Cracked piston on high mileage stock bottom end

[jasjamz]

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.

Did you see them using the PP? If you were to add a 1/2-1" spacer, would you still use the PP? I assume if you did it would be under the spacer right?
Oh, and thanks for letting us pick your brain!

 

[bison]

Did you see them using the PP? If you were to add a 1/2-1" spacer, would you still use the PP? I assume if you did it would be under the spacer right?
Oh, and thanks for letting us pick your brain!

Only Jason Cramer had the plate on his TSM car that i saw. Yes, i had the 1" with the plate over it on mine. CAr made a lot of power and i did not see it as a problem. Its only here say at this point.

 

[Turbo6Smackdown]

Ok then, to try and get a little more understanding of this subject, since I will be in your guys' boat next summer. How about a stock plenum with alky and no plate. Does that help anything out, in terms of even/uneven cylinder breathing or leaning?

 

[bison]

Ok then, to try and get a little more understanding of this subject, since I will be in your guys' boat next summer. How about a stock plenum with alky and no plate. Does that help anything out, in terms of even/uneven cylinder breathing or leaning?

Only data logged egt #'s on every cylinder would tell. No one has posted them anywhere on here yet. Everything else is just a bunch of BS hearsay.

 

[Turbo1dr]

Only data logged egt #'s on every cylinder would tell. No one has posted them anywhere on here yet. Everything else is just a bunch of BS hearsay.

Ain't that the truth!

 

[BUFORD93]

What type of fuel pump and lines did you have on the car when the piston let go?

 

[bison]

What type of fuel pump and lines did you have on the car when the piston let go?

Stock lines drilled out at the restrictive areas. DC was in the mid 60's to as high as 73% (q16) with six 83lb/injectors. Dual nozzle alky cranked all the way up but with 3.5 bar MAP sensor so it never got to more than about 90% flow on the alky at 33psi. No evidence of lean out whatsoever. Ill do this again on a fresher stock engine sometime and shoot for 9.70's @140+. It will take it for a while if its not detonating and you are lucky.

 

[BUFORD93]

Thanks.. What type of fuel pump?

 

[bison]

Thanks.. What type of fuel pump?

XP or 340 doubles at 14v. Not sure which of my cars has the xp's and which has the 340's.

 

[pacecarta]

well add me to the list

thought it had blown a gasket , just tore it down and found this , but they were cometic 060s and they were fine

motor had around 600 mid 10 passes and was now running on fast and turning just about 6k trough the lights and shifting at or just over 6k a few times since going to a th400trans
and on the last pass it made before getting towed home all seemed ok till the 1/8th ...yeah there was a lot of smoke behind me when i finally looked :redface:
1.480
4.28
6.67@102.4
8.76
10.56@124

 

[Dr.drivability]

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.

was tod it puddles the alky. Bison, you prolly have a better idea on hp than me, never dynoed. Told it should be 800+? Never went to the track this year either. BTW motor came apart now cracked cylinder walls 2&4. New 109 together waiting to go back in!

 

[yullose]

I'd say you guys have found (and exceeded) the limitations of a stock shortblock.

Paul... how much boost were you putting to it ?

 

[pacecarta]

launching 12psi , 25 out of the hole ,running 24 and less in third , boost slowly fluctuates down and back up about 1.5psi over 1 sec but never exceeds program which was 24

bob wren was still going wth stock block and had enough in it for 9s

oh and i wasnt running a powerplate ... mease sheetmetal intake without his distribution plate, no spacer and stock unported lower manifold,

not much to blame for it excepthad a lot of runs and it was stressed , egts were always monitored and every pass to date was logged and aside from a couple broken rockershafts and a recent crank sensor failure ( im sure it didnt help) the motor never had a hiccup and piston was #3 so lean rich it doesnt fall into the problem areas of #1 beleived to be caused by alky use and the rocker shaft ends that broke were on passenger side #2 and #6, and its been on wideband error correcting since 2006 running 11.0-11.2 or richer

 

[yullose]

its been on wideband error correcting since 2006 running 11.0-11.2 or richer

What WB setup are you using ? Same as what I have here on Jim's old car ? Innov LM1 ?

