Technical Switching grades and types of engine oil and its affects on engine noise, exhaust etc.

I have been wrenching on a heavily modified custom fairlane for a friend over the past 4 years which has a 427 Ford W that is stroked and bored out with 8 webber carbs and a full open exhaust, Compression is 10.5:1 with a pretty big roller cam. The engine builder told us they broke the engine in on the Dyno using 10W40 Lucas Motoroil, non synthetic. My buddy put 1000 miles on it and then switched to Shell Rotella 15W40 due to a suggestion from another old timer we know. He has run the Rotella for 4 years now in all seasons changing it every 1500 miles or so. Engine now has over 8k miles on it so we did another oil change this past weekend to Royal Purple HPS Synthetic 10W40 Race oil because he just happened to see it in the store and wanted to try it being it was on sale.

so far we notice the oil pressure is perfect and actually higher , engine fires up faster but the engine is making some weird ticks and sounds now plus the exhaust fumes smell worse all of a sudden, granted the temps dropped to the 30's and i am sure we got the winter blend of fuel now. Was this a bad idea to switch to this RP Synthetic now and should we just go back to the Rotella? He hasn't driven the car much since we changed the oil maybe 50 miles or so.

Looking for some explanation primarily on the exhaust fumes change all of a sudden. Wondering if the RP is too thin causing oil to seep between the rings or something. I personally have never used RP oils in any of my cars as its too darn expensive and hard to find around here.

 

The viscosity of the 2 oils is actually very close. The only time the viscosity of the RP oil is lower is at start up, as the temp of the oil comes up the viscosity of the two should equalize. At operating temp they should be the same (both should be SAE 40 grade at operating temperature). You even noted that the oil pressure is fine, even a little higher, that should convince you that the viscosity is fine.

I can't tell you about the ticks and sounds, no telling from this description what they are from. The synthetic nature of the RP oil should reduce the volatility of the oil, so it should have less oil loss due to evaporation. I doubt that the RP oil has any effect on the smell of the exhaust, that would be highly unlikely. Any fumes you may smell would more likely be coming from the breather, if the engine is equipped with one.

I don't think the change to RP was a mistake, but there was nothing wrong with the Rotella either, it's decent oil.

 

i just came back from his place and i swear it smells like its burning a tiny bit of oil now with this RP swap, the engine runs like a top, strong as hell. i think we will play with the webbers this weekend to see how that works out. I had an old 302 that had head issues and lots of white smoke years ago and this almost reminds me of that but to a much lesser degree, no white smoke on his 427 which is good. he is calling the engine builder this weekend to get his suggestions as well

 

I don't know if this has anything to do with or not, but I'll tell my story. In 1980, I bought a new Chevrolet Monza (please, no off-color comments). After it had a couple of thousand miles on it, the local Mobil dealer that I had great confidence in convinced me to change to Mobil-1 10w-30. After it had been in a while, I would notice that the lifters started "ticking" on long trips when the engine was fully warmed up. To make a long story short, the only thing that stopped this ticking was to change back to regular 10w-30 "Dinosaur" oil. I'm still puzzled by what happened, but I was there and spent a lot of time (and oil/filter changes) trying to stop the "ticking". I have no explanation.

 

This wives tale is still out there.... Multigrade oils DO NOT thicken or increase viscosity when they warm up; don't believe me, get a viscometer and check multigrade against straight grade at the same oil operating temp. When you look at the 'number' for multigrade (10W-40, 20W-50, etc), the first number is the actual viscosity. Multigrade oil is a thinner oil with additives, etc added to meet the same load-bearing specs as the equivalent straight grade oil as given by the second number. So a 10W-40 oil is 10 weight oil that can carry the same load as a 40W straight-grade oil. But it's still just a 10W oil in terms of viscosity...

All this was straight out of the mouth of a Standard Oil of California engineer.

Now, the odd noises you're hearing could be from the viscosity change. It could also be a change in the additive package to reduce friction. Some oils have more 'clingability' than others ('sticking' on parts better), most race oils are designed to not do that as that tends to foam the oil. Most race oils also don't have good detergents or corrosion inhibitors as the oil isn't designed for long-term use; it's expected to be changed after each race.

Full synthetics are also more prone to leaking out of places, that may be what you smell.

 

I never realised people actually thought that.

I was told it is the other way round, one figure is the cold viscosity, sort of heavy and thick, the other is how thin it gets when up to temp. Nobody has EVER tried to tell me oil gets thicker when hot.

