Cox Engines Forum
You are not logged in! Please login or register.

Logged in members see NO ADVERTISEMENTS!


Cox aluminum piston? Cox_ba12




Cox aluminum piston? Pixel

Log in

I forgot my password

Search
 
 

Display results as :
 


Rechercher Advanced Search

Latest topics
» Cox Texaco and Texaco Jr. built with Kustom Kraftsman's parts.
by BillLee Today at 1:06 pm

» COX .020 RC PROJECT
by TD ABUSER Today at 11:30 am

» Jim Walker Firebaby
by rdw777 Today at 9:36 am

» Project Cox .049 r/c & Citabrian Champion
by rdw777 Today at 9:27 am

» OS MAX-D
by Yabby Today at 6:09 am

» Irvine Mills .75 replica
by ffkiwi Today at 5:29 am

» Happy Birthday Robert ( Rsv1cox )
by Kim Today at 3:48 am

» **VOTE-ON-THE-NEXT-COX-ENGINE-OF-THE-MONTH** (October 2024)
by GallopingGhostler Today at 12:01 am

» WILLY NILLY
by MANDALAY Yesterday at 10:56 pm

» Stick built rubber powered Scientific ME-109
by DPCM Yesterday at 5:36 pm

» The Cabin.........A carpenters nightmare.
by rsv1cox Yesterday at 5:26 pm

» Cox 020 PeeWee rebuild questions
by rdw777 Yesterday at 2:12 pm

Cox Engine of The Month
September-2024
F4D Phantom II's

"Surestart .049 geared opposed twin"



PAST WINNERS
CEF Traveling Engine

Win This Engine!
Gallery


Cox aluminum piston? Empty
Live on Patrol


Cox aluminum piston?

Page 1 of 2 1, 2  Next

Go down

Cox aluminum piston? Empty Cox aluminum piston?

Post  Jason_WI Mon Feb 11, 2019 11:28 pm

Bought a babe bee with an advertised aluminum piston. Curiosity got the best of me and I pulled the BIN lever.

Is this something Cox experimented with? It looks professionally machined. Has a standard steel ball conrod and ballsocket in the piston.

Cox aluminum piston? Ae0f3910
Cox aluminum piston? 3aca2610
Cox aluminum piston? 7ab4a110
Jason_WI
Jason_WI
Top Poster
Top Poster

2022 Supporter

Posts : 3123
Join date : 2011-10-09
Age : 49
Location : Neenah, WI

Back to top Go down

Cox aluminum piston? Empty Re: Cox aluminum piston?

Post  1/2A Nut Tue Feb 12, 2019 7:39 am

How much does the piston and rod weigh? Was the ball socket fit good when received?
1/2A Nut
1/2A Nut
Top Poster
Top Poster

Posts : 3474
Join date : 2013-10-20
Age : 61
Location : Brad in Texas

Back to top Go down

Cox aluminum piston? Empty Re: Cox aluminum piston?

Post  Jason_WI Tue Feb 12, 2019 9:12 am

The aluminum piston weighs 1.78 gram and the steel one is 3.05 gram. The ball socket fit is perfect.
Jason_WI
Jason_WI
Top Poster
Top Poster

2022 Supporter

Posts : 3123
Join date : 2011-10-09
Age : 49
Location : Neenah, WI

Back to top Go down

Cox aluminum piston? Empty Re: Cox aluminum piston?

Post  Mudhen Tue Feb 12, 2019 10:20 am

.


Last edited by Mudhen on Wed Nov 17, 2021 2:40 pm; edited 1 time in total
Mudhen
Mudhen
Gold Member
Gold Member

Posts : 489
Join date : 2011-09-19

Back to top Go down

Cox aluminum piston? Empty Re: Cox aluminum piston?

Post  Jason_WI Tue Feb 12, 2019 11:24 am

I don’t think it’s specific to any particular engine. It was from this eBay link. The aluminum piston is the only reason I bought it.

https://rover.ebay.com/rover/0/0/0?mpre=https%3A%2F%2Fwww.ebay.com%2Fulk%2Fitm%2F292929953538

Jason_WI
Jason_WI
Top Poster
Top Poster

2022 Supporter

Posts : 3123
Join date : 2011-10-09
Age : 49
Location : Neenah, WI

Back to top Go down

Cox aluminum piston? Empty Re: Cox aluminum piston?

Post  Mudhen Tue Feb 12, 2019 12:39 pm

.


Last edited by Mudhen on Wed Nov 17, 2021 2:40 pm; edited 1 time in total
Mudhen
Mudhen
Gold Member
Gold Member

Posts : 489
Join date : 2011-09-19

Back to top Go down

Cox aluminum piston? Empty Re: Cox aluminum piston?

Post  EXModelEngines Tue Feb 12, 2019 12:50 pm

Forget exactly when they were experimented with but I believe it was in the late 70's and 80's. There were a couple versions, one like the one Jason had with the steel rod and aluminum piston and another with both aluminum rod and aluminum piston. The all aluminum version was not very durable from what I have heard, but the version with the steel rod worked well. I believe I have a small bag of all aluminum pistons somewhere.

Matt
EXModelEngines
EXModelEngines
Platinum Member
Platinum Member

Official Cox Dealer
Posts : 863
Join date : 2011-06-07
Location : Central CT, USA

http://www.exmodelengines.com

Back to top Go down

Cox aluminum piston? Empty Re: Cox aluminum piston?

Post  balogh Tue Feb 12, 2019 2:35 pm

I wonder how the different thermal expansion of aluminum piston (higher) and steel cylinder (lower) will work out? I would expect that if the fit is as tight as with the stock COX piston/cylinder combo, the engine may tighten up when hot...if the fit is lose when cold, it may become well fit when hot, but then cold starting may become difficult. This metal combination in normal size engines is common but I believe the fit is lose and compression is maintained by compression rings rather than piston/cylinder fit dimensions.

Sorry for the theoretical approach, I know that real use in life will tell the truth more than theories.
balogh
balogh
Top Poster
Top Poster

2022 Supporter

2023 Supporter

Posts : 4905
Join date : 2011-11-06
Age : 65
Location : Budapest Hungary

Back to top Go down

Cox aluminum piston? Empty Re: Cox aluminum piston?

Post  Jason_WI Tue Feb 12, 2019 2:48 pm

The fit in the cylinder this engine came with was somewhat loose. I don’t have an accurate enough micrometer to measure the difference. Work has a laser mic but it’s kept in a locked temp controlled room.
Jason_WI
Jason_WI
Top Poster
Top Poster

2022 Supporter

Posts : 3123
Join date : 2011-10-09
Age : 49
Location : Neenah, WI

Back to top Go down

Cox aluminum piston? Empty Re: Cox aluminum piston?

Post  KariFS Tue Feb 12, 2019 2:52 pm

That’s quite a weight reduction, I suppose much better than what was achieved with the lightened steel pistons. Probably good performance but short life... either because the expansion thing as Andras suggested, or the small end of the con rod getting loose quick.

It would be an interesting experience to see how fast would a Tee Dee or a Killer Bee run with a piston like that Eyebrows

KariFS
KariFS
Diamond Member
Diamond Member

Posts : 2035
Join date : 2014-10-10
Age : 52

Back to top Go down

Cox aluminum piston? Empty Re: Cox aluminum piston?

Post  1/2A Nut Tue Feb 12, 2019 5:29 pm

if used with the high performance crank the lower weight of the piston may balance out well enough
to provide a smooth running engine.

Matt if you have some and willing I would like to buy a few of the steel rod / aluminum piston versions.

Thank you!  Small Cox Logo
1/2A Nut
1/2A Nut
Top Poster
Top Poster

Posts : 3474
Join date : 2013-10-20
Age : 61
Location : Brad in Texas

Back to top Go down

Cox aluminum piston? Empty Re: Cox aluminum piston?

