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Discussion Starter #1


4 good passes then this . no warning just happened . too rich or too lean? plug was intact
 

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That doesn't look reusable IMO............ :eek:
 

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He hasn't even said anything about his tune. No one has any idea about n/f ratio (pills). But I can tell you 100% that you have too much timing for the given tune. Start there.

If you are gonna tell him it's too much fuel, which I quite possibly is, shouldn't we ask what he has first?
 

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Discussion Starter #7
He hasn't even said anything about his tune. No one has any idea about n/f ratio (pills). But I can tell you 100% that you have too much timing for the given tune. Start there.

If you are gonna tell him it's too much fuel, which I quite possibly is, shouldn't we ask what he has first?
6degrees of total timing.14 to 1 comp 77nos 59fuel its a cross plate so that's times 2 . I think it went fat and couldn't clean up. left good on this pass and layed over at 8k shifted it picked up then burned up . did not change the timing from the previous 3 passes just shortened the ramps
 

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The nitrous guy
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Damage like that doesn't just happen out of the blue on one pass. It was eating itself before the failure and the rings on that hole just finally gave up most likely.

While the tune may indeed be rich.........too much timing and the introduction of oil into the cylinder is where that blow torch came from. It appears to be at 12 oclock on the piston..........another usual indicator of overtimed.

While 6 degrees total certainly would not seem to be too much in normal circumstances with that tune.........if it was oiling, that changes things drastically
 

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EFI/N2O JUNKIE
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I was thinking about this. Oil in the chambers really kills the octane rating of race fuel. If we were racing diesels we would never have to worry about it now would we. Too bad diesels are too big and slow............ That piston is a mess. :(

What did the pan vacuum look like that day?
 

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Discussion Starter #15
thankyou for all the replies. im putting it back together and going to start over with the tuneup. also changing the carb. the carb leaks down into the motor after the runs and messes up the readings alittle but most of the plugs are very dark(its a backup carb good one was destroyed by fire).

it is a small block ford and it is #2piston pictured
 

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Discussion Starter #16
What is engine combo ?? What fuel, plug, cam, quench, chamber size ??? That jetting could be better but is not terrible. SJ
420 cid sbf
dedicated nos cam(cant find specs)
11 ngk plug
vp c23
piston is 20 in the hole
chamber is 62

ive been running this eng for awhile .it was freshened up over the winter just don't have the time to go test as much as I used to.
 

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420 cid sbf
dedicated nos cam(cant find specs)
11 ngk plug
vp c23
piston is 20 in the hole
chamber is 62

ive been running this eng for awhile .it was freshened up over the winter just don't have the time to go test as much as I used to.

how many passes on it after the freshen?
 
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