Broken Diamond Piston. Pics why????

[quickt]

This is my version of detonation. His dont look like that You cant see clearly but the top of the piston looks like a sponge over most of the top. The others not as bad but similar. BTW the rod in this cylinder was bent as was the pin on this rod pin and the ring land was beat up. Complete with a crack in the steel crank. This piston was detonated. This was a 109 in the 740+ rwhp range run very hard using alky. And yes we were very aggressive during the learning curve.

 

[87we410877]

why ??? it's the greatest thing for a street car to run some boost sorry alky didn't do this damage.

True, but unlike yourself, i dont know how to tune it and im not at the track every weekend fine tuning it. For the 100 miles a year i drive it, i can put 116 in it. Not have to deal with running out, pump failures, ext.

 

[87we410877]

Lonnie ya hit it right there .. Life in the big city so to speak ! They are all goin to break sooner or later! BUT...ya always a BUT.. Melissa's motor has 15k on it with Diamonds in it. We took that motor from my Buick RX7.. Had stock headgaskets on it so we took the heads off to swap in the Cometics. I looked at the pistons and commented to Russ about the "thin spots on the edge". Scatched my head for a minute and said.. Lets throw it in the car an see what it does. Melissa, Russ and I beat the living hell out of it.. DRIVE IT LIKE YA STOLE IT !! Like ya said get out and have fun with it! Blows up tomorrow ??? so what ... look at the beating it took .. Oh ya.. If ours did blow we would have been running long before this thread will end !
....I still go back to detonation for doin the damage BUT Dan knows a lot more than me:biggrin: Also have to remember how much power to most of the Buick guys run ??? Maybe 400/550?? Dan has BIG POWERED cars out there !! Nothing small like most of us run

OH... DAMMIT LEAVE THE ALKY SYSTEM IN IT It's a street car .. No fun running around with 15#s of boost!!

Ive had this car since 2003 and it has never run right!!!! Alky is gone, its just one less thing i have to worry about, put 116 in it and go. FAST may be the nest to go. I just want to drive the damn thing w/o a problem.

Diamond pistons have me concerned with that clearance issue in the valve relief. Big difference in the ross.

And grumpy, 15#? i was thinking more like 30#. That may also be an issue with the 93 octane/alky tunners, Your running 24 lbs. I like to be higher. As i said, it was fine at 24. higher is where sh*t went wrong.

 

[quickt]

These pistons are NOT from my motor that pic's coming later. This piston is very similar to the one we are discussing.

This pic is a comparison of Diamond v.s. a Ross that was HEAVILY abused and detonated but did not fail (Notice the ring placement)

Detonation or not there is a design issue with that piston IMO.

You must keep everything. I cut those apart like 5 years ago.

 

[thadeal4real]

lol

i think theres a problem with that cross section photo comparison

 

[thadeal4real]

fun

if you look at the pin bore to depth comparison well figure out for yourself?
the rings were the problem with the motor (which may or may have not caused detonation) that butted and caused the piston to fail

 

[quickt]

i think theres a problem with that cross section photo comparison

One is for 6" rod 3.625 other 6.5 rod 3.625 Both were inverted dish. Both were cut threw the thinnest spot on the top of the piston. The comparison was to see how thin the material was that supports the ring land at the thinnest spot.

 

[thadeal4real]

lol

one piston has two pin bores the other one u do the math?

 

[quickt]

one piston has two pin bores the other one u do the math?

What math??

 

[Grumpy]

And grumpy, 15#? i was thinking more like 30#. That may also be an issue with the 93 octane/alky tunners, Your running 24 lbs. I like to be higher. As i said, it was fine at 24. higher is where sh*t went wrong.

you believed me with TSM boost Good Luck with your new build Oh forgot to add we are not racing the car every weekend .. Just driving the hell out of it !!

 

[thadeal4real]

quickt

pistons are built with taper to relive gas pressure so your pic was a bit misleading cause you tell me what effect rings or there gap in ? has on the piston top

 

[quickt]

Anyone if free to have their own opinion. Nothing misleading about the pics. The pistons were cut at the thinnest point from the top. One is a universal Inverted dish (diamond) that was sliced threw an existing crack. The other is a 4-6 Inverted dish Ross. That thin point happen to be in a slightly different location as the piston designs are slightly different. The comparison was not meant for you or even this thread for that matter. I am a little pi$$ed that Chris posted them. The pics you dont see are the ones where they were finish cut in pieces like a pie. At no point were the pistons any thinner than the pictures shown.

 

[quickt]

Ive had this car since 2003 and it has never run right!!!! Alky is gone, its just one less thing i have to worry about, put 116 in it and go. FAST may be the nest to go. I just want to drive the damn thing w/o a problem.

Diamond pistons have me concerned with that clearance issue in the valve relief. Big difference in the ross.

And grumpy, 15#? i was thinking more like 30#. That may also be an issue with the 93 octane/alky tunners, Your running 24 lbs. I like to be higher. As i said, it was fine at 24. higher is where sh*t went wrong.

Good luck you will get it sorted out. This is not the place you will find your answers. Call one of the engine builders they are most always willing to help.

 

[Pronto]

Ive had this car since 2003 and it has never run right!!!!

How about putting a running stock engine that's OK in and finding the real problem? Get that to "run right" then put in your high dollar, big hp engine.

 

[turbobuick]

Lonnie,
People can believe what they want but here is a fact you and I know for certain. I burnt up two engines in 2008 costing me close to $12k. We had a 8.70@159 car in 2008. You rebuilt my motor using CP pistons Dan @ DLS spec'ed and we made absolutely ZERO changes to the motor for 2009. This year I ended up running 8 teens at over 170mph, once again with the ONLY change to the motor being made where the PISTONS!

The lesson I learned with those pics and the info you provided was a hard and expensive one. The pics the gentleman who started the thread posted, look eerily similar to the problems we had and the problems you've seen with Diamond pistons. I personally think that should be public knowledge so others don't have the same expensive problems. Some will appreciate it others will not, oh well.

BTW here is how you burn a Diamond piston

 

[87we410877]

So who wants to buy 5 diamond pistons? hahah. Im afraid to put JE or Weisco in since they are probably close to the same. I like the way the Ross look and havnt seen the CP's yet. I'll call Bobby and see what he likes.

As a Mechanical Engineer, i cant see how someone in the design field would let that clearance go. Clearly they knew nothing about strength of materials, materials science, and fattigue.

 

[quickt]

So who wants to buy 5 diamond pistons? hahah. Im afraid to put JE or Weisco in since they are probably close to the same. I like the way the Ross look and havnt seen the CP's yet. I'll call Bobby and see what he likes.

As a Mechanical Engineer, i cant see how someone in the design field would let that clearance go. Clearly they knew nothing about strength of materials, materials science, and fattigue.

Piston manufactures build what you tell them to. They all can build a good piston if its speced correctly. The CPs we have been getting from Dan I think are bullet proof. I am sure Bob will also be able to point you in the right direction.

 

[turbobuick]

In all fairness to Diamond I feel they are still capable of building a good piston. I would use J&E without hesitation and I've never used Weisco. You can't go wrong with whatever RPE suggests.

BTW these pictures and this info was shared with Diamond. After, the second set of pistons peeled the top ring land off at the 60' mark on an essentially new motor, Diamond did spend considerable time inspecting them and looking at my motor. While they never admitted fault I did get a pretty cheap set of pistons out of them and the new piston was completely re-designed and I will probably run them this year. I think Diamond looked at a 1500hp V6 and V8 the same when the V6 is actually requiring much heavier duty piston with two less cylinders at the same power level.

 

[SS/GN]

Just a thought

Have you tried calling diamond and discussing this problem.We have had problems in the past(catastrohic)and called the vendor and they helped us out as we found a problem that eventually saved them money.Sometimes you get lucky.Just my opinion.Thanks for sharing and good luck.

Kevin

 

[87we410877]

Have you tried calling diamond and discussing this problem.We have had problems in the past(catastrohic)and called the vendor and they helped us out as we found a problem that eventually saved them money.Sometimes you get lucky.Just my opinion.Thanks for sharing and good luck.

Kevin

Im sure they will give me the run around. And even if they give me another piston for free, its still a bad design.

Whats the news on this new designed diamond piston?