So, earl.. you're saying that you die by CP's. It just seems like that when you hear of burning a sharp edge on the piston, CP's are the name you hear associated. My friend with the CRX is running a complete standalone Autronic system. He started on low boost, and tuned his way up over the matter of months. Perhaps the tuning wasn't PERFECT (I have no idea).. but there is no doubt that it is/was pretty damn good.. as good as most tuners on this board would do most likely.

So this brings me to my question about deburring.. Since you say CP's are pretty much THE BEST: Will deburring the sharp edges unbalance the piston? I'm stuck on what to do, and I want the best shelf piston that I can buy for the money that I have.. but then again, I don't want detonation/burning on the piston.

 

CP will tell you that any mods to the top of a piston can destroy the flatness of the land. I once felt that it was wrong to deburr a CP for fear of destroying this flatness. I have changed my attitude slightly and now say that it would be ok to polish off any sharp edges. To answer your concerns, just because the name CP is on the piston, people may think they can push the tune-up further. You really can't. Aluminum melts at a given temp. It does not matter whose name is on the forging. It's just simple laws of nature.

One of the two keys to good ring seal (the other being ring seating) is how perfectly flat the ring lands are. The way most pistons are manufacturered, the ring lands are final cut in the middle of the manufacturing process. With CP, they are only rough cut during the process. Once the piston is completely done, the final step is a precision laser guided ring land finishing. This insures that the lands are perfectly flat. Other piston companies would charge you more for this service. It is called the "flat ring land option". Every CP is made like this.

BTW, I could make more money selling another brand of piston but I choose CP for their quality over any other manufacturer.

 

Earl, your a god.

 

...

I'm even more confused now than when I started reading this thread.

What about Wiseco's?

 

I really won't knock any brand of piston but prefer to share why I use CP's.

 

Earl, I know the guy whose CRX melted a piston. He is ridiculously conservative with his igntion timing. He is meticulous about the AFRs he runs. He did tune the car doing some loading on the dyno dynamics dyno, but did so with conservative AFRs and not much timing. The set of CPs in questions didn't melt because of aggressive tuning. I can tell you that 100% for sure.

 

If the pistons were defective, all 4 would melt equally at the same time, not just one. If a piston were to break a pin boss, that would be a defect. If a piece of skirt were to break off with no heat showing on the piston, that would be a defect. If pistons came from the factory out of round or a collapsed land, that would be a defect. But pistons don't melt because of a defect.
Remember A/F ratios are an average from 4 cylinders. 3 fat cylinders can mask one cylinder that is leaning out and give you a perfect A/F.

 

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by earl &raquo;</TD></TR><TR><TD CLASS="quote">Remember A/F ratios are an average from 4 cylinders. 3 fat cylinders can mask one cylinder that is leaning out and give you a perfect A/F.</TD></TR></TABLE>

There is tremendous truth in earl's statement above, hence why you see a wideband O2 and a EGT on every cylinder in certain applications ...

 

This is true.. but it doesn't explain this "phenomena." This is a common problem, so I'm coming to believe. The metal around the valve reliefs come to very sharp edges. Thinner metal heats faster, which leads to detonation. This is why people 'debur' the tops of the pistons. But why should I buy a piston that is machined perfectly flat for a reason, just to ruin that aspect so it won't expletive up my engine?

 

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by earl &raquo;</TD></TR><TR><TD CLASS="quote">If the pistons were defective, all 4 would melt equally at the same time, not just one. If a piston were to break a pin boss, that would be a defect. If a piece of skirt were to break off with no heat showing on the piston, that would be a defect. If pistons came from the factory out of round or a collapsed land, that would be a defect. But pistons don't melt because of a defect.
Remember A/F ratios are an average from 4 cylinders. 3 fat cylinders can mask one cylinder that is leaning out and give you a perfect A/F.</TD></TR></TABLE>

how would all 4 melt at the same time? what if those 4 pistons you bought were proccessed and forged at 4 different times on diff machines... how do you know that you didnt get a diff. pistons mixed in from another batch of the same? and maybe only 1 or 2 were defective? how do you know that metal isnt fagtiuges or defective from the block or chunk it was cnc'd out of? you dont.

