Melted a piston - unsure why.
I’m very much on board with his method of thinking, which is exactly what I said I thought caused my problem (lean and high iat’s). Can anyone give me s Definitive answer on the crank relearn, if that corrects for the advance being off or not. That very well could also be the culprit here if I was told wrong Information
http://www.msextra.com/doc/triggers/crankrelearn.htm
It sounds like the case procedure just calibeates the computer to the sensor and will not compensate if your reluctor is off or cam timing is off. I've never gotten the CASE relearn to hit the 4k rev limiter on setups I've tried with EFI live.
Thread Starter
Teching In
Joined: Jun 2018
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Aint no logic allowed in here!!
Based on this link
http://www.msextra.com/doc/triggers/crankrelearn.htm
It sounds like the case procedure just calibeates the computer to the sensor and will not compensate if your reluctor is off or cam timing is off. I've never gotten the CASE relearn to hit the 4k rev limiter on setups I've tried with EFI live.
Based on this link
http://www.msextra.com/doc/triggers/crankrelearn.htm
It sounds like the case procedure just calibeates the computer to the sensor and will not compensate if your reluctor is off or cam timing is off. I've never gotten the CASE relearn to hit the 4k rev limiter on setups I've tried with EFI live.
I know some of the OGs on here are big on verifying cam timing. Most people arent going to tear their stuff apart if timing is off unless its making the car run like crap. My stance us if you start timing really conservative and read the plugs and work your way up it doesn't really matter if your timing is off or not because the motor will be getting the right amount of timing for that setup. In other words if your timing is off by +2 degrees and you put 13 degrees of advance in the tune or your timing is off -2 degrees and you put 17 degrees in the tune as long as you're reading the plugs and they look good then the tune is right for the combo. All depends on how much you want to maximize the combo and wring out every ounce of performance. I don't race for a living or own a shop.....I just tune street cars and only pump gas no meth.
I’m very much on board with his method of thinking, which is exactly what I said I thought caused my problem (lean and high iat’s). Can anyone give me s Definitive answer on the crank relearn, if that corrects for the advance being off or not. That very well could also be the culprit here if I was told wrong Information
Its really easy to verify spark advance. I use a peice of tig rod bent up to make a pointer for the balancer. take the rockers off number one cylinder and use a piston stop threaded into the sparkplug hole. Roll the motor over fwd and mark the balancer, roll it back the other way and mark. Halfway between is piston TDC mark there and erase the others. Then you'll want to degree it. Take the diameter D x 3.14 thats the circumference C. Then divide C by 360 degrees and that'll give you an inch increment per degree. Multiply that by what advance number ( i use 20*) you want and measure CW from the TDC mark and make a nice visible mark, with like silver sharpie or a white paint pen.
Put it all back together, and fire it up with an old school timing light on it. Go into the scanner and lock the timing on 20* and all should jive. This is how we found my friends' MS retarded 6*
I'd really only consider checking this on an aftermarket pcm or where an aftermarket crank or reluctor wheel is used. I check my own stock crank stock pcm stuff because, well I've blown up enough **** this last couple years. I'm jinxed.
Put it all back together, and fire it up with an old school timing light on it. Go into the scanner and lock the timing on 20* and all should jive. This is how we found my friends' MS retarded 6*
I'd really only consider checking this on an aftermarket pcm or where an aftermarket crank or reluctor wheel is used. I check my own stock crank stock pcm stuff because, well I've blown up enough **** this last couple years. I'm jinxed.
Its really easy to verify spark advance. I use a peice of tig rod bent up to make a pointer for the balancer. take the rockers off number one cylinder and use a piston stop threaded into the sparkplug hole. Roll the motor over fwd and mark the balancer, roll it back the other way and mark. Halfway between is piston TDC mark there and erase the others. Then you'll want to degree it. Take the diameter D x 3.14 thats the circumference C. Then divide C by 360 degrees and that'll give you an inch increment per degree. Multiply that by what advance number ( i use 20*) you want and measure CW from the TDC mark and make a nice visible mark, with like silver sharpie or a white paint pen.
Put it all back together, and fire it up with an old school timing light on it. Go into the scanner and lock the timing on 20* and all should jive. This is how we found my friends' MS retarded 6*
I'd really only consider checking this on an aftermarket pcm or where an aftermarket crank or reluctor wheel is used. I check my own stock crank stock pcm stuff because, well I've blown up enough **** this last couple years. I'm jinxed.