I use straight 40 weight Rotella diesel oil in my SBC.

 

YES, to the OP question !!
I know Of several guys with oil issues going From R-P to Rotella oil ,

 

Kinda scary to think what 0W-30 is.

 

I NEVER said the oil thickened as it warmed up. Read my post again. I said "as the temp of the oil comes up the viscosity of the two should equalize. At operating temp they should be the same"

FYI, I am a Lubrication Engineer with a major international lubricants company, and a Certified Lubrication Specialist with the STLE. I do know what I'm talking about here.

The first number is not "the actual viscosity", it is a rating of the oils viscosity at very cold temperatures. The second number is a rating of the oils viscosity at 100C. That is fact whether you like it or not, or whether you even understand it or not. Please, don't attempt to lecture me about oil.

At 100C both a 15W40 and a 10W40 have the same viscosity (at least within a range of viscosity that makes up the SAE 40 grade, i.e. 12.5 - <16.3 centistokes).

Viscosity is technically referred to as "resistance to flow", not load bearing specs. Viscosity at 100C is determined by measuring the time it takes oil to flow through an orifice and over a measured distance. A low viscosity oil flows easily and quickly, a high viscosity oil has more resistance to flowing, it takes longer for it to flow over the same distance.

There is also something known as "Viscosity Index", which is a rating of how the oil's viscosity changes relative to temperature. All oils decrease in viscosity as they warm up, but not all oil change at the same rate. The viscosity of some oil changes rapidly as the temperature changes, these oils have a low viscosity index. Other oils do not change much at all as the temperatures increase, these oils have a high viscosity index. Synthetic motor oils, such as Royal Purple, tend to have much higher viscosity index than mineral oils, like Rotella. The fact that the RP is a 10W40 and the Rotella is 15W40 indicate that the RP has a higher VI than Rotella. This means that Rotella has a greater rate of change relative to temperature. I.e, the viscosity decreases at a more rapid rate. That is why at operating temp both oils have the same viscosity. The RP may start out with less viscosity, but it doesn't lose viscosity as quickly as Rotella, it maintains its viscosity better, and that's why at operating temp it has the same viscosity as Rotella.

Now that we've settled that both oils have the same viscosity at operating temperature, it should be clear that any noises the OP hears are not caused by a change in viscosity, because there isn't any, except at start up.

BTW, Royal Purple HPS 10W30 motor oil is NOT "race oil", it is High Performance Street oil. It is intended for, and formulated for street use. I would caution however that Royal Purple does not license the oil with the API, and the oil does not carry an API service category spec. You are just taking Royal Purple's word for it's suitability for use, for whatever that is worth.

 

Hopefully it should be clear by now that 0W30 motor oil is an oil with very good flow characteristics at very low temperature, and very common SAE 30 grade viscosity at operating temperature. At 100C it has the same viscosity as any 5W30 or any 10W30 or even straight grade 30 oil.

You're welcome.

 

That is correct.

Ooooh, not good. Straight grade (weight is not an accurate word for viscosity) oils are old technology oils, you're not getting any benefit from using them and you are missing out on more than just multi-viscosity performance. Rotella straight grade 40 is only a CF quality oil, the current specification is CJ-4, moving very soon (within weeks) to CK-4. You're leaving a tremendous amount of performance on the table by using that oil. Less anti-wear, less oxidation resistance, increased deposits, less detergents, less dispersants, less anti-foam, in every area of performance that oil is weak. Why do you choose it?

 

Blues4U,, what you know about oil , Is the statement correct I posed,, the guys I know have there motors build by respectable engine builders around the USA , they are $50,000 & up motor , they been fighting oil issues as in lost oil presser, oil blow bye , bearring showing wear , with R-P ,they switched over to the Rotella and the issues have whent away , myself I Run Lucas break in oil 20/50 or straight 60 and also Valvoline race Vr1

 

White smoke typically indicates water ingestion into the combustion chamber. Or raw unburnt fuel being expelled out the exhaust.

There can be a condition with a change in engine oil chemistry where the detergents in the new oil start to remove deposit buildup left by the previous oil. We've seen where oil consumption will go up after a change for a period of time, usually a couple of oil change intervals, until the oil consumption goes away. You might be experiencing that. Has the oil level dropped?

I'm not a fan of Royal Purple or trying to talk you into using it, just giving you an honest and professional advice. I've seen people blame all kinds of things on a chance in motor oil. A guy once had his wife leave him and his dog died after he changed brands of motor oil, and he swears it was the new oil that caused it. Really, both of those oils are good products, maybe not what I would chose to use, but nothing wrong with them. I think you're fine.

 

I don't know, that's too wide a variable to answer. Royal Purple makes a lot of different oils, which one were they using? I'm not a fan of RP, in fact I've had to compete with them in the field as they tried to steal my customers, but I always respect they put out a quality product. Even if they do use some hokey marketing schemes. Rotella is also a good product, used in millions of diesel engines all over the world. Rotella is the #1 diesel engine oil in gallons sold. It's a good product. Maybe not the best, but it's good.

 

I didn't want to be a jerk and quote your credentials (which are IMPRESSIVE) just to take up space, simply to say....THANKS for posting all of this info. I was struggling with picking the right oil for my older 305 that's been running cruddy. I switched to a 10W-40 with no real change; HOWEVER, I figured out that my fuel pressure was too high, pushing excess fuel into the engine, past the pistons (it leaked after shut down), and into my oil.....THUS creating the white smoke you mentioned in another post. You learn SO much here on the HAMB. If you ever get tired of being an oil man, I know there's probably PLENTY of need for "Lube Specialists" here in the San Fernando Valley....BAZINGA!

 

I thought Royal Purple had more to do with someone holding something too tight, normally while driving a Fast and furious style import........ as an oil I wont touch it, over priced and under preforming, more for bragging rights for people with no idea ........ Rotella was ok but whats the zinc like today? if its the same use that, and stop swapping around.

 

Great info posted here guys, much appreciated I just fw this thread to my friend and he is def switching out the RP tomorrow Blues4U il send you a PM quick question.

 

I will continue to use the Rotella. It still has zinc. I use in in everything tractors cars bulldozers gas & diesel. If its not broke don't fix it.

 

Blues4U, a question for you.

What "type" of oil would you recommend for the guys running old style solid lifter, flat tappet motors to get the best possible lubrication at a reasonable cost.

Great post, highly educational. Thanks

Canuck

 

Any feedback on the Valvoline vr1 oil in sae40 or 20w50, not the synthetic , I did a search seems a lot of guys with 427w use this in their speed boats or cobra and gt40 replicas, wondering of the 20-50 is to thick? Valvoline is a great brand I use to always use this brand when I was a kid at the strip

 

Post reminds me to watch who you poke a stick at. I use VR1, works for me.

 

Yeah, Rotella should still have ~1100 - 1400 ppm of zinc, along with some Boron, and many of the diesel engine oils are adding in some moly as well. Anti-wear is still a premium concern in heavy duty diesel engines, these engines cost a lot of money and when they go down the down time can cost more than the repair. So anti-wear has remained a premium concern among the OEM engine mfgr's, and engine oils need to prove they provide wear high level of wear protection in tests before receiving API license.

 

I'd also like Blue's recommendation for a solid lifter engine. My engine builder said I should use 40 weight in the flathead he put together, but what is the best brand nowadays? And I don't do much winter driving, so is a straight weight better, or should I still use a multi weight?

 

I use Castro 10/30 in my 327/300 with 2 oz. of Lucas Break in oil
its a 1963 engine Stock Never been Rebuilt
Thats what Lucas told me to use on every OIL change
because Older engines Need the Zinc.!

Just my 3.5 cents
or when the Cows
come Home..!

 

x2 - I have been using Lucas Hot Rod & Classic 10 - 40 (high zinc content) in a '67 Ford 390 GT /solid lifter- seems good but, expensive

 

Diesel oils may work OK in gas engines, but spark rated oils are formulated different than compression and are a better choice, imo. My choice is Valvoline VR-1 that is street friendly, retains high ZDDP, readily available along with several straight and multi grades.

 

I use Lucas hot rod oil and Rotella in my cars, this Valvoline seems great what grade do you run? I see 20-50 being popular for sbf and stuff when I did a search earlier

 

Oil threads are always interesting. Spill it Blue, what's best for an old school solid lifter motor with some compression, without going boutique?

 

I use 10W30 and 20W50, or a blend of 10W30/20W50, to get 15W40, depending on the engine. VR-1 has been my HP favorite many years.

 

Like all of you, I've struggled with the same question. Federal emissions reg's have forced the redesign of gasoline engine oils with reduced levels of zinc anti-wear additives. This is mainly to protect catalytic converters from being "poisoned" by phosphorus, and the main source of phosphorus is the zinc diaklydithiophosphate (ZDDP or just ZDