Who can name the weakest part??
12-09-2008, 09:08 PM
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Who can name the weakest part?? Looking for a list in order of the weakest-to-strongest part in the stock LT1 rotating assembly. With mileage being no concern (figure only 15k on the completely original and stock motor if you want), what will be the first thing to go out on our motors? Including everything from the piston skirts to the rings, wrist pins to the bearings. What gives out in the high rpms, and what gives out due to large amounts of spray?
From what I've read, the crank can handle gobs of power, rods are the strongest of the gm motors for its time, and the bearings seem to be able to handle hundreds of thousands of miles. But when someone decides to take that extra step and push a 200 shot through her, or spin her upwards of 6800 what lets go??
Now i understand that most of our motors are high mileage so the bearings tend to be a common issue, but is this due to weakness or just simply due to wear and tear.
From what I've read, the crank can handle gobs of power, rods are the strongest of the gm motors for its time, and the bearings seem to be able to handle hundreds of thousands of miles. But when someone decides to take that extra step and push a 200 shot through her, or spin her upwards of 6800 what lets go??
Now i understand that most of our motors are high mileage so the bearings tend to be a common issue, but is this due to weakness or just simply due to wear and tear.
12-09-2008, 09:23 PM
#2
right now i have a stockbottom end in my car with a 150 shot and i spin it to 7500 i have about 60 passes on it this past season and have not had 1 problem i dont expexct it to make it long next year when i up the spray
12-09-2008, 09:32 PM
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I think he's talking about an LT1 bro....
you can't spin a stock LT1 to 7500 #1 but i'm assuming from your SN that you own a SOHC mustang...
LT1 will most likely spit the piston first.... you'll bust a ringland or just straight up shatter the piston...
HyperuCRAPtic pistons..... rods and crank will handle a bunch. But detonation will kill the rod and the piston most likely together....
you can't spin a stock LT1 to 7500 #1 but i'm assuming from your SN that you own a SOHC mustang...
LT1 will most likely spit the piston first.... you'll bust a ringland or just straight up shatter the piston...
HyperuCRAPtic pistons..... rods and crank will handle a bunch. But detonation will kill the rod and the piston most likely together....
12-09-2008, 09:41 PM
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I know that detonation can wreak havoc on even the strongest pistons. But assuming your tuning is within reason, there should be no reason for detonation to be a problem. Even with a 300 shot, if your fuel requirements and timing are where they should be, combustion should be fine. Next you are merely looking at component strength. Is the Lt1 piston actually the weak point of the motor?
12-09-2008, 10:02 PM
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I don't care what tune you have in the car.... hyperutectic pistons are brittle and a 300 shot even with a perfect AF ratio will buckle every piston in the car under the extremely high cylinder pressure....
I won't even get started with the fact that a stock rotating assy LT1 with your average ignition system (read opti) could barely generate a strong enough spark to ignite a fuel/air/nitrous mixture on the level of a 300 shot.....
I run as a minimum an HVC II Coil (thanks tony), a digital 7 programmable ignition, a crank trigger and a true rear mount dist.....
but if you did somehow ignite it it would shatter that piston in a heartbeat..... there is a reason why forged pistons setup for large amounts of spray have thick ringlands. Mine have a 300 top ringland.... using a 6" rod in a 383....
I won't even get started with the fact that a stock rotating assy LT1 with your average ignition system (read opti) could barely generate a strong enough spark to ignite a fuel/air/nitrous mixture on the level of a 300 shot.....
I run as a minimum an HVC II Coil (thanks tony), a digital 7 programmable ignition, a crank trigger and a true rear mount dist.....
but if you did somehow ignite it it would shatter that piston in a heartbeat..... there is a reason why forged pistons setup for large amounts of spray have thick ringlands. Mine have a 300 top ringland.... using a 6" rod in a 383....
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12-09-2008, 10:08 PM
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im talking about my lt1 i have spun it to 7500 since day one trying to break it it has yet to come apart believe me or not i know its true
the "BS" Flag has just been raised in my castle....
12-09-2008, 11:06 PM
#16
I know this is off the topic, but I have a question about the rpm limit of the stock pcm. The main fuel table on my 93 goes to 7000 using Tunerpro RT, but the PE vs. RPM table goes to 7500. Does the pcm shut down at 7200? I don't plan on spinning my motor that high, I just always wondered about this.
12-10-2008, 06:36 AM
#20
I don't care what tune you have in the car.... hyperutectic pistons are brittle and a 300 shot even with a perfect AF ratio will buckle every piston in the car under the extremely high cylinder pressure....
I won't even get started with the fact that a stock rotating assy LT1 with your average ignition system (read opti) could barely generate a strong enough spark to ignite a fuel/air/nitrous mixture on the level of a 300 shot.....
I run as a minimum an HVC II Coil (thanks tony), a digital 7 programmable ignition, a crank trigger and a true rear mount dist.....
but if you did somehow ignite it it would shatter that piston in a heartbeat..... there is a reason why forged pistons setup for large amounts of spray have thick ringlands. Mine have a 300 top ringland.... using a 6" rod in a 383....
I won't even get started with the fact that a stock rotating assy LT1 with your average ignition system (read opti) could barely generate a strong enough spark to ignite a fuel/air/nitrous mixture on the level of a 300 shot.....
I run as a minimum an HVC II Coil (thanks tony), a digital 7 programmable ignition, a crank trigger and a true rear mount dist.....
but if you did somehow ignite it it would shatter that piston in a heartbeat..... there is a reason why forged pistons setup for large amounts of spray have thick ringlands. Mine have a 300 top ringland.... using a 6" rod in a 383....