Whats up with these Euro R Pistons

[GlassJAw]

One of the guys down here has just stripped down his Euro R H22A engine to do a rebuild and this is what his pistons look like:

Question I have for you fine folk..... wtf is that stuff on the top of the pistons, thought it was running super lean but the dyno tune from a month before shows thats not the case. Any idea guys??

 

[HondaLuver83]

Carbon build up from overly rich engine or burning oil. Start and stop short distances driving as well.

 

[Mike's_Taffeta]

Is it carbon build up? That second pic looks like metal flaking. If it is carbon buildup, its more than likely a rich condition or oil like hondaluver said.

 

[ryan s]

yeah, it looks like the metal flaking. that would be a product of running super lean, methinks...

 

[FunnyVictor86]

i would let them soak in carb cleaner for a couple minutes and hit them with a wire brush ... get all crap off and see what's underneath it ... hopefully it's just build up

 

[Drift]

Just about every motor Ive pull apart looks similar to that. Except for the race motors that don't run emissions. The recirculating oil vapors back into the intake cause a lot of that carbon build up.

Looks normal to me.

 

[GlassJAw]

Cheers guys, knew you would be able to help!!

 

[pattywak]

Just about every motor Ive pull apart looks similar to that. Except for the race motors that don't run emissions. The recirculating oil vapors back into the intake cause a lot of that carbon build up.

Looks normal to me.

So would it be best to replace that hose that connects to the intake with one of those small filters that can be found at a parts store? I know some people do it for rice, but if it prevents carbon buildup that would be a legitimate reason correct?

 

[GlassJAw]

I use a small fuel filter in the line that leads from the PCV valve to the intake manifold, you would be surprised how much gunk gets caught in there..... and the fuel filter is cheap as chips (approx $4USD)

 

[Drift]

So would it be best to replace that hose that connects to the intake with one of those small filters that can be found at a parts store? I know some people do it for rice, but if it prevents carbon buildup that would be a legitimate reason correct?

Yeah thats one way of doing it.

I use a small fuel filter in the line that leads from the PCV valve to the intake manifold, you would be surprised how much gunk gets caught in there..... and the fuel filter is cheap as chips (approx $4USD)

Thats basically the same thing I did, but I used a $10 water/air spectator for an air compressor in line with my PCV system. I empty it of oil vapor about once every 2 weeks or so. It doesnt fill up, but there is usually a good bit of oil in there.