Put it all back together, and fire it up with an old school timing light on it. Go into the scanner and lock the timing on 20* and all should jive. This is how we found my friends' MS retarded 6*
I'd really only consider checking this on an aftermarket pcm or where an aftermarket crank or reluctor wheel is used. I check my own stock crank stock pcm stuff because, well I've blown up enough **** this last couple years. I'm jinxed.
High EGT = TOO MUCH FUEL/LOW SPARK INSTANT Hi Loud Mouse, as you see most here are NOT good tuners.
My knowledge is based on my 1000+ turbo tunes, thirty years of tuning turbosupercharged engines, as the OEM engine supplier for Jerry Wiegert (Vector Cars), Indy Car racing (Menard V-6 & Cosworth), Rally Racing (RS-200 & Subaru EJ-20), Marine BBC Twin Turbo engines (PFM), Turbo LS engines in Sand Cars/Street Cars, etc.
MY INVENTION of the 60-2 (GM 58X) Crankshaft Target Wheel in 1986 has allowed the ECU I MANUFACTURE to operate an engine with a Spark Accuracy of 1/4 Degree.
THUS I know how to tune at a Spark Instant of 60 DEGREES ATDC at the Start Line WITHOUT engine damage.
GM also uses the SAME METHOD to protect Truck 4WD drive trains using a LOW Spark Advance to LIMIT Torque.
THE DIFFERENCE is the GM Truck AFR is close to 14.7 NOT 11.2.
Good Tech, Loud Mouse, as you are one of the few here who knows this fact !
Lance
My knowledge is based on my 1000+ turbo tunes, thirty years of tuning turbosupercharged engines, as the OEM engine supplier for Jerry Wiegert (Vector Cars), Indy Car racing (Menard V-6 & Cosworth), Rally Racing (RS-200 & Subaru EJ-20), Marine BBC Twin Turbo engines (PFM), Turbo LS engines in Sand Cars/Street Cars, etc.
MY INVENTION of the 60-2 (GM 58X) Crankshaft Target Wheel in 1986 has allowed the ECU I MANUFACTURE to operate an engine with a Spark Accuracy of 1/4 Degree.
THUS I know how to tune at a Spark Instant of 60 DEGREES ATDC at the Start Line WITHOUT engine damage.
GM also uses the SAME METHOD to protect Truck 4WD drive trains using a LOW Spark Advance to LIMIT Torque.
THE DIFFERENCE is the GM Truck AFR is close to 14.7 NOT 11.2.
Good Tech, Loud Mouse, as you are one of the few here who knows this fact !
Lance
Hi Loud Mouse, yes YOU are correct AND a measurement of EGT is easy.
NO AFTERCOOLER ???
This too ADDS EGT increases.
SURE detonation can be a result of a bad tune AND the added information provided by the OP points to that broken piston, NOT a MELTED piston. ( OP's Question)
BUT/INSTALL an EGT Gauge.
A HIGH EGT is a result of a too low Spark Instant.
WHAT is your EMAP at 11 .lbs ?
WHERE is your EGO/UEGO sensor located ?
MY tune target is from .866 -.902 Lambda AND finding the lowest EGT, found with CORRECT Spark Advance.
Lance
NO AFTERCOOLER ???
This too ADDS EGT increases.
SURE detonation can be a result of a bad tune AND the added information provided by the OP points to that broken piston, NOT a MELTED piston. ( OP's Question)
BUT/INSTALL an EGT Gauge.
A HIGH EGT is a result of a too low Spark Instant.
WHAT is your EMAP at 11 .lbs ?
WHERE is your EGO/UEGO sensor located ?
MY tune target is from .866 -.902 Lambda AND finding the lowest EGT, found with CORRECT Spark Advance.
Lance
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Lance,
What is CORRECT timing and how are you finding it? EGT only??
I also question the definition of correct AFR. I'm a total turbo newb but have plenty of Nitrous experience. I see a crap ton of turbo tunes in the 11.5AFR range and they seem to survive and make good power. I do think it's pig rich from previous experience but wonder if turbos differ in AFR needs from nitrous and why?
What is CORRECT timing and how are you finding it? EGT only??
I also question the definition of correct AFR. I'm a total turbo newb but have plenty of Nitrous experience. I see a crap ton of turbo tunes in the 11.5AFR range and they seem to survive and make good power. I do think it's pig rich from previous experience but wonder if turbos differ in AFR needs from nitrous and why?
Hi Loud Mouse, as you see most here are NOT good tuners.
My knowledge is based on my 1000+ turbo tunes, thirty years of tuning turbosupercharged engines, as the OEM engine supplier for Jerry Wiegert (Vector Cars), Indy Car racing (Menard V-6 & Cosworth), Rally Racing (RS-200 & Subaru EJ-20), Marine BBC Twin Turbo engines (PFM), Turbo LS engines in Sand Cars/Street Cars, etc.
