cracked pistons!!!!

[copteaser]

Hey guys long story made short. I lost compression on my #1 piston, I tore the engine apart and found that the "Nos" had burned a hole on the side piston. As I inspected the remaining 5 pistons I discovered that 4 had a crack on the bottom of the piston. Almost in the exact place! The pistons are "theurapautics"from Poston(I know I misspelled it) and they are about 6 months old and approx 7k on them.

My question is was "Nos" the culprit of the crack or could it be that the pistons were defective...Any suggestions for the above reason.

 

[Nick Micale]

I do not believe a hole burned in a turboed, sprayed piston could be considered a manufactures defect!

 

[Joe 1320]

Whether NOS or turbo or supercharger, melting metal means too lean. If it was broken, that's a different matter....

 

[REDS HOT AIR]

cracks sound like the piston to wall clearence was too loose hypo's are desighned to be set up tight if they are set to forged cleances they can crack skirts.

dont matter what they are made of with boost and gas if you lean out it will burn.

 

[Chuck Leeper]

SMokin a Crack!!

Teaser, SHAME ON YOU!!!
The pistons that cracked were the "lucky ones"! They held off melting long enough to crack.

Forged pistons are HIGHLY recommended, as in ABSOLUTELY required, for your application.
Hope it didn't get the crank or rods.
W/ that much cylinder PSI, I'd have EVERYTHING magged B4 re-using any of it, including the heads...

Good luck w/ the rebuild....

 

[OneQuikSix]

Hyperucraptic pistons

Guys,

About three years ago I went through a rebuild. At the time, my machinist told me that cast pistons were difficult to find. He said that he found some "better custom pistons for me." They were very lightweight and would probably make the rpm's jump very quickly. FWI, these were the hyperutectic (sp?) pistons.

Everyone told me to steer away from these exploding, grenading, etc... pistons. However, the machinist with his good intentions talked me into using them. At the time he said that they were completely redesigned and were much stronger.

About one year ago, I decided to freshen up the bottom end of my engine. In doing so, the same machinist ate his words when he saw the condition of the pistons. Three of the six had serious cracks completely through the piston wall. The others just had some minor cracking and serious discoloration. If I had not "freshened up" when I did, I would have had to locate a new block and many other parts to rebuild the next time (TRW forged )

Now, let me say that my combo with the hyperexploding pistons was completely stock with the exception of a mild (206) cam. I even had the stock turbo. This lasted me 30,000 miles of hard driving. Yes, it probably could have lasted longer in a naturally apirated regal, but those just aren't any fun I should probably mention that I sprayed every substance known to man through that engine in an attempt to make it go faster.

Just thought I'd chime in and hopefully prevent a costly block repair due to a hyperutectic meteor shower.

 

[Intercooler]

Re: Hyperucraptic pistons

Originally posted by OneQuikSix
Guys,

About three years ago I went through a rebuild. At the time, my machinist told me that cast pistons were difficult to find. He said that he found some "better custom pistons for me." They were very lightweight and would probably make the rpm's jump very quickly. FWI, these were the hyperutectic (sp?) pistons.

Everyone told me to steer away from these exploding, grenading, etc... pistons. However, the machinist with his good intentions talked me into using them. At the time he said that they were completely redesigned and were much stronger.

About one year ago, I decided to freshen up the bottom end of my engine. In doing so, the same machinist ate his words when he saw the condition of the pistons. Three of the six had serious cracks completely through the piston wall. The others just had some minor cracking and serious discoloration. If I had not "freshened up" when I did, I would have had to locate a new block and many other parts to rebuild the next time (TRW forged )

Now, let me say that my combo with the hyperexploding pistons was completely stock with the exception of a mild (206) cam. I even had the stock turbo. This lasted me 30,000 miles of hard driving. Yes, it probably could have lasted longer in a naturally apirated regal, but those just aren't any fun I should probably mention that I sprayed every substance known to man through that engine in an attempt to make it go faster.

Just thought I'd chime in and hopefully prevent a costly block repair due to a hyperutectic meteor shower.

Well someone didn't do their homework on your engine. Cracking at the bottoms sounds more like piston to wall problems being too loose. Melting any piston on the other hand is leaning it out so it wouldn't matter what piston you had there! Piston material type isn't a band-aid for proper tuning and setup. I will go with Chuck and say that the forged pistons will be a little more forgiving to tuning and setup inadequcies but hypers are decent (talking about the Federal Moguls) as many Supra's can vouch for. I have hypers going in my new motor again so we will see. Here is a little snip from another thread where Banning has been running my old motor for over 2 years with hypers and .040" over to boot with no problems. Made the last two National's and won the Buick vs. Mustang class at Englishtown last year with them.

