• To ALL forum users - As of late I have been getting quite a few private messages with questions about build ups here on the forum, or tech questions about your personal project. While I appreciate the interest, sending me a private message about these topics distracts from, and undermines the purpose of having a forum here. During the day I wear many hats as a small business owner-operator and I work tirelessly to provide the absolute best service possible to you, our valued customer. When I created this forum I rounded up some of the best minds I knew so that any tech question you might have could be asked and answered by either myself or one of my highly experienced moderators, this way the next time this same question is asked the answer can be easily found and utilized by the next IH enthusiast having the same question. This allows me the freedom to run the day to day operations of the business and minimize the impact to shipments and shop activities that these distractions can cause. It is of the up most importance for me to complete the daily tasks in order to best take care of you our customer, all the while providing you a forum to get the level advice and input you have come to expect and deserve from the premier IH shop in the country.

    So with that I ask that anyone with a question about one of our build ups or a general tech question to please use the forum as it was intended. I am absolutely available by telephone to answer your questions as well but at times may direct you back to our website to better field your question or questions. Most other private messages I will be glad to answer for you.

    Thank you for your understanding.

    Jeff Ismail


DF Sales&Marketing

Oil Tech Moderator
in part from an article written by john martin, engine builder magazine

auto manufacturers and lube oil marketers worked closely with the American petroleum institute (api), the American society for testing and materials (astm), and the society of automotive engineers (sae) to specify pcmos as well as they knew how.
Oils were developed by analyzing actual field failures and developing laboratory engine tests that would replicate the field failures. It seemed everyone worked closely together without much dissention in the ranks.

Enter the epa
then the environmental protection agency (epa) got involved in chemical regulations, and the game became more adversarial and political. You must first realize that the epa and most environmentalists couldn’t care less about our internal combustion engines..
The epa first flexed its muscles when north American passenger cars began utilizing catalytic converters in 1975 to reduce co and hc emissions. Some laboratory engine tests using oils highly over-dosed with zinc dithiophosphate (zdp or zddp) extreme pressure (ep) additives showed that the phosphorous tended to “glaze” over the face of the catalyst substrate slowly rendering it ineffective.
No field tests that I’m aware of ever corroborated these lab test findings, but the epa flexed its muscles anyway and pushed for new lube oil chemical restrictions to minimize phosphorous (therefore zdp) content. They’ve been on this bandwagon ever since, and no one in our federal government has ever successfully moderated their powers.

Oil in the ’80s
by the 1980s auto manufacturers began pushing for the specification of new oil performance categories in which they could guarantee improved fuel economy. This brought about the development of friction-modified passenger car oils.
Oil marketers and auto manufacturers now had two new performance issues to deal with. The api, the astm, and the sae began developing new oil performance categories as quickly as they could. But the process of defining oil performance deficiencies, developing laboratory engine tests, and achieving consensus among all involved is slow and methodical and it costs millions of dollars to develop a useful new specification.
By the late ’80s American auto manufacturers (aama) decided the oil industry either wasn’t moving rapidly enough or weren’t addressing some of their specific needs, so they formed their own trade association. They formed the new group called the International lubricants standardization and approval committee (ilsac) to make sure their needs were being addressed.
The traditional api approach defined general pcmo performance level categories labeled as api sg, sh, etc., up to the current api sn. Ilsac members from the alliance of automobile manufacturers, which included european auto manufacturers and the japanese auto manufacturers association (jama) specified new performance categories labeled as gf-1, gf-2, etc., up to the current gf-5.

Oil and oes do mix
after much debate, the auto manufacturers and the oil industry learned to coexist, and the paired specification system sl/gf-3) sm/gf-4, etc.) continued forward through five oil performance upgrades and considerable expense through 2011. These upgrades occur every four years, and there is no end in sight.
I’m not sure I, or anyone else for that matter understands why general motors decided to get into the lube oil licensing business around 2010. [editor note: does “follow the money” ring home?] But they developed their own set of pcmo performance specifications (dexos 1, etc.) and required oil marketers who met these specifications to pay them a licensing fee if they wished to use the dexos name on their products.
I know of at least one lube oil marketer who told GM to go pound salt.
Here are the facts you need to know to intelligently purchase pcmos. First, pay no attention to the marketing hype. Look for the api “donut” or the ilsac “starburst” symbols [or statement which reads it meets the specification - there are many lubricant companies who do not subscribe to the api, or ilsac, but still meet the guidelines and specifications; they are still inspected by the api “watchdogs” and held to task if they are sub-standard]. The only currently active api specifications are api sj, sl, sm, and sn. Only ilsac gf-5 is currently active. Ilsac gf-4 was obsoleted one year after gf-5 was introduced.
If a dexos label also appears, that’s good news for GM warranty protection, but I wouldn’t lose any sleep over it if it weren’t there. Dexos oils are not gaining much traction in the marketplace.
Currently look for api sn/gf-5 because that will provide the best fuel economy for your late model (post 2006) passenger cars without valve train modifications.
However, if you have an older engine design or you have altered the valve train (high lift cam, etc.), all bets are off!
There are a myriad of hot rod or racing oils which are out there, [along with a few high performance specialty oils, such as “swepco’s 306 supreme formula engine oil”, api sl/ci-4] Which have higher zddp levels to protect pushrod tips and flat tappet cams and lifters.
Although these oils are expensive, they are not nearly as expensive as a replacement cam and lifters.

when it comes to engine oil, the
more recent the specification, the
better the oil performance except
valve train wear and ep protection.