earl has been building successful motors for years, so he is going to go with what works for him plain and simple.. GE has been building successful motors for years as well also... and the same with ERL, all three are good engine builders and the thrive and use what works for them and what they trust, and what makes them the most profit...

really all the technology is very similar, its a flucking piston not a spaceship... i think all this best theory is a bunch of bullsh*t.. the difference is that this bussiness is all about politics and money.. company X has more money then company Y so they have this special machine to do this blah blah blah.. marketing, advertising, and preference is what its all about.

you can't come on here and expect everyone to chime in and tellyou to buy this piston, b/c then you will just base your decision on what someone told you.. do some research on the company and find figure it out.. you have to sleep confident at nite knowing your comfortable with your choice.

i heard that bill miller guy who sells pistons knows a thing or 2.

arias, CP, JE whatever... if you build it correctly and tune accordingly you should have success, unless their is a defect or rarity that happens when other things are constant... but now we get into a whole nother chapter of how it was built and the techniques used, see where im getting at?

make a choice with what you feel confident in, not based on what someone told you or price or blablahahahah...

good luck.

 

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by ccivic &raquo;</TD></TR><TR><TD CLASS="quote">Thinner metal heats faster, which leads to detonation. This is why people 'debur' the tops of the pistons.</TD></TR></TABLE>This is what confuses people. If the temperature is correct INSIDE the combustion chamber, meaning the tune-up is proper, razor sharp edges will NOT become hot enough to cause detonation.<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by ccivic &raquo;</TD></TR><TR><TD CLASS="quote"> But why should I buy a piston that is machined perfectly flat for a reason</TD></TR></TABLE>Perfectly flat ring lands are CRITICAL to ring seal. Without that, pressure can escape from behind the ring. That is just as important as ring to cylinder seating.

 

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by manikGSR &raquo;</TD></TR><TR><TD CLASS="quote">how would all 4 melt at the same time? what if those 4 pistons you bought were proccessed and forged at 4 different times on diff machines... how do you know that you didnt get a diff. pistons mixed in from another batch of the same? and maybe only 1 or 2 were defective? how do you know that metal isnt fagtiuges or defective from the block or chunk it was cnc'd out of? you dont.</TD></TR></TABLE>Haha, it doesn't work that way. There are only one or two aluminum foundrys in the USA that supply the raw material to piston manufacturers. All piston companies buy their blank slugs from these companies. They are all made from the same aluminum. If one piston is defective, 5000 pistons will be defective. The difference in quality is all in the machining process, the quality of the machines, the operators, the method of QC checking at each machine stage, etc.

 

great thread. i'm probably going with wiseco's myself because i've found them to be very competitively priced.

MY QUESTION is this: i'd like to probably keep the stock sleeves for now but may upgrade later on. should i stay with the 81mm bore or go bigger? i'm aiming for 450-500 whp in my b17. or should i just stick with the stock sleeves and a block guard for my hp target?

 

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by earl &raquo;</TD></TR><TR><TD CLASS="quote">Perfectly flat ring lands are CRITICAL to ring seal. Without that, pressure can escape from behind the ring. That is just as important as ring to cylinder seating.</TD></TR></TABLE>

My point is, I understand that the pistons are machined the way that they are for a reason. But, people seem to have problems with the sharp edges; which makes me want to 'debur' the sharp edges. I don't want to ruin the flatness/design of the pistons by polishing off the edges, but this seems like the 'correct' way to do it. It seems like either way I turn, it's the wrong way.

 

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by weirRacing &raquo;</TD></TR><TR><TD CLASS="quote">great thread. i'm probably going with wiseco's myself because i've found them to be very competitively priced.

MY QUESTION is this: i'd like to probably keep the stock sleeves for now but may upgrade later on. should i stay with the 81mm bore or go bigger? i'm aiming for 450-500 whp in my b17. or should i just stick with the stock sleeves and a block guard for my hp target?</TD></TR></TABLE>

From everything that I've read/heard, it's proper engine building technique to bore .5mm over what you already have. The reason for this is so the cylinder walls are perfect.. all clearances are perfect, etc. Cylinders get egg shaped after a while (not visible to naked eye), so boring it out .5mm takes it back to a perfect circle. This is why I'm boring my block out, then when I get my sleeved block next year it will be 81.5mm to match the internals that I'm getting now.

