Zinc oil additive?? (Page 2/2) Patrick AUG 07, 04:17 PM quote Originally posted by fierofool: I have been running Shell Rotella T4 10 w 30 in my Fieros for years. It has the zinc already in the oil at the right concentration. Charlie, when did you start using Rotella? I found This post from 2007 regarding the ZDDP content of Rotella interesting. quote Something to keep in mind regarding Rotella T, which is favored by a lot of motorcycle owners, mainly because of it's ZDDP content. While it has higher levels of ZDDP than most others, it has undergone a formulation change recently that reduced these levels. And since Diesel engines will soon have emissions requirements, many of the diesel oils will likely reformulate to comply. fierofool AUG 07, 08:44 PM Patrick, I have about 55-60K on the 3.4 engine in the 87. At the time I bought it, it was said to have about 83K on it. The previous Camaro owner probably used conventional oil. Oil pressure was very low so we installed new cam bearings as the lobes and journals looked good, and we put in a new crank kit. The pistons were never pulled from the bore nor the heads removed. I've been running the Rotella T4 since the install. La fiera AUG 07, 09:06 PM This is the best oil for flat tapped cammed engines. It has about 1200ppm of each zinc and phosphorous plus another 1000ppm of Molybdeum disulfide which is an element that more pressure is exerted on it, the slicker it gets. I've used to for over 15 years and still use it today on all my Fiero engines and have never had a worn or wiped lobe and I use very high spring pressures. You can get it at your local Advance Autoparts store. PhatMax AUG 07, 10:01 PM I used Rotella in my old Honda motor cycles. The engine ran quieter and the trans shifted better than any other oils I’ve tried. reinhart AUG 10, 01:05 PM I bought my V6 with 20Kmi and put another 100KMi on it using normal synthetic. I had to tear the top and bottom of the engine apart after a couple pushrods loosened enough to cause the lifters to come apart (there's a thread in the forums I did). The valve adjustment nuts backed off I suspect due to a badly cracked front exhaust manifold causing a vibration or resonance in that side only, because only the lifters on the front came apart and it was all of them but none of the rear lifters. Anyway all that to say that the lifters came apart in no way due to the oil I was using. When I inspected the engine, there was no visible cam wear or crank wear. I replaced the lifters and bearings (used standard size replacements and all plastiguaged in spec) and the engine runs like new. I did use a zinc additive on the first 300 miles after the rebuild but am back to normal synthetic now and will continue with it. TLDR: Synthetic seems to be doing a great job protecting my V6 engine. armos AUG 24, 03:28 PM Valvoline VR-1 is made for this issue. They market it for racing, but the gray bottle version is detergent oil so you can use it in a street engine. It comes in 10w30 and 20w50 (and a bunch of straight weights). I think it's about 1300ppm phosphorus/1400ppm zinc or something like that. There's a datasheet with the specs on it. You can mix it with "regular" oil to moderate the amount of ZDDP as desired, and also to tweak the viscosity if you want. Amazon sometimes has a good price on it, but they won't sell it to California because California passed a nanny law a few years ago that made it illegal to sell there. In California it's now only legal to sell motor oil that API has certified. VR-1 can't be API certified because the ZDDP content is too high, which is the whole point. Up until recently the 20w50 version did have API SN certification because the limits didn't apply to 20w50. Now I think all grades are restricted. Due to cheapness and availability, I've mostly used Shell Rotella T5 10W30 and T4 15W-40. Those are certainly easier to find at local stores. I bought a cat in California 10 years ago, my last test there was 8 years later in 2020. By then my test results were starting to slip noticeably so I might have needed a new cat at 10-12 years. I think that's typical of aftermarket cats so I don't think my oil choice really made much difference. The more oil you burn the more it matters though. My engine burns oil when coasting down, I think I've been losing about 1qt every 1000-1500mi the whole time I've had it, for a total of about 50K miles. The O2 sensor gets the same contamination as the cat, but Fiero O2 sensors are cheap and worth replacing occasionally anyways.