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Sleeve damage

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hello all,

have some pics of a broken sleeve attached. Was wondering what can the causes be? Car is a supercharged B18C with 10psi. Cans such a problem occur if the bore is honed too much and poston to bore clearance is more that specified?

attached also last datalog

Attached Files

There could be a range of causes for this failure. It's unlikely that at 10 psi of boost you would be making enough cylinder pressure to crack the factory liners, however if they were bored/honed to a point where there isn't sufficient thickness then a failure could occur at a lower power level. Detonation would be another consideration as this causes sharp spikes in pressure in the cylinder.

I'd be considering the current bore diameter and also carefully inspecting the pistons for damage from detonation.

Hi Andre,

i was controlling knock during mapping. No signs whatsoever. Was also using VP Sv05 as fuel

bore was only honed and kept the standard 81mm. Howerever when putting the pistons back I couldn’t notice that tight fit as usual with OEM pistons

Please find photos attached of pistons 1 and 2. No sign of detonation.

Attached Files

Have you got any measurements made during reassembly? Piston to bore clearance and ring gap might shed some light?

Measurments were taken by the machine shop. Didn’t check again after him. I will re check when disassambling.

If the engine was still at the stock bore diameter, it's unlikely that enough material could be honed out of the cylinders to result in this particular problem without causing a separate set of issues due to excessive piston to bore clearance. I'm can't give you a definitive answer unfortunately as to why this failure has occurred. It could be an unfortunate freak occurrence as there may have been an inherent weakness in that particular cylinder. What I can tell you is that when well tuned, the stock sleeves can handle significant power increases over stock so this is not normal or expected.