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RWD4ME
That said, my high school failure in the Type 1 got me thinking about why the one particular piston in your case melted. Why that one and not the one beside it?

Interesting question and one which was on my mind in this....the question of why one piston more than others as a general thing. My one experience with excess timing advance was one piston meting and another just showing some signs. I would be curious to hear from others on similar situations if their meltdowns were just one piston for case of overall advanced timing or AFR or spark plug heat range being off across the whole engine, or did several melt; JVL's last post seemed to impy several pistons had issues. For N/A engines, the distribution of mixture and filling between cylinders will vary quite a bit. I suspect this may be less so for pressurized engines but still will happen to some degree (based on turbo piston A/C engine info). So, when approaching the 'bad' zone, then the first cylinder to hit the 'bad zone' will start piston failure. I suspect we hear that as soon as it really starts or feel a 'hitch' in the engine as the piston/crown expands and partly seizes. Whan the piston holes, then the whole manifold pressure changes and the overall engine operating condtions change a lot, and the others don't see the problem condition any more.

I expect overly advanced timing is a case of direct preignition. Well, for what it is worth....

Only thing I know that make enough heat to roast the piston to that point is sustained detonation, what caused that is to me the question.
Octane?
Poor fuel distribution---good chance?
Comic rays?
Karmic justice? only he can answer that

One thing fo shore is I would make sure there were pistons with a lot more meat near the edge, and maybe a thicker crown.. Less meat=much quicker heat up and Subaru's dumb OEM designs are dumb enough they didn't use that design in their WRC cars...what was that phrase I gotta look up
Oh yeah "empirical reasoning" says go the direction they themselves did when pounding on things, not what they did for glorified grocery-getters.

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John Vanlandingham
Sleezattle, WA, USA

Vive le Prole-le-ralliat

www.rallyrace.net/jvab
CALL +1 206 431-9696
Remember! Pacific Standard Time
is 3 hours behind Eastern Standard Time.

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RWD4ME
Has anyone mixed Xylene with pump gas in order to increase the octane?

Xylene is 117 R+M/2 octane.
Toluene is 114.

I've used both, but never more than 20%.

Note: between you and me, don't use a credit card; pay cash. No need to get your name on some list, if you know what I mean.

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Iowa999

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RWD4ME
Has anyone mixed Xylene with pump gas in order to increase the octane?

Note: between you and me, don't use a credit card; pay cash. No need to get your name on some list, if you know what I mean.

Solid advice that. Also, Toluene is wicked stinky.

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Kirk Coughlin
Woodbury, MN and River Falls, WI

Quemadmodum gladius neminem occidit, occidentis telum est.

Glad to see you got a good tuner

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Chris

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Do It Sidewayz
Glad to see you got a good tuner

Yeah, unfortunately there were other variables that led to the failure of the motor on the dyno. At least I have a "podium" of failures. It's, in his words, one of the best failures he's seen on a car that wasn't one of his own that he was intentionally pushing.

Car wasn't producing power, acting strange, and it let go - horrible leak on the cylinders (up to 65%) and lots of noise. It's bad.

Time for ANOTHER engine. We talked about your motor quite a bit tonight over beers, Chris...

In case I missed it, are you running the stock fuel lines or has it been modded to the parallel configuration?

Eric,

Sorry to hear about the failures, especially on something so new!

Soak up all the knowledge Mike will throw at you! He likes beer and good food!

Good luck, i hope the pocket book recovers ok!

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Chris

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EricW
Put it this way - Won Rally West Virginia with the fresh motor. No issues in 2 days of racing. 93 octane purchased just off of the highway at a Sunco outside of Winchester, VA.
Melted down one of the pistons 1.5mi into SS1 start at the next event. Fuel purchased just off of the interstate in PA.

I wish there was a simple fuel test kit that one could use that did on-the-fly octane verification of a given fuel sample. If there is one, I haven't seen it yet.

Sounds like you already have one, but the testing process is perhaps a bit cumbersome.

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Pete Remner
Cleveland, Ohio

1984 RX-7 (rallycross thing)
1978
Silence is golden, but duct tape is silver.

Well, my brand new motor just ate itself with 2 miles on the odo. No Sandblast for me.

There is one constant in all of these failures and that is going to be eliminated next time.

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EricW
Well, my brand new motor just ate itself with 2 miles on the odo. No Sandblast for me.

There is one constant in all of these failures and that is going to be eliminated next time.

Dang dude, no bueno. Tooner? What happened this time?

Will discuss more at SB.

Not wanting to pry (too much), but whatever you can share just might save someone else some grief or at least give them an idea of what to keep an eye out for.

Thanks!

Dave

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DaveK
Not wanting to pry (too much), but whatever you can share just might save someone else some grief or at least give them an idea of what to keep an eye out for.

Thanks!

Dave

Plus Juan...

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John Vanlandingham
Sleezattle, WA, USA

Vive le Prole-le-ralliat

www.rallyrace.net/jvab
CALL +1 206 431-9696
Remember! Pacific Standard Time
is 3 hours behind Eastern Standard Time.

Quote
john vanlandingham

Quote
DaveK
Not wanting to pry (too much), but whatever you can share just might save someone else some grief or at least give them an idea of what to keep an eye out for.

Thanks!

Dave

Plus Juan...

Motor was built incorrectly. Teardown will confirm exact issues in the next few days. My crew guy was flying in to help me for final prep for Sandblast direct from 100AW. Looks like he'll get to play pathologist instead.

Car didn't let go under boost - it was acting unhappy all day.