm's also are looking for 2 sensors in parallel or just a single sensor.

My harness is set-up for 2 in parallel but i only run 1 sensor as that is all the pcm is looking for.

[AI#97]

So anyone interested in buying a white LS 4th gen??? It's ready to take the podium with any halfway decent nut behind the wheel.

Really? What you gonna do instead? take up golf with special 9 finger clubs? ;)

[mach1]

Sorry to hear about it Pranav. There was a reason why you won some NASA award last year I think.

Mechanically the LT is a great engine-clutches are a little suspect. But I am so glad I went with the LS due to all the gremlins with the LT and how hard it is to find the problem. I don't blame Pranav for throwing in the towel-I would have a long time ago. I'm all in favor of allowing the aftermarket solutions.

So anyone interested in buying a white LS 4th gen??? It's ready to take the podium with any halfway decent nut behind the wheel.

I'm interested, looking forward to a test drive at TWS for R1-R4

[Supercharged111]

Pranav... Just throwing this out for something to check on power loss.

Over the years of the LT1 the knock sensor located in the block had a couple different variations for resistance. These are very specific to the PCM you are running.

I ran into this when I switched from a 93 engine that matched my PCM to a 95 engine I bought used. The engine was complete so I just dropped it and went, but I was down about 40hp. I think it did throw a code though about the knock sensor was how I found it.

It is a quick check though to pull it and see if the part number stamped on the part matches the year of your PCM.

This was my smoking gun. Car came with a newer Corvette LT1, but car was a 93. I suspect the knock sensor matched newer engine.

Personally I'm on my 4th opti, but none of the old ones were bad. The car was so electrically ghetto rigged and fitted with the wrong coil, ICM, and knock sensor that I kept blaming the opti when it never was to blame to begin with (plus I didn't realize the car would chug when down 7ish gallons of gas, so I swapped in the spare for that too). I'm currently running an AC Delco opti I bought in 2014 and have a spare AC Delco opti of unknown age/mileage boxed up in the trailer. I wouldn't wish parts store electrical junk on my closest competitor.

[Al Fernandez]

You'll figure it out Pranav, always do.
optis seem to be very polar; people either have excellent luck or flat terrible luck with very little inbetween. I did ask Gary to do some research into opti alternatives to see if something hasn't come along since the last time we considered alternatives in the rules several years ago.

[Fbody383]

I did ask Gary to do some research into opti alternatives to see if something hasn't come along since the last time we considered alternatives in the rules several years ago. I would gladly support an alternative - even the evil "timing adjustable MSD." Was always funny to me we could deal with a distributor but not this. Here's the install guide: http://documents.msdperformance.com/8381.pdf. Put torque-seal on the adjuster after the dyno.

The Delteq always seemed to be the "one and done solution;" good thing we allowed big brakes instead...

[AllZWay]

Even though I have had great luck, I still think an alternative should be considered.

[Supercharged111]

I would gladly support an alternative - even the evil "timing adjustable MSD." Was always funny to me we could deal with a distributor but not this. Here's the install guide: http://documents.msdperformance.com/8381.pdf. Put torque-seal on the adjuster after the dyno.

The Delteq always seemed to be the "one and done solution;" good thing we allowed big brakes instead...

You can adjust timing on stock LT1s, this would just make it easier and tech-able.

[RichardP]

I would gladly support an alternative - even the evil "timing adjustable MSD."

The Delteq always seemed to be the "one and done solution;" good thing we allowed big brakes instead...

The MSD is still a crappy Optispark, it just allows base timing adjustment. Reviews on the internet roast it as worse than a standard Opti.

The Delteq separate coils still use the optical sensors inside the Opti but take the high voltage lightning strikes out of the box. That should really help with reliability and longevity. Thing is, Delteq has been out of business for years. There are other options out there to convert away from the Opti but they are stoopid expensive and incorporate other features that wouldn't ever fly in CMC. I haven't checked, but they are probably out of business, also.

That's kind of the key. The only people using these engines are poor people who have an old car and can't afford to buy a newer one. These people wouldn't pay for high quality OE or upgraded parts if they did exist. So they don't exist anymore. Using these engines in a performance application at this point is just flat out stupid so no one is doing it anymore. Well, except for CMC...


Richard P.

