arias pistons [Merged 8-8]

[Styler91TSIAWD]

I have a choice between weisco and eagles for 700 and arias and eagles for 800.

My questions are as follows.

From a reputable souce to run weisco pistons you need a .003 tolerance with JE you need .004 and with Ross you need around .005.

He mentioned nothing or arias pistons. I don't know tha much about thema and a search on here did nothing for technical inquiries.

Please post personal experiance with arias pistons and weisoc pistons. 9:1 compression on a turbo motor with a 20g. If you don't have personal with this setup please.

I was told forged pistons tend to get piston slap more than a cast piston becasue when cold there ther pistons tolerance is set more than a cast piston because of heat expansion. I know both of these pistons are high quality and people have done very well on both pistons. Thanks for you comments

 

[autronicDSM]

I seized 2 Wiseco pistons. I'm waiting fo my bore gauge to see what exactly happend (machine shop ####up or Wiseco quality).

 

[Brian Nutter]

Hi there, our recommended clearance is .003 clearance measured at the bottom of the skirt. Quite a few machine shops measure at 90 degrees from the wrist pin (common to several other manufacturers) and it can lead to problems. My personal observations are this. Seized Wiseco pistons at .003 are pretty rare due to most owners giving them a long (at least 500 miles) break in. For the guys going straight to the track or chassis dyno for an immediate beating, I'd recommend .004. The 500 miles gives the cylinder wall time to get familiar with the piston

If a customer has easy break in and still has problems, something like the machine shop issue listed above can usually be traced back. Overheating from air pockets in the cooling system sometime occur w/out the guage showing incorrectly, but that's pretty rare.

Forged pistons will almost always make more noise than cast, but to help compensate,-Wiseco offsets the wrist pins like the factory o.e. to allow the piston to "roll" up the cylinder wall instead of straight pinned pistons slapping the top land against the cylinder at rock-over at tdc.

As for price, I thought the bean-counters would add $100 to them, so we kept them low to begin with...Maybe we should raise to price to be indicative of the quality put in them compared to what I've seen from some other manufacturers.

For the guy that had a couple seizures, please feel free to call me at 800-321-1364 ext. 3177 and I'll see what we can do to help.

Thanks, Brian Nutter-Wiseco Piston co.

 

[autronicDSM]

Whatever you do don't raise prices!

I haven't disassembled the whole motor yet, waiting for my bore gauge to come in. But after checking some things over I've noticed that one piston (not damaged) actually has some slack at TDC and can be moved with a finger quiet easily. Seized pistons don't have that slack therefore I think machine shop is at fault. I was trying to call you guys soon to get clearence information but I see you posted it already. Thank you.

 

[Brian Nutter]

It will be interesting to see what you find. A little known fact to most is that most pistons are anywhere between .035 to .045 smaller at the top land than the bottom of the skirt. This is due to the much greater heat in the crown than what the skirt -which is much closer to oil temperature.

You can definitely expect the pistons to rock side-to-side when you push down on one side or another if the piston is in good shape. As you said, if the others are massively seized-they won't move mch. Let me know what you find whe you pull the pistons/rods.--Good Luck, Brian Nutter

 

[tmizer]

Brian,
Why is measuring 90 degrees to wrist pin bad? That would be at the widest part of the piston right? I've done the thermal expansion calculations as well, and my cold 0.006 clearance drops to 0.001 for a 2618 aluminum plug in a cast iron block. A machinist I work with who builds off shore blown motors verified my 0.006 (Ross spec) clearance on 2618 aluminum pistons. Now, given vertical taper (measured 0.200 " above skirt, 90 deg to pin), I'm going to go have another "discussion"....
-Tom

 

[quarter]

Originally posted by autronicDSM
I seized 2 Wiseco pistons.

that is because wiseco is for dirtbikes.

 

[Brian Nutter]

This is a great question. Here's some food for thought.

There isn't anything really wrong w/ measuring at 90 degrees to the wrist pin if a manufacturer wants you to read it there. We run our 4.500 bore blown offshore pistons at .006 clearance as well, but we're talking about a 3.346 bore here (26% smaller). The other difference w/ blown marine engines is they use cold water cooling (60 degree's) which shinks the bore more than automotive applications (180 degrees). Generally an automotive 4.500 bore piston is done w/ .005 clearance, shrinking it by the same 26% nets us .0036 clearance (more like what we run).