 

thanks for the answer. makes complete sense.

 

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by ccivic &raquo;</TD></TR><TR><TD CLASS="quote">From everything that I've read/heard, it's proper engine building technique to bore .5mm over what you already have. The reason for this is so the cylinder walls are perfect.. all clearances are perfect, etc. Cylinders get egg shaped after a while (not visible to naked eye), so boring it out .5mm takes it back to a perfect circle. This is why I'm boring my block out, then when I get my sleeved block next year it will be 81.5mm to match the internals that I'm getting now.</TD></TR></TABLE>

and ull need new everything anyway (seals, rings, bearings)??!?! why not go bigger? make some POWA

 

I know things have gone a little nuts on a thread when our customers start emailing me about it. Things seem to have gotten a little out of hand.

First, I know the guys at every piston manufacturer, with very few exceptions we're all very friendly with each other and enjoy competition as much as any racer does. Many of these manufacturers make good useable parts overall. Each one messes up once in a while, but they obviously average well enough to stay in business. Machining quality is a matter of averages...it's easy to make one perfect piston, but it's difficult to do it "perfectly" every time. Wiseco puts a LOT of effort properly engineering even our least expensive parts. It costs relatively little to get it done right the first time, but a LOT if we get it wrong.

Each manufacter has a stated level of tolerances...whether they adhere to them or not depends on how much they can afford to scrap, if they're behind on shipments, or whether they feel a given customer is going to notice or be able to measure it or not. I can tell you that Wiseco is up to the challenge of a truly independent person ordering pistons from INDEPENDENT distributors and taking them to a independent company with a CMM. This way you're measuring averages produced by manufacturers and not "ringers". Heck, I'd even buy the piston back myself after testing, but the guy that's tested it is going to want 3 more when everything is said and done

Actually, "The test" has been done before, so I feel very confident about it. The person who did the test couldn't be considered ABSOLUTELY in dependent because he didn't carry all the different brands. I believe that the results he came up with were accurate though. We measure all of our competitions parts on consistent basis and I know the truth. I've had disgruntled customers from all the piston companies call us for help to fix their errors and I'm sure the other piston manufacturers could say the same about us. Most importantly, not everyone who gave opinions above have the deepest deal with all the manufacturers and can't be considered independent until they do because of potential lost sales. It will take a racer to do it.

If anyone is interested in repeating the test, it was superior to anything I've ever seen. It was truly inspired, but unfortunatly never reached the mass market due to considerable legal issues. I told him Wiseco wouldn't touch it with a ten foot pole Imagine that this person would be sued by the loosing 7 piston companies...he'd have to keep those samples locked up in fort knox to get him out of the issue, but even then...their would be considerable expenditures necessary to protect himself in the courts. To give you an idea, the test measured piston weight, pin weight and thickness, ring thicknesses and quality, valve pocket depths and diamters, valve pocket to edge thicknesses, deck thickness and the thickness beneath the valve pockets, skirt thickness, skirt taper measurements, pin oiling, ring land thicknesses, pin to oil ring measurements, hardness (heat treat), recommended skirt clearances, pin to pin bore clearance and finish, pin bore to deck parralellism, alloy purity, etc. He also looked at features like pin offset and skirt coatings.

There are some issues that I feel that ALL manufacturers have a harder time dealing with. At what horsepower level do you tell someone to move up to a .200 wall tool steel pin that costs a bunch of money. Does one decrease the valve diameters and shallow the pockets if it adds strength to the lands, but everyone with big cams and oversize valves snaps the heads off (and blames the valve maker) At what horsepower level is it necessary to increase skirt to bore clearance and begin ordering custom pistons with custom land diamters, deck thicknesses, and skirt tapers. These are all grey areas because some go far with little and some go 30 feet with a lot. I can tell you that the highest horsepower customers in sport compact racing don't use any manufactuers "shelf stocking" pistons because of these issues. If they do, they're loosing horsepower if not breaking engines. Wiseco has the AEM cars, the Skunk cars, and numerous others making more power than anyone else in their prospective classes. There are more, but I can't say with all CERTAINTY that we're ALWAYS in their best engines. Each manufacturer has their "all stars"...often had by giving away parts. Wiseco will give you every bit of technology your wallett can endure. We'll be very honest about whether our shelf stock pistons are going to handle the power you will produce....we'll save you money if we can, but will spend it if we need too. A broken piston costs Wiseco more than you can imagine. Our goal is no broken parts due to design or manufacturing errors.

