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What happened to your ChampCar today 2021 ??


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1 minute ago, petawawarace said:

Can you see the piston ring? The split in the one is actually the ring end gap.  You shouldn’t be able to see that.   There’s 2 almost identical pieces of piston missing and have exposed the ring.  

Ouch!  How long was it run with out spark. Not sure just blowing fuel through the cylinder would cause piston to break apart but crazy poop happens. Damage like that is tough. 

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7 minutes ago, TimS said:

Ouch!  How long was it run with out spark. Not sure just blowing fuel through the cylinder would cause piston to break apart but crazy poop happens. Damage like that is tough. 

The driver at the time described it as a miss under acceleration out of the corner so we told him to keep going.  It was likely a miss all the time, but was masked at higher rpm.  We changed coils with the next driver and it didn’t get better. Then we found the broken wire, but damage was done by that point. Likely 1.5hrs of it with no spark at race pace. 

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26 minutes ago, petawawarace said:

Can you see the piston ring? The split in the one is actually the ring end gap.  You shouldn’t be able to see that.   There’s 2 almost identical pieces of piston missing and have exposed the ring.  

 

Looks like detonation to me.  But just a guess.  In my opinion cylinder washdown would not do this, but hey I am wrong multiple times/day.

 

Edit: Quick look before, I see what you mean, no other indication on the piston that you would think you would see from just detonation. Sucks either way.

Edited by Rodger Coan-Burningham
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6 minutes ago, petawawarace said:

The driver at the time described it as a miss under acceleration out of the corner so we told him to keep going.  It was likely a miss all the time, but was masked at higher rpm.  We changed coils with the next driver and it didn’t get better. Then we found the broken wire, but damage was done by that point. Likely 1.5hrs of it with no spark at race pace. 

Broken wire probably didn’t happen all at once and may have been causing the detonating/missing to damage piston. Either way a lot of work to repair. 

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Going to have to look up the dynamics of this, as mentally, I’m not sure how the top of the piston would be affected by a lack of lubrication in a cylinder not generating heat, I would think the skirt would scuff, on the other hand, a broken wire can change the timing a bit as it fails. 

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1 hour ago, Team Infiniti said:

I’ve never heard of that theory before, mender can you explain this?

More pictures? 

 

Usually that damage is because of detonation (visible on the top of the piston) which causes the top ring to expand enough to butt and lift the top ring land. 

 

Better check the cylinder wall for cracking/splitting, pretty common collateral damage... 

Edited by mender
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2 minutes ago, Team Infiniti said:

Going to have to look up the dynamics of this, as mentally, I’m not sure how the top of the piston would be affected by a lack of lubrication in a cylinder not generating heat, I would think the skirt would scuff, on the other hand, a broken wire can change the timing a bit as it fails. 

Detonation,  spark happening to early, could also be water in fuel causing poor combustion.

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1 hour ago, petawawarace said:

Can you see the piston ring? The split in the one is actually the ring end gap.  You shouldn’t be able to see that.   There’s 2 almost identical pieces of piston missing and have exposed the ring.  

Ohhhh...  yeah, I was looking for WAY less obvious.  Damn!

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It could be detonation if the broken wire was partially broken and altering the spark timing, but an increase in resistance with a partially broken wire would lead to a delay in spark I would think.  Regardless, I think it’s safe to say the broken wire caused this.  We fixed the wire, replaced the engine and it ran perfect the next day.  
 

Those pictures are from a cheap borescope         I will pull the head and get a better look.   I just did that as a quick check.  If it was major damage, I would just scrap the whole thing.  The cylinder walls don’t appear to have scoring and the top of the piston isn’t beat to crap so perhaps the rest is ok.  

Edited by petawawarace
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<philosophy> oh boy.....i can't even begin to catalogue racing from a day-to-day perspective. Started off racing sailboats at 10, did that through college and after....picked up bikes, road and mountain, after a chunk of time in USMC Recon Battalion tear-assing around the planet, then ended up here in car craziness....

 

My wife is a Saint, my kids think I'm nuts (except for the one that got my racing genes), and I'm a lost cause for all of this insanity. But i just love the process...I don't know how else to put it...so ya, the car doesn't start....poop flies off.....you crash, and are all f*****-up, or you just don't have the A-Game that day....but!!! you are racing!!!!

 

All in all......racing is just.....racing, which makes it so great and a bit of a mirror on the human condition....</philosophy>

 

I now return you to your regularly scheduled programming.....

 

 

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On 8/21/2021 at 12:18 PM, Team Infiniti said:

Nope! That was the time when an RX7 woofed two or three pit stalls behind me while doing my work. 🤯

 

Oh man...  you work on a lot of fuel pumps...

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1 hour ago, atxe30 said:

<philosophy> oh boy.....i can't even begin to catalogue racing from a day-to-day perspective. Started off racing sailboats at 10, did that through college and after....picked up bikes, road and mountain, after a chunk of time in USMC Recon Battalion tear-assing around the planet, then ended up here in car craziness....

 

My wife is a Saint, my kids think I'm nuts (except for the one that got my racing genes), and I'm a lost cause for all of this insanity. But i just love the process...I don't know how else to put it...so ya, the car doesn't start....poop flies off.....you crash, and are all f*****-up, or you just don't have the A-Game that day....but!!! you are racing!!!!

 

All in all......racing is just.....racing, which makes it so great and a bit of a mirror on the human condition....</philosophy>

 

I now return you to your regularly scheduled programming.....