MY INVENTION of the 60-2 (GM 58X) Crankshaft Target Wheel in 1986 has allowed the ECU I MANUFACTURE to operate an engine with a Spark Accuracy of 1/4 Degree.
THUS I know how to tune at a Spark Instant of 60 DEGREES ATDC at the Start Line WITHOUT engine damage.
GM also uses the SAME METHOD to protect Truck 4WD drive trains using a LOW Spark Advance to LIMIT Torque.
THE DIFFERENCE is the GM Truck AFR is close to 14.7 NOT 11.2.
Good Tech, Loud Mouse, as you are one of the few here who knows this fact !
Lance
My knowledge is based on my 1000+ turbo tunes, thirty years of tuning turbosupercharged engines, as the OEM engine supplier for Jerry Wiegert (Vector Cars), Indy Car racing (Menard V-6 & Cosworth), Rally Racing (RS-200 & Subaru EJ-20), Marine BBC Twin Turbo engines (PFM), Turbo LS engines in Sand Cars/Street Cars, etc.
MY INVENTION of the 60-2 (GM 58X) Crankshaft Target Wheel in 1986 has allowed the ECU I MANUFACTURE to operate an engine with a Spark Accuracy of 1/4 Degree.
THUS I know how to tune at a Spark Instant of 60 DEGREES ATDC at the Start Line WITHOUT engine damage.
GM also uses the SAME METHOD to protect Truck 4WD drive trains using a LOW Spark Advance to LIMIT Torque.
THE DIFFERENCE is the GM Truck AFR is close to 14.7 NOT 11.2.
Good Tech, Loud Mouse, as you are one of the few here who knows this fact !
Lance
Originally Posted by ddnspider
The arrogance of this post is impressive. You continue doing what you do. I'll continue doing what I do, and I haven't blown a single engine yet.
9 Second Club
Joined: Nov 2003
Posts: 13,616
Likes: 185
From: Norn Iron
Lance,
What is CORRECT timing and how are you finding it? EGT only??
I also question the definition of correct AFR. I'm a total turbo newb but have plenty of Nitrous experience. I see a crap ton of turbo tunes in the 11.5AFR range and they seem to survive and make good power. I do think it's pig rich from previous experience but wonder if turbos differ in AFR needs from nitrous and why?
What is CORRECT timing and how are you finding it? EGT only??
I also question the definition of correct AFR. I'm a total turbo newb but have plenty of Nitrous experience. I see a crap ton of turbo tunes in the 11.5AFR range and they seem to survive and make good power. I do think it's pig rich from previous experience but wonder if turbos differ in AFR needs from nitrous and why?
In the absence of a dyno....it's kinda a guessing game and people take various routes to achieve their goals.
Thanks Stevie, so in a nut shell unless it's a max effort build taking a conservative approach is where most of us are at. It isn't hard to read plugs and takes very little time. I think EGT is an excellent option here too but plugs will let you know if timing is in the ball park.
TECH Enthusiast
Joined: Dec 2011
Posts: 531
Likes: 5
I'm with you ddnspider, sometimes pantera is waayyyyy out there. According to his logic my car shouldn't even run without melting the pistons. I've run my car as rich as 10.0:1 and 10* when I was tuning it just slowing bringing in the timing and taking out some fuel. It now runs at 11.5:1 and 18-22* depending on iats. But it ran fine at lower timing and pig rich, just wasn't making as much power.
His posts kind of remind of that one dude who also took an arrogant tone fairly often (PrincessTalon), and also spoke in parables and other twisty riddle me this type stuff. Always worth a good laugh either way.
TECH Junkie
Joined: Jul 2015
Posts: 3,012
Likes: 48
For me, it's not so much arrogance, it's the random all caps words. Stuff reads like a nightmare. I challenge you to find one post of his that isn't like that.
Thread Starter
Teching In
Joined: Jun 2018
Posts: 21
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Little more info here, took the short block apart. All 7 other pistons look great, no signs of detonation or extreme heat. #6 rod is bent pretty good, the others look good. All bearings look mint. I’m still wierded out by the fact #1 had issues and #7 didn’t.
I'd be curious about fuel distribution and injectors as to whether they were flow matched or not. If your wideband said 11.5 on 91 octane, that 1 cylinder could have been leaner than the rest. Combined with high timing and "poor" octane, it went boom. Like I been saying lean and high timing is a good way to blow up a boosted pump gas LS.....the trail of parts is well documented on this site over the last 15 or 20 years lol.