In Wiseco's case, we make a pistons in a variety of different heights, some of which ARE so short that measuring 90 degree's to the wrist pin wouldn't give you the pistons largest diameter. Our "1.300 below oil ring groove" will always lead a customer to measure a piston at a point where the diameter will be the greatest. This keeps our customers out of trouble.

As for expansion, 2618 alloy has basically the same expansion rate between all the piston companies that use it. Forging design is more important than alloy when it comes to how tight you can run a forged piston. We've designed the forging to be very forgiving to clearance changes. Skirt shape (cam and taper) play a huge roll as well and we've spent a long time getting it right.

The crown of a piston may only average 650 degree's by the time you average the power stroke and the cooling intake stroke. The bottom of the skirt bleeds off heat through the cylinder wall and see's something closer to 260 degree's or so (similar to oil temperatures). -This is why rings lands are so much smaller in diameter than piston skirts and why pistons grow larger in diameter the farther down the skirt you measure.

I'll phrase the next part this way, hopefully it explains a lot of differences between piston companies: Some companies do not have forgings that are dedicated to the Mitsubishi 4g63. They often weigh 30-60 grams more than a Wiseco. They often require a lot of internal milling to get the weights comparable to a Wiseco. Their expansion is greater because of the extra mass and the parts cant be run as tightly as a Wiseco. --Because we design forgings, build forging dies, and build our own forgings, our K548m85 kit comes in at 327 grams. This is light compared to most companies even though our crown thickness is greater. Look underside most Wiseco pistons and you won't see any "hacking" to get the weight down. This keeps the piston MUCH stronger as the "skin" of the forging prevents stress-risers from forming.

 

[Brian Nutter]

Originally posted by Brian Nutter
This is a great question. Here's some food for thought.

There isn't anything really wrong w/ measuring at 90 degrees to the wrist pin if a manufacturer wants you to read it there. We run our 4.500 bore blown offshore pistons at .006 clearance as well, but we're talking about a 3.346 bore here (26% smaller). The other difference w/ blown marine engines is they use cold water cooling (60 degree's) which shinks the bore more than automotive applications (180 degrees). Generally an automotive 4.500 bore piston is done w/ .005 clearance, shrinking it by the same 26% nets us .0036 clearance (more like what we run).

In Wiseco's case, we make a pistons in a variety of different heights, some of which ARE so short that measuring 90 degree's to the wrist pin wouldn't give you the pistons largest diameter. Our "1.300 below oil ring groove" will always lead a customer to measure a piston at a point where the diameter will be the greatest. This keeps our customers out of trouble.

As for expansion, 2618 alloy has basically the same expansion rate between all the piston companies that use it. Forging design is more important than alloy when it comes to how tight you can run a forged piston. We've designed the forging to be very forgiving to clearance changes. Skirt shape (cam and taper) play a huge roll as well and we've spent a long time getting it right.

The crown of a piston may only average 650 degree's by the time you average the power stroke and the cooling intake stroke. The bottom of the skirt bleeds off heat through the cylinder wall and see's something closer to 260 degree's or so (similar to oil temperatures). -This is why rings lands are so much smaller in diameter than piston skirts and why pistons grow larger in diameter the farther down the skirt you measure.

I'll phrase the next part this way, hopefully it explains a lot of differences between piston companies: Some companies do not have forgings that are dedicated to the Mitsubishi 4g63. They often weigh 30-60 grams more than a Wiseco. They often require a lot of internal milling to get the weights comparable to a Wiseco. Their expansion is greater because of the extra mass and the parts cant be run as tightly as a Wiseco. --Because we design forgings, build forging dies, and build our own forgings, our K548m85 kit comes in at 327 grams. This is light compared to most companies even though our crown thickness is greater. Look underside most Wiseco pistons and you won't see any "hacking" to get the weight down. This keeps the piston MUCH stronger as the "skin" of the forging prevents stress-risers from forming.

 

[Brian Nutter]

Kinda funny then that a "motorcycle" piston company's pistons were in the 2003 Championship winning cars for Winston Cup, World of Outlaws, IDRC PRO, and NHRA Prostock Championships in 2003-some of the Best funded and most advanced engine programs in the US. I think that speaks volumes about Wiseco's technological capabilities!

Besides, 200hp per liter motorcycle engines are the very close relatives to the 4g63. Who know's 4 valve engines better than Wiseco in that respect? -Brian Nutter-Wiseco Piston

 

[quarter]

honda has winning f1 cars. whats your point?

"the best funded and most advanced programs in the us". that speaks volumes of nothing. your "technological capabilities" arent nearly put to use on our cars like on your championship vehicles, so please spare the bs.

