shiroitenshi

Actually there is the question of how sludge forms. According to some articles, they say wrong grade of oil, or use of non synthetics on new engines, some claim infrequent oil changes, etc. etc.

One thing I've realized is that full synthetics can actually last more than 5000kms. But for engines where the PCV system routes the engine oil vapour to be burned, like our B series, don't think you can drag one oil change to 20,000kms.

Honda specs the oil filters to 10,000kms, but I change them at 5K anyway, because it's only like +/-RM20 extra

Seems like BMW actually spec their oil changes to be around that mileage :P Not sure though, I heard it from a BMW owner.

So I don't know how sludge forms either.

Let's discuss this as a topic. Anyone has ideas?

I already mentioned in my first sentence what I've heard. How about you guys?

Vagabond, not sure what you meant, sludge inside the cyclinder head at the rocker arms, tappets, etc, or in the combustion chamber?

The black stuff in your combustion chamber is carbon deposit, usually it's quite a lot if you have the PCV system (that small plug on the VTEC valve cover) plugged in your intake (stock is like this), but if you use an oil catch can, you can reduce it. But carbon can also form somewhat, not because of the engine oil, but because petrol also has carbon from incomplete burn (due to changing weather and engine. conditions, sometimes combustion gets an incomplete burn, so carbon gets stuck inside. But carbon will be less than the stock setup of having the PCV plugged into the intake.

So anyone else has more information on how sludge forms?

     

JINEIL2EN

using semi-syn & above, the suitablr grade of oil,
if oil change every 5000km, flush the engine with Engine Flush(branded ofcos) every 10000km.... sure won't see any sludge... i think...

     

Vagabond

I think i meant carbon deposits all over the area , adjacent to the valve openings ?
(if i'm reading my engine head correctly)

     

JINEIL2EN

if carbon, then easy job loo... hahahaha....