Pranav catches the LT1 misfire zeka

[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