To answer some specific questions, Wiseco pistons can be custom ordered with brushed tops. Only $4 each! You won't hurt ANYONES pistons by polishing the tops, but don't expect to cut domes down or deepen valve pockets without *some* ring groove distortion or skirt collapse. By all means debur and polish the pistons...you're just that much further away from harm if you spend 20 minutes doing it. Gram weight changes (very very slight) from doing this are far less costly than snapping off a ring land due to hot spots generated by the sharp edges outside the valve pockets.

There was also a comment about 20 year technology...it's true that a 5 year old company can use old technology in the same way a 64 year old company can...It's all about pushing the boundaries and spending money on forging design etc. In that respect, I think Wiseco is the most innovative because we do our forgings in house and we pull technology from Cup, Pro Stock, IRL, GP bikes etc. No B.S. there...Just look at our record since 2002 when our sport compact catalog came out. The person that made the statement about "laser guided ring land finishing" will have to have a conversation with me over a beer sometime or have a talk with BRUNO our lathe operator There was also some B.S. about Laser micrometers and such- that's old technology as any familiar engineer can attest. Our particular machines are Mahr guages...a piston engineer's wet dream. I can tell you that JE has an excellent temperature controlled lab and we do as well. Others might, but I can't say one way or another because I haven't been there.

All piston companies use 2618 alloy in our best parts. Wiseco starts with extruded bar stock rather than buying forging from another forging house, so I can't say anything positively or negatively about the other piston companies in that regard. I can tell you that Wiseco's forgings are constantly evaluated and built up if necessary because it doesn't cost Wiseco as much to make these changes as the other companies would have to endure. We also do the heat treat in-house. We also sell forgings to some of the other piston companies. We are the sole U.S. distributor for NPR rings and we sell these excellent rings to the other piston companies. A company like that doesn't take their choice in partners lightly. The last point I'll make is Wiseco has 2 in-house dyno's that we test with. Forgings, materials, skirt shapes, etc...all the time and have for years. As a Dover company, I can tell you we have a LOT of R&D money at our disposal and we use it.

My goal isn't to offend or mock anyone here, but there aren't too many people directly outside the piston companies themselves that know the whole truth. As always, anyone that has an issue can give me an email at bnutter@wiseco.com . I believe Wiseco is the best at addressing any negative issues with our shelf stocking pistons quickly. It costs us very little to make a manufacturing or specification change if not completely updating to a new part number if changes are necessary. Just let us know how we can help.

Thanks, Brian Nutter-Wiseco Piston


Modified by BrianNutter at 10:05 PM 12/5/2005


Modified by BrianNutter at 10:08 PM 12/5/2005

 

This Is Why RLZ uses Wiseco in Everything we build .......

 

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by MAX_CFM &raquo;</TD></TR><TR><TD CLASS="quote">This Is Why RLZ uses Wiseco in Everything we build .......</TD></TR></TABLE>

My buddy has a 524whp (@ 0 psi, no spray no nothing all motor ) 427ci in his C5 corvette, and it uses Wiseco pistons as well.

 

There will be numerous people that come forth with whatever success they have had using whoever's pistons. I really believe that most of it comes down to experience using any particular piston and the resutls from that. Some builders will prefer one company over another, some tuners are the same way, some people base their decisions on their friends experiences, point is that there is no ONE definitave " BEST PISTON" manufacturer. They all have their pro's and cons. With that sais, I again have used A LOT of different piston manufacturers, and I swear by Arias, always have. I have put them into the AEM Landspeed Record holding car, into Ed Bergenholtz's motor, into numerous other high HP applications and street machines, all of them with excellent results.

I do appreciate some real piston manufacturers response on here ( Briannutter ). I think that is a very good thing to do and wish we saw more of it from others as well.

 

Wiseco

 

Weisco