FYI....... My bottom end knocked on startup with the 15-50 synthetic oil. Put in new AC Delco filter and Castrol 10-40 dinosaur oil and the knock is gone. Be careful with synthetic. Tom Telesco told me years ago to never run synthetic gear oil in the rear. If Tom says it then it is so. I believe he also told me the same thing about motor oil.
Be careful with any filter besides AC. When another brand was put on my GS at a quick oil change place, I heard lifters and bearings on startups. Even a NAPA GOLD filter let oil drain back to the pan. AC all the way now!
Yeah, I usually use AC. I never had a problem before. Must have been the synthetic as I DID have an AC filter on at the time. Hope I didn't do any damage... I have known about the drainback problem for years, just never experienced it myself until now.
I have AC and Valvoline still on the shelf from the 80's, and never had a problem. Wix made them in the states for Valvoline back then, but who knows anymore, could be China today...:rant:
Yards that happened to my 350 SBB with a fresh build and mild cam. I switched to synthetic after about 5000 miles. After a short trip on a hot day. I stopped to eat, the car sat for about an hour. When I started it I detected a little rattle coming from the bottom end. I drove straight to a lube shop and went back to dino oil. End of problem. Bob H.
A board member wiped a 350 cam with Brad Penn oil and no additives. I wiped a cam using the STP Blue crap. Lesson learned! Never use either of those products!!!
It's important to remember that it's not just the oil / ZDDP / additives that wipe cams... proper break-in, spring pressure, mileage, oil change interval, usage, parts selection, filters, cam core material, lifter manufacturing process (country), installation procedure, viscosity choice, and machine work can all have an affect. There seems to be a different combination of these factors in every incidence, too. I just wish it would stop happening. We wiped one on a dyno 4 years ago with all good parts and lube... it's hit or miss. Sucks.
I agree with Kevin. There are many variables that contribute to break in success or failure. Blaming it on one variable just because someone else had a similar problem with that one factor in common is about as unscientific as you can get. Even the experts don't have good control over all the variables. If they did, there wouldn't be so many never-ending threads and opinions to wade through. I thought this thread was about the use of ZDDP additives with synthetic oils? Devon
In my Peterbilt I use Rotella 15-40 with STP additive and after 800,000 miles of running for when a rebuild is in order, the bottom-end and valvetrain never let me sat.
Devon this is your second negative post regarding the answers in this thread. Why so grumpy?o No: Bob H.
I dunno, maybe because it's about the tenth time a thread has been started with specific questions and has degraded to the same old oil banter. That and it got cold out again. Those are my excuses and I'm sticking to them. Devon
YES...ZDDP & SYNTHETIC OIL Mobil 1 synthetic 15w-50 has 1200 ppm zink and NO circle or starburst on the jug. $25 for 5 qt jug (CHEAP!). (1200 ppm is minimum acceptable for our engines) "FOR RACING AND FLAT TAPPET APPLICATIONS" Check their many sites for 2 page info chart on zink. Keep searching for the right one. Try "Mobil 1 product guide" to search. Mobil 1 Racing 4t 10W-40 has 1700 zink!!! and low detergent. Its for motorcycles but OK for Autos. (Has no gas mileage modifiers in the oil). The correct 15w-50 with 1200 zink, should have less detergent and allow the zddp to stick (VERY IMPORTANT), so you could spike it with a little pure zddp and not get detergent dilution. Could also add 2 qts of Brad Penn 10w-30 (1600 zink) Some say Mobil 1 causes engine noise and others do not. But, synthetics do not cause detonation if a little gets up into the combustion like dino oil does. Hope I got back to the orig question.
