[Mk2] [Turbo] over fueling

[sawicki]

just got head off and pistons out and found piston has broke again taken piston in to engine specilast and have been told it has gone because its over fueling. just wounded what could be causeing this.

[GTS GAV]

again , more info buddy, other wise everyone will be

this has happend before? how long did you have it on the road for before it did the same thing?

mod list would help, boost your running? standard pistons? forged?

[sawicki]

had it back on road for about 4000 miles replaced with standard pistons and rings. mods: berk downpipe nur spec exhaust hks ssqv and boost at 1 bar on mbc
cheers

[GTS GAV]

who built the engine?

[sawicki]

i striped it down sheffield engine services re built engine and i dropped it back in.

[GTS GAV]

what did they have to say about it?

and have you a FPR fitted?

[sawicki]

they dident say much when i had it rebuilt first time but i know they rebord it as it had scored one of the cylinders they also balanced the crank and put new shells in. what is a fpr
cheers

[Ryan S]

fuel pressure regulator

[sawicki]

no it doesent have a fuel pressure regulator

[bobhatton]

The stock pistons get damaged all the time from knock.
The stock engine is designed to run at 0.8 bar or so on 99 ron fuel.
When the boost is turned up the stock timing should be taken back to 8deg btdc to stop the knock.

All the stock turbo engines run very rich to cool them and try to stop the knock but it can only do so much.
From what I know a rich running engine will not damage a piston, if it was way too rich it could seize a piston in the bore but not damage a ring land.

Do you have a photo of the damage to the piston?

[sawicki]

will get a photo up tommorow

[sawicki]

spoke to engine builders again today they say its not over fueling that has caused it just been driven too hard there saying now. sounds like there full of xxxx to me because there saying a standard set of pistons and rings will be £300 + vat when last time they were only £180 + vat and that were only 6 month ago im thinking they put na pistons in and not turbo ones just wounded if this was possible.

[ashley]

Do you have a picture of the pistons they fitted? Difference between NA and turbo pistons is really obvious...

NA pistons:



Tubby pistons:

[sawicki]

its defently turbo pistons then looking at that cheers for help

[ashley]

Edit

[sawicki]

cheers but thinking forged pistons

[ashley]

Sounds sensible

(as long as you sort whatever killed your last pistons first- would be expensive killing a set of forgies!)

[bobhatton]

Please post a photo of the damage to your piston then we can tell you what caused it.

[sawicki]

will do but not got them at minuet as engine builders have got them

[sawicki]

some pics off broken piston


forgot to mention piston ring are not damaged at all. hope this helps