 

[STECARS]

yOU can also get ROSS pistons, they are pretty inexpensive.

 

[tmizer]

Brian-
I appreciate your effort on this board populated by, well, you know... anyways, while I have your ear, here's another question:

Grain structure and it's implications on coatings. My machinist was also verifying my use of coatings on a blown engine of Pr > 2.0 saying it's a must, must, MUST. However, he said, abrasive machining is a bit of a no-no in his book. Basically, the tighter grain structure on the O.D. of the piston, due to forging, is more compact and thus stronger. He said to avoid removing them and losing their structural benefit via an abrasive process, he would use some sort of "reverse" electrolysis... can't remember the name of the process, but the end result would be the same as grit blasting basically, giving the TBC or DFL coatings a surface just coarse enough to grip.

Do you know of what some of your customers are doing as these coatings are becoming more and more common or is there even a recommendation from Wiseco for such surface prep?

Btw, I've been riding motorcycles longer than 96.4% of the members of this site have been alive (by the current demographics apparently). And as an engineer in the aerospace industry I've worked with many other engineers and machinists who are also "enthusiasts" and the mere mention of Wiseco will start a near teary-eyed reminiscing of some blown KZ1000 or an obscure Husqvarna or some future blown 'Busa, or in the case of the machinist downstairs, one of his many offshore motors and the stories that go along with the eccentric millionaires he built them for. Btw, my GSX-R *must* have forged pistons because it sure does slap alot on a cold idle(!)... they're so loud, Suzuki must have sourced them from JE, heh!

Thanks for the answers, and any info on surface prep would be appreciated.
-Tom

 

[modifyer]

Originally posted by quarter
honda has winning f1 cars. whats your point?

"the best funded and most advanced programs in the us". that speaks volumes of nothing. your "technological capabilities" arent nearly put to use on our cars like on your championship vehicles, so please spare the bs.

I have used Wiseco pistons in lots of snowmobile , bike and auto engines many of them are used for racing . Almost all of these pistons were off the shelf parts and any problems that We have had have never been traced back to initial piston failure . As explained previously forged pistons have different characteristics than stock cast parts and require an understanding of this when being fitted to the engine .

 

[STECARS]

Originally posted by STECARS
yOU can also get ROSS pistons, they are pretty inexpensive.

has anyone considered ross pistons. are they no good ? basically since were comparing arias and wiseco can we include ross also and J/E , Imean its a piston discussion thread right , so lets discuss all the options.

 

[tmizer]

Short of piston design and forging process, one has 2 choices to make in a forged piston IMHO:

2618 or 4032 alloy choice.

2618 - stronger, but expands more
4032 - not as strong, expands less

I believe Arias is the only manufacturer offering a 4032 piston for a 4G63.

Wiseco, Ross, and JE are what's left and they're all 2618 alloy.

I would've got Wiseco P/N K548m85 if Ross P/N 99815 hadn't come my way inexpensively... never heard of Ross till I got a DSM, but like others here, I've certainly heard and used Wiseco. JE I crossed off my list because of the countless issues it seems to have had in DSM applications. My Ross pistons certainly appear bulletproof... but given that OEM pistons are good for 400+ WHP, these or any for that matter, forged pistons seem overkill for my *mostly* urban daily driver.
-Tom

 

[tmizer]

More info:

Wiseco: 336 g
Ross: 343 g
Arias: 362 g
JE: 342 g

These are all 2G 0.020 over pistons. Brian Nutter was indeed correct in saying that Wiseco has the lightest pistons for a 4G63.
-T

 

[STECARS]

Thanks thats been more help than all that other stuff posted earlier. I just dont understand it.(not saying it wasnt good info) but i dont comprehend it.
I was offered evo stock pistons the 85mm pistons , what do you guys think of those for a 2g with 1g rods ??

 

[tmizer]

Pistons are fine, but the 1G rods will have to be machined. You might check on how much a machine shop would charge to enlarge the small end (21mm to 22mm) and slim down the big end (you'll need to "search" that spec, I don't recall that one). Sometimes the extra machine shop cost makes a more expensive part(s) seem more reasonable.
-T

 

[STECARS]

yeah i agree , but i mean wouldnt putting eagle rods on 2g stock pistones be a waste.? would it even work.? See i need a direct dropp in , other than machining the 1g rods. Imean how much could that cost?

 

[Brian Nutter]

Concerning the coatings, Wiseco's done extensive dyno testing on them w/ 2 stroke test engines (much harder on pistons than 4 stroke). The quality of material and application is very apparent especially on the exh. side of the piston.

Coatings are used by some and not by others. It's not mandatory by any means. Our Cup and Pro Stock customers use them as $35 per piston is cheap to them for the extra bit of added insurance. We've got a couple sport compact racing customers making 250-275hp per cylinder that don't use coatings.

The 2618 alloy is the alloy of choice for boost/nitrous as it's temperature/strength characteristics are much better than 4032. The floating silicon particles in 4032 make it "porous" in effect. When a failure ccurs w/ a 4032 piston, it's pretty spectacular. 4032 will turn into a pile of shrapnel versus the 2618 alloy which "wads up" like taffy. The downside to using 2618 is this: because it lacks silicon-it get's shiny and scratches easier due to foreign material in the crankcase. It's an esthetic issue, but one that should be dealt with if possible. Wiseco added a basic (break-in) dry film lubricant to all stocking sport compact pistons as of Jan.2004 to help combat this.

Most of the coating companies purchase their chemicals from Dupont. These are modified (sometimes) and applied by Polydyn, Calico, Swain and a few others Application is done either by spray or or screen printing. Wiseco uses a couple different types of processes and even electroplating depending on the application.

The media blasting is necessary to make the coatings adhere in the long term. If the piston is properly masked, it won't cause any problems. If it isn't properly masked, the ring grooves/pinbores could be damaged or even made un-useable due to the tight clearances used. The media could be shot into the forced pin oilers with the unhappy consequenses of coming out later if the piston isn't thoroughly cleaned.

On top of that, the heat-treat hardness of the piston could be baked out if the company does the curing too high of a temperature or too long. That's why we heavily recommend leaving it to the Pro's at the above listed companies.

 

[Brian Nutter]

I know I ramble a lot, but what Wiseco does for pro customers does directly apply to shelf stock or customers that need customs. I'm the same guy taking the phone call. The engineers are the same for all customers. The modeling and programing is the same. The CNC machines are the same. The machists are the same. The material is the same. The inspectors and inspection equipment is the same. These are guys that sign off on designs and feel a pride in making a good part no matter who it's for.

The only thing that's much different on a $106-$260 piston is A: the forging is dedicated specifically to the customers dome/valvepocket/bore/height combination to get out every last gram. At about $15k per forging die, that can get expensive. B: a couple treatments to extend the useable life of the piston in 500 mile endurance races and the anodization of ring grooves which is not needed or cost effective to mortals like myself and the majority of racers.

To put it another way, I just got a piston back from a DSM customer that put down 820hp to the wheels. It's got our stock pin, the xx ring pack, the same thickness and the same forging etc. as our normal parts. It could be put back in the engine and run again if needed. We've got a 2jz toyota guy putting down 1200 to the wheels w/ our shelf stock kit. If you saw our pistons in the AEM car of Papadakis that set the record at 209mph, you won't find any significant changes except a wrist pin upgrade. At the same time one of our usually smart employees melted a piston in a 210hp motor cause he was in too much of a hurry to race instead of dynoing to find out the injectors signed off at about 180hp.

A lot of time is spent on a shelf stock piston (dedicated forging etc.) because we make a LOT of them and it quickly pays for itself to spend more engineering time up front. We're also out there to beat up on the other piston companies in competition as often as possbile even when we know them on a personal basis. Simply put, we like seeing the Wiseco sticker in the finals on TV every weekend. Kind of like living vicariously through your customers.

 

[tmizer]

Brian,
Thanks for the wealth of info! There are alot of details, minute and general, in this thread. Seems all the details are covered.

I might add 2 more coatings vendors: HPC and Keco. HPC actually does a nozzle for one of our helicopter engines, and the coating seems to hold up very well. Keco is involved with racing locally here in Indianapolis, and HPC does an immense amount of IRL and CART work it seems, and they are "Johnny-on-the-spot" with customer support.

STECARS,
When I was looking for Eagle rods, it seemed the cheapest non-ebayer's were www.nolimitmotorsport.com . I believe you can specify a OEM-type press-fit pin for Eagle rods, versus the typical floating pin found on forged pistons. You'd have to do that when ordering the rods, so check with the vendor first.
-T

 

[STECARS]

^^^ actually i 'm an ebayer. They usually got them on there for $300. thanks for everything and the link , i'll call them up, but ? still remauins
"is it worth putting eagle rods on stock pistons" ? Will it go well together?

 

[crankbender]

Brian: I have some questions reguarding your pistons and some setups including methanol use. would you like them here or in an e-mail?