LBZ: LBZ pistons I'm scared

[Big Block 88]

Okay so I will be comein home on leave here in about 2 months, soooo I will be beating the hell out of the LBZ.

My question is how terrified should I be that I will crak a piston? I run some fairly big tunes at or above the 500 RWHP mark, Am I just bein a little :baby: or should I buy a set of back up piston LB7/LLY and get them De-lipped at my machine shop, just to be ready for the inevitable? If a piston does crack then I will have an excuse to do my planned build up, but I would prefer to invest money else where right now.

Thanks, Jordan Blake

 

[Pondsy]

That really your choice IMO. Some make it and others don't. Personally, I've decided to hold off on big tunes until I purchase a replacement motor. That way I don't have much down time if I blow up the stock motor.

I'll build the spare while I play with the stock motor, but at least I'll have a replacement that can drop right in or be used for parts if need be.

Be safe!

 

[Bako_Dmax]

It seems to be hit or miss. Ive ran my truck hard, not just on the street but in the sand, mud, and snow.

 

[McRat]

Casper ran LBZ pistons and they didn't crack, as have many others. Wendy hasn't cracked pistons either, and both run quite a bit of timing. Casper ran 754rwhp worth of fuel, then a .070" jet on top for special occassions, and the pistons eroded, but never cracked.

 

[duratothemax]

its a million dollar question.

will yours crack running the truck the way you run yours? Dunno...only one way to find out.

 

[LBZrcks]

Okay so I will be comein home on leave here in about 2 months, soooo I will be beating the hell out of the LBZ.

My question is how terrified should I be that I will crak a piston? I run some fairly big tunes at or above the 500 RWHP mark, Am I just bein a little :baby: or should I buy a set of back up piston LB7/LLY and get them De-lipped at my machine shop, just to be ready for the inevitable? If a piston does crack then I will have an excuse to do my planned build up, but I would prefer to invest money else where right now.

Thanks, Jordan Blake

I would either build a motor before or keep the $ aside. Unless you buy some 40 or 60 over pistons to be safe. You never know how bad if any the cylinder(s) walls can get after cracking or blowing a hole in a piston.

 

[LBZ]

I would either build a motor before or keep the $ aside. Unless you buy some 40 or 60 over pistons to be safe. You never know how bad if any the cylinder(s) walls can get after cracking or blowing a hole in a piston.

X2.
I am in need of starting this project. 40 000miles of beating on my truck and it's still holding but who knows for how long. It really is hit or miss.

 

[draftee]

IMHO keep an eye on your EGTs .... Don't let them get to high.

 

[Big Block 88]

i have seen 2100 degrees on the pyro a couple times while pullin a big load, but that is not an everyday thing. The truck is cruisin the streets back hom right now with dad and she is sittin on stock minus the EGR crap. An engine build will happen I know the truck gets run hard and worked even harder with me drivein. So I guess I will start shoppin around for a set of .40 overs, just to be safe. I guess we will see if I am one of the lucky ones.

I never knew casper ran a set of LBZ's that makes me fel alot better, Wendy was the only truck I have heard of that is havein luck with the LBZ's. Hope I didn't just jinx you Pat:rofl:

 

[slowlmm]

Casper ran LBZ pistons and they didn't crack, as have many others. Wendy hasn't cracked pistons either, and both run quite a bit of timing. Casper ran 754rwhp worth of fuel, then a .070" jet on top for special occassions, and the pistons eroded, but never cracked.

How many passes did you have on those lbz pistons ?

 

[BLACKLBZ]

I'm running what I have in my sig with Robs Hotstreet tune bumped up a little and so far so good. I do keep a close eye on the ol' pyro though.

 

[McRat]

How many passes did you have on those lbz pistons ?

I'd have to do a search to figure that out. My guess is 40? Dunno. Nitrous erosion killed them at the closing day of LACR dragstrip. It still drove, but there wasn't much piston crown left on any of the pistons. With half the crown material missing, and 750hp+nitrous, with EGT's so high they melted the riser pipes and turbine, you'd think they would crack, but didn't.

Only one of the LLY Bonneville pistons had a very small crack starting, but that piston was also very much destroyed.

My best guess is a poor quality control at the casting stage is the culprit at this point.

 

[Big Block 88]

I know there was a point when people where only putting LBZ pistons in there built motors, and now all I seem to read is that the big power is crackin them. I assumed it was from the sled pullers who get the EGT jacked way up there, and then the motor cools rapidly after the pull, thus causing a crack.

 

[JoshH]

Most of the LBZ piston failures I've seen aren't cracked but rather have a hole melted in the bowl, through the oil cooling gallery, and out through the oil control ring. Personally, I think it's a piston cooling problem, not EGTs or timing.

 

[duratothemax]

Most of the LBZ piston failures I've seen aren't cracked but rather have a hole melted in the bowl, through the oil cooling gallery, and out through the oil control ring. Personally, I think it's a piston cooling problem, not EGTs or timing.

I agree

 

[Drholliday]

I've been having good luck with mine too, I don't know how many passes I have down the strip, but its getting up there, I hit 1850-1900 on the pryo each pass. I'm just waiting for the run that kills it. I've been reading the theories on the pistons cooling too fast, so when I'm at the strip my truck doesn't get shut off between runs and I let it idle for 15 minutes or more before I shut it down after the last run, might be over kill.

 

[SIKDMAX]

Most of the LBZ piston failures I've seen aren't cracked but rather have a hole melted in the bowl, through the oil cooling gallery, and out through the oil control ring. Personally, I think it's a piston cooling problem, not EGTs or timing.

Whaddya know, sounds familiar!

Whats interesting is that once my dad found out, he started writing all kinds of letters to GM etc and has written word from them that they would replace my motor and do all the labor to install it back, even with the CVN being wrong and them being told it had a 500hp tune in it.

Wont happen though, as I dont want another POS stock motor in there. I dunno how he pulls off some of the stuff he does :rofl:

 

[duratothemax]

so when I'm at the strip my truck doesn't get shut off between runs and I let it idle for 15 minutes or more before I shut it down after the last run, might be over kill.

yeah I did that too and I still cracked 5 pistons on my LLY.


guys if you dont want your shit blowing up, run a stock tune and drive it like GM intended you to. End of story.

ben

 

[SteveFord]

yeah I did that too and I still cracked 5 pistons on my LLY.


guys if you dont want your shit blowing up, run a stock tune and drive it like GM intended you to. End of story.

ben

That wouldn't be any fun!

 

[McRat]

It's the nature of hot-rodding. It's certainly a risky proposition no matter what.