2618 Piston Street Use Longevity

General engine tech -- Drag Racing to Circle Track

Moderator: Team

Barry_R
Guru
Guru
Posts: 1232
Joined: Wed Jan 18, 2006 8:57 pm
Location: Detroit area
Contact:

Re: 2618 Piston Street Use Longevity

Post by Barry_R »

MadBill wrote:
4vpc wrote:... but for the builder reducing crevice volume to the absolute minimum pays surprisingly large power dividends. (math available on request)
That line of thought might lead somebody to try running the piston out of the hole by a fair amount and using a thick head gasket right at bore diameter to get the desired quench. Keeps the top ring in a nice safe place on the piston, uses more of that really rigid part of the bore up into the deck area, reduces crevice volume.

Never heard of anybody doing that....but those .066 and .078 Cometics sure come in handy.... :wink:
Survival Motorsports
www.survivalmotorsports.com

WD for Comp, Manley, Blue Thunder, Diamond
Probe, Holley, Clevite, Federal-Mogul, Scat....
User avatar
MadBill
Guru
Guru
Posts: 15024
Joined: Tue Nov 15, 2005 10:41 am
Location: The Great White North

Re: 2618 Piston Street Use Longevity

Post by MadBill »

Unfortunately there is less tolerance control on gasket ID and alignment than on bores, so a thick gasket would likely result in a larger minimum safe CV.

Speaking of same, lots of guys wouldn't think twice about using an oversize ID gasket but a say 4.200" x 0.040" one on a zero deck 4.030" block would result in a substantial increase in minimum attainable CV.
Felix, qui potuit rerum cognscere causas.

Happy is he who can discover the cause of things.
4vpc
Pro
Pro
Posts: 337
Joined: Thu Jan 21, 2016 6:26 pm
Location:

Re: 2618 Piston Street Use Longevity

Post by 4vpc »

Barry_R wrote:
MadBill wrote:
4vpc wrote:... but for the builder reducing crevice volume to the absolute minimum pays surprisingly large power dividends. (math available on request)
That line of thought might lead somebody to try running the piston out of the hole by a fair amount and using a thick head gasket right at bore diameter to get the desired quench. Keeps the top ring in a nice safe place on the piston, uses more of that really rigid part of the bore up into the deck area, reduces crevice volume.

Never heard of anybody doing that....but those .066 and .078 Cometics sure come in handy.... :wink:
Yeah they sure do. More than a few times I've taken a dished aftermarket forged with the wrong CR, put it in the lathe and turned the top off, used a thinner Cometic and gained half a point along with less crevice volume.
There is no S on the end of RPM.
302ford
Member
Member
Posts: 147
Joined: Sat Sep 22, 2007 11:03 am
Location:

Re: 2618 Piston Street Use Longevity

Post by 302ford »

Hi Bill this is Randy have something I'd. Like to discuss something with you on this subject by email but have lost it, thanks Bill
CharlieB53
Pro
Pro
Posts: 223
Joined: Fri Nov 22, 2013 2:44 pm
Location: Wright City, Missouri

Re: 2618 Piston Street Use Longevity

Post by CharlieB53 »

Heating a piston in the oven to measure the crown may be fine but measuring the skirt may be misleading.

Follow the heat path in operation the contact areas of the skirt should prove measureably less than the none contact areas 90 * off.

This difference in temps could transfer a cold oval into round at running temps.
englertracing
Guru
Guru
Posts: 1547
Joined: Thu Sep 29, 2011 8:55 am
Location:

Re: 2618 Piston Street Use Longevity

Post by englertracing »

4vpc wrote: Sat Aug 05, 2017 9:13 am If you can get your hands on a forged OE Honda F20C piston then I would recommend it, you'll learn lots with a straight edge and simple measuring tools and that's a design that is now 17yrs out of date. Top ringland is barrel shaped and looking on top of the crown you'll notice it's oval too. Bore clearance is less than leading manufacturers were using with cast pistons many years ago, and not by a little bit either, spec on P182 here: http://www.wedophones.com/Manuals/Honda ... Manual.pdf

