Piston Pin Buttons?

[Nessism]

While tearing down my 8V 1000 engine (with Wiseco BB kit) I found three piston pin buttons missing(!) and the remaining buttons were fretting away in the pin bore. Three of the pistons have damage in the pin bore hole out near the circlip groove. The pistons look good other than this damage.

I think the pistons are useable if new pin buttons are installed but what do you guys think? Also, where can pin buttons be sourced and how snugly are they supposed to fit?

A member here and I are working out details of a trade where he is going to take the Wiseco?s in trade for some stock parts. I?m starting to get a little nervous since I don?t know crap about pin buttons and don?t want to pass bad parts off on anyone.

Thanks for any advice.

 

[sharpy]

First time ive seen metal buttons. But has to be a first for everything.

 

[Tarbash 27]

Talk to this guy, he sold me some new buttons a few weeks ago. He can get them cut to size. You just have to measure your wristpin length, diameter(18mm) and cylinder bore.

http://cgi.ebay.com/ebaymotors/MTC-...62QQcategoryZ34284QQihZ015QQitemZ250118617629

 

[blowerbike]

measure pin lenght and contact schintz/APE/WISECO ect.. they will sell you the 8 teflon buttons that you need.
the buttons float and should not have any pressure on the bore, marks that you can see and not feel are normal in the bore with buttons.
alm. buttons was common years ago.
hone wrist pin holes in the pistons if the pins are not smooth going in and out.
do the same to the small end of the rods if the pins are not smooth fitting.

 

[rosco15]

Throw the buttons out and just use the clips. I had some galling when I was running buttons. Went to the clips. No more galling.

 

[blowerbike]

Throw the buttons out and just use the clips. I had some galling when I was running buttons. Went to the clips. No more galling.

buttons to wide or wrist pin(s) start galling in the rods or pistons?
and there is the ever so slight amout of H/P freed up when using clips(no drag on the bore)
i am a button kinda guy though

 

[Nessism]

Throw the buttons out and just use the clips. I had some galling when I was running buttons. Went to the clips. No more galling.

The issue here is that the piston pin bore in the pistons is damaged - the C-clip grooves are rounded over so I don't trust a clip to say in place.

Seems to me that the pin buttons are just space fillers and don't need to do much. Please let me know if any of you guys think there is risk with running these pistons further as long as some new buttons are used.

 

[blowerbike]

i wouldn't use them...
send them to me
but seriously...
the buttons can not get away...
use them.

 

[rapidray]

Ed, I can hone the pin holes in the pistons for you on a Sunnen rod honing machine & get the teflon buttons for you also. Call me & let me know if you want me to help. Ray.

 

[Guest]

We have a large selection of buttons in stock.

 

[rosco15]

When I had the galling I had a local car shop run a hone thru the pin holes in the pistons. The pins slid in like butter after that. Seems like you could do exactly like ray said. It's kinda hard to tell looking at the pics how bad your damage is.

 

[blowerbike]

damn,
seems like i said the same thing early on
oh well...
ray did you find a damaged big end alt. rotor yet?

 

[rapidray]

No, Terry, STILL looking! Ray.

 

[4cyl h2]

Blower bike would u ck your inbox. Looking for some cams.

 

[trippivot]

I like the Teflon buttons , the wrist pin comes out so easy when the circlip groove is not mushroomed out. slip - slip - instead of a wrist pin vise getting it in - and - out half turn at a time.

I use them every chance I get . but if you run a slipper skirt piston - you're not so lucky.

 

[madmikeracing]

I also prefer the Teflon Glass filled Buttons, I have had some issues with cir clips in one engine, I always install them burr side out (smooth side against the wrist pin!) Actually had one come out pin nailed the liner, wasn't nice, I do drive the bejeezus out of my street bikes though, With buttons you dont have any worries assuming the rods are straight!!! Mike

 

[trippivot]

The engine building secret is this. the opening of the circlip HAS to be located at 12 o'clock or 6 o'clock PERIOD.

 

[ArttuH]

Every now and then I see/hear comments that the buttons may cause glazing of the bore walls in long term street use. I wonder if there is any truth behind this?

 

[rapidray]

Every now and then I see/hear comments that the buttons may cause glazing of the bore walls in long term street use. I wonder if there is any truth behind this?

Not with Teflon buttons. I've seen issues with aluminum buttons if the pin got stuck to one side & wouldn't move.
Ray.