WTB: 051 Piston

Been looking for same ...Matt n Bernie no got

Our friend from this site advertises on ebay for $24 or $19 so called original NFFS .051 pistons

I refuse to buy them from him just cuz of his crap on this site

What's the difference between NFFS and a regular 051 piston?

I imagine I really need a reset tool, just haven't bought one yet.

WingingIt74 wrote:What's the difference between NFFS and a regular 051 piston?

The NFFS one will only fit the NFFS cylinder are the bore is marginally bigger.

Thanks Bernie!

As far as I know a .051 piston is a .051 piston but not really sure, some claim the NFFS cylinder is tapered and the pistons are specific to it. I am not sure of this

From one web site http://www.mh-aerotools.de/airfoils/cox_frameset.htm

"To make the illegal usage of Tee Dee .051 cylinders impossible, these Medallions were to have dual slot exhausts. The transfer system of the untapered cylinder consists of two bypass flutes each having a single boost channel (the Tee Dee hast two boost channels). The later Killer Bee .051 has exhaust slits of different size. The piston shows an added grove to indicate the .051 displacement."

Mr 049 on E-Bay Sez "You may say NO, those are cox 051 that fit killer bee..
NO those are NOT taper ground, These fit the #7 medallion 051 piston ONLY!"

The fellow who sells so called NFFS .051 pistons is banking on an obscure claim that these were produced specially for the NFFS engines. His documentation is questionable

$9~$12 should be a fair price (ok maybe a few bucks more for their limited supply)

I have heard of folks with success heating and swelling a .049 or plating the .049 then lapping to fit the .051 cylinder....too much trouble for me. I have 4 .051s 2 TD and 2 Medallion (I try to have two or more of all Cox engines I intend to run (I am NOT a collector)

I am looking for .051 pistons and cylinders...no luck so I bid on almost all .051 engines on e-bay... my bail out point is usually less than the $65 to $75 these used and new .051s are getting some NIB end up over $100

I bought 2 from Tom (engine049)
Both work fine in 051tee dee cylinders.
Cheap?
No

John, you ever put a micrometer on them to see if they were tapered?

I did but I can't remember which was and which wasn't Travis.
It sparked one of those yaaaaaaaawn debates about whether Snap On gauges were accurate enough on a Thursday afternoon after Lent on here so I withdrew gracefully.
If you look through the threads somewhere you'll find it along with (I think) some photos I took.

P.S.
Ron sent me an 051 early last year which I (king kong) snapped the con rod by flooding it whilst trying to
start it.
I stuck Tom's 051 piston in it, ran three tanks through it and layed it up until the tach race in November.
If I recall after the tach race, Ron said my 051 was quite markedly the most powerful and would have easily won
if it hadn't lunched it's starter spring mid run.
Make of that what you will.

I don't think the Medallion 51s had a tapered bore

Snap on vernier or micrometers are always accurate so long as there zeroed in at start
Mine is only a blue print one .... Will have to check my 051 now to see if it's tapered

Out of interest do all the 051 pistons have rings on them as my one does /did/ has can't actually see very well where they brass copper ally ????

I've have one with 1 ring and I have another with 2 rings.

Oh ok so some have 1 some have 2 apart from said rings any other differences ? Size taper etc

Based on what I've read (and if you read it on the internet it must be true), the NFFS pistons are not tapered. The Killer Bee .051's are tapered and have two grooves and the NFFS has only one groove.

John Goddard wrote:I bought 2 from Tom (engine049)
Both work fine in 051tee dee cylinders.
Cheap?
No

How did you get them to fit? My NFFS pistons did not go into 051 cylinders.

And, yes, the ones Tom are selling are legit overages. Cox made 200 pistons and only 168 engines, hence there are bits and pieces floating around out there.

All NFFS have a single groove? The killer widow has a single groove and my killer bee has a double groove.

Yes, single groove.

Was there any 051s, besides NFFS, that were not tapered? What about the Tee Dees?

WingingIt74 wrote:Just in case Rusty jinxed me LOL

I don't have a spare

I don't recall what I said to start you worrying about that? I guess it was about my only .051 being my best runner and no spare.

I did find a new style short skirted piston in an .old style 051 SPI cylinder, and the short piston had no groove. It wouldn't have run that way with double SPI. Maybe someone shortened a regular .051 piston and removed the groove. Who knows.

All mine are mated in #5 cylinders with twin bypass twin boost and one grove on piston of my 4 cylinders three are thick walled and one is thin walled. all stamped #5...as configured all have SPI

On subject--- Like the OP I am seeking .051 pistons or P/C sets for my RUNNING engines

RknRusty wrote:

WingingIt74 wrote:Just in case Rusty jinxed me LOL

I don't have a spare

I don't recall what I said to start you worrying about that? I guess it was about my only .051 being my best runner and no spare.

I did find a new style short skirted piston in an .old style 051 SPI cylinder, and the short piston had no groove. It wouldn't have run that way with double SPI. Maybe someone shortened a regular .051 piston and removed the groove. Who knows.

You wished some bad voodoo on his Killer Widow during the tach race.