Shell Rotella T
Designed for the harsh environment within a diesel engine, Shell ROTELLA T has aptly earned the reputation as a high-quality, maximum-protection lubricant. With the reformulation of gasoline-engine oil a few years ago, many hobbyists with flat-tappet camshaft engines have found salvation in commercial-grade oils like ROTELLA T, which have typically maintained high levels of the desirable anti-wear additives.
Produced by Shell, commercial-grade ROTELLA T has been a popular off-the-shelf choice for flat-tappet camshaft engines, but rumors of recent reformulation have sent hobbyists scurrying for options. The truth is that the current API CJ-4 category rating offers enhanced levels of anti-wear protection and, according to Shell, ROTELLA T was designed with flat-tappet camshaft protection in mind.
The '07 model year brought on many changes for diesel engines. Among them was an exhaust system catalyst, and another oil classification standard-CJ-4. One would assume from past events that the addition of said exhaust catalyst would ultimately lead to ZDDP reduction, but Shell's OEM Technical Service Manager, Stede Granger, says otherwise.
High Performance Pontiac: You're likely aware that ROTELLA T is used by many automotive hobbyists with flat-tappet camshafts. Are there any negative effects when using commercial-grade oil in gasoline engines?
Stede Granger: Assuming we're speaking about older gasoline engines that are no longer under warranty, and emissions aren't a concern, there are no major negative effects when using ROTELLA T. In fact, it carries an API S-series category rating. The only possible concern I see is viscosity-15W-40 will not circulate as quickly during initial start-up in extremely cold climates as a lesser viscosity, and our 5W-40 synthetic is then an option.
HPP: We've heard that the current CJ-4 category rating has significantly reformulated diesel oil for 2007. Can you elaborate on that?
SG: Most diesel engines for 2007 utilize an EGR system, an exhaust catalyst, and a Diesel Particulate Filter (DPF) to help lower emissions, and the new CJ-4 category is designed to ensure that there are no detrimental effects to this equipment, maximizing its service life.
HPP: Does the addition of an exhaust catalyst mean a drastic reduction of the high-pressure wear additives found in ROTELLA T oil?
SG: The exhaust catalyst found on diesel engines isn't the same as that of a typical passenger-car application, so we're able to retain high ZDDP levels. The API specification change to CJ-4 for 2007 has resulted in moderate zinc reduction from about 1,400 ppm to 1,200 ppm. And even at these slightly decreased levels, ROTELLA T 15W-40 conventional and 5W-40 synthetic still contain three to five times the amount of the desirable anti-wear additives as some current gasoline-engine oils.
HPP: Is there any chance your company could reformulate ROTELLA T in the near future, and drastically reduce its high-zinc content?
SG: Historically speaking, commercial-grade oil classification changes occur every two to four years, but the new CJ-4 category offers the best all-around protection of any previous rating. So I feel there's little reason for any immediate change, and expect to see it around for at least a few years.
A point to remember is that zinc not only protects flat-tappet camshafts against wear, but also any high-pressure metallic surface that relies on pressurized oil for lubrication, such as the piston rings, cylinder walls, and rocker arms/pushrods. When oil can't carry the load, zinc steps up and creates a chemical barrier, and the high levels of zinc in commercial-grade oil contribute to the fact that some diesel engines run a million miles or more. I don't see us reducing the zinc content in ROTELLA T unless an organization like API imposes a lesser chemical limit on a subsequent category.
COMP Cams suggests using its No. 159 Camshaft Break-In Oil Additive at all times with any flat-tappet camshaft. Stating that it's compatible with any mineral-based or synthetic oil, the company suggests combining it with mineral-based oil during break-in, and any high-quality mineral- or synthetic-based oil after that.
Comp Cams
COMP Cams is among the most recognizable names in aftermarket camshaft manufacturers. As one of the largest in the industry, the company has publicly addressed oil formulation issues in the past, and with word of reformulation buzzing about, we were confident that it had developed a long-term solution. We contacted the company's Tony McCurdy to address our concerns.
High Performance Pontiac: Is current oil formulation an area of concern for COMP Cams?
Tony McCurdy: Yes, definitely. Because of tightening environmental regulations, modern engine oil isn't the same as it was just a few years back. The federal government recently required the reduction of key ingredients such as zinc and manganese in all types of gasoline and diesel-engine oils, and that continues to plague flat-tappet camshaft engines.
HPP: Have these changes affected the way your company manufactures or markets flat-tappet cams?
TM: No, not at all. Premature flat-tappet camshaft failure isn't necessarily brand or type specific. Many times hobbyists quickly suspect the manufacturing process, but we've found that's rarely the cause. We feel that modern oil has created the potential for failure during break-in and normal use. We have, however, found ways that hobbyists can discourage that trend.
HPP: Can you explain those?
TM: Proper break-in is a key element in the longevity of any flat-tappet camshaft, and we include detailed installation and break-in instructions with each cam and lifter set we sell.
We strongly recommend that the new flat-tappet camshaft and its lifters be liberally coated with our No.153 Cam & Lifter Installation Lube, which is supplied with each set. We also suggest adding a 12-ounce bottle of our No. 159 Camshaft Break-In Oil Additive to the crankcase.
We prefer that the inner valve springs be removed to better allow the lifters to establish rotation and develop a wear pattern. As soon as the engine fires, increase its speed to 2,000 to 2,500 rpm for the first 30 minutes of operation, and it can be periodically varied to ensure direct splash oiling on all areas of the camshaft.
COMP Cams feels so strongly about its Camshaft Break-In Oil Additive that it securely attaches this label to every camshaft it sells.
After the break-in process is complete, we suggest changing the oil and filter to remove contaminants, reinstalling the inner valve springs, and filling the crankcase with the customer's choice of high-quality conventional [mineral] or synthetic oil, and adding a bottle of our No. 159 Camshaft Break-In Oil Additive.
HPP: You suggest No. 159 Cam-shaft Break-In Oil Additive for long-term use. Can you explain its advantages?
TM: The product was initially developed specifically for break-in protection, but subsequent testing has proven long-term durability benefits for flat-tappet cams. It contains a special blend of additives that replace some of the desirable ingredients that the oil companies have removed from modern oil, and protects the camshaft and lifters against premature wear.
We feel that it's cheap insurance, and is the first step toward avoiding oil-related flat-tappet camshaft issues. In fact, we attach a small label, suggesting its use, onto each flat-tappet camshaft that owners must literally cut off.
HPP: Is there any chance your company could discontinue or reformulate this product in the future?
TM: We plan to market No. 159 Camshaft Break-In Oil Additive as long as we offer flat-tappet camshafts, and there aren't any foreseeable changes in the future.