Not to totally derail the thread, but I looked into this. The end customer received a lot of iffy info from his engine builder or tuner. I still don't know the full extent of what happened. He apparently didn't have pictures, so we sent him some today. He had been told on or the other of them that: 1.) The pistons fell out of the block and the skirts were cracked. 2.) The pistons were 4032 instead of 2618. 3.) We had "bad bunch of "castings" that got past quality control". None of which is true, so maybe some CYA or just plain lack of knowledge going on here. Folks here will have to make their own judgement.

We only received two pistons out of 8 to look at. No pins or rings either, which doesn't give us much to go off of. The small area outside of the pockets was cracked due to a lean condition in those cylinders. Would another out of the box piston have fare better? No, and most wouldn't hold up even "as long" if they were 4032. That being said, the piston could have been prepped by the engine builder a little better and it would have held up a little longer under the lean condition....Hopefully long enough to spot it.

So what is considered a proper level piston preparation and who's responsibility is it? We live in the day and age of 1200whp crate/street engines that don't get the level of prep they did 10 years ago, yet 99% of the engines built are fine with an out-of-the-box piston. So how do you keep from being the 1%?

Anyone who's ever spent time prepping a piston will know the conundrum of "how much is too much" relieving in this area. The more you pull it back, the more it thins the ring land directly above the ring.

As a manufacturer, we leave as much material as we can out there and still provide adequate piston valve clearance (way more common problem with catastrophic results compared to flaking reliefs). A good rule of thumb is to have at least 2mm worth of material outside the perimeter of the intake pocket. This amount material is enough to hold up even under low level detonation and lean conditions. If it's less than 2mm, we drop an end mill down in there to relieve it further. This helps, but still leaves two other points and it's still not a miracle cure. Even if it's perfect, it's still the thinnest area of the crown and will be the first area to go when a cylinder is lean.

So what else can be done by the engine builder to help further? No matter which manufacturer's piston it is, an engine builder can cartridge roll this area back. If you do it once, you'll know what a proper "nub" looks like. It requires a steady hand, but even a beginner can do it if they're careful. Deburr afterward to keep the resulting flashing off the cylinder wall. It's an hour worth of work, so the engine builder that does it (and charges for it) is rare.

As a personal note, we produce pistons for most of the top LS engine builders. Most of the engines built on this forum use out of the box Wiseco pistons. We appreciate your business and constantly work to provide the best piston. A lot of guys on this board know they can always contact me and I'll do my best to keep them out of trouble to begin with and help them out if they do have an issue even if it isn't the pistons fault.

Again, apologies to the op for sending the thread off on a tangent.

 

With all the info brian posted it is easy to see that most of the piston manufacturers care about their product. But it is often blamed for failing. Proper machine work and setup sure go a long way but no one brings that up. And its not JUST bearing tolerances and ptb and piston to deck clearance. Its proper valvetrain setup and using quality parts also.

Oh yeah, and the TUNE. Some people think that their tuner is beyond reproach. Well we are all human and we all make mistakes. Mine is getting out of bed in the morning.
You cant imagine the problems that internet viewers never get to see on here. Not everyone runs and posts.

 

Thanks for this. A lot of companies may care, but won't post solutions because of liability etc. My personal belief is education (even on the negative aspects of racing engine failures) always pays off in the long run.

 

that^

 

Big Wiseco fan here, although I might be biased

 

Wiseco fan here too!

 

I did not trash but simply spoke a truth. Hellfire rings are not made by Mahle they come from Speed Pro. The standard rings from Mahle are moly faced ductile iron. The Hellfire ring is also an iron ring and can't endure the stress that a steel ring can. The Hellfires are tough on the cylinder walls. I'm sure the tractor is using Power Pak pistons as well.

 

You trashed me. I am a competent engine builder. And mahle has many more offerings than just the rings that come with their power pack pistons.
The tractor isnt using the power pak pistons, like i said they are custom stainless, showing the capability of their company.

 

Been running a set of 3.908 Mahle pistons in my LS1 since 06. No problems!

 

Wiseco over Mahle. All of the big power vette guys run Diamond or Wiseco.

 

Quick question not to hijack but do yall carry any pistons. For a 404? Or 4.010

 

Ill send you a pm.

 

I'm sure both Mahle and Wiseco make fine and capable pistons. Any product can fail when not applied, used or prepped correctly.

 

Well Brians point and mine are that its not just the piston or piston prep/deburring that would be the issue but is normally blamed. You have to look at the engine as an entire unit. The piston is only 1 of many components.

 

For a N/A street/strip motor I'd say whoever makes a 4032 alloy piston that meets the specs you need. A motor with 2618 pistons will need torn down and "freshened up" around 30-60k miles. A motor with 4032 will be fine for 100k+miles, it just wont be as durable in a FI or N2O motor.

 

Mr FrY,
Is it typical to need a freshening within the milage you stated with 2618 pistons VS. 4032 s ? What are the benefits of the 4032s? Is that the low expansion piston Mahle sells? If so, wouldn't that be fine for a 95 % street car? Thanks in advance.

Jim

 

4032 and 2618 are the types of metal forgings that most piston companies use. Unless you're planning on a large amount of nitrous or boost, I'd run the 4032.

 

I don't want to pretend to be some motor building expert, but I saw it mentioned once sometime back so I did some searching and couldn't find a lot on here about it. I ended up reading some different threads on several different forums and articles or different web site's all agreeing that motors with 2618 alloy pistons have a much shorter life spans. While on the other hand 4032 alloy pistons have been used in several OE applications and can last for hundreds of thousands of miles. The trade off is that 4032 pistons are more brittle so they aren't as durable in higher boost or N2O applications, and yes this is all because 2618 alloy aluminum has a more thermal expiation requiring looser cold clearances. But like i said I haven't seen it mentioned here much and I feel there are people having motors built that don't know about this until it's to late, so I think it needs talked about more. This is one of those instances where over building a motor just in case you might spray it a little someday doesn't pay off.

 

That's one of the reasons I went with Mahle's in 2007 is because they were the only manufacturer offering a 4032 piston. Bottles are for babies, and I have no intention of putting a blower on. Even if I do, the 4032 alloy is far superior to stock castings in a forced induction application.

 

Speed pro has a very small selection in a "4032" pistons as well, and have had them for quite a while.