Non a-series but thoughts appreciated! little end failure.
Turbo Mini Forums

Some of you may know some of you may not, i run a 1.4 k-series turbo. as teh weathers been real nice lately iv been commuting in her aswell as blatting around at the weekend so rackign up the miles very fast. bottom end is standard.

a few days ago i noticed she had started burning some oil, and one one occation i could have swore i heard a big end rattle. but it went away so i didnt think anything more of it thinking it may have jstu been a sticky lifter or i got the oil too hot.. saterday there i was out playing and the rattle came back, much louder and didnt go away, so i nursed the car the 25 miles home and started to strip it down. In my work i hear alot of big end failures, recognise the sound instantly. so was a bit miffed when on stripdown my engine appeared to have no big end bearings with excessive play...

heres what i found, cylinder 2's wrist pin decided to wander ou the little end and start chewign the liner :( this is an interference wrist pin, this just shouldnt happen :( have i been unlucky or is this a common ish issue for engines which are rev'd hard?(she gets rev'd to 8k, tho on teh day she went my telltale showed i hadnt even went above 6900!)

apart frm the pin sliding out the piston looks fine still. no signs of cracks anywhere or any kidn of failure which would abnormally load up the little end.






apologies for the poor pictures.

turbo 16v k-series 11.9@118.9 :)

Denis O'Brien.

Looks like you have found your achillies heel.

What you have not mentioned is that you are currently putting out more than 300hp.

Saul Bellow - "A great deal of intelligence can be invested in ignorance when the need for illusion is deep."
Stephen Hawking - "The greatest enemy of knowledge is not ignorance, it is the illusion of knowledge."

i dont know if i have though, as the other 3 pins are right where they ought to be .. im putting another std eary damp liner bottom end in jsutnow(same as i am currently running w.r.t pistons and block construction) itll be interesting to see how that copes. im hoping its a 1 off as iv never seen an inteference fit pin fail before :S but my expereince is pretty limited!

turbo 16v k-series 11.9@118.9 :)

Denis O'Brien.

ive had interference fit pins come loose before

Although this was on all 4 so im pretty sure i must have had a dodgy bunch on my old hepolite pistons

can you machine the pistons to run circlips? I believe they are preferable for high revving engines

isnt enough meat to machine the pistons sadly :( ptfe buttons are an option i guess, or i could stop being a tight arse and jsut buy some proper pistons with a decent pin retension system.

turbo 16v k-series 11.9@118.9 :)

Denis O'Brien.

Ptfe buttons get my vote.

does the K have oil squirters?

a bit more oil up ther might just keeps stuff just thet little bit cooler.

have you really got more than 300bhp?

no longer a series, but still 1.3 turbo.

it dont have oil squirters, and cant really see any way of fitting any tbo :S i dont believe thre are any gallaries around the base of the liners.

and as for the power. its a bit of a touchy subject she recorded over 300hp@7917rpm and 220ft/lb also at 7917 rpm. so she makes big numbers but she has a shit torque curve and i dont believe the big number generated by that particular run..

Now iv upped the CR and also running more boost. the torque curve is much less peaky, if anything it seems to tail off a bit at the very top but not had it on the rollers to se how she fares. definately faster tho. lol. and a right good kick at 5k when the boost really shoots up. maxing out 480cc injectors at 11:1 afr so im nudging close to the 300hp mark for sure. but i have no proof and that engiens dead now anyways

turbo 16v k-series 11.9@118.9 :)

Denis O'Brien.

wow that is impressive!! i had no idea it was that powerfull mate! congrats! as for the topic i am unable to contribute, sorry.

For the cost of a bit of PTFE (£5 from Ebay) and and hour in the workshop, PTFE buttons would be a cheap and easy safegaurd.

But as you say, it's only happend on one so most likely an isolated on-off occurence.

I think that the modesty people have about their cars and banana values on this site is a credit to everyone.

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

If you need, I've got ONE 1.4K series rod in the shed. Bought it off Ebay a while back. (When I was a bubble owner :) )

Is there any way you could measure (or have someone) measure the bore of the little end and compare it with another known good one to check it hasn't enlarged at all?

If its the only one that has gone, it could just be that it was at the larger end of tolerance from the factory and the others may do the same not long after?

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

www.fusionfabs.co.uk



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

Perhaps the rod end as cracked, at high revs and hot engine temperatures, relieving the interference fit alowing the pin to walk out??

How would PTFE buttons work with a slipper type recess like that??
Regards
Dave

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

my pistons where like that, and PTFE buttons failed, :(

Team Racing

First KAD engine we had had same prob. on one pin . cosworth pistons . They then fitted buttons on all theirs , we never had any more issues . Go for buttons , cost nothing , no harm trying them in your std replacement to see how they wear.

turbo 16v k-series 11.9@118.9 :)

Denis O'Brien.

turbo 16v k-series 11.9@118.9 :)

Denis O'Brien.

http://www.rabdunn.co.uk/

I'm much more fond of this car since reading this thread.

In the 13's at last!.. Just

Indeed! 8k rpm and 300 Bs sounds like fun.