What oil and filter should I use
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There is so much advertising and word of mouth
that few know what is the real difference in the various oils
anymore. First and foremost what was true 10 years ago is not
true today. Here is the real scoop with how it pertains to
modular motors specifically. Motor oil has to meet certain criteria, the latest as of 2011 is that regular passenger car oil is losing more antiwear additive and is also made from better basestocks that the same oils 10 years ago. Today to meet the SM/GF4 spec ALL oil is now basically semi-synthetic regardless of whether or not it says so on the package. IMHO - it doesn't really matter anymore whose name is on the outside, the stuff on the inside is basically the same for the uses we need. However what you really need to look for if you are planning to race your modular: Antiwear additives - these are the compounds that allow metal to metal contact to not hurt the motor as bad. With the new oil standards higher levels of these will only be found in diesel spec and racing spec oils now. To meet SM spec the limits are nearly half of what they were for SJ spec which most racing oils would classify under. Most diesel specs still classify at the SL level at the time of the writing of this article. Cleaning agents - this is the real difference between diesel spec and racing spec for our consideration. Diesel spec has double to triple the amount of cleaning agents as regular passenger car oil. Racing spec oils have little to none since usually they are changed more often. Viscosity - passenger car modulars are speced for 5W20, the GT500 is speced for 15W50, and overseas modulars (I am told) are speced for 40W oils. So everybody has something different to say about what oil thickness should be used. I have found that the thinner the oil the more HP you make, and the thicker the oil the better the bearing surfaces will be especially in the cylinder head cam bores. Most of my core heads come from fleet vehicles that spent their entire life running on diesel spec 15W40 oils and 99% of them have perfect cam bores and nearly zero wear on all other parts. The most common oil related failures for modulars I see are oil starvation. That is found by spun rod bearings, damaged cam bores, and scratched cam caps. A thicker oil will lower this damage potential when the pressure drops, that is a fact. Or - you just make sure the oil level is always good, these motors are known for consuming oil. As to what I personally use its always a straight 30W or 15W40 diesel spec in all my vehicles except the NA race car which gets a 10W racing oil (and is heavily modified for this). I would use regular 5W20 in a NA modular turning 6000RPM but not in one turning 7000 unless it also had a larger aftermarket oil pan and oil control modifications. A turbo motor would only get diesel spec if it was up to me. As far as oil filters its tough to beat the factory designed part you can get at nearly any auto parts store. It has the bypass on the threaded end like it should be, is built like a tank internally, and flows more than enough for any combination I have yet seen. |