My turn to crack a piston

Stingpuller

The Pusher Man
Jan 11, 2007
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Pistons

They are still a cast piston. They are still a high silicon piston. Jon, you are a smart guy. Nobody will say anything different but if your chamber was the answer don't you think GM would do it? I'm just a dumb guy who like to race and has done so for almost 30 years and have seen a lot in that time. I'm not saying your pistons are not a little better than a normal piston. But what I am saying is you can't compare it to a purpose built race piston. When they have more than a handfull of high power passes then maybe we can say there better than a normal piston. The original post's pistons lasted 3 years but he didn't race it alot. I race EVERY WEEKEND! I wear my stuff out. It has to last or I don't win. I can't take chances on a maybe. I have been down that road to may times.
 

Leadfoot

Needs Bigger Tires!
Dec 27, 2006
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They are still a cast piston. They are still a high silicon piston. Jon, you are a smart guy. Nobody will say anything different but if your chamber was the answer don't you think GM would do it? I'm just a dumb guy who like to race and has done so for almost 30 years and have seen a lot in that time. I'm not saying your pistons are not a little better than a normal piston. But what I am saying is you can't compare it to a purpose built race piston. When they have more than a handfull of high power passes then maybe we can say there better than a normal piston. The original post's pistons lasted 3 years but he didn't race it alot. I race EVERY WEEKEND! I wear my stuff out. It has to last or I don't win. I can't take chances on a maybe. I have been down that road to may times.


Not saying Fingers will or won't last, but to answer your question as to why GM didn't do it, I have an edumucated guess on that. The industries toroidal design and emissions testing (millions of dollars invested) proved these pistons to meet EPA guidelines as well as longevity testing in THEIR test fleet. GM had no reason to "reinvent the wheel" (or piston in this case). It met all their criteria. Just because a SMALL portion of completely stock guys have experienced a failure and many modded guys have on stock pistons does not warrant a change by GM.

While these pistons may very well be stronger, they most likely are not emissions friendly (GM probably couldn't use them even if they proved capable of handling 1500RWHP).

If forged pistons have worked for you and make you feel warm and fuzzy, run them. I know I have run things JUST because they have proven to work for me and/or my engine builder when alternative are in the market.

I can appreciate you letting people know your experiences and even your concerns, but if people want to "test" a new design I say let them. Maybe an alternative can be found to what we have.

I don't think Fingers ever said his pistons wouldn't fail, just that one of the main areas of weakness in the stock configurations had been addressed with his design. Maybe they will last up to repeated abuse at 1200+ HP, or maybe not, but lets see. If I were to run a set I know it would be without any guarantees and I assume others realize this as well. There are some "blessed" stock pistons that are living in some serious torture builds. Fingers is building on the success of what works while removing the possible weak points. If the stock pistons were collapsing then I would be worried as that is any area he hasn't addressed, but that doesn't seem to be an issue...yet.

Edit: All that being said, as long as there is no negative feedback on the monotherms, those are what is going in my engine in 2014 (known as the year of the build). ASSuming my original motor holds until then.
 
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Rhall

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Aug 12, 2006
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Not saying Fingers will or won't last, but to answer your question as to why GM didn't do it, I have an edumucated guess on that. The industries toroidal design and emissions testing (millions of dollars invested) proved these pistons to meet EPA guidelines as well as longevity testing in THEIR test fleet. GM had no reason to "reinvent the wheel" (or piston in this case). It met all their criteria. Just because a SMALL portion of completely stock guys have experienced a failure and many modded guys have on stock pistons does not warrant a change by GM.

While these pistons may very well be stronger, they most likely are not emissions friendly (GM probably couldn't use them even if they proved capable of handling 1500RWHP).

If forged pistons have worked for you and make you feel warm and fuzzy, run them. I know I have run things JUST because they have proven to work for me and/or my engine builder when alternative are in the market.

I can appreciate you letting people know your experiences and even your concerns, but if people want to "test" a new design I say let them. Maybe an alternative can be found to what we have.