[dtanker65]

I am very new to this game. When I decided what car to build, I thought I was too inexperienced for AI and I didn't want to start with a worn out car in CMC. I very much respect the talent in CMC, just that I have been resurrecting old cars my whole life and I wanted something more up to date and still supported with factory parts. Spec Iron was a bit of a costly disappointment, but I did gain a lot of experience.

I do not understand why the CMC rules are so restrictive, they are like SCCA rules only SCCA restrict the parts, but let you make as much power as you can figure out how to. With the Nasa power to weight rules, why the need for the restriction? If a guy is going to cheat, he will find a way. The rules should be opened up to let the guys running older equipment to use whatever means it takes make them reliable. Power is power. Preparing a racecar is brutal enough as it is and it is crazy not to take advantage of the advances in automotive engineering.

CVAR is where you want to go if everything has to stay original, ah adjusting lash on solid lifter cams with a hot engine between races sounds great! Drum brakes too!

I challenge anyone to find a running LT1 in the boneyard. High metal prices have caused most of the older cars to be scrapped.

I am a big fan of ingenuity and elegant engineering, but I want to win because I drove better than the other driver and maybe set the car up better too, not because the other guy broke.

I really like what Sean has done with his car. The newer motors are good, check the oil and hit the starter, rinse and repeat.

[Supercharged111]

I've got a good boneyard LT1 on the stand right now waiting for the current powerplant to ventilate itself. The problem with opening up the rules is the perception that spending money on a perfect power curve will make you more competitive. Power to weight ratios, track width, a lot of stuff is based on how these cars act with compliant engines in their respective platforms, i.e. carbed Fords have no rev limiter to compensate for the lack of torque they make. How many people would run out and open their wallets to make a motor 10x better than they have now in hopes that it'd help them win races?

[Pranav]

To answer a few of the questions here:

-I run the 96+ obd2 setup so I have the best possible lt1 control setup

-90% sure I have the right knock sensor but I can pull/swap it with a spare as I had planned to flush the water out of the block anyways. I always have ordered the acdelco one for the later model LT1s

-Harness does have a second knock sensor plug but my f body ecm has run fine without anything hooked up to it for years

Sure I can borrow an opti, swap it and bring a borrowed PCM to the dyno if it still (likely) misfires. Using my opti signal analyzer I really didn't have much evidence to say the opti was at fault. No missed cylinder events and the sign charts were as expected, but I could be wrong.

There may or may not be some mechanical concerns over the motor I bought (not built by my usual builder) that may need to be addressed. This last dyno I was down another 5ft lbs of tq for a total of 20, so something mechanical is happening or the fuel/spark issue is getting worse.

Anyways I have about a week to decide if I want to go ahead and do this LM4 swap (aluminum block 5.3 rated at 290hp/325tq, Sean makes 260/309 with his!). I'm blown away by the availability of all of the ls swap parts I need. There are three lm4 long blocks listed for $600-800 in salvage yards in the Houston area. Most of the ls1 swap parts I need are showing up in Craigslist in multiples. Most of the swap parts, I have at least two lt1 parts I can sell off to match.

The most painful part will be swapping the input shaft and faceplate on the t56 but I'm hoping I can spend a few nights over at orange is fast garage learning how to go through my t56 :)

If I went through with this I would have to get the car turned around and ready by Dec 10th. I'd do a cheap local track day then park it for my winter vacations and be ready to kick some ass in January, maybe try get a member day or something in before our usually MSRH opener.

Finally to Richard's comments, there is actually one really good solution out there Al and I talked about. I have known someone that ran this setup on an insane lt4 track build and loved it. For a little more than the price of a new GM optispark, you can buy a custom made adapter that lets you basically removed the opti spark and install an ls1 crank position sensor in its place. You can then get some ls1 sensors and coils on the engine and run an ls1 pcm and harness. In the end it isn't the simplest of solutions but the more "OEM" and proven way to go:

https://www.eficonnection.com/home/product/efi-24x-crank-and-cam-signal-kit-wo-ckp-sensor

[BryanL]

Pranav-which year model LS1 computer does it use? Would it run off the factory LS1 tune or have to have a custom tune?

If you went with the swap you also need a 98-02 subframe and LS engine mounts both are easy to find. Then wiring harness/computer. Cheaper to make what you have work unless you are pulling the motor for a rebuild. Yes, the parts availability-especially the truck long blocks is tempting. Or just sell your car and buy mine.