 

[pacecarta]

up until march of this year i was on the tt6.0WB beta chip using the lm1 that was designed before PL so it worked without needing powerlogger , tracking was very accurate and i never had any time that a/f was off more than 0.1 - 0.2 , running an xd16 gauge so i can see the AF at all times and i do run a caspers led knock and an egt (was consistent 1570s).
took that off to try classic fast
still have the lm1/xd16 and egt.. now with fast i can log a/f and inlet temps at plenum with sensor mounted near #1 so i know its getting effect of alky as inlets at full boost were never over 80degrees and were constant through run, in summer when track surface was over 110 ,typically temps ran 40* cooler than inlet temps with no boost
that pass inlet temps were 66 degrees , timing since going with fast was set at 22* (checked and adjusted for bhj balancer) and 10.9 af above 20psi and 5500

 

[bison]

was tod it puddles the alky. Bison, you prolly have a better idea on hp than me, never dynoed. Told it should be 800+? Never went to the track this year either. BTW motor came apart now cracked cylinder walls 2&4. New 109 together waiting to go back in!

IMO the plate was doing nothing in my situation. It wasnt hurting anything or helping in any way. The pistons fail because the wrist pin bore clearance opens up too much and the piston is getting hammered into it with extreme cylinder pressure. If you have 800hp at the flywheel your car will be trapping 142mph @3600 lbs roughly. Too my knowledge their is less than 5 who have ever done this with a stock block outside of TSM and had cars that were actually capable of being driven thousands of miles without maintenance.

 

[bison]

I'd say you guys have found (and exceeded) the limitations of a stock shortblock.

Paul... how much boost were you putting to it ?

The limitation is time under power. Its not a actual hp number as pacecarta's engine has shown. 600 passes on a stock engine. No fault of any tuning on his part. Parts just wear out and you get the same failure. So thats 3 in the same thread with the same type failure without detonation

 

[Otto J]

was tod it puddles the alky. Bison, you prolly have a better idea on hp than me, never dynoed. Told it should be 800+? Never went to the track this year either. BTW motor came apart now cracked cylinder walls 2&4. New 109 together waiting to go back in!

Who told you that? when the alky under pressure leaving the nozzle and hits the heat it turns from a liquid into a gas.

 

[Super6]

Paul

sorry to hear you broke a piston..we are learning something though. i plan on pushing mine to the limit in Reynolds. i want to make only 9sec passes on 93, on drag radials..alot to ask but i think i can do it..i am sitting on 30lbs with 93 octane with no signs of knock. i am spraying plenty of alcohol and the 72's are about 70% duty cycle. i removed my power plate after i installed the cometic head gaskets but i agree with Bison..i don't think it was hurting me or helping me. i think my car has some 140mph traps in it but the question is will it hold together to get them..we will soon find out....get that thing back together......Bob

 

[jasjamz]

sorry to hear you broke a piston..we are learning something though. i plan on pushing mine to the limit in Reynolds. i want to make only 9sec passes on 93, on drag radials..alot to ask but i think i can do it..i am sitting on 30lbs with 93 octane with no signs of knock. i am spraying plenty of alcohol and the 72's are about 70% duty cycle. i removed my power plate after i installed the cometic head gaskets but i agree with Bison..i don't think it was hurting me or helping me. i think my car has some 140mph traps in it but the question is will it hold together to get them..we will soon find out....get that thing back together......Bob

I am curious to know have you noticed any differences in the data you get since removing the powerplate? You say you dont think it wasn't hurting or helping. Are you using a stock doghouse? Are you using a stock shortblock besides the cam? I don't have any intention in removing my PP, just wanted to see what made you want to try it? Good luck on the 9sec pass!