They are a proven piston but as any cast piston they do have their limitations in what the material can withstand. I am not a fan of the haze at idle on a daily driven truck that I've seen in a few motors around here with a multitude of tuners.
Mahle Motorsport cast piston VS Fingers Oval
- Thread starter Chilly
- Start date
They are a proven piston but as any cast piston they do have their limitations in what the material can withstand. I am not a fan of the haze at idle on a daily driven truck that I've seen in a few motors around here with a multitude of tuners.
Carrillo rods have failed before fingers pistons. you want to rate them at 1000hp as playing with fire?
i wont discredit the pistons run dirtier but that doesnt mean they cant be cleaned up via tuning and actual engine setup. its been done many times and ive personally had them clean up easily.
If I do recall, about 8 months ago a forum member cracked a fingers piston at ~1200whp mark. They are an unknown. Some have held 1600-1800hp and some have failed closer to the 1000hp mark. Are they better than a standard motorsports piston? Hell yes. Are they guaranteed not to break to "XXXX" hp? Nobody knows because it is a material limitation and unknowns/accepted processes in industry. There is a certain level of porosity that is accepted in cast parts, there is no way around it. I'm not saying there are huge air voids in motorsports pistons but the manufacturing process provides inconsistencies.
A forged piston, while still having some inconsistencies in the manufacturing process, has a much lower possibility for these flaws. Nothing is a guarantee as to this product will always hold XXXXhp, just a little better odds. As for cleaning up idle, yes I will 100% agree it can be done and has been. It takes more work with your tuner but it can be done. Some customers HATE getting multiple revisions of tuning to fix something just to potentially be told that they can't be cleaned up (not by that tuner or other engine configuration etc).
This isnt facebook, if you are going to make that claim, bring facts with it. There has been plenty of "hearsay" over the years about the pistons and John has either proven them incorrect (he has a list of all hes sent out) or the story never added up because its was a "friends, son, brothers, wifes, second cousin" crap. you need to go through johns threads and read why and where he has fixed the issues. porosity was NEVER the main cause. stop spewing shit out here that doesnt circle around the true issues. Again, as you side stepped my comment on the carrillos that broke (3 different engines, 2 at the UCC last year). you dont hear people saying they are limited to 1000hp.
if you are building an engine at 800+hp and expect 1 single tune to dial the truck in, you are high or the truck was dropped off with the tuner, left to be properly dialed in and then picked back up by the customer. when you get to that level, there are way too many variables to make a cookie cutter tune for all trucks at that hp. its almost guaranteed there will be hiccups in a new setup that will require diag and fixing no matter what so i dont buy into this "customers hate mulitple revisions", i buy into the fact the customer was misinformed by the builder/tuner/shop on what is all entailed and the work required for a truck that will be 100% ready.
To counter, I never said porosity IS the issue, I said it CAN be an issue as with the manufacturing process and is a potential unknown variable making every piston theoretically different. I also have not said they are limited to 1000hp, I said my personal reservations with recommending any cast piston past 1000hp. You cannot deny the facts that they have indeed failed and not all of them have failed in the same power range. You cannot compare a drag/competition engine to something that will get daily driven year round at that power level which is what the OP seems like he is going to do. I also have not said that I personally expect 1 single revision to to be the one tune to work on the truck, I have stated that there are some people out there who do expect this. I have personally had this occur at my shop, the customer did not like that his truck took 3 revisions to get running in tip top shape to work out some rail shudder issues on a CP3 converted LML when he had chosen the tuner to work with and was informed it has been a known issue with said tuner.
For the 3rd time, they are one hell of a proven piston. The issue that lies here is that there is no hard data/trend line showing where they become they tend to fail. Some live well past 1000hp and other's just barely over. I can agree that they do tend to live in the 1200-1400 range for quite awhile but have had some outliers both above and below.
Smh... you said enough to make my point. Awful hard to create a trend line for breakage when there is no evidence to support it
The truck was a 2wd single cab short bed LMM that had a couple of different setups on it. It had a 364.5/480 compound setup for a while, and it had a single 400 (72mm for a couple of months and a 76mm for about 10 months). With both turbo setups, the truck had 100% over Exergy injectors. I drag raced it somewhat regularly. I mostly ran it in the 11.90 index class with the NHRDA before they quit their program, but I also did some test and tune stuff for fun at a couple of different local drag strips. I would say the worst abuse was on the street though. I beat on it quite a bit, and it never let me down. I would not be afraid to run another set of the same pistons in another motor making the same power. I had a set of cut/coated pistons years ago that failed in about 3 months with maybe 2000 miles on them making similar power. The motorsports pistons have proven themselves to me.
