QUOTE(BelaCHAN @ May 25 2018, 12:42 AM)
Compression Loss and "1Liter engine oil loss per 5000km" through the valve, at the 260K km mark =D
When opened engine top (head), found 4 valve seats (out of 12) badly worn off.
Had to change the whole engine top.
Foreman noted highly likely spark plugs too hot. I could agree.
Nothing to do with engine oil, everything inside the engine was pristine, except the worn valve seats.
Stock plugs are temp range 6, the platinum iridium i was using temp range 7.
Coupled with frequent sustained High Speed highway runs over the years
(consistently in excess of 160km/h, KL to Penang,Terengganu,JB),
valve seat gave way =D
Now using stock plugs, but change more often =D
Ahhhh, plat iridium which brand?
No picture when overhaul being carried out?
Back to topic, IMO.
Fully syn, is good for longer OCI others benefits quite minimal.
Semi syn is definitely better for your oil seals than mineral.
If we gonna talk oil, is gonna be long process what is good and not.
Base oil, additive, OCI, filters & etc.
Just stick to your budget, monitor your oil and change your oil when is due.