Fully floating pistons
Turbo Mini Forums

Alright folks, bought some new forged pistons of a guy whos changed his plans... theyre fully floating, all im missing is the gudgeon pin circlips, any idea where i could get some of these?
they are IASA 73mm 8cc pistons if thats any use.
searched mini speed and med etc, maybe im best calling up...

Minispeed sell them I believe, so they will be the best bet.

Failing that they may be able to be converted to take PTFE buttons instead.

I would get some ptfe buttons made instead,

Am i correct thinking ptfe buttons just push on the side of the gudgeon pin then the cylinder bore keeps the pin in? i've never heard anything of them before to be honest

Edited by dev 11 on 6th Nov, 2012.

I'd get the circlips if you can!

Why v? Every thing you read says the end up popping out and writing their name on the inside of the bore?

I run a supercharger and I don't care the TB is on the wrong side.
VEMS + 12 PSI + Liquid Intercooler = Small Bore FUN!

Proper circlips don't do that. You'd think they were designed to stay where they are designed to be, no?

I understand what your saying, reading Des Hammill's book at the mo, the full circle clip looks the most reliable, the normal style that pinch in seem to wear a fair amount, good old Des says if you can turn them easily in the recess they should be replaced. He also says you should use the minimum distortion to install them. They seem a bit fragile to me and as such im going for buttons.

I'm finding out that some of the details of an engine build is down to what you decide to do and it's application. What works for some doesn't others? Getting a healthy pinch of good luck helps, I know I'm going to kiss my crank before final install...

Edited by gr4h4m on 6th Nov, 2012.

I run a supercharger and I don't care the TB is on the wrong side.
VEMS + 12 PSI + Liquid Intercooler = Small Bore FUN!

All the race engines I built (550 bhp +) used circlips and floating pins and never had any come out, although they are a bastard to get in. I'd be trying to locate the clips if possible.

i have buttons they work... and as far as im aware they cant fall out and make love to my beautiful cylinder walls

Yes i moved to the darkside

Instagram @jdm_brett

Also rpm seems to count for a lot with our old aseries... Under 6 k and not many people seem to have a failure, up the rpm and I think a few on here have had a set make a bid for freedom. Not sure about love Brett!!!!!

I run a supercharger and I don't care the TB is on the wrong side.
VEMS + 12 PSI + Liquid Intercooler = Small Bore FUN!

Yes i moved to the darkside

Instagram @jdm_brett

:)

I run a supercharger and I don't care the TB is on the wrong side.
VEMS + 12 PSI + Liquid Intercooler = Small Bore FUN!

http://skeptic-quokka.blogspot.co.uk/2011/...on-buttons.html

I went to interference pins. I felt uneasy about the shape of the new teflon buttons on the Accralite piston pins, since the pins have a tapered core and were alot shorter than the last set of piston pins I used with the buttons.

Interesting link. But as with all gospel on the web, you take away what you want from it.

Personally, I've had buttons in my cars for years, 20k in the current engine. No problems as described. But I've had too many circlip failures to risk using them again.

Not sure about the cooling theory on the cylinder wall either.

Fastest 998 mini in the world? 13.05 1/4 mile 106mph

I've been using the circlips that come with the latest Omega pistons. I cannot believe that these could possibly fall out at the revs we're using when properly installed.

All the pistons at work use spring clips, and they are a right fucker to get out and back in again. I mentioned about PTFE buttons, and no one has ever heard of a clip coming loose...maybe its a mini thing? lol

https://www.facebook.com/pages/Fusion-Fabri..._homepage_panel

www.fusionfabs.co.uk



1/4mile in 13.2sec @ 111 terminal on 15psi

Interesting Mr Des also mentions that you can put them in the wrong way around.

I know out of the engine I just stripped has some loose ones.

I run a supercharger and I don't care the TB is on the wrong side.
VEMS + 12 PSI + Liquid Intercooler = Small Bore FUN!

Has anyone used these 73mm Iasa pistons yet? Can they be used with circlips/floating pins, as that would be a definite advantage to my short stroke engine.

I use iasa pistons at work, all of which are fully floating and using spring clips. I'd be amazed if they worked there way out.

https://www.facebook.com/pages/Fusion-Fabri..._homepage_panel

www.fusionfabs.co.uk



1/4mile in 13.2sec @ 111 terminal on 15psi

modern piston c clips, snap rings etc are miles ahead of the older style circlip in terms of retention,

ill be using the PTFE type on my build due to ease of assembly/dis assembly also id rather not risk buggering up my new bores..
that said when i asked the shop to turn some out on there lathe i received a funny look and the reply use spiral locks you will have no problems at your rpm (6200) he also made it clear that the spiral locks are a right pain to put in/out and if not done with care youll bugger something up.. so PTFE it is in my book simple and easy..

spiral locks
http://www.smalley.com/images/photos/ring-compare.jpg

Edited by Turbo This.. on 25th Nov, 2013.

Minispeed just confirmed they are fully floating with circlips. I will confirm the reliability of the circlips in the future, but as joe points out, things improve with time (generally speaking) so I'm not too worried.