Twisted

You may be right. I always thought synthetic just flowed better...for molecular reasons, but was no thinner than dino. Maybe someone will chime in.

HACKGT350

maybe but i have heard a couple different times that if you have high miles it can slip right past the rings and start leaking out of seals around the engine so ill just stick with conventional

Twisted

I agree. I've tried to switch to synthetic on numerous old motors, and the results were almost always increased leaks and oil consumption. Like you, I just use conventional now.

5pointslow91

hell im using 10w-40 on my old motor

Evil_F

Yeah, but synthetic doesnt seem to foul plugs as easily as dyno oil does. I aint burning much. But when my car is out of tune, and running rich. It causes one of my plugs to foul easily. Making tuning it difficult. Plus, I just replaced practicly all the seals. The rear main seal is new, and I just didnt do the front main. The rest is new. Though I am sorta' worried that my new rebuilt heads have a valve seal prob.

HACKGT350

that just sounds like running rich is fouling plugs thats not oil thats too much gas

racingboy

Okay, a conventional oil is thicker because the molecule is cyclic (like a hexagonal, octagonal, etc type shape). A synthetic oil is linear (more like a straight line or a fatty acid chain). Because it's linear it will find holes easier, because it flows smoother. For an older car usually go with the conventional. Sythetic oil is just refined more than conventional. For a good synthetic oil there's no chemical additives involved.