The top ringland is not only oval in circumference and barrel shaped from the side, but it's also been treated in some way as it's dark grey, I'm assuming anodised, to stop it wearing, but unsure why they only did that part.
A lot of aftermarket piston manufacturers are still pretty dumb and so are your pistons, that's why they still say use .040 clearance on a 3.385 piston, they haven't done any R&D, so as long as it slops up and down ok without nipping it does the job - to a fashion. I wouldn't be at all surprised if aftermarket slugs for that engine are nowhere near as cleverly designed as the Honda ones were.
The problems are finding an intelligent piston manufacturer who has the equipment to do the job and also someone who can design one, but if you take some pointers yourself from something like the F20C you'll get a lot closer than most to designing a good piston, then you've got to do your own R&D and find out how close you can get it before it hits the bore, because your block and bore is unlikely to be made in the same way as that one was......
Fyi
Not only is CP capable of doing it, they recommended it while I was revising a set of pistons. They said they find it most effective in bores less than 85mm. Costs 15$ per piston. Ring lands 0.005" narrower on the pin axis.
I'm not sure what it's really worth.
DCal
Expert
Expert
Posts: 769
Joined: Fri Aug 11, 2006 11:37 am
Location: mooresville nc

Re: 2618 Piston Street Use Longevity

Post by DCal »

englertracing wrote: Tue Aug 27, 2019 12:32 am
4vpc wrote: Sat Aug 05, 2017 9:13 am If you can get your hands on a forged OE Honda F20C piston then I would recommend it, you'll learn lots with a straight edge and simple measuring tools and that's a design that is now 17yrs out of date. Top ringland is barrel shaped and looking on top of the crown you'll notice it's oval too. Bore clearance is less than leading manufacturers were using with cast pistons many years ago, and not by a little bit either, spec on P182 here: http://www.wedophones.com/Manuals/Honda ... Manual.pdf

The top ringland is not only oval in circumference and barrel shaped from the side, but it's also been treated in some way as it's dark grey, I'm assuming anodised, to stop it wearing, but unsure why they only did that part.
A lot of aftermarket piston manufacturers are still pretty dumb and so are your pistons, that's why they still say use .040 clearance on a 3.385 piston, they haven't done any R&D, so as long as it slops up and down ok without nipping it does the job - to a fashion. I wouldn't be at all surprised if aftermarket slugs for that engine are nowhere near as cleverly designed as the Honda ones were.
The problems are finding an intelligent piston manufacturer who has the equipment to do the job and also someone who can design one, but if you take some pointers yourself from something like the F20C you'll get a lot closer than most to designing a good piston, then you've got to do your own R&D and find out how close you can get it before it hits the bore, because your block and bore is unlikely to be made in the same way as that one was......
Fyi
Not only is CP capable of doing it, they recommended it while I was revising a set of pistons. They said they find it most effective in bores less than 85mm. Costs 15$ per piston. Ring lands 0.005" narrower on the pin axis.
I'm not sure what it's really worth.
My bothers (CP Pistons) were just out here for a get-together at my house and we read this thread in its entirety and I've been filled in on what's going on at CP;
Still doing the Z06 pistons
Still doing the Porsche GT-3 pistons
Still doing 7 models of KTM motorcycles
Still doing the Porsche 918 pistons
Working with GM on other projects that I can't divulge. I don't think that technology is dead in the piston industry or that we make "dumb pistons"
rebelrouser
Guru
Guru
Posts: 1944
Joined: Tue Sep 15, 2015 2:25 pm
Location:

Re: 2618 Piston Street Use Longevity

Post by rebelrouser »

all my race engines use ross pistons with 2618-T61 alloy, very strong tuff pistons. When I build a dual purpose street strip type engine I use the 4032 alloy. The main reason is that I have seen a lot of scuffing and cylinder wear from the skirts of the 2618 alloy pistons when used in street engines for a lot of miles. The silicone wears better for a lot of miles. And I have never really built a serious street strip engine I guess, most of my street N/A are in the 500 to 600 HP level. For what my experience is worth.
4vpc
Pro
Pro
Posts: 337
Joined: Thu Jan 21, 2016 6:26 pm
Location:

Re: 2618 Piston Street Use Longevity

Post by 4vpc »

englertracing wrote: Tue Aug 27, 2019 12:32 am
4vpc wrote: Sat Aug 05, 2017 9:13 am If you can get your hands on a forged OE Honda F20C piston then I would recommend it, you'll learn lots with a straight edge and simple measuring tools and that's a design that is now 17yrs out of date. Top ringland is barrel shaped and looking on top of the crown you'll notice it's oval too. Bore clearance is less than leading manufacturers were using with cast pistons many years ago, and not by a little bit either, spec on P182 here: http://www.wedophones.com/Manuals/Honda ... Manual.pdf

