Ok so we're rebuilding the fieros engine due to the cam lobe being eaten up, but I needed to ask, do I need to use zinc additives in the oil? I want this engine to last as long as possible.
can kill a cat... also many additives can mess or kill O2 sensors, injectors, etc. Many additives "bottles" are many for 15 to 20 gallons of gas minimum and mix w/ less can cause many problems.
------------------ Dr. Ian Malcolm: Yeah, but your scientists were so preoccupied with whether or not they could, they didn't stop to think if they should. (Jurassic Park)
Zinc additives in the crankcase should have no effect on the injectors. It should only affect the o2 sensor and converter if it's burning a lot of oil. Lots of people on this and other forums have spoken of all kinds of additives in their fuel tank, like acetone, denatured alcohol, automatic transmission fluid, etc. Some people swear by fuel injector cleaner on a regular basis. Actually, almost all of today's fuels have detergents already in them that reduce the likelihood of clogged injectors.
Flat tappet cams need zinc as a lubricant. Our 2.5, 2.8, 3.1, and 3.4 engines are generally of that design. If used as an additive, as TheOgre pointed out, don't overdo it. Add the prescribed amount for the amount of oil.
For flat-tappet lifters, the zinc additive is a good idea. Since you deleted the catalyst, there should be no side effects. Even with a catalyst, it should take a long time (i.e. a couple decades) for the zinc to affect the catalyst.
EDIT: Here's a question for you. Would you rather replace a bad catalyst, or rebuild an engine? If you forego the zinc to save the catalyst, you run the risk of destroying the camshaft and one or more lifters. And the debris from that can affect other parts of the engine. IMO, destroying the engine to save the catalyst is a false economy.
[This message has been edited by Blacktree (edited 08-07-2022).]
------------------ 1965 Tempest 400 CID 2018 Chevy Colorado Z71 3.6 2017 BMW X3 3.0 T 2015 BMW 535iX M Sport 2008 G6 GT "Street" Coupe 200K miles 2005 Buick 3.6 Rendezvous 225K miles
Duh Ogre... think oil not gas.... But oil additive have similar problems. Many use way too much and even have right oil for a given car, believe API SF here but not digging thru charts, Zinc and Phosphorus in oil can wreck the cat and O2 but just take longer do to it.
You burn some oil no matter how good the engine is made. You just don't see the small amount but Cat and O2 hate this. Think bad for Fiero? Many current models have Multiple O2 sensors costing Way More Money to replace. (Worse if you have coolant problems and engine "burns" that.)
Is a big reason Why EPA and others worldwide force Engine Oil to have less of both every time get new specs. Currently API SN SN+ and SP. (I'm told API skipped SO because letters are old Standard Oil brand.)
------------------ Dr. Ian Malcolm: Yeah, but your scientists were so preoccupied with whether or not they could, they didn't stop to think if they should. (Jurassic Park)
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 postfrom 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.
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.
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.
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.
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.