I don't think Fingers ever said his pistons wouldn't fail, just that one of the main areas of weakness in the stock configurations had been addressed with his design. Maybe they will last up to repeated abuse at 1200+ HP, or maybe not, but lets see. If I were to run a set I know it would be without any guarantees and I assume others realize this as well. There are some "blessed" stock pistons that are living in some serious torture builds. Fingers is building on the success of what works while removing the possible weak points. If the stock pistons were collapsing then I would be worried as that is any area he hasn't addressed, but that doesn't seem to be an issue...yet.

Edit: All that being said, as long as there is no negative feedback on the monotherms, those are what is going in my engine in 2014 (known as the year of the build). ASSuming my original motor holds until then.

Why do u think they won't pass emissions? That mean less efficient which means less Power...

On another note I lost a cast piston due to what I think was heat, I'm not sure any bowl design would have held. I run forged now. Monotherms need to be proven also, they were all the hype with the Cummins, then fell off. I heard rumors of failures, not sure tho.
 

Stingpuller

The Pusher Man
Jan 11, 2007
2,019
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central Ohio
Pistons

I'm not telling anyone to run forged piston. There not for everyone. Matter of fact I wouldn't run them in a daily driver but I also wouldn't try to run a daily driver at 900 or 1000 hp. I WOULDN'T expect any motor to last at that power level. I'm not or never will say Jon's pistons are not good for a guy wanting to drive/race sometimes but if you turning up the wick there are options. Just like stock rods you can polish the beams, put good bolts in them, cryo them and even bless them but in the end they are still stock rods. That's what im trying to say. I'm sure Jon has forgot more than I know about stuff but I can assure most everyone I have wasted a TON of money racing and learning. I have been there and done and I'm tired of doing it over and over. I will stay out of this as i'm not trying to start a storm just giving my .02 on the matter.
 

Leadfoot

Needs Bigger Tires!
Dec 27, 2006
904
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Western MA
www.matpa.org
Why do u think they won't pass emissions? That mean less efficient which means less Power...

On another note I lost a cast piston due to what I think was heat, I'm not sure any bowl design would have held. I run forged now. Monotherms need to be proven also, they were all the hype with the Cummins, then fell off. I heard rumors of failures, not sure tho.

From what little (several documents but nothing compared to the volumes of materials available) I've read, the shape of the toroidal bowl design promotes better burn especially at low temps and rpms (idle). When emissions was not a concern a traditional dish was adequate. As for power, if the toroidal design was more efficient especially at high RPM's I would ASSume Scheid and others would be utilizing it in all out builds.....but to my knowledge they aren't.

Edit: I would think (not a machinist) a toroidal bowl involves more material and machining therefor not a wise choice from a penny pinching standpoint. OEM's require it for a reason (emissions).

The toroidal design does seem to be more efficient at low rpm. I have not read much on the effects at high rpm's but I'm assuming it is not as effective or otherwise others would be utilizing it in performance apps. As many guys have stated and/or paraphrased: If the cost is reasonable, it's available, and it makes more power, guys are going to use it.

Edit: I'm assuming it's like a cam. It has a "sweet spot" operating range. While a cam will work for 0-10,000rpms, it is more efficient in a given rpm window. I'm assuming the toroidal bowl design is more effective at idle and low rpms to satisfy a need. Most performance motors especially with high stall converters, big turbos, and high rpm cams could care less about idle rpm efficiency...

You stated you lost a piston to heat. While a reworked cast piston would most likely not have saved you (almost willing to bet money it wouldn't), would a forged one be much better? It sounds like that was a fluke (stuck injector) if it was a single piston or you are flirting with the line where a monotherm (now that they are somewhat available) would be a wiser long term investment.
 