The top ringland is not only oval in circumference and barrel shaped from the side, but it's also been treated in some way as it's dark grey, I'm assuming anodised, to stop it wearing, but unsure why they only did that part.
A lot of aftermarket piston manufacturers are still pretty dumb and so are your pistons, that's why they still say use .040 clearance on a 3.385 piston, they haven't done any R&D, so as long as it slops up and down ok without nipping it does the job - to a fashion. I wouldn't be at all surprised if aftermarket slugs for that engine are nowhere near as cleverly designed as the Honda ones were.
The problems are finding an intelligent piston manufacturer who has the equipment to do the job and also someone who can design one, but if you take some pointers yourself from something like the F20C you'll get a lot closer than most to designing a good piston, then you've got to do your own R&D and find out how close you can get it before it hits the bore, because your block and bore is unlikely to be made in the same way as that one was......
Fyi
Not only is CP capable of doing it, they recommended it while I was revising a set of pistons. They said they find it most effective in bores less than 85mm. Costs 15$ per piston. Ring lands 0.005" narrower on the pin axis.
I'm not sure what it's really worth.
It's good to know someone recognises it and is applying it, also since writing that i've examined a few more pistons and found the oval-around-the -crown thing to be nothing new, i've found it in engines designed in the 80s too.
What i'm trying to point out overall is that there are many things to be learned from OEM pistons, that the aftermarket doesn't utilise them, we need to recognise them and push for them.
I would say your average engine builder has no idea what they're putting in an engine, just as long as it says 'forged' on the box and it's shiny it's good to go and we'll give it .1 clearance.
I recently looked at an old (2006) Mazda designed piston in regards to pin oiling. They'd drilled through the oil ring groove and then at 90' to that from below right through the pin boss and over the other side until the holes joined up. Also they had two oil grooves through the pin boss making 8 pin oilers per piston so the pin was getting fed every 90' of it's circumference. It had done 120k and had practically zero wear on it (anywhere), it would have done double that easily.
I then looked at its aftermarket forged replacement - four grooves fed from the inside of the piston only.
So they'll be on the mill today for some extra holes putting in them. :D
There is no S on the end of RPM.
User avatar
MadBill
Guru
Guru
Posts: 15024
Joined: Tue Nov 15, 2005 10:41 am
Location: The Great White North

Re: 2618 Piston Street Use Longevity

Post by MadBill »

Speaking of piston evolution, I am extremely puzzled that with the exception of Bombardier (per attached) no O.E.M. or aftermarket mfgr. to my knowledge has taken advantage of this advanced (15-year old!) NASA alloy MSFC-398. Maybe our researcher extrodinaire, Kevin J. can drill down on the subject...:-k

https://www.nasa.gov/centers/marshall/n ... 4-117.html




For release: 04/22/04
Release #: 04-117

Thanks to NASA technology, patented high-strength aluminum alloy makes outboard motors quieter and cleaner

Photo description: Jonathan Lee, a Marshall Center structural materials engineer, displays a variety of uses for NASA's High-Strength Aluminum Alloy used for pistons in a line of outboard engines from Bombardier Recreational Products.
Some boating excursions are now quieter, cleaner and their boat engines enjoy improved fuel mileage and increased durability — all thanks to a NASA invention. The Boats and Outboard Engines Division at Bombardier Recreational Products of Sturtevant, Wis., uses NASA's patented High-Strength Aluminum Alloy for pistons in its Evinrude® E-TEC™ outboard engine line. The technology was developed at NASA's Marshall Center.

Photo: Jonathan Lee, a Marshall Center structural materials engineer, displays NASA's High-Strength Aluminum Alloy. (NASA/MSFC/E. Given)

A NASA invention that can make outboard engines quieter, cleaner, gives better fuel mileage and increased durability has been adapted for commercial use by a major international corporation.

The Boats and Outboard Engines Division at Bombardier Recreational Products (BRP) of Sturtevant, Wis. — has begun using NASA's patented High-Strength Aluminum Alloy for pistons in its new Evinrude® E-TEC™ outboard engine line.

The alloy, developed at NASA's Marshall Space Flight Center in Huntsville, Ala., is used in a new piston design that reduces the so-called "slapping" sound when pistons slide up and down in the engine's cylinder. The alloy can greatly improve piston durability because it is two and half times stronger than conventional cast aluminum pistons at high temperature and can be produced with a material cost of less than $1 per pound. It exhibits dramatic strength at temperatures as high as 500 to 700 degrees Fahrenheit.

Engineers working on BRP's Evinrude E-TEC engine also saw environmental advantages from the alloy; it would help the new engines comply with California Air Resources Board emissions standards—some of the most stringent in the United States.

It was simply a matter of searching the information highway. BRP met with NASA in April 2002, after seeing an ad on the Internet for a high-strength aluminum alloy. The prototypes were complete by July, and the final product was ready in February 2003. "We worked very closely with NASA to refine the details," said Bob Young, vice president of product development for BRP. "The demands of the outboard engine are more significant than any other engine NASA had encountered, even those in the auto industry. The team from NASA was on the fast-track, learned all the intricacies and delivered an outstanding product."