[Pranav]

Yes it would use the ls1 pcm with stock tune. I'd just get a normal ls1 cable throttle pcm.

Looked at an lm4 today and spent a couple of hours going over Sean's setup in his garage.

Yes putting in a borrowed opti and pcm to take to the dyno is way cheaper.

I'm aware that the k member, rack, and trans input all have to change as well as having to start over with a new harness, sensors, accessories, etc. I've spent the past few days getting details on all the required swap parts and labor costs before I have to chain myself to the car for a month to do the work.

What I'm banking in is the sale of the lt1 stuff to make it a relatively low cost swap. It will take a lot of patience on the sell side for sure. Buying a few key ls1 parts used vs new is helping out a lot.

[Rob Liebbe]

Found a new home for Pranav's LT1.

http://bringatrailer.com/listing/1989-volvo-740/

[mach1]

Found a new home for Pranav's LT1.

http://bringatrailer.com/listing/1989-volvo-740/

Wow, awesome wagon!

[Fbody383]

Wow, awesome wagon! Stay away from BAT: http://bringatrailer.com/listing/1999-bmw-528it/


edit: woo hoo... another thread blown up.

[Pranav]

Found a new home for Pranav's LT1.

http://bringatrailer.com/listing/1989-volvo-740/

You'll be surprised how many "LT1 candidate" cars have come across my radar lately. Makes me feel good about putting mine on the market come tax refund season. Just selling off the small/loose stuff for now, got a nice big space where the motor can sit for a while until someone brings money for it.

Picking the LM4 back up next week, hope to have it dyno ready right after Thanksgiving.

[Fbody383]

Picking the LM4 back up next week, hope to have it dyno ready right after Thanksgiving. And should have a fresh-ish new LS style bellhousing/front plate/input shaft T56 to attach to it next week as well.

[Pranav]

We got the T56 back together at OIF garage Wednesday. Got the motor back on Thursday, spent all weekend on it, but the car is finally LS (LM4) equipped!

Once I get the exhaust done it's all easy from there.

[Pranav]

After much work over the past 60 days, I now have a running ls 5.3 car.

Started on the first try, ran great after I flipped one of the coil harnesses around, while the rest of the myriad of electrical and plumbing connections worked great on the first try. No leaks of fluids or electrons.

I'm way behind on the schedule I set for myself, but now that most of the tedious stuff is out of the way hopefully I should be able to zip thru buttoning up the rest of the car.

Now I take a two week break while I wander aimlessly around Japan and South Korea.

I'll try get the car driving and ready for the dyno when I get back.

Someone buy all of my LT1 crap!

[Pranav]

Bringing this back up, here's a great option for making lt1s more reliable:

http://www.torqhead.com/buy-24xlink-products.html#!/24xLink-Conversion-Kits/c/14327802/offset=0&sort=normal

$1-1.5k, use your existing engine harness. The only thing that would need to be cleared up is details on their base tune but maybe they could come up with a CMC tune for us.

New Optis are pushing $400. Full 5.3/Ls1 conversions for lt1 4th gen cars are not cheap given how many parts you have to change just to get it to fit.

Could potentially be a good middle way solution.

[Supercharged111]

Never heard of them. There is EFI Connection, they've been working the 52x 4th Gen LS conversion too.

https://www.eficonnection.com/home/category/engine-hardware/crank-and-cam-signal-kits/efi-24x-product-line/efi-24x-lt1lt4

[Pranav]

Yeah familiar with EFI, just pointed out TH because their kit is pretty close to plug and play. The take an LS1 PCM and modify it to accept stock lt1 harness plug, then add a 5th plug with a few wires for the extra sensors. Pretty slick IMO.

[Pranav]

Or how about this:
http://www.delteq.com/opti_pricing.htm

At first glance the whole kit is 50% more in cost than a new Delphi opti, which you can't even buy any more.

With 6 months and a couple events left in the year I'd strongly suggest someone consider testing a solution in preparation for an RCR.

Without Delphi Optis bring available and seeing more and more lt1 cars struggle with issues each event, I'm surprised the search for a viable solution hasn't gained more traction.

If I hadn't ditched the lt1 last year I'd be leading the charge right now.

Ls-5.3 swaps for 4th gens are unbelievably expensive.

