A few weeks ago we got in a car running on 3 cylinders with 94,000 miles on it. We did a compression test. 180/165/120/0 What we found was the exhaust valve was burnt in cylinder #4. So what was the cause? After close inspection we found that the oil broke down from the massive amount of heat these cars generate in a small engine compartment. Car was completely stock including a stock air filter setup and not tune or mods.
Our cars run HOT!! We recommend changing oil every 5-7k but after seeing this car we now recommend every 5K. Most oils do not HOLD UP. This customer was using Castrol Edge 5w40 which is generally an excellent oil but still the oil broke down from heat. Our recommendation is to only use Motul Xcess 5w40 and for cars over 70K Motul Sport 5w40. Again change every 5K. Motul is the only oil we know of that will hold up to the heat from these cars. Even our Italian friends recommended Motul. It can easily be found on Amazon so just buy it there for the best pricing. DO NOT AND I REPEAT DO NOT USE ROTELLA....YES it is cheap but it is the wrong oil. It is for diesel vehicles. Many customers because of price buy this but again do not.
If you have any further questions give us a call. 973-343-6546 www.dicorse.com
I have attached photos of head where you can see the oil deposits on valves and burnt valve. For some reason I cannot attach but email me for photos. email@example.com