If your flat tappet camshaft isn’t very radical, or if you are utilizing rollers, you might take a second approach. Break the engine in on one of the many break-in-oils out there. This will coat the cam and lifter surfaces with the sacrificial zddp film the valve train needs for proper component protection. Then you can switch to a lower zddp oil (api sn/gf-5) to maximize vehicular fuel economy. You might need to use a hot rod/break-in/specialty oil periodically to replenish the zddp but the question remains as to when to do that.
This is not as safe an approach as is the use of specialty oils, because no one is certain how much zddp your valve train actually needs.
Carefully consider viscosity grades for late-model engine designs (e.g., ls engines, modular fords, etc.). Since most of them were designed for very low viscosity oils, they don’t like thick oils us old school, old racers are fond of. I know of several examples where both ls and modular engines have failed because of their inability to pump thicker oils through all the engine oil passages. Play safe and use an oil specifically designed for these new engine families.


Just wondering what this purple sludge is that drops out of solution on the bottom of your quart bottles of 15w40 306. Hope it’s not all the extra zinc and special additives. Noticed this before, but decided to cut the bottom off the plastic bottle for a closer look when I changed the oil this weekend. Even shook it up well before pouring it in the motor. Seems to me the best additives in the world won’t do much good if they settle out in the bottle or bottom of the pan.



Hmmm, no answer, guess I just go with rotella, and add a half bottle of redline engine oil break-in additive from here on out.


Administrator & Owner
Staff member
Please be patient as dick is out on vacation and away from the computer. I'm sure once he is back to work he will give you a response.


Administrator & Owner
Staff member
No need for the sarcasm is this problem is being taken care of like all problems we encounter. A sample has been sent to swepco for analysis which we are waiting on the results. Sorry that no one has posted to let everyone know what is going on.

DF Sales&Marketing

Oil Tech Moderator

Yes, we did have a long vacation, in fact we returned and back to work on Monday, October 12th. It is unfortunate that something would come up while we were gone and it took so long to get any information, and I do apologize for not getting a reply back sooner, as time did go by faster than I had realized.

It took some time for me to connect with greg (hondo) to get more information, and also to verify the quality control (qc) number. Upon checking the retained sample from this batch, it found that the oil was in spec, and that there was no “purple sludge.” because of this, the chief chemist requested that a sample be sent, even if it was just another “fresh” quart out of the case which this came from. Greg sent the requested quart, along with the cut container containing the questionable residue by ups on Friday, October 23rd, and through tracking, I see that it was delivered to our lab on Friday, October 30th.

This particular qc batch produced thousands of gallons of product, packaged in cases, kegs and drums and totes, and there has been no other incidents or complaints about the condition which was shown in the picture. We take any product complaint very seriously, and I know that there will be a very thorough examination to have this resolved.

blue smoke

Sorry my comment was taken not as intended. The intent was not to offend but rather bring this back to attention because I was wondering what that was in the bottom of that bottle.

DF Sales&Marketing

Oil Tech Moderator
Regarding the "purple sludge" issue:

first of all, for clarification, not all of the people who read the posts are familiar enough to know that swepco engine oil is colored purple. With that being said, if there is a sludge issue, it stands to reason that it would be purple.

Secondly, after a thorough inspection and testing of the samples which were sent to us, john barnes, our head chemist has reported the results as follows:

"we did receive a quart of batch 44833adi, a quart of an older batch and the cut away bottom with sludge. Both our retain and the quart of batch 44833adi were in specification and no sludge or separations was noted. The quart bottle of the older batch did have a small amount of sludge present in the bottom of the bottle. Analysis of the sludge indicates that it is from a batch produced in 2011 that had a separation issue. We had identified the issue in 2011 and tried to recall and replace as much product as possible. No performance issues were noted nor has any damage been reported. We are still finding small quantities out in the field. We will be happy to replace any stock the customer has left with new stock. Please let us know if you have further questions."
With kind regards,

john barnes
southwestern petroleum corporation
senior scientist, manager of research, development, and technical services.

Once again, with my vacation and the absence from the plant last week by mr. Barnes, I offer our apology, but these things take time to review and check to make sure we are achieving the correct results. Swepco has been in business since 1933 and they take great pride in producing quality products, and they take comments seriously.

Greg, if you have any product left, get back to me and we will send out replacement for you.

Thanks for your patience,

dick floryanowich