What specifically causes a rod to snap in half?
09-06-2005, 08:08 PM
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Re: What specifically causes a rod to snap in half? (mike93eh)
I know for sure that the hardest thing for a rod to do is pull down the piston when it's heading back up (expansion of the rod). Elasticity in metal weakens them while compression (power stroke) isn't so bad.
In Lemans (sp?) terms revving is really what kills them. Usually rod bolts will go and the rod will then break. Power of course also is bad, but revving is much worse
In Lemans (sp?) terms revving is really what kills them. Usually rod bolts will go and the rod will then break. Power of course also is bad, but revving is much worse
09-06-2005, 08:16 PM
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well my last motor did this. wasnt making much power so its not that. what do you mean by revving? put a y8 head on my b7 and it lasted a whole 2 minutes before the rod snapped in half. just trying to figure out why it happened.
Uberdata/Crome/TurboEdit Tuner and ECU chipping - Chicagoland and Central Missouri areas
central missouri?? thats where i am. anymore info?
Uberdata/Crome/TurboEdit Tuner and ECU chipping - Chicagoland and Central Missouri areas
central missouri?? thats where i am. anymore info?
09-06-2005, 09:09 PM
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Re: (Adi Raaa)
<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by Adi Raaa »</TD></TR><TR><TD CLASS="quote">Oiling issues would have done it too...
Over reving the motor is what he is talking about, and also bolt failiures..</TD></TR></TABLE>
what kind of oiling issues? well i didnt over rev it so its not that. and why would i have bolt failure on a greddy turbo kit running stock 5 psi.
Over reving the motor is what he is talking about, and also bolt failiures..</TD></TR></TABLE>
what kind of oiling issues? well i didnt over rev it so its not that. and why would i have bolt failure on a greddy turbo kit running stock 5 psi.
09-06-2005, 09:39 PM
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Wouldnt a very incorrect timing put alot of stress on the motor as well? Say your igniting way to late or way to early?
What rpm did the rod let go on your motor? Under boost?
What rpm did the rod let go on your motor? Under boost?
09-06-2005, 10:01 PM
#7
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Re: (Civicman86)
Realistically what happens is the big end of the rod gets so hot that it welds itself to the crank. When that happens, the rod swings around until it hits something hard and then snaps. This can be done at low rpms with no oil available from the oil pump.
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09-06-2005, 10:14 PM
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Re: (earl)
<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by mike93eh »</TD></TR><TR><TD CLASS="quote">
Uberdata/Crome/TurboEdit Tuner and ECU chipping - Chicagoland and Central Missouri areas
central missouri?? thats where i am. anymore info?</TD></TR></TABLE>
Rolla, MO is where I go to school
and now that I read that it broke at low RPM I would say it was oil starvation and earl pretty much said it from there. The incorrect timing statment shouldn't happen because the piston "should" let go way before the rod does if it was heat.....this has happened before on built motors too
Uberdata/Crome/TurboEdit Tuner and ECU chipping - Chicagoland and Central Missouri areas
central missouri?? thats where i am. anymore info?</TD></TR></TABLE>
Rolla, MO is where I go to school
and now that I read that it broke at low RPM I would say it was oil starvation and earl pretty much said it from there. The incorrect timing statment shouldn't happen because the piston "should" let go way before the rod does if it was heat.....this has happened before on built motors too
09-07-2005, 09:18 AM
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Re: (adseguy)
<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by adseguy »</TD></TR><TR><TD CLASS="quote">Rolla, MO is where I go to school
and now that I read that it broke at low RPM I would say it was oil starvation and earl pretty much said it from there. The incorrect timing statment shouldn't happen because the piston "should" let go way before the rod does if it was heat.....this has happened before on built motors too</TD></TR></TABLE>
it happened while i was just cruising along at about 3200 rpms.. what caused the oil starvation?
pm'd you..
and now that I read that it broke at low RPM I would say it was oil starvation and earl pretty much said it from there. The incorrect timing statment shouldn't happen because the piston "should" let go way before the rod does if it was heat.....this has happened before on built motors too</TD></TR></TABLE>
it happened while i was just cruising along at about 3200 rpms.. what caused the oil starvation?
pm'd you..
09-07-2005, 11:06 AM
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Re: (adseguy)
<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by adseguy »</TD></TR><TR><TD CLASS="quote">
Rolla, MO is where I go to school
and now that I read that it broke at low RPM I would say it was oil starvation and earl pretty much said it from there. The incorrect timing statment shouldn't happen because the piston "should" let go way before the rod does if it was heat.....this has happened before on built motors too</TD></TR></TABLE>
So its more likily for the piston to go from incorrect timing than a rod to go? But in a rare case it could?
Rolla, MO is where I go to school
and now that I read that it broke at low RPM I would say it was oil starvation and earl pretty much said it from there. The incorrect timing statment shouldn't happen because the piston "should" let go way before the rod does if it was heat.....this has happened before on built motors too</TD></TR></TABLE>
So its more likily for the piston to go from incorrect timing than a rod to go? But in a rare case it could?
09-07-2005, 02:16 PM
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Re: (Flr Power)
<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by Flr Power »</TD></TR><TR><TD CLASS="quote">Also if the piston to wall clearance is too tight and the engine overheat, the piston will try to weld itself to the cylinder and then the rod breaks.</TD></TR></TABLE>
that didnt happen in my case.
that didnt happen in my case.
09-07-2005, 04:08 PM
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Re: (Muckman)
<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by Muckman »</TD></TR><TR><TD CLASS="quote">How do the bearings look on the rod?</TD></TR></TABLE>
they looked fine to me. but i dont know what bad ones would look like either.
they looked fine to me. but i dont know what bad ones would look like either.
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