Engine autopsy
- Thread starter TrentNell
- Start date
Well put! So matt didn't even touch his pistons and just put rods in it? That's a pretty neat idea it'll be nice to see how it does.
Yes Ed. My forged made about 8 total passes(6 on spray) before melting a quarter sized hole down the outer wall of one. What bothered me the most was the way all 7 others were deteriorating rapidly(spray pattern).
They are 80,??? mi stockers. Out and right back in with rods. I will keep you guys updated. So far they have 10 passes. Half were 1/8 mi(6.50s to 6.70s)
Dustin he asked what temp does the PISTON ITSELF SEE. The piston is not getting to 2000*, Ill tell you that right now. Come on, its aluminum, it would have melted way before then...
The piston is exposed to temps that exceed 3000 degrees. Thankfully, the piston itself does not get that hot.
ok if ALL cracking failures are parallel to the wrist pin then what is the wrist pin diameter in relation to the wrist pin bore on the piston.
the lbzs all have brass bushings that may be the cause. i'm just throwing ideas out that may help us narrow down the culprit and work our way on to the next weakest link (hopefully a more easily serviceable one for when we break them hahaha)
the lbzs all have brass bushings that may be the cause. i'm just throwing ideas out that may help us narrow down the culprit and work our way on to the next weakest link (hopefully a more easily serviceable one for when we break them hahaha)
No worries
Tuning was the least of my issues last year.
The biggest mistake i made was using procomp jounce bumpers off a lifted truck on the rear, We thought it would push down the axle
Instead it would bounce on shifts! Sooo the harder the launch the slower i would go Hence the poor 60s all year on low ET passes. The first 10 second pass of the season was actually with a 2.1 second 60'
I also think that was the reason for taking out the trans from it bouncing into second gear.You could not see it in any vids that we got but alot of people in the crowd said it litterly jumped on the shift and then bang snap carnage.
When we got to the end of the season we put Rancho 9000 and removed the jounce bumpers and the truck really came alive for the first time of the season but i was so scared to launch hard and break something from all the carnage all season that i litterly walked the 60s up by 3 psi boost increments. Like I said the 1st 10 sec pass was 10.8 at 140mph with a 2.1 60
I took out 2 intercoolers,2 brand new turbos 1 flexplate, 2 converters 1 c2 hub and blew out a slick on the front going well over 130mph and be darned if i could keep a intercooler boot from blowing!!!!!! The DPR oil pump that i have has cost me thousands of dollars
I actually have a true 1" drain off my PBK turbo now and this is the exact same setup that trent ran with the normal 1/2" but beecause of the high volume pump it destroyed the brand new turbos SOOOO NOOO i dont worry about what you say I do however not worry at the end of the day what my pistons are doing and if im being um whats the word? "unessicarly rough" Im not bitching cause honestly a lot of fellow members have had worse luck, but it does start to frustrate a person when ya work so hard and it just doesnt work!
Juddski you are however right to follow people on this forum....i gained a ton of knowlege and if you can even learn a lil bit from me then good on ya
Dustin he asked what temp does the PISTON ITSELF SEE. The piston is not getting to 2000*, Ill tell you that right now. Come on, its aluminum, it would have melted way before then...
Ben, you know if you just answered the question instead of coming off with attitude......More people might respect you.
JUST SAYIN
Agreed, and the guy asked what a piston sees, not what the temperature of the metal is.
Exactly what I was explaining - I've been in and seen 120* temperatures, doesn't mean that my core temperature got that high.
The famous kid's experiment. Take a blow torch to a paper cup full of water. The paper does not burn below the water line.
Playing with FEA
Ive been fine tuning a bowl design that I hope to cut into the top of some pistons. In the process, I ran it's model and the model for the Stock LLY and delipped LLY pistons through a Finite Element Analysis program. All three were run with the same anticipated load on the piston face. Only the chamber designs differ.
Stock LLY:
This first image highlights where the stress in the piston exceeds the strength of the material. No surprise there.
This colorful bugger is the stress distribution.
Delipped LLY:
This is from a model of a typical delipped LLY piston. Same as before. The Chamber is slightly larger than the stock, so compression and ultimately, the pressure on the piston would be less, but this analysis used the same load.
Oval Chamber:
Here is a design I have been working through. The chamber is the same volume as the stock LLY. The load is the same as the previous two models.
Ive been fine tuning a bowl design that I hope to cut into the top of some pistons. In the process, I ran it's model and the model for the Stock LLY and delipped LLY pistons through a Finite Element Analysis program. All three were run with the same anticipated load on the piston face. Only the chamber designs differ.
Stock LLY:
This first image highlights where the stress in the piston exceeds the strength of the material. No surprise there.
This colorful bugger is the stress distribution.
Delipped LLY:
This is from a model of a typical delipped LLY piston. Same as before. The Chamber is slightly larger than the stock, so compression and ultimately, the pressure on the piston would be less, but this analysis used the same load.
Oval Chamber:
Here is a design I have been working through. The chamber is the same volume as the stock LLY. The load is the same as the previous two models.
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John, are you going to get some blanks somewhere to machine? I guess there is no room left in a stocker if the chamber volume is going to be kept the same. This is pretty neat I would like to see some results.