Development of the NASA High-Strength Aluminum Alloy began seven years ago when a major automobile manufacturer approached NASA seeking a solution to reduce the costs of aluminum engine pistons, as well as to lower engine emissions. NASA was also interested in developing an alloy with higher strength and wear-resistance at elevated temperatures, for aerospace applications. So, in this case "necessity as the mother of invention" was a motivator from two directions and the Partnership for Next Generation Vehicles was born.

Jonathan Lee, a structural materials engineer in the Marshall Center 's Materials, Processes and Manufacturing Department, and co-inventor PoShou Chen, a scientist with Morgan Research Corp., in Huntsville, tackled the project. The result was discovery of what would become the basis for a new aluminum alloy, MSFC-398 or NASA High-Strength Aluminum Alloy. The NASA Technology Transfer Partnership introduced it during the 2001 National Manufacturing Week show in Chicago.

Evinrude's outboard engine piston is the result of more than a year of intensive work between the company's piston casting vendor and NASA's inventors to learn about and refine the process of casting the new alloy.

"Having a proper mixture of the alloy's composition with the correct heat treatment process are two crucial steps to create this alloy for high temperature applications," said Lee. "The team at Bombardier Recreational Products worked hard with the casting vendor and NASA inventors to perfect the casting of pistons, learn and repeat the process, and bring its product to market. Chen and I are honored to see something we invented being used in a commercial product in a very rapid pace. We still have to pinch ourselves occasionally to realize that BRP's commercialization effort for this alloy has become a reality. It's happened so quickly."

"The usual cycle for developing this type of technology, from the research stage to the development phase, and finally into a commercial product phase may take several years and more than a $1 million investment," Lee said. In this case, it has occurred in less than four years at a fraction of the cost.

The Evinrude E-TEC outboard engine line uses pistons made with the NASA High-Strength Alloy in its mid-power range of recreational boating in its current 40-90 horsepower engine offering.

BRP projects it will manufacture several hundred thousand pistons for outboard motors using the NASA High-Strength Aluminum Alloy over the next several years.

"The weak link in any two-cycle engine has always been the piston, due to the high operating temperatures. The strength of this piston is stronger than anything we ever used or ever seen," said Young. "It's now at least double the strength of the previous alloys and within our rigorous testing schedule, we have yet to see an alloy-related piston failure."

The license agreement between BRP and NASA was signed in July 2003. The Research Triangle Institute in Raleigh, N.C., a contractor to NASA, working with Marshall 's Technology Transfer Department, played a key role in bringing the parties together. The Institute offers research and development in areas ranging from health and environmental protection, education and training, economic and social development and advanced technology.

"This is another outstanding example of NASA's Innovative Technology Transfer Partnerships program at work with a variety of industries to move the benefits of aerospace technology to the public and private sector while supporting NASA's goal of improving life on Earth," said Sammy Nabors, commercial technology lead in the Marshall Center 's Technology Transfer Department. Nabors predicts many other uses for the alloy in the future, as well, as additional commercial licensing agreements.

For more information on the Marshall Center 's Technology Transfer program, visit:

http://www.nasasolutions.com

For more information about Bombardier Recreational Products visit:

http://www.recreation.bombardier.com

For supporting materials for this news release – such as photographs – please visit the NASA Marshall Center Newsroom at:

http://www.msfc.nasa.gov/news

For more information:
News release
Photo


Contact
Jerry Berg
Public Affairs Office
(256) 544-0034

Dave Thompson,
Director of Communications
Bombardier Recreational Products
Boats and Outboard Engines Division
Sturtevant, Wis.
(262) 884-5399)

Graphic for line

E-mail

Get releases sent directly to you!
Contact:
Betty Humphery

Graphic for line



› Back To Top
Felix, qui potuit rerum cognscere causas.

Happy is he who can discover the cause of things.
PackardV8
Guru
Guru
Posts: 7633
Joined: Sun Jul 30, 2006 2:03 pm
Location: Spokane, WA

Re: 2618 Piston Street Use Longevity

Post by PackardV8 »

If I'm reading this correctly, these are cast pistons. Anyone see anything about its application for forgings?
Jack Vines
Studebaker-Packard V8 Limited
Obsolete Engineering
4vpc
Pro
Pro
Posts: 337
Joined: Thu Jan 21, 2016 6:26 pm
Location:

Re: 2618 Piston Street Use Longevity

Post by 4vpc »

Why would you need a forged piston when this new cast alloy is 2.5 times stronger than the old type?
For all we know it may be in use by several companies already....
There is no S on the end of RPM.
Post Reply