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Leadfoot

Needs Bigger Tires!
Dec 27, 2006
904
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Western MA
www.matpa.org
I'm not telling anyone to run forged piston. There not for everyone. Matter of fact I wouldn't run them in a daily driver but I also wouldn't try to run a daily driver at 900 or 1000 hp. I WOULDN'T expect any motor to last at that power level. I'm not or never will say Jon's pistons are not good for a guy wanting to drive/race sometimes but if you turning up the wick there are options. Just like stock rods you can polish the beams, put good bolts in them, cryo them and even bless them but in the end they are still stock rods. That's what im trying to say. I'm sure Jon has forgot more than I know about stuff but I can assure most everyone I have wasted a TON of money racing and learning. I have been there and done and I'm tired of doing it over and over. I will stay out of this as i'm not trying to start a storm just giving my .02 on the matter.

At least from my standpoint, I don't think you are starting a storm. You do have a ton of experience, have proof to stand behind what you've done. I think words/text on the net can get misconstrued at times.

Maybe it's a part of me that's hoping this will be a good alternative for quite a few who turn up the wick but "daily drive". I agree a full on competition motor will most "likely" need something else, but it will be interesting to see how far people push these. As with anything, push hard enough and it will fail. The first few who push past that mark will find out the hard way on their dime (I'm sure you have been there in regards to other parts and platforms). Until somebody reaches that limit nobody knows where it is.

Unfortunately someone has to be the guinea pig. As long as they are aware of it....
 

TheBac

Why do I keep doing this?
Staff member
Apr 19, 2008
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Not saying Fingers will or won't last, but to answer your question as to why GM didn't do it, I have an edumucated guess on that. The industries toroidal design and emissions testing (millions of dollars invested) proved these pistons to meet EPA guidelines as well as longevity testing in THEIR test fleet. GM had no reason to "reinvent the wheel" (or piston in this case). It met all their criteria. Just because a SMALL portion of completely stock guys have experienced a failure and many modded guys have on stock pistons does not warrant a change by GM.

While these pistons may very well be stronger, they most likely are not emissions friendly (GM probably couldn't use them even if they proved capable of handling 1500RWHP).

If forged pistons have worked for you and make you feel warm and fuzzy, run them. I know I have run things JUST because they have proven to work for me and/or my engine builder when alternative are in the market.

I can appreciate you letting people know your experiences and even your concerns, but if people want to "test" a new design I say let them. Maybe an alternative can be found to what we have.

I don't think Fingers ever said his pistons wouldn't fail, just that one of the main areas of weakness in the stock configurations had been addressed with his design. Maybe they will last up to repeated abuse at 1200+ HP, or maybe not, but lets see. If I were to run a set I know it would be without any guarantees and I assume others realize this as well. There are some "blessed" stock pistons that are living in some serious torture builds. Fingers is building on the success of what works while removing the possible weak points. If the stock pistons were collapsing then I would be worried as that is any area he hasn't addressed, but that doesn't seem to be an issue...yet.

Edit: All that being said, as long as there is no negative feedback on the monotherms, those are what is going in my engine in 2014 (known as the year of the build). ASSuming my original motor holds until then.
Thank you.
 

Rhall

Old Skooler
Aug 12, 2006
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From what little (several documents but nothing compared to the volumes of materials available) I've read, the shape of the toroidal bowl design promotes better burn especially at low temps and rpms (idle). When emissions was not a concern a traditional dish was adequate. As for power, if the toroidal design was more efficient especially at high RPM's I would ASSume Scheid and others would be utilizing it in all out builds.....but to my knowledge they aren't.

Edit: I would think (not a machinist) a toroidal bowl involves more material and machining therefor not a wise choice from a penny pinching standpoint. OEM's require it for a reason (emissions).

The toroidal design does seem to be more efficient at low rpm. I have not read much on the effects at high rpm's but I'm assuming it is not as effective or otherwise others would be utilizing it in performance apps. As many guys have stated and/or paraphrased: If the cost is reasonable, it's available, and it makes more power, guys are going to use it.

Edit: I'm assuming it's like a cam. It has a "sweet spot" operating range. While a cam will work for 0-10,000rpms, it is more efficient in a given rpm window. I'm assuming the toroidal bowl design is more effective at idle and low rpms to satisfy a need. Most performance motors especially with high stall converters, big turbos, and high rpm cams could care less about idle rpm efficiency...

