My 26/30 Is Rooted

[Duncan]

old oil stank of petrol and had about a litre too much in, bear in mind i run twin pumps and 1000cc sards. wont take long at 8.0.1 afr to do that.was changed after afr set and prior to dyno run,car was never driven with the contaminated oil in the motor

sounds very bad to me.....fuel is a rubbish lubriant, almost as bad as coolant

but assuming you changed it, most of it was removed (no oil cooler?), and the problem was fixed that may not be it.....you don't have the oil that just came out of it?

[snozzle]

What engine oil do you run / where you running when the engine failed?

[rockabilly]

right guys a further development. looks like we have looking in the wrong place. i now suspect something has gone through the engine.from where i am not sure. below are pictures of the head on number 5 the one that spun and number 5 piston crown,, i was running a 1mm headgasket. question is whatever caused these marks would it be enoug on a 1mm gasket to jam the piston enough to cause the crank to hit the bearing momentarily?.

[rockabilly]

i have stripped the turbo, nothing wrong there?. had a look in the exhaust there is some very small shiny magnetic fragments?. any idea where something that could do this had got in from..

[Duncan]

whatever that was it was tiny. mine ate a washer once and it made waaay more damage

[Risking]

detonation

[rockabilly]

detonation

you reckon mate?.

[Marlin]

The indentations look a lot like spark plug electrode mate.

I once left mine at a "reputable" tuner for dyno-ing after a forged rebuild and was not happy with the results, (less power everywhere with higher specs) and after lots of head scratching I pulled it out and found the pricks had melted plugs in it (dash 8's) and simply put new ones in it and gave it back to me.

[James_03]

yeah +1 for detonation.

would also explain why the bearing has gone on no5 too.

You would think it would be across the board but and evident in all cylinders. I suppose if no5 injector had issues there's a possibility.

What do the other cylinders looke like?

[TiTAN]

detonation causes pitting, they look like impact marks

[rockabilly]

plugs that came out, had to drive the car cold hence why they are this colour, needed to load on trailer

head nearer to front

cylinder 4 ,5, 6

[unique1]

+1 detonation

Edited April 6, 2010 by unique1

[rockabilly]

pictures of all 6 pistons cleaned off lightly

front three

back three

[Cartman]

odd thought... but had you used a die grinder on or near your intercooler piping or anything that would have been open on the intake setup weather it be plenum, TB, ic piping, comp housing, intake pipe....

that pitting either looks like the result of ceramic bits off a sparkplug or metal filings from something not being cleaned properly after working on it..

[rockabilly]

hi Cartman, no mate if i ever do anything like that the cars is not in the garage, you can see some die grinding work on the head in the pics, i have over the weekend fully ported and polished the head. its away now for a light skim. now the piston tops are cleaned of they almost look as good as the day they went in..lol

[T04GTR]

all the valve guides in 1 piece? ive seen the inlets fracture and do similar damage.

that wont be the cause of the damage. its not detonation.

to only dammage 1 bearing its only oil contanimation. fron the look of it something has been sitting in the crank and got loosed. did you have the crank grubscrewed when it was first built?

of have you recently put on a oil cooler?

[rockabilly]

hi t04gtr

cars has always had a 19row oil cooler fitted.feedsin the top and drain at the bottom, the oil filter is mounted low on a remote so when you do and oil change the cooler empties too.

no grub screw mate, collar was sweated on and has never moved

no valve guides damaged at all.

i find it hard to believe det after looking at the pistons..

still wondering why?.

bernie

[Scooby]

If you had lost an engine at 900klm you would feel the same way as Marko. The engine in question was a low revving item that was never put under stress...N1 went bang.

GTRNUR...correct...the mains are all shiny from eating rod bearing material.

So what kind of revs was it pulling and under what circumstances did it go bang? Drag/circuit?

[Marko R1]

If it was pinging 1 would that the pitting would be across the board? Not just cylinder no.5

[zebra]

Not if it is running lean on certain cylinders