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You know there are several kinds of motor oils around. I just wonder what oil I should use. I got a 77 small block chevy with around 100 miles on it. It has conventional oil in it now for the break in, but I am thinking if I should switch to a full synthetic or a synthetic blend later on. And if so, do I have to flush the engine to make the switch. I have also heard of many of todays oils not being very good on hydr. flat tappet cams. Any suggestions?
You shouldn't need to flush the system to either use a full or blended synthetic oil. The issue with the flat tappets and older engines is a little more grey. Some say that these engines need zinc in their oils to reduce wear. Some oil company reps say that their oils meet all of the requirements of these engines as well as all more modern stuff. In any case there are some oils, mostly in the 20w50 viscosity range that still contain ZDDP and there are also ZDDP additives that can be purchased to add to your oil.
For more information on this subject do a search on ZDDP and read the comments. A lot of good information but as usual you got to wade thru it to get to it.:D
Thanks for the info Mopar34. Do you think that synthetic oils are worth the extra money?
John,
In my Jeep I have been using Rotella 10W30 as it is formulated for diesels and still has some of the additives to keep the cam & lifters lubricated. However, I just learned a couple of days ago that "they" say not to use it long term as it lacks the detergents, and tends to sludge more - can't win.
I have never gone with full synthetic, as I can't get comfortable with the extended change intervals and the cost is prohibitive at 3000 miles!! In my wife's Grand Cherokee I use MotorCraft's syn blend, as it calls for a 5W20 and there are not too many out there. I have read that some of the syn blends have very little synthetic, and in the past I have mixed my own using about 25% full synthetic staying in a common brand.
There is a web site, Bob Is The Oil Guy, http://www.bobistheoilguy.com/, where you can spend hours learning more about oil formulation than the average mind can digest.
I went to using Mobil 1 in my 7400# F350 with V10 in hopes that I might just get a bit more in gas mileage. Nah, not a chance - it was 11mpg before and, guess what, 11mpg after. So instead of my oil changes costing $40+/- every 4-5K miles, its less then half that by using the Motorcraft semi synthetic 5W (or 10W)-30 (it takes 7 quarts) and I still get around 11mpg with 13/14 on long haul trips or 9/10 with my 12K camper hung on. Wear and tear - half a quart in 5K says there isn't much at 56K miles.
So with that said, there probably isn't much need for full synthetic oil. It might help starting below zero, but my truck sat outside last winter and started every day, including several -5 or more days. Is it good stuff - yep, but not that much better then a semi synthetic. What, IMHO, it boils down to - oil company advertising !! And yep, there will be some here that swear by it as well.
I'm running Rotella T 30 wt in my T and pretty much have switched over to it in everything except my daily driver Ford, and in there I have Mobil 1 synthetic. I went with Rotella because of the zinc thing too and the fact, as mentioned, that lots of diesels use it. But who knows, I think it boils down to what you think you have had good luck with in the past and what you have heard.
For years I ran Castrol GTX and can't say I ever had an oil related problem that I know of.
Don
I have read and been told that Rotella T is an excellent oil, but it no longer has the Zinc content that it once had. It seems that Valvoline VR-1 (20w50) or Castoil 20W50 is the choice of most who want the added Zinc protection without adding an additive like ZDDPlus, (which ain't real cheap I might add :eek:).
It all comes down to your needs and your wallet as to what is best for your car. Ask 10 different people and get 8 different answers.:LOL::LOL: