I really don't know the answer to your question, BUT, I did switch to synthetic on a high mileage motor once and regretted it. Yes, it did seem to run a lot smoother, but it developed little leaks that weren't there before. Switching back to dino oil didn't help the situation.
that is a load of bravo sierra. you can switch back and forth anytime you like after the engine is broken in. break in should be done with conventional oil otherwise parts dont wear in properly.
I really don't know the answer to your question, BUT, I did switch to synthetic on a high mileage motor once and regretted it. Yes, it did seem to run a lot smoother, but it developed little leaks that weren't there before. Switching back to dino oil didn't help the situation.
actually it didnt develop leaks, they were there already. what happens in that synthetic oils are much more aggressive at cleaning out engine deposits that the deposits that were plugging the leaks were cleared away. by the way, modern conventional oils are getting very aggressive at cleaning and keeping an engine clean and free of deposits as well.
I'm planning on running Agip Racing 10W-60 and STP Oil Treatment. I read on another board that the STP Oil Treatmnet adds sink to the oil, which helps the cam to survive. Gonna break in the engine with regular oil.
BTW, I got a question; I've just had my engine apart for the first time, nothing major except new rings, gaskets, and bearings. Does the cam need to be broken in again ? It's a hydraulic flat tappet.
BTW, I got a question; I've just had my engine apart for the first time, nothing major except new rings, gaskets, and bearings. Does the cam need to be broken in again ? It's a hydraulic flat tappet.[/QUOTE]
No, but you should put the lifters back into the same bores you got them out of. A cam and a lifter wear in together making a certain pattern for lack of a better word.
If you put the lifters back onto a different cam lobe they will have different patterens and will cause the cam and lifter to wear into each other again. This kinda makes for more wear than it really should have.
As far as mixing synthetic and dino oil; Ford recommends their "Synthetic Blend" everywhere in the owner's manual for my '02 F150; and it appears that it was used exclusively in my truck (owner always took it to the dealership for that stuff) until I bought it!
Since then, it's been fed Mobil 1 "Extended Performance". A little cheaper than Auto Parts House prices when bought by the "1-1/4 gallon jug and 1 quart bottle" (total of six quarts per oil change) from Wally World and changed in my carport.