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Discussion Starter · #5 ·
trash made it through the filter. clogged the fuel jet on the #2 hole. same tune up ive ran for seasons and other 7 were perfect!
 

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trash made it through the filter. clogged the fuel jet on the #2 hole. same tune up ive ran for seasons and other 7 were perfect!
I had the exact same thing happen; clogged a 32 fuel jet and the only syptom was the car slowed down bout .05-.08 in the 1/8th. I got lucky and did not hurt anything though. I was running 1/8th mile..
 

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The nitrous guy
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I am going to give a different opinion. That is likely not lean and I doubt a clogged jet caused that. They way that piston is eaten away, in the 12 oclock position, tells me it was overtimed on that hole. The fact that this was the only one it hurt and the fact that you have run this before, indicates that oil got into that chamber and caused the timing issue. The skirts show signs of abuse and I would bet if you measured the skirt, they are hammered in on that piston. If the skirts are knocked in, the piston rocked, the rings don't seal, oil gets in, kills the octane rating and you get detonation on that hole, which pulls the alum off the piston and also knocked that hole in it.

Monte
 

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I am going to give a different opinion. That is likely not lean and I doubt a clogged jet caused that. They way that piston is eaten away, in the 12 oclock position, tells me it was overtimed on that hole. The fact that this was the only one it hurt and the fact that you have run this before, indicates that oil got into that chamber and caused the timing issue. The skirts show signs of abuse and I would bet if you measured the skirt, they are hammered in on that piston. If the skirts are knocked in, the piston rocked, the rings don't seal, oil gets in, kills the octane rating and you get detonation on that hole, which pulls the alum off the piston and also knocked that hole in it.

Monte


Sounds about right.. Definetly wasnt due to going lean
 

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I am going to give a different opinion. That is likely not lean and I doubt a clogged jet caused that. They way that piston is eaten away, in the 12 oclock position, tells me it was overtimed on that hole. The fact that this was the only one it hurt and the fact that you have run this before, indicates that oil got into that chamber and caused the timing issue. The skirts show signs of abuse and I would bet if you measured the skirt, they are hammered in on that piston. If the skirts are knocked in, the piston rocked, the rings don't seal, oil gets in, kills the octane rating and you get detonation on that hole, which pulls the alum off the piston and also knocked that hole in it.

Monte

I hate to be the bad guy here, but I totally disagree with this statement... I have been doing this for well over 30 years and have seen a plugged fuel jet do this many times before !!!

That piston has the look when you see a lean burned piston and or an overtimed piston. In this case, no fuel thru the jet equals a lean burn down and the results of severe detonation as well.

As for the skirt showing abuse, of course it is going to. It just detonated it's ass off as it was burning down. Got hot, started melting, detonating, unsettling the rings, oiling, collapsed the skirt and so on.. It's a somewhat normal sequence when this happens.. SJ
 

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I kill parts
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I'll bite. Either scenario is very likley/simliar, the question is what came first; the chicken or the egg? Was the piston already worn enough that it was letting oil in, was it close to doing so and the plugged jet finished it off, or did the plugged jet just wipe it out?

No matter which scenario, the solution remains the same. Clean the jet, clean/replace the fliter, new piston and check the plugs every pass as always.
 

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I have the intake with the fogger from the motor and the nozzle had trash in it, the motor had minimal passes on it before this happened. Andy had these tune-ups from the original company that did the installation and that's what we used and had no issue up to this point. We are making an intake change for this season along with the installation of a new fogger from Steve so I think we should be in good shape.
 

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How and why did trash get in it. I filter from the mother bottle to my 15lb bottles. Also have the LARGE screens in the fittings going into the fuel noids. Never bad a clogged anything. I know sj makes his fittings with the screens that are largest I have seen. May be a thought
 

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The nitrous guy
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We have seen many threads, about people leaving their fuel pump completely off and making a banzai nitrous hit, with NO additional fuel and never hurt a thing, but some of those same people claim a clogged jet burns a hole to the ground. Sorry, don't buy it, never will, that a lean condition will do that. No fuel, no heat, no burn. Timing did that, most likely because of oil in the chamber.