Post  Jason_WI Tue Feb 12, 2019 5:33 pm

Hard anodizing might help with engine life using these pistons but I’m not an expert in such things if that would be beneficial or ruin the piston fit.
Jason_WI
Jason_WI
Top Poster
Top Poster

2022 Supporter

Posts : 3123
Join date : 2011-10-09
Age : 49
Location : Neenah, WI

Back to top Go down

Cox aluminum piston? Empty Re: Cox aluminum piston?

Post  EXModelEngines Tue Feb 12, 2019 6:02 pm

1/2A Nut wrote:if used with the high performance crank the lower weight of the piston may balance out well enough
to provide a smooth running engine.

Matt if you have some and willing I would like to buy a few of the steel rod / aluminum piston versions.

Thank you!  Small Cox Logo

Only have a small handful of the aluminum pistons themselves, not assembled with the rod.
EXModelEngines
EXModelEngines
Platinum Member
Platinum Member

Official Cox Dealer
Posts : 863
Join date : 2011-06-07
Location : Central CT, USA

http://www.exmodelengines.com

Back to top Go down

Cox aluminum piston? Empty Re: Cox aluminum piston?

Post  Admin Tue Feb 12, 2019 6:25 pm

It definitely looked like a Cox made piston when I first spotted it in the eBay listing. Had the same machining pattern in the top. After reading what Matt said, it sure seems to be legit.

Lower compression engines tend to start easier. So with an aluminum piston, it may start easier, and as it warms up, compression could increase to maybe the normal amount as with a steel piston. All in addition to the lighter weight.

Let me know if you plan to part with any of those pistons, even if un-assembled Matt.

_________________
-Jacob


Admin
Admin
Administrator

Posts : 6544
Join date : 2010-07-27
Location : Roseville, Minnesota

http://sites.google.com/site/coxenginecollection/

Back to top Go down

Cox aluminum piston? Empty Re: Cox aluminum piston?

Post  Cribbs74 Tue Feb 12, 2019 6:29 pm

I’d be down for a couple too... Eyebrows
Cribbs74
Cribbs74
Moderator

2022 Supporter

2023 Supporter

2024 Supporter

Posts : 11907
Join date : 2011-10-24
Age : 50
Location : Tuttle, OK

Back to top Go down

Cox aluminum piston? Empty Re: Cox aluminum piston?

Post  1/2A Nut Thu Feb 14, 2019 7:49 pm

FYI guys I bought 3 from Matt will post results.

Matt said the steel rods are not connected to the aluminum ball socket, my plan is
to use a .09 socket reset tool to initiate the rod setting then finish out with the
.049 reset tool. If it works will post some results any helpful observations.
I will bench test with a Killer Bee clone engine I made up has all the lower end correct
parts but missing the piston and polished cylinder. I have a real KB can compare results
with my previous KB tests.

1/2A Nut
1/2A Nut
Top Poster
Top Poster

Posts : 3474
Join date : 2013-10-20
Age : 61
Location : Brad in Texas

Back to top Go down

Cox aluminum piston? Empty Re: Cox aluminum piston?

Post  Oldenginerod Fri Feb 15, 2019 4:42 am

1/2A Nut wrote:
..... my plan is to use a .09 socket reset tool to initiate the rod setting then finish out with the
.049 reset tool.

It would take quite a bit of heavy swaging to fully enclose the socket, as opposed to just squeezing a couple of thousandths during a reset.  My fear would be that the piston might distort with all that pounding.
Oldenginerod
Oldenginerod
Top Poster
Top Poster

Posts : 4010
Join date : 2012-06-15
Age : 61
Location : Drouin, Victoria

Back to top Go down

Cox aluminum piston? Empty Re: Cox aluminum piston?

