GTI-R powered NX-R - died

[waynos]

hey does any one know wat would cause detonation on one piston i just finnished rebuild the little B#@*ch eg o-ring block, ceramic coated pistons, balanced crank, new through out and NO. 1 piston just melted down on one side ( i have my ideas of a bung injector) any one else!!!!

[RS-11]

You should post this in the general, or down in the gen technical section... that way more people will see it

[THE ASH]

Why did you rebuild it the first time, same issue? I'd definately look at testing the injectors as a starting point.

Perhaps the design of the intake manifold or fuel rail makes one pot leaner than the rest & hence makes it fail first on a marginally lean overall mixture.

ie: overall = 12.5:1
cyl 1 = 13.0:1
cyl 2 = 12.9:1
cyl 3 = 12.4:1
cyl 4 = 12.1:1

(figures pulled outa my arse, as an example)

[PLAYA]

this is pic of piston

http://img.photobucket.com/albums/v430/SR910/DSC00015.jpg

http://img.photobucket.com/albums/v430/SR910/DSC00017.jpg

[intehnet]

fuck me

yeah if it's happened before on the same cylinder, i'd say leaky injector or something.. under what conditions did this happen? load?

[PLAYA]

previous problem wasnt a melted piston in had a big end knock previous time.

[bigmuz]

Lean and hot- possibly pre igniting cos the piston was glowing.

Could be air leak at manifold or damaged inlet valve?

Driver should use ears more often to listen for a piston gouging shit out of the block..

[AndyMac]

I'd agree.

air leak

[waynos]

It got rebuilt the first time cause of a big end !!!
it was under load but on low boost when it happened!!!

as for listening to the motor it sounded reasonably normal.

[80DGY]

No offence man, but I doubt that fucker banging around in there sounded normal :D

[waynos]

NONE TAKEN, but how would u know wat it was doin.... were u sittin next to me everytime i was driving

unless u have something constructive to say id apreciate it if u keep your coments to yourself ... THANKS

[bigmuz]

Relax Pal. Bodgy is here to help.

What did it sound like? What did the head gasket look like?

Is the head flat? Was the manifold sealing?

What made you shut it down?

Muz

[waynos]

head gasket fine head flat never got hot!!! inlet gasket a little ruff but sealing

sounded fine the only time i shut it down was when it busted through the piston and lost all conpression and got it towed

just sounded like a bit of a dig to me!!! i did the whole converion myself but im no professional!!! but i do agree if there was a knock i would of noticed it!!!

[bigmuz]

Usually burning metal like that is from air blowing in in a localised fashion. That said it could just have been extremely lean and that side of the piston was the leanest.. but that would have been so hot the thing would have not been running well imo.

So that is why we suggest air leak- harleys do it all the time if the head gasket or inlet manifold leaks- it is like a white hot jet of fire that will melt anything. Gotta be pretty bad though. Get the injectors tested and go from there. If the inlet manifold was a bit iffy get it milled or linished flat and make sure it seals. Exhaust side is the same- but you can usually hear a leak there.

Let us know what you find mate.

Muz

[80DGY]

just sounded like a bit of a dig to me!!! i did the whole converion myself but im no professional!!! but i do agree if there was a knock i would of noticed it!!!

haha nah, not hanging shit champ, you haven't seen some of my atrocities yet!

Hang about here long enough and no doubt you will, in fact, I'm expecting to post in the next month or two...

Why is the rod from this fuckin chev hanging out the side of the block

:D

[waynos]

Got the injectors back all flowing ok guess i put all back together new pistons rings NEW SEALS all round then head straight to a tuner to see wat the deal is!!

[PLAYA]

i would still be checking fuel pump, afm, fuel reg etc.