And if the motor was slowly eating at that hole, you would not likely see it on the plug. Takes a lot of oil to actually see it wet on the plug. My guess, that hole has been a problem for a while, slowly eating itself up from oil contamination. The rings finally give up, let a LOT of oil in and you get the ashtray. Seen it many times. That did not happen in one pass. Now while I have seen some serious torched up stuff after one pass, the way that piston is rolled over on the edges, tells me that happened over time and finally gave it up big.

Monte
 

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Discussion Starter · #18 ·
We have seen many threads, about people leaving their fuel pump completely off and making a banzai nitrous hit, with NO additional fuel and never hurt a thing, but some of those same people claim a clogged jet burns a hole to the ground. Sorry, don't buy it, never will, that a lean condition will do that. No fuel, no heat, no burn. Timing did that, most likely because of oil in the chamber.

And if the motor was slowly eating at that hole, you would not likely see it on the plug. Takes a lot of oil to actually see it wet on the plug. My guess, that hole has been a problem for a while, slowly eating itself up from oil contamination. The rings finally give up, let a LOT of oil in and you get the ashtray. Seen it many times. That did not happen in one pass. Now while I have seen some serious torched up stuff after one pass, the way that piston is rolled over on the edges, tells me that happened over time and finally gave it up big.

Monte
That piston has 13 passes on it after being all brand new from buck on the freshen up. That's the number 2 hole that always runs warm which I already had 1.5 additional degrees pulled out of that hole with my ict. This is same tune up I've ran in this motor for 3 seasons and never even nipped a plug. I'm a nobody compared to people like you that do this for a living. That's why I posted it for an opinion. But if this was 13 passes old from a reputable builder such as buck with all brand new rods pistons and rings and same tune I've ran for years I look at what's different. Which when we pulled it apart the fuel jet on that hole was clogged shut that you couldn't see daylight through it. Hit it with air from the outlet side of jet and voilà could see through it perfect and it pinned out to correct size with no burrs. So maybe that's not what causes the issue but why else did the hole magically burn if it never has before?
 

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We have seen many threads, about people leaving their fuel pump completely off and making a banzai nitrous hit, with NO additional fuel and never hurt a thing, but some of those same people claim a clogged jet burns a hole to the ground. Sorry, don't buy it, never will, that a lean condition will do that. No fuel, no heat, no burn. Timing did that, most likely because of oil in the chamber.

And if the motor was slowly eating at that hole, you would not likely see it on the plug. Takes a lot of oil to actually see it wet on the plug. My guess, that hole has been a problem for a while, slowly eating itself up from oil contamination. The rings finally give up, let a LOT of oil in and you get the ashtray. Seen it many times. That did not happen in one pass. Now while I have seen some serious torched up stuff after one pass, the way that piston is rolled over on the edges, tells me that happened over time and finally gave it up big.

Monte
Come on Monte, You have to compare apples and apples. NOT apples and basketballs.. :confused:

There's a HUGE difference in clogging the jet in one system and the nitrous from that system as well as the nitrous and fuel from the other system still trying to feed the same hole.. And leaving the fuel pump OFF.

In the senario of leaving the fuel pump off. YES, I have seen the fuel pump left off many times without any damage.. But just to help you understand the difference, when you leave the fuel pump off, there's basically NO fuel to burn and make heat and so on.

When you block one fuel jet in a larger or multiple system deal there's still enough fuel getting into that cylinder it WILL burn it up nearly everytime.. There's a big difference between a little fuel and no fuel.. I'm sure there are a few exceptions out there?? But I'll bet about anyone who's plugged a fuel jet up at least burned a plug.. SJ
 

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i have seen this happen before. not from a clogged jet, but from a cracked line at the jet.
i was helping a guy with a sbf car. same tune we always ran and it burned up the whole right side of the engine.
turned out there was a split in the hard fuel line right at the fuel jet on one of those cylinders.
when the nitrous was activated, the pressure in that side would fall and all of the pistons would be toast.
if there had been no fuel at all it might have been ok, but there was just enough heat in the cylinder to start the burn, but not enough fuel to protect it.
i have had a fuel pump become disconnected on my own car and never hurt anything. this is a totally different senerio.
 
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