Honda K20 Piston and Conrod Failure

[Westfield]

Hi Guy

This is the No. 4 piston and conrod from a Honda K20 Engine which I have been given to rebuild. Firstly a bit of background, the engine had just been rebuilt, not by me I may add, and is standard bar Cams and Forged Pistons with remote oil filter and oil cooler. The engine had just been put into the car and had only got a half day track day as a run in when it let go. The crank is seized solid and has not been removed yet. As you may see this kind of damage a lot, could you point me in the right direction as to the cause, my thoughts are that the bigend bolts may have been the cause, but why the crank seizure? The first three bigend shells show no sign of any damage.

Gary

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[Guy Croft]

The blueing of the rod end suggests that the failure emanates from the crank-bearing assembly and the seizure of the crank (which is very rare) supports this.

Loss of oil pressure, oil starvation at the pump, dirty crankcase build (blocked oilways), overfuelling (with loss of oil viscosity) are some primary causes.

Forget rod or bolt failure for now and start looking for other causes, because you can only prove that in about 1/10 cases and to rule it out - or prove it - here where the failure is so catastrophic it's smashed everything to bits you need to go over every other detail of the build and operating condition first including the oil lines and circuit itself. This kind of failure needs the most careful strip and inspection. It may have been built with the crank tight..

G

[Walezy]

I heard from a guy that is racing Civic type R that those engines suffer from oil starvation if the rev limiter is rised above 9000rpm as the head does not have enough drain holes for oil to get back to the oil sump. Maybe it is worth checking it. I heard from that guy that a good thing is to make additional external drain hose that will take oil to the sump but i have no additional info about that.

[Honza]

I heard that Honda's summoned cars with a certain serial number (first years of production..) to repair a manufacturing defect, which resulted in a similar problem. I do not know details about it and the exakt production numbers, but the engine after the repair had an 3 dots on engine block...or something like that.

try to ask some Honda dealer for details...

[Guy Croft]

Thanks for both offering advice. I am certain this will not be the fundamental cause unfortunately. Nice if life were so easy.

GC