Post  coxaddict Fri Feb 15, 2019 6:06 am

Did some of the pistons with the circlip assembly have alloy rods?
coxaddict
coxaddict
Gold Member
Gold Member

Posts : 429
Join date : 2013-01-27
Location : north shore oahu, Hawaii

Back to top Go down

Cox aluminum piston? Empty Cox aluminum pistons

Post  Paulgibeault Sat Feb 16, 2019 3:33 pm

HI Jason,

I guess somebody must have put together a " one off " special for you. Alum. pistons were a failed experiment tried by Cox. (They wore out very quickly apparently).

I also obtained these alum. pistons off Ebay a long time ago. They polish up like a mirror so I made ear rings for my wife out of them!

Cheers,

Paul G.    Cox aluminum piston? P1070710




[quote="Jason_WI"]Bought a babe bee with an advertised aluminum piston. Curiosity got the best of me and I pulled the BIN lever.
Is this something Cox experimented with? It looks professionally machined. Has a standard steel ball conrod and ballsocket in the piston.
Paulgibeault
Paulgibeault
Gold Member
Gold Member

Posts : 259
Join date : 2011-09-24
Location : Leduc, Alberta Canada

Back to top Go down

Cox aluminum piston? Empty Re: Cox aluminum piston?

Post  1/2A Nut Thu Feb 21, 2019 4:00 am

Parts came in I went with a low compression head and thin walled cylinder
ground down cooling fins to reduce weight.

By doing so this .049 engine with prop spinner is the lowest weight
.049 I have ever owned, of course the aluminum piston assembly
has contributed to the effort. This engine is not much more weight
than a TD .020 or the Pee Wizzer. The engine can replace a .020
powered project that is lacking punch for just a bit more nose weight.

With my scale 1.9g vs 3.2g steel piston /rod.
All up engine weight is just 33.7g less spinner and prop.
Ready to run with a carbon 4x4.5 and  TD spinner 38.7g!
Cox aluminum piston? Imag9314

When setting the steel piston rod to the aluminum ball socket use
the .049 reset tool and tap very light add oil to the socket first
light taps rotating the cupping tool every tap. Light taps like your
resetting a TD .010!
Cox aluminum piston? Imag9316

Compressing is good with a low compression plug which will help to put less stress
on the aluminum ball socket. Low mass prop such as a 5x3 will make a .020 plane
haul butt with possible unlimited vertical. Key is don't over load the over all setup,
avoid using with a heavy plane. Common sense can get some suitable lasting use with
the aluminum piston.

Oil the cupping tool end and piston footing to help avoid abrasion during the seating process.
Cox aluminum piston? Imag9317

Small Cox Logo RC Plane
1/2A Nut
1/2A Nut
Top Poster
Top Poster

Posts : 3474
Join date : 2013-10-20
Age : 61
Location : Brad in Texas

Back to top Go down

Cox aluminum piston? Empty Re: Cox aluminum piston?

Post  EXModelEngines Thu Feb 21, 2019 2:18 pm

1/2A Nut wrote:Parts came in I went with a low compression head and thin walled cylinder
ground down cooling fins to reduce weight.

By doing so this .049 engine with prop spinner is the lowest weight
.049 I have ever owned, of course the aluminum piston assembly
has contributed to the effort. This engine is not much more weight
than a TD .020 or the Pee Wizzer. The engine can replace a .020
powered project that is lacking punch for just a bit more nose weight.

With my scale 1.9g vs 3.2g steel piston /rod.
All up engine weight is just 33.7g less spinner and prop.
Ready to run with a carbon 4x4.5 and  TD spinner 38.7g!
Cox aluminum piston? Imag9314

When setting the steel piston rod to the aluminum ball socket use
the .049 reset tool and tap very light add oil to the socket first
light taps rotating the cupping tool every tap. Light taps like your
resetting a TD .010!
Cox aluminum piston? Imag9316

Compressing is good with a low compression plug which will help to put less stress
on the aluminum ball socket. Low mass prop such as a 5x3 will make a .020 plane
haul butt with possible unlimited vertical. Key is don't over load the over all setup,
avoid using with a heavy plane. Common sense can get some suitable lasting use with
the aluminum piston.