Perfect! That is what I like to hear. You remember what your compression ratio was? I plan on sticking around 16.5 due to me daily driving it.
My Fingers are at 16.1 with dirty ass ii injectors, they idle fine with only a slight haze when cold. Not much difference between my 04 with stock compression and injectors... If I was building a street truck that was going to see some mileage, hands down fingers pistons. They are proven to hold 1k plus, no problem. Crank or block will give up before the pistons imop.
I recall talk way back in 07 about better pistons on the dieselplace forum. I still have a ton of personal messages back and forth between Mahle (Eric) and myself. I was pushing for the monotherm because I had first hand experience with it some months earlier in the 5.9. They were not even known yet since they were prototype government parts I had seen after being dynoed for hours on end in a test cell, then removed and inspected.
For the duramax, my plea to Eric was; if we cant get a monotherm then how about some type of scaled down, articulated, 2 piece set up since overall weight was a concern with the duramax. It seems this was going to cost a LOT of money to develope though. The overall height of the duramax piston is an obstacle to 2 piece as well.
That left us with improving the material the piston was cast from, using a forging, or pushing the forged steel monotherm part. Improving material and adding some meat in stressed areas seemed the way to go at the time. Of course forgings are used now too.
I have actually never held an oval bowl in my hand. It seems brilliant from a strength point of view if the idea there was to help avoid folding the piston over the wrist pin? Looking at the bowl though, I cant help but wonder what the effect of mixing and combustion is. The tighter area in the bowl is certainly causing spray jet overlap. Or at least leading to rich zones that are short on oxygen. Its not a rip on the design in any way. Just an observation. Typically one starts by trying to avoid jet overlap. This is done by dividng the bowl into a pie with all portions being equal. This begins the process of how many jets or spray holes you will use to maximize even mixing for a given design.
The motorsport piston is certainly superior for mixing to an oval from a glance, but on the other hand a broken piston cant make ANY power and the oval has added strength. So, you have trade offs. Pick your poison.
For the duramax, my plea to Eric was; if we cant get a monotherm then how about some type of scaled down, articulated, 2 piece set up since overall weight was a concern with the duramax. It seems this was going to cost a LOT of money to develope though. The overall height of the duramax piston is an obstacle to 2 piece as well.
That left us with improving the material the piston was cast from, using a forging, or pushing the forged steel monotherm part. Improving material and adding some meat in stressed areas seemed the way to go at the time. Of course forgings are used now too.
I have actually never held an oval bowl in my hand. It seems brilliant from a strength point of view if the idea there was to help avoid folding the piston over the wrist pin? Looking at the bowl though, I cant help but wonder what the effect of mixing and combustion is. The tighter area in the bowl is certainly causing spray jet overlap. Or at least leading to rich zones that are short on oxygen. Its not a rip on the design in any way. Just an observation. Typically one starts by trying to avoid jet overlap. This is done by dividng the bowl into a pie with all portions being equal. This begins the process of how many jets or spray holes you will use to maximize even mixing for a given design.
The motorsport piston is certainly superior for mixing to an oval from a glance, but on the other hand a broken piston cant make ANY power and the oval has added strength. So, you have trade offs. Pick your poison.
Let me interject a little here. In no particular order.
I know I missing something here.......
- Oval pistons are not "perfect". None are.
- The "tight" portion of the bowl is actually the same width as a stock bowl. The lobes are bigger. As such, spray stays in the bowl just as much, if not better than stock. And there is less "quench" area.
- Ovals are cut from the same castings as the motorsports pistons. That is, they share the same material and base design. Just tweaked.
- I am aware of only two sets failing. One, I think was a combination of a material flaw and oil cooling failure. The other was the set that Brett was running in his C10. I am confident in this case that the cracks came from oil cooling issues. Neither cracked up to the crown.
- HP is the wrong metric for measuring piston stress. Cylinder pressure is what kills pistons. Very rapid temp swings can kill cast pistons.
- Ovals are available in Forged.
- Personally, I would not run Forged on the street in a daily driver.
I know I missing something here.......
In your Oval piston sales what was the average CR going out the door? Or if you could narrow it down farther, specific to street trucks? I assume most are still running 16.5?
I've done a fair amount of research and cannot find to many people cracking the Motorsport pistons, all factory replacements.
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