 

 

Have you or your family seen The Art of Racing in the Rain? Awesome movie and book. Sad in spots funny in others yes, but explains us gear heads very well! A movie the whole family could enjoy.

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1 hour ago, Timothy G. Elliott said:

Have you or your family seen The Art of Racing in the Rain? Awesome movie and book. Sad in spots funny in others yes, but explains us gear heads very well! A movie the whole family could enjoy.

oh ya....that movie was heavy duty......(not gonna post a pic of our yellow lab)......and fortunately the lights were low when we watched it!!!

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On 8/21/2021 at 5:17 PM, Rodger Coan-Burningham said:

Yeah, I go back to my first thought, what throws things off is the varnish look on most of the top of the piston.  But if you look at this area of the ring land it tells a story.

 

image.png.c1d2910f3418438d50c0932de112285f.png

Which could be impact damage from the missing pieces of piston getting caught between the edge of the piston and the quench area. The presence of a fairly uniform shiny area around the perimeter of the piston makes me lean toward the physical damage scenario, but that doesn't preclude detonation as the lead cause of the ring land damage. 

 

The exposed ring ends are pretty typical of an overheated top ring that butted hard enough to lock up and rip off the upper ring land. The ends will flex up more readily than a continuous part of the ring and will apply a point load. The thinnest part of the upper ring land is right beside the valve pocket so if the gap is there the land will fail fairly easily.

 

Interesting that an identical piece is missing from the other valve pocket. Knowing that it was a boroscope picture explains the reflection off the cylinder wall. 

 

Silly question: is the damaged cylinder the one that had the broken plug wire or is it the one that preceeds it in the firing order?

 

Edit: I was thinking plug wires and crosstalk, not coil on plug. Hmmm.

Edited by mender
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7 hours ago, mender said:

Which could be impact damage from the missing pieces of piston getting caught between the edge of the piston and the quench area. The presence of a fairly uniform shiny area around the perimeter of the piston makes me lean toward the physical damage scenario, but that doesn't preclude detonation as the lead cause of the ring land damage. 

 

The exposed ring ends are pretty typical of an overheated top ring that butted hard enough to lock up and rip off the upper ring land. The ends will flex up more readily than a continuous part of the ring and will apply a point load. The thinnest part of the upper ring land is right beside the valve pocket so if the gap is there the land will fail fairly easily.

 

Interesting that an identical piece is missing from the other valve pocket. Knowing that it was a boroscope picture explains the reflection off the cylinder wall. 

 

Silly question: is the damaged cylinder the one that had the broken plug wire or is it the one that preceeds it in the firing order?

 

Edit: I was thinking plug wires and crosstalk, not coil on plug. Hmmm.

I couldn’t get a great picture but it was evident on the video that there were impact marks on the piston in that “clean” area.  I could still see the machining marks in that spot so I doubt detonation but it is possible.

 

Yes, the damaged cylinder was the one with a broken wire. It was one of the 4 wires going to the coil on plug.  

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2 hours ago, petawawarace said:

I couldn’t get a great picture but it was evident on the video that there were impact marks on the piston in that “clean” area.  I could still see the machining marks in that spot so I doubt detonation but it is possible.

 

Yes, the damaged cylinder was the one with a broken wire. It was one of the 4 wires going to the coil on plug.  

Any chance of that wire grounding randomly and causing the coil to fire?

Edited by mender
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18 minutes ago, petawawarace said:

Doubt it. It was broken inside the weather pack connector.  Took us a while to find once we found we had no spark.  

As soon as the wire opens the coil will discharge and when ever the power stops! So yes that coil could easily fire way early!

 

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Finally got the car out to Harris Hill Raceway for engine break-in. Started off poorly as the car immediately was running bad. Seemed like a misfire of sorts and the spark plug in cyl 2 was black. After trying to solve it with more difficult things we went back to basics and checked the plug wires. Yup somehow the wires for 1 and 2 were swapped. Put them back correctly and the car fired right up sounding great.

 

The rest of the day was fun but uneventful. The three drivers took turns constantly for about 6 hours until the track closed. Car ran perfect, good AF, good temps and pressures. We slowly ramped up the RPMs but only got to 5000. I’ll go back tomorrow and turn more laps until we’re at 7000 rpm and the engine well broken in. Feels strong already and I’m barely getting into the powerband. I’m looking forward to tomorrow!

 

My friend let me slum it with his cars overnight at the track garage…

637BDC11-DEC6-4D1A-8B33-0CDDD48E5695.jpeg

Edited by QuaTTro
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9 hours ago, QuaTTro said:

Finally got the car out to Harris Hill Raceway for engine break-in. Started off poorly as the car immediately was running bad. Seemed like a misfire of sorts and the spark plug in cyl 2 was black. After trying to solve it with more difficult things we went back to basics and checked the plug wires. Yup somehow the wires for 1 and 2 were swapped. Put them back correctly and the car fired right up sounding great.

 

The rest of the day was fun but uneventful. The three drivers took turns constantly for about 6 hours until the track closed. Car ran perfect, good AF, good temps and pressures. We slowly ramped up the RPMs but only got to 5000. I’ll go back tomorrow and turn more laps until we’re at 7000 rpm and the engine well broken in. Feels strong already and I’m barely getting into the powerband. I’m looking forward to tomorrow!

 

My friend let me slum it with his cars overnight at the track garage…

637BDC11-DEC6-4D1A-8B33-0CDDD48E5695.jpeg

 

Dyno at John?

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