Banning was also running well and the best I saw him go was like 11.56@115 with a PTE-51, Ford FM (looked cool!), 72's, Max-Effort, ported irons, 218/221 cam, naturally aspirated crank (2 years in the running!) and .040" hyperutectic pistons (also 2 years)! Pretty amazing!

 

[OneQuikSix]

Cracking at the bottoms sounds more like piston to wall problems being too loose.

I'm not sure of my terminology, but its possible I didn't describe the cracking adequately.

Melting any piston on the other hand is leaning it out so it wouldn't matter what piston you had there! Piston material type isn't a band-aid for proper tuning and setup.

Very True Again, you have to remember all the experiments I tried on this engine. I tried a nitrous dry kit....once. It leaned out bad enough to blow a 2 inch strip of headgasket out of the middle cylinder on both sides of the motor. It also cracked a valve spring. I also experimented with many gallons of isopropyl (sp?) alcohol with my homemade alcohol injection kit.

Even after all this abuse, the engine was running when I took it apart to "freshen up."

 

[TTA89]

Originally posted by OneQuikSix


Very True Again, you have to remember all the experiments I tried on this engine. I tried a nitrous dry kit....once.

Yikes! On a Stock GM Maf?

 

[Steve Wood]

Nah...you guys don't understand! These hypers are the absolute trick for our engines! LOL

Me, I am an old dog, and I have learned all the tricks, I can. I would rather spend the money up front on a good forged piston than spend ten times the amount later because the piston came apart.

I know we old guys are just a bunch of dummies that don't know nuttin' but I am waiting to see some of you guys doing Fram commericals...pay me now, or pay me later.....(just keep your hands to yourselves.....)

 

[Intercooler]

Different strokes for different folks! Funny though considering stock pistons are cast. Did I say cast? Yes cast C-A-S-T!

 

[Steve Wood]

Cast with an insert inside which not only makes it heavy, but makes it super strong. It is modelled after diesel piston design where high compresson really pops the pistons. You cannot get off simply by claiming they are cast.

Until you start winding them up to higher rpms, they are a great piston and I would much prefer them. They are not availabe anymore. They sometimes cracked too but they generally stayed together and you discovered it when doing a rebuild.

Chuck another red herring out there. We know you and Red love hypers. (Red special orders his turbos with hyper wheels) Some of us have seen too many pictures of them after the fact to want to use them. And yes, I know some have had good success with them.

But, Jesse, your success does not count...you change engines weekly...long term to you would be three passes! j/k

 

[Intercooler]

Get out while the getting out is good Works for me!

 

[Steve Wood]

I need to take some lessons...

 

[fc227]

Hi guy's,

Any pictures of the melted piston ?

 

[Intercooler]

Was at my machine shop today pulling some valve springs on his tester and he showed me a ZZ4 the guy took the Hypers out of to put in TRW forged. He leaned it out and tore the top ring gland off (not from the rings butting, it melted). I didn't have the digital camera with me but all I could say for about 10 minutes is I need to take a shot of this forged unit so everyone ranting about them can see. I bet he paid $350 or more for the set. I think I will stop in tomorrow again just to take a picture (especially for Mr. Wood) so everyone can see that a proper tune is worth loads more than piston type. Stay tuned!

 

[REDS HOT AIR]

Originally posted by Steve Wood
Chuck another red herring out there. We know you and Red love hypers. (Red special orders his turbos with hyper wheels) Some of us have seen too many pictures of them after the fact to want to use them. And yes, I know some have had good success with them.

YOU SO FUNNY !!

 

[Steve Wood]

waal now, Red....everyone knows that only 51's that you buy melt the wheels off. No repair center has ever seen one from anyone other than you!

Therefore, I figure it is those special order wheels....


Jesse...you can break anything if you push it too far....you just don't have to push a hyper very far.

 

[Intercooler]

Why Steve, you talk like a man that has used Hypers. You have used them haven't you or have you been hanging with Brick?

 

[Steve Wood]

I bought an engine with a set....two broke.

It now has trws because the engine had already been bored. Some of us have actually done things in spite of not having the advantage of youth.