Oil the cupping tool end and piston footing to help avoid abrasion during the seating process.
Cox aluminum piston? Imag9317

Small Cox Logo RC Plane

Looks good! Let's see some tests and if they run well maybe something to experiment with in the future!
EXModelEngines
EXModelEngines
Platinum Member
Platinum Member

Official Cox Dealer
Posts : 863
Join date : 2011-06-07
Location : Central CT, USA

http://www.exmodelengines.com

Back to top Go down

Cox aluminum piston? Empty Re: Cox aluminum piston?

Post  Admin Thu Feb 21, 2019 9:18 pm

1/2A Nut wrote:Parts came in I went with a low compression head and thin walled cylinder
ground down cooling fins to reduce weight.

By doing so this .049 engine with prop spinner is the lowest weight
.049 I have ever owned, of course the aluminum piston assembly
has contributed to the effort. This engine is not much more weight
than a TD .020 or the Pee Wizzer. The engine can replace a .020
powered project that is lacking punch for just a bit more nose weight.

With my scale 1.9g vs 3.2g steel piston /rod.
All up engine weight is just 33.7g less spinner and prop.
Ready to run with a carbon 4x4.5 and TD spinner 38.7g!
Cox aluminum piston? Imag9314


Really cool!

Replace the crankcase with a narrow neck case and cut the weight even more! Does the aftermarket "Killer Bee" cranks Matt n' Bernie offer weigh less than a stock crank? One of those might squeeze some more weight out of it too.

_________________
-Jacob


Admin
Admin
Administrator

Posts : 6544
Join date : 2010-07-27
Location : Roseville, Minnesota

http://sites.google.com/site/coxenginecollection/

Back to top Go down

Cox aluminum piston? Empty Re: Cox aluminum piston?

Post  1/2A Nut Thu Feb 21, 2019 10:44 pm

Thank you gents  Thumbs Up  yes true Jacob was wondering what the weight variance is.
Even after the least weight crank is selected I may need to remove some mass
off the flywheel side of the crank.

The crank weight is 4.5g:
Matt's site says:
Manufactured to Killer Bee Specs
Handles up to 30,000 RPM
Extra Hardened Steel Crank

This is good for all out power but in this case I need the least amount of weight.
Cox aluminum piston? Imag9318
Cox aluminum piston? Kb_pis10
Killer Bee
Cox aluminum piston? Imag5710
Stock
Cox aluminum piston? Imag9320

Small Cox Logo RC Plane


Last edited by 1/2A Nut on Fri Feb 22, 2019 12:46 am; edited 4 times in total
1/2A Nut
1/2A Nut
Top Poster
Top Poster

Posts : 3474
Join date : 2013-10-20
Age : 61
Location : Brad in Texas

Back to top Go down

Cox aluminum piston? Empty Re: Cox aluminum piston?

Post  Jason_WI Thu Feb 21, 2019 11:15 pm

Those conrods that were sent have a thicker bottom than normal ones. They would be heavier and somewhat offset the lighter piston.
Jason_WI
Jason_WI
Top Poster
Top Poster

2022 Supporter

Posts : 3123
Join date : 2011-10-09
Age : 49
Location : Neenah, WI

Back to top Go down

Cox aluminum piston? Empty Re: Cox aluminum piston?

Post  Admin Thu Feb 21, 2019 11:18 pm

What if one were to sacrifice an early 3-piece piston for it's aluminum conrod?

_________________
-Jacob


Admin
Admin
Administrator

Posts : 6544
Join date : 2010-07-27
Location : Roseville, Minnesota

http://sites.google.com/site/coxenginecollection/

Back to top Go down

Cox aluminum piston? Empty Re: Cox aluminum piston?

Post  Sponsored content


Sponsored content


Back to top Go down

Page 1 of 2 1, 2  Next

Back to top

- Similar topics

 
Permissions in this forum:
You cannot reply to topics in this forum