You stated you lost a piston to heat. While a reworked cast piston would most likely not have saved you (almost willing to bet money it wouldn't), would a forged one be much better? It sounds like that was a fluke (stuck injector) if it was a single piston or you are flirting with the line where a monotherm (now that they are somewhat available) would be a wiser long term investment.

It wasn't a fluke, it was not a stuck injector. It was due to setting on the line for over a minute with exhaust temps over 1200 trying to light my turbo. Forged have held up every since. Why do u think monotherms would be a wiser long term investment? What testing have u seen that no one else has? Ive heard of a few Cummins failures with far less power than I have. I also heard high HP was not the intention for them, daily driving with medium range HP was. Everybody jumps to spend tons of money on new parts just cause someone says its the answer to our problems. Sorry, from what I've heard, and seen, ill let someone else take that $4k gamble, while ill run what works for me.
 

Harbin_22

Active member
Dec 4, 2010
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It wasn't a fluke, it was not a stuck injector. It was due to setting on the line for over a minute with exhaust temps over 1200 trying to light my turbo. Forged have held up every since. Why do u think monotherms would be a wiser long term investment? What testing have u seen that no one else has? Ive heard of a few Cummins failures with far less power than I have. I also heard high HP was not the intention for them, daily driving with medium range HP was. Everybody jumps to spend tons of money on new parts just cause someone says its the answer to our problems. Sorry, from what I've heard, and seen, ill let someone else take that $4k gamble, while ill run what works for me.

Off topic, you pulling in Kentucky tonight?
 

SmokeShow

Well-known member
Nov 30, 2006
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Do the forged have a higher melt point than cast? Rob, have you roasted your forged pistons w/ 1200+* for over a min or did you fix the spooling problem at the same time as the melted pistons?
 

JoshH

Daggum farm truck
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Feb 14, 2007
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It wasn't a fluke, it was not a stuck injector. It was due to setting on the line for over a minute with exhaust temps over 1200 trying to light my turbo. Forged have held up every since. Why do u think monotherms would be a wiser long term investment? What testing have u seen that no one else has? Ive heard of a few Cummins failures with far less power than I have. I also heard high HP was not the intention for them, daily driving with medium range HP was. Everybody jumps to spend tons of money on new parts just cause someone says its the answer to our problems. Sorry, from what I've heard, and seen, ill let someone else take that $4k gamble, while ill run what works for me.
What kind of failures have you seen or heard of with the Monotherms?
 

Rhall

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Aug 12, 2006
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It's been on the Cummins side, typical cracked piston symptoms. Of course they claimed it was just a head gasket. There's no results from the duramax side yet, so to say its a good investment is funny.
 

Rhall

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Aug 12, 2006
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Do the forged have a higher melt point than cast? Rob, have you roasted your forged pistons w/ 1200+* for over a min or did you fix the spooling problem at the same time as the melted pistons?

The forged have held up so far, I made the Spooling worse due to a stupid mistake when we first did the swap, but now made it better
 

Leadfoot

Needs Bigger Tires!
Dec 27, 2006
904
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48
Western MA
www.matpa.org
It wasn't a fluke, it was not a stuck injector. It was due to setting on the line for over a minute with exhaust temps over 1200 trying to light my turbo. Forged have held up every since. Why do u think monotherms would be a wiser long term investment? What testing have u seen that no one else has? Ive heard of a few Cummins failures with far less power than I have. I also heard high HP was not the intention for them, daily driving with medium range HP was. Everybody jumps to spend tons of money on new parts just cause someone says its the answer to our problems. Sorry, from what I've heard, and seen, ill let someone else take that $4k gamble, while ill run what works for me.

Not sure where you heard your information, but the ability to withstand heat better than any form of alumimum (cast, forged, etc) was a key factor on why many think they would be better. Your pistons failed due to heat (regardless of reason), so a material that is better suited to heat would tend to be less resistant to failure in your case. There are guys that are/were running more power than you on CAST pistons, so HP isn't the be all and end all of measurements.

I said it "sounds" like a fluke as you said you lost A cast piston and not I melted a complete set. It was a valid inferrence. If the entire motor was that hot, more than one should have been melted and if it was that bad you would think ALL would be and I would have thought you would have stated such (maybe not). Even if they all showed signs, if one was worse than the others it would be a logical assumption that something was different in that cylinder (could have been a piston from a different run with slightly different chemical composition, could have been an injector that was not flowing as close to the others, could have been valve lash, something else, a combination, etc.), which is why I assumed you stated one piston versus a set. I just went off what you posted and made and inference, maybe it was wrong.

Other Pro's of the Monotherm piston design/material: Tighter PTW tolerances (documented fact), ring life (documented fact), and I'm going from memory but I think they were a few grams lighter (or that was the target) which would be better on balancing and bearings. Not too many 200HP builds are melting pistons from sitting at the line with 1200 degrees for over a minute, so that is where the high HP application of these would come in. I never stated they were indestructable, but there have been a few Cummings making power and running these with zero issues SO FAR. If they are breaking in other Cummins builds then they are breaking, but would a forged have lasted longer in that environment (not saying it would or wouldn't, just asking). Remember guys are killing pistons in DMax's at a lot lower power level than you. It's not all about an HP number.

I believe you were the one on CompD that was talking about guys taking it to the next level and trying different things to gain an edge on the competition. How is this any different. Without someone willing to try things how does a sport progress? Some guys are going to find cost effective ways to be innovative (which you seemed to have done a great job at) and some guys are going to spend money regardless. If DMax guys run these at high HP levels and have a significantly lower failure rates than even forged pistons and you have trouble with your new pistons, I would think you would consider these even if the price tag is a little higher....or no?

As for MY money, I'm not planning on re-using my LBZ pistons, I don't trust buying a used set of any design, so I'd be buying brand new (possibly was looking at Fingers design) and would have them top coated and the skirts coated (my personal beliefs). Buying 8 new pistons, modifying them, and coating them is a fairly $$$ purchase compared to some who have had luck with modifying their existing pistons. The monotherms in the grand scheme (if they work) would not be that much more money.

You can run rubber pistons in your motor for all I care (we each have to make decisions on our own and sleep at night), but with the current batch of pistons available having one issue or another, it's nice to know there are those trying things to see if they can come up with a better design (Imaging where we would be if there was only stock axles available for the AAM 11.5?, even the first batch of aftermarket axles and even first batch of large diameter axles proved not to be enough when running duals until someone tried something else). I'm assuming you are running something more than a stock axleshaft as someone else proved it works better? I just don't like to see people saying they won't work without proof (especially when the design "seems" to address many of the current issues). Doesn't mean everyone should buy them and run them, just that they should get a fair shake before they are dismissed, just like Fingers design. Depending on the intent of the build, each may have their spot.

Remember how even "people in the know" said aluminum heads on a diesel was a big mistake....lol
 

Leadfoot

Needs Bigger Tires!
Dec 27, 2006
904
31
28
48
Western MA
www.matpa.org
The forged have held up so far, I made the Spooling worse due to a stupid mistake when we first did the swap, but now made it better

Also from my experience in the gasser world, forged pistons generally handle heat better anyway so it would make sense a forged piston is less affected by heat than a cast one.

No personal proof of which, but I did hear an engine builder state a forged piston is more "dense" and has a higher ability to absorb heat. Cast pistons tend to heat the surface and tend to cause detonation as they produce hot spots, that combined with heat making cast pistons brittle (his words not mine) is why there are catastrophic failures with cast piston in performance gas motors as detonation and brittle pistons don't mix well.

If this is the case (uniform heat absorbsion) it would describe why your switch worked for you, but a case could be made on the same token as to why a monotherm could be better (when the only factor you are trying to combat is heat).

I'm curious (as I'm sure many people are), what has failed on the monotherm builds you are aware of. Have they melted, split (if so along the pin), collapsed skirts, etc, etc. If they are failing it would be nice to know how and under what circumstances (again nothing is indestructable) and who knows, maybe the monotherms on the market could end up being worse than stock pistons....
 

Rhall

Old Skooler
Aug 12, 2006
2,241
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Texas Y'all
Not sure where you heard your information, but the ability to withstand heat better than any form of alumimum (cast, forged, etc) was a key factor on why many think they would be better. Your pistons failed due to heat (regardless of reason), so a material that is better suited to heat would tend to be less resistant to failure in your case. There are guys that are/were running more power than you on CAST pistons, so HP isn't the be all and end all of measurements.

I said it "sounds" like a fluke as you said you lost A cast piston and not I melted a complete set. It was a valid inferrence. If the entire motor was that hot, more than one should have been melted and if it was that bad you would think ALL would be and I would have thought you would have stated such (maybe not). Even if they all showed signs, if one was worse than the others it would be a logical assumption that something was different in that cylinder (could have been a piston from a different run with slightly different chemical composition, could have been an injector that was not flowing as close to the others, could have been valve lash, something else, a combination, etc.), which is why I assumed you stated one piston versus a set. I just went off what you posted and made and inference, maybe it was wrong.

Other Pro's of the Monotherm piston design/material: Tighter PTW tolerances (documented fact), ring life (documented fact), and I'm going from memory but I think they were a few grams lighter (or that was the target) which would be better on balancing and bearings. Not too many 200HP builds are melting pistons from sitting at the line with 1200 degrees for over a minute, so that is where the high HP application of these would come in. I never stated they were indestructable, but there have been a few Cummings making power and running these with zero issues SO FAR. If they are breaking in other Cummins builds then they are breaking, but would a forged have lasted longer in that environment (not saying it would or wouldn't, just asking). Remember guys are killing pistons in DMax's at a lot lower power level than you. It's not all about an HP number.

I believe you were the one on CompD that was talking about guys taking it to the next level and trying different things to gain an edge on the competition. How is this any different. Without someone willing to try things how does a sport progress? Some guys are going to find cost effective ways to be innovative (which you seemed to have done a great job at) and some guys are going to spend money regardless. If DMax guys run these at high HP levels and have a significantly lower failure rates than even forged pistons and you have trouble with your new pistons, I would think you would consider these even if the price tag is a little higher....or no?

As for MY money, I'm not planning on re-using my LBZ pistons, I don't trust buying a used set of any design, so I'd be buying brand new (possibly was looking at Fingers design) and would have them top coated and the skirts coated (my personal beliefs). Buying 8 new pistons, modifying them, and coating them is a fairly $$$ purchase compared to some who have had luck with modifying their existing pistons. The monotherms in the grand scheme (if they work) would not be that much more money.

You can run rubber pistons in your motor for all I care (we each have to make decisions on our own and sleep at night), but with the current batch of pistons available having one issue or another, it's nice to know there are those trying things to see if they can come up with a better design (Imaging where we would be if there was only stock axles available for the AAM 11.5?, even the first batch of aftermarket axles and even first batch of large diameter axles proved not to be enough when running duals until someone tried something else). I'm assuming you are running something more than a stock axleshaft as someone else proved it works better? I just don't like to see people saying they won't work without proof (especially when the design "seems" to address many of the current issues). Doesn't mean everyone should buy them and run them, just that they should get a fair shake before they are dismissed, just like Fingers design. Depending on the intent of the build, each may have their spot.

Remember how even "people in the know" said aluminum heads on a diesel was a big mistake....lol


What are u talking about?? Do u just ramble? Where did I say anything about innovation and pistons? I said saying they are a fix before they are proven is retarded. Anybody that is into building anything knows that. You have no clue how much power I make, or how long I ran cast pistons. Do u like just typing long winded paragraphs that mean and prove nothing? Maybe it was valve lash??? Lmao umm no.