I got out of mine within a half second. thought i melted it but was glad to see i didnt when i tore it down.
Cracked piston on high mileage stock bottom end
- Thread starter bison
- Start date
I got out of mine within a half second. thought i melted it but was glad to see i didnt when i tore it down.
Turbo1dr
9 Sec Wanna-Be
- Joined
- May 25, 2001
That is some awesome carnage guys, good work!
When the rod let go the part that was still attached to the crank came around and windowed the block on both sides AND bent the girdle down...but the crank never budged! It was a .020 .020 crank!
QuickWrench
Don't Read This
- Joined
- Jan 28, 2002
bison said:
x2.
Have you measured the pin and bore diameters on the failed slug? My guess is that the failure originated in that area from the clearance opening up.
The stock pin oiling seems work if the clearance is spot on and the pin bore is not ovalled, but if it gets develops an extra .0005-.0008, the cast part of the stockers crack near the top of the pin when it gets pounded just after TDC on the power stroke.
You're making SERIOUS cylinder pressure on that thing ATDC, I'd say it gave good service.
QuickWrench
Don't Read This
- Joined
- Jan 28, 2002
That is a real testament to the girdle...kind of like the SBF guys. It may not save the parts, but it does a nice job of keeping the broken sh!t all together.
x2.
Have you measured the pin and bore diameters on the failed slug? My guess is that the failure originated in that area from the clearance opening up.
The stock pin oiling seems work if the clearance is spot on and the pin bore is not ovalled, but if it gets develops an extra .0005-.0008, the cast part of the stockers crack near the top of the pin when it gets pounded just after TDC on the power stroke.
You're making SERIOUS cylinder pressure on that thing ATDC, I'd say it gave good service.
Ill try to get measurements some day. I doubt the accuracy after pressing them apart. Your theory makes sense though. .0005-.0008 would be a bitch to measure even with the parts brand new unless you had a very good calibrated bore gauge. I have access to one so ill try it when i get it apart. It gave excellent service. Im not complaining. I though the caps or webbing would fail. Some day ill take a low mile shortblock and throw the 33psi tune at it with some timing and go for the undisputed stock bottom end record. Should go in the 9.6-9.7 range @about 140mph if it stays together. hat engine originally went from a high mile stocker to a 10 sec engine in about 2-3days. Got booted after the first pass which was a 10.88@126mph 2 years ago. All stuff i had laying around and none if it was new except the gaskets and seals.
Bison,my car is a fairly low mileage car 62k easy miles and 10k hard miles. i am turning mine up in Reynolds to 30 plus i have been to 30 with 93 pump and alcohol with no knock. i plan on making a few 9 sec passes in Reynolds in the TAI class...i know it feels good on 30
i hope it holds together...BobBison,my car is a fairly low mileage car 62k easy miles and 10k hard miles. i am turning mine up in Reynolds to 30 plus i have been to 30 with 93 pump and alcohol with no knock. i plan on making a few 9 sec passes in Reynolds in the TAI class...i know it feels good on 30
You should be well into the 9's. I went 10.29 and about 5 mph faster on a 1.59 60'. Id get the tune nailed down and go balls out on a couple passes.
Dr.drivability
9 second wannabee
- Joined
- Oct 1, 2005
I cracked 1 & 6 using a plate and alky. Never registered knock on fast log!!! Was told to ditch the plate by a VERY reliable source.
bison,nice piston i have 2 that look exactly like that with no detonation recorded egts never went over 1400 degrees and an afr at 10.2 on 93 and alky and nitrous,i also run the plate with rjc gaskets.i agree that the pistons become the the weak link as long is there is no detonation.just curious what kind of pluds were you running and more importantly what gap?
i have 2 that look exactly like that with no detonation recorded egts never went over 1400 degrees and an afr at 10.2 on 93 and alky and nitrous,i also run the plate with rjc gaskets.i agree that the pistons become the the weak link as long is there is no detonation.just curious what kind of pluds were you running and more importantly what gap?bison,nice piston
CR42TS .028-.030
What hp were you at? Over 650hp?
jasjamz
THS Racer
- Joined
- Sep 30, 2004
Why would the PP and alky cause a problem? What does the 650hp mark change when using them?
1&6 Crack
Just wondering are you saying, your reliable source said the Plate cause 1&6 to crack. If you can let us know why he thinks that. All info helps here. Thansk.
Just wondering are you saying, your reliable source said the Plate cause 1&6 to crack. If you can let us know why he thinks that. All info helps here. Thansk.
I never said it caused any problem and my engine did not experience detonation or a lean out. The 650hp mark is wear another member saw piston failure exactly like mine. Thats why i mentioned it. No one has ever posted any accurate info on whether the plate works or not. EGT probes before and after installation are the only thing i would believe. Increasing plenum volume has shown to be effective in cyl to cyl EGT control in other types of engines so i wouldnt doubt it works on our 6 cylinder too.
I think he meant he was running a plate when he cracked 1&6 but had no proof of it causing the failure so he remove it and has not had the problem since
Yeah its kinda like saying I was wearing a red shirt the last time I got in a car crash...so I now I don't wear red shirts and I haven't been in a crash since...
Plenum spacers are the cheapest easiest way. Aftermarket intakes with more area will become a lot more popular in the next couple years. Just about every TSM car i saw ran a thick spacer and they are going way faster than almost any one here with the stock intake (unless they changed it in the last year) and dont seem to have problems with lean cylinders.