[Adam Ginsberg]

Ls-5.3 swaps for 4th gens are unbelievably expensive.

Can you elaborate, thoroughly, on this statement?

[Pranav]

Of course a 5.3 by itself can be had for $500-800 easily, I paid $866 for my aluminum lm4 and sold $200-300 worth of truck junk off of it. It is a direct swap for an 98-02 ls1 Camaro, and can go into a third gen with less pain parts changes than an lt1 4th gen.

However to LS/5.3 swap a 93-97 LT 4th gen you have to:

Replace or modify the t56 (swap front plate + input shaft)
Replace lt1 bellhousing, clutch/fw assembly, pedal assembly, master and slave cylinder pair+line, and throttle cable with LS1 versions
Source all front LS1 Camaro alternator, ps pump, tensioner, and all brackets, hub/damper, water pump
Source LS1 intake, throttle body, exhaust manifolds, fuel rail, exhaust y pipe
Source LS1 Camaro steering rack, lower steering column shaft
Source 5.3 long block
Source LS1 ECM and full engine harness
Source LS1 Camaro coils and Camaro coil bracket assemblies
Source LS1 camaro motor mount assemblies
Source LS1 Camaro k member and engine stands
Source Camaro pan + pickup (and baffle if you use a stock pan)
Replumb power steering, oil cooler, radiator stuff.

I'm sure I left a couple of things off. I got into this thinking I'd fetch more than I've actually gotten for my good LT1 parts, and my lt1 remains unsold for the moment although I've been too busy to try hard to sell it. I just did a cold leakdown on it and was happy with the numbers so it will be listed soon.

The Canton pan was a cheaper shortcut that left me with horrible ground clearance so I'm burning cash going back to a more expensive stock or Holley pan with IR baffle this summer.

Given that the Camaro LS1+t56 take out is the gold standard for swaps, most everything Camaro specific fetches a premium, especially in the accessories and transmission department. Good luck finding a used, ready to go LS1 tremec t56 for much less than $2k. I was very fortunate to have Francis and Richardson help me convert my lt1 borg warner t56 which still ended up being $500 in parts.

You may get lucky finding a complete pullout for cheap or stumble across a wrecked donor car, but neither are often cheap. One guy did buy a complete pullout for cheap in this region but the engine blew in the first event and they did have to rebuild the trans.

I had my very specific reasons for swapping away from an LT1, but for most others that have perfectly healthy lt1s in their cars, doing such a massive swap to avoid ignition issues seems a bit excessive.

The delteq external northstar coil conversion seems to be a pretty solid option. On the upside you get the move to a more robust ICM and coil pack assemblies, removing the ignition source from within the Opti housing making the optical piece last longer.

On the downside you are also still relying on the optical portion of the opti, but I've never actually had an issue with that part. Some have however. You are also relying on the delteq "brain" which is an obscure, low volume aftermarket part from a company supporting a dying lt1 market for who knows how much longer, especially when Delphi has stopped Opti production and the market for clean lt1 hard parts is drying up.


If I were still an lt1 guy and in my third round of chasing misfires, I'd volunteer being the guinea pig.

[Sook]

I tried to get a hold of a delteq kit before swapping and wasn't able to. I think the company is dead but the website lives on?

[Pranav]

Ah bummer, is the LTCC conversion still around? It's $399 for a module and harness, you just have buy the coils brackets and make the plug wires so probably about the same cost as the delteq

[Supercharged111]

Man apparently I need to start sniping optis. Last AC Delco opti was under 3 hundo shipped from Amazon and it's been ticking since 2014 knock on wood. Have a spare in the trailer ready to go and a generic presumably good opti on a spare junkyard engine.

[Pranav]

The ACDelco one now is a re-man, which may not be a bad option possibly; Cardone also has a reman.

Ultimately for a delteq/ltcc style conversion you just want a good Mitsubishi optical sensor and straight wheel.

[Supercharged111]

Were you the only one having this bad of a rash of issues? Mine ended up being a ghetto ass wiring job and either a bad or incorrect knock sensor.

[Pranav]

Nope, two cars ran at COTA this past weekend with issues again; down here we're good to see multiple LT1 cars have some kind of dumb issue come up every season. Most times it's fixed after throwing a part or two at it but we've had a few guys chase a miss for multiple events.