Well we’ve discussed fuel and coolant additives in part 1 and part 2 so now it’s time for crankcase additives.
For those faithful readers who have been waiting for this for awhile I apologize for the delay. I had hoped to get this done before the start of the FRC Robotics season. Unfortunately one of the reasons I gladly accepted this opportunity was to get experience as a “professional” blogger and transfer that knowledge to my Team’s website. In addition to getting that up and running I masterminded a Facebook contest to promote our page and thus website among the FIRST community at the annual kick-off event. Due to snowfall Mon and Tue and projected heavy snowfall for today we did not end up building Wed so I was able to finally concentrate on this. Now back to your regularly scheduled programing.
Engine oil additives are most likely the most commonly found miracle worker in a can on auto parts store shelves. Like the others they come in a number of basic flavors. Most of them can be broken down in to two main categories.
Many fall under the “cleaner” category, and the are supposed to improve operation by cleaning the engine, freeing sticky rings, valves and lifters, and sometimes stop oil consumption due to leakage. Most of the products that are sold in this segment rely on some sort of solvent similar to the fuel system cleaners, in fact products like Marvel Mystery oil and Sea Foam state it is great for use in your crankcase just as well as your fuel tank. Yes solvents will clean the inside of your engine, as the name implies this products work by dissolving the oil sludge and gum. The problem is that a solvent isn’t selective in what it acts on so it will attack the engine oil too possibly lowering it’s viscosity. This can be a bad thing as the oil may not be able to have enough film strength to prevent wear. Because of this some products such as Sea Foam state that it should mainly be used as a pre oil change flush and if you are going to install in with fresh oil that you should monitor the oil closely and you may need to change it earlier than “normal”.
What if you pop the valve cover of your newly aquired Curbside Classic and it looks like this.
You might be tempted to use an Engine flush product.
These products sold specifically as flushes often instruct the user to only run the engine at idle and then just for a few minutes. These can be quite dangerous to your engine. Not only does the large volume of solvent degrade the oil significantly, on a very dirty engine with a lot of thick deposits it can break free a ton of big chunks. Those chunks can often plug an oil pump pickup screen solid completely starving the engine of oil. Those that aren’t large enough to be trapped by the screen must travel through the oil pump before they can be removed by the filter. If the filter is already partially plugged it may open the bypass valve either somewhere in the engine itself or the filter, and it won’t be filtered out. Either way freeing those deposits that weren’t on areas that are lubrication points and making it circulate to those points where the oil does serve as a lubricant and possibly plugging things like lifter passages and squirt holes is not a good idea.
Many that claim to stop seal leaks by “conditioning” the seals actually use solvents that purposely aren’t compatible with the common materials used to make shaft seals and gaskets. These are often referred to as seal swellers because they are actually absorbed by said seal causing them to swell. In the process of swelling rubber seals in particular get much softer which may allow them to conform to the shaft better, for a while. The fact is these products reduce the strength of the rubber and it will wear quicker as well as be easier to tear.
The next big group of crankcase additives are what I’ll call fortifiers. Most of these are either a high viscosity base oil or include friction modifiers to improve its hot viscosity performance. They usually claim the following benefits, quieter running engine, reduced oil consumption due to both leakage and burning, better oil pressure, or improving performance and MPG by increasing compression. They also often claim that engine wear, often specifically start up wear is reduced. Many of those claims are true to some extent or another. Thicker oil will usually result in a higher oil pressure reading than a thinner oil when you are operating below the pressure relief valve setting. It may also quiet or hide knocks and clatter by providing a better “cushion” of oil. Thicker oil also is less likely to leak past worn seals and valve guides. Higher viscosity may even provide a slight increase in compression and reduction in blow by due to its higher film strength providing a better seal for the rings. Due to the increase in thickness they may also slow down the natural affect of gravity draining the oil out of the passages which could reduce start up wear. On the other hand that thicker oil will take longer to build full oil pressure and reach the end of the lubrication system thus increasing wear. Thicker oils can also cause a form of oil starvation on engines that operate at high rpms. The oil is sheared rather than flowing when the speed of the surfaces exceeds the flow rate of the oil. So if you have a engine with low oil pressure, leaky seals, guides or rings these may provide some benefits but of course they will not repair parts that are worn.
Because of the sheer number of types and brands of crankcase additives you’ll have to stay tuned for part 3b, hopefully in the not to distant future, when we will discuss some of the best known, most controversial and litigated crankcase additives.
As always send your questions to CurbsideClueless@Gmail.com, as I do need a break from Robotics now and again and frankly answering questions is easier for me than composing an article from scratch.
Marvel Mystery Oil is supposed to actually be good – in old cars and maybe lawn mowers, I doubt I’d put it in a new car.
I’m still out to lunch on synthetic/part-synthetic oils, though my Impala now has that, thanks to my mechanic who did the 90K service.
STP? I used that on my early oil-burners, too. Also used re-refined oil for 19¢ a quart.
The photo of the sludged rocker arm? So THAT’S what Chrysler 2.7Ls looked like!
Marvel Mystery Oil is good and stopped the oil burning in my Olds 307 V8 which developed a quart every 3000 miles habit around the 100,000 mile mark. One of those quart of Marvel plus 4 quarts conventional oil did the trick.
That engine also had ticking lifters its whole life and my Dad’s mechanic told him he could use a miracle additive but he could only use it for X amount of time and then the engine had to be drained or there would be “dire consequences.” Dad decided to keep the ticking lifters.
I used Wynns every tank fill on a Mitsubishshi that was burning 4 litres per tank it cut oil consumption to 1 liter per tank seemingly clogging the rings up that car a huge mileage with me right around Australia and a trip up and down the east coast but was never driven hard.
Have used slick 50 on most of my engines. Demonstrable benefits in reducing engine temperatures during my early experience with it. Houston summers in the early 80s. I have heard of people clogging screens and eating seals when the product was new. Never seen any actual proof of that.
I am a big believer in synthetic oils. Seems most people who don’t like it are the oil change folks who want to pumb a fresh collection of dead dinosaurs into your engine every 3k miles.
I manage to neglect my engine and get a batch of miles out of it. I have always credited the products above with that. Probably can generate a lot of disagreement with that but it seems to work for me.
Newer oil formulations have lower and lower levels of “ZDDP”, a zinc compound that bonds to metal parts and forms a “sacrificial” film in case there is any metal-on-metal contact in the engine. This is significant for older flat-tappet engines. Cam manufacturers claim that increasing flat tappet cam and lifter failures are due to the reduced ZDDP content. I run 15W40 diesel oil in my Chryslers because it has higher ZDDP levels. There are also ZDDP additives available.
Another possibility is molybdenum sulfide, aka “moly”. Most flat tappet camshaft break-in additives are moly. There is one synthetic oil (Royal Purple) that has moly mixed in. The only additive I know of intended for fulltime use is MolySlip. One possible complication with moly is that it is not really soluble in oil but remains suspended. It is possible that it may be filtered out by super-fine synthetic-media oil filters and clog them up.
All of the idiots that I go to school with (think 19 year-olds that smell like crap and think that they are good at fixing cars) think that these additives are the greatest things. Their favorite seems to be Marvel Mystery Oil; once someone gets them singing the praises of this crap, they do not seem to stop!
If you are inordinately intrigued with oil, you might check out this guy:
I always called those engine flushes “rebuild in a can’ because within a few weeks of using it, you will be needing a rebuild. Better to just use good oil and change it more often.
Let me just debunk a few myths associated with oil:
*Oil pressure is a measurement of volume times restriction. Gum up the engine more, add thicker oil, you will get “better” pressure.
*Oil lubricates at the molecular level. Using thicker oil or having higher pressure to get more oil cushion in the bearing surfaces is bunk.
*Thinner oil lubricates better under almost all circumstances. When very hot it will show lower pressure but that means less restriction per volume. That means it is better able to dissipate heat do to it’s higher flow rate
*If your engine is leaking or loud, get it fixed.
I’m not sure that I agree with you a hundred percent on your policework there, Lou.
When it comes to journal bearings, the viscosity of the oil definitely has an impact in the stiffness of the film strength which in turn effects the response of the journal in the bearing.
I’m a little rusty in my rotordynamics, but the long story short is like adding air to your tires…more viscosity is like more air. Great for supporting the shaft and preventing metal/metal contact, to a point, then it’s going to be too much and cause new problems like shear instead of slip and you have fun stuff like oil whirl or whip concerns.
When it comes to “thick” or “thin” oil, don’t believe the hearsay. Your modern engine was designed with a specific viscosity range because that’s what the physics determined would be best. If it asks for 10W-30, buy 10W-30.
+10 cool points for the Fargo reference
Viscosity or viscosity rate? It sounds like you mean viscosity rate which is not the same. The rate will effect the sheer/pour index much more than the API viscosity rating. Film strength is important, but it is not a function of thickness.
The oil space provided in the journals was meant to admit just enough oil to keep things cool by volume. Oil works on a molecular level, no amount of oil will cushion a rod pounding against a journal.
Remember, when adding oil “fortifiers” or heavier weight oil, or even upgrading to a hi-volume, hi-pressure pump, that there are a couple unforeseen side effects, such as:
1: Heavier oil, or a hi-pressure pump, put more load on the oil pump drive mechanism, therefore creating more work for the engine, thereby robbing horsepower. Not too important in a daily driver, but more important at higher performance levels.
2: Too much oil pressure in conjunction with old, soft seals, can lead to oil pushing past the seal lip and becoming a leak. It is possible to push oil past old, soft seals without exceeding the by-pass valve pressure rating.
I will go into those additives containing Teflon/PTFE and the importance of ZDDP in the next installment, those 2 things are a big reason I elected to split crankcase additives into multiple parts.
Unfortunately by the time this article went live I had lost internet and power due to the snow, freezing rain and wind we had in western Washington last week. So while some robotics meetings were canceled and I would have liked to finish part 3b I was unable to. Instead I spent my time keeping the fire stoked, listening to branches and trees fall and cutting up/dragging the resulting debris out of my driveway and the street.
Unfortunately for those patiently awaiting the next installment it may be awhile as now we are working overtime at robotics to make up for those lost days and I’ve still got piles of debris to clean up. At least we can get out of the driveway with a car instead of a SUV and people don’t have to drive on the shoulder to get past our house.