this is why MY crankcase was pressurized
07-10-2007, 04:38 PM
#1
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this is why MY crankcase was pressurized
#4 Piston
It's kinda supposed to look like this if you don't know:gay:
anyways...still in the process of being fixed. Some of my valves were hella sharp and worn.
This piston failure is probably a mixture of to little fuel and too much boost.
the question is...should I go beefier rods as well as pistons?
It's kinda supposed to look like this if you don't know:gay:
anyways...still in the process of being fixed. Some of my valves were hella sharp and worn.
This piston failure is probably a mixture of to little fuel and too much boost.
the question is...should I go beefier rods as well as pistons?
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Ouch, yup that will do that. GL
07-11-2007, 09:29 AM
#12
If you have the bottom end apart, replace the rods. They are the weakest link after all.
EDIT: Actually I came back after rethinking this. Previously everyone would harp on how the rods were the failing point of our stout motors, however out of all the blown motors (lots lately) I haven't seen rods break. It would seem an abnormal amount of people on this board lately are running 10-12+ PSI and the failing point is quickly becoming the rings/pistons. Namely the rings though.
EDIT: Actually I came back after rethinking this. Previously everyone would harp on how the rods were the failing point of our stout motors, however out of all the blown motors (lots lately) I haven't seen rods break. It would seem an abnormal amount of people on this board lately are running 10-12+ PSI and the failing point is quickly becoming the rings/pistons. Namely the rings though.
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07-11-2007, 11:16 AM
#13
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^ that is what I was thinking. The stock rods are actually surprisingly beefy and a really good design.
I'd like to know who has had rod failures and if so, at what point. What psi, what engine mangement( if any)
Honestly for what I'm looking to run after I get it fixed, I think some forged pistons would do me fine. But then I think to myself. since it's already apart I minis well replace it with something better just in case I will feel the need to go more( rods, pistons) That would def give me a super strong bottom end.
Still contemplating what to do. all I know is that I want to have it running 200rwhp before I ever get rid of it.
Still searching for emanage blue possibly with autotune and p&p boomslang(for a 90-93). So serioulsy if anyone is getting rid of theirs and upgrading to MS. Send me a PM.
I'd like to know who has had rod failures and if so, at what point. What psi, what engine mangement( if any)
Honestly for what I'm looking to run after I get it fixed, I think some forged pistons would do me fine. But then I think to myself. since it's already apart I minis well replace it with something better just in case I will feel the need to go more( rods, pistons) That would def give me a super strong bottom end.
Still contemplating what to do. all I know is that I want to have it running 200rwhp before I ever get rid of it.
Still searching for emanage blue possibly with autotune and p&p boomslang(for a 90-93). So serioulsy if anyone is getting rid of theirs and upgrading to MS. Send me a PM.
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07-11-2007, 11:21 AM
#14
Most of the rod failures i have seen are from nitrous cars and cars running more hp than we do. stock motor should hold 300whp for about 15K miles if the tune is just rightseveral have done it. Alot of our failures are just from being to greedy and not lifting or just pleain tired motors of 100K+ miles failing at more than twice there intended hp level. So get a cheap stock kit if 200whp is all you want need etc. But if you want tranny breacking wheel standing power then get some rods and pistons. So long as you dont over rev the motor or shock laod it like with Nos you should live a happy and powerfull life. As bryan downs once said to me broken pistons is detonation= bad times.
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07-11-2007, 11:59 AM
#16
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I by no means needed the rods, pistons, and valvetrain parts. However, I wanted to build this motor one time, and be confident that with a conservative tune at 250whp, I'll be able to get it home from the race track.
Unfortunately belfab only offers an 8.6:1 pistons...but I guess I'll have to suffer with the off boost slowness on my 99 motor. I don't know how aggressive I can get off boost <100kpa, but hopefully I can tune out the drawbacks from lower compression.
Unfortunately belfab only offers an 8.6:1 pistons...but I guess I'll have to suffer with the off boost slowness on my 99 motor. I don't know how aggressive I can get off boost <100kpa, but hopefully I can tune out the drawbacks from lower compression.
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07-11-2007, 12:11 PM
#19
true try the standard equations first measure what you have in cc's for the combustion chamber then measure the swept volume. assume the piston to be maybe 20cc or so then work from there. the change in the swept volume is small the most increase comes from the smaller combustion chamber but be carefull we dont want to make an interference engine out of your track maven.
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07-11-2007, 12:33 PM
#20
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true try the standard equations first measure what you have in cc's for the combustion chamber then measure the swept volume. assume the piston to be maybe 20cc or so then work from there. the change in the swept volume is small the most increase comes from the smaller combustion chamber but be carefull we dont want to make an interference engine out of your track maven.
However that means many more track days at one of the best technical road courses in the nation...and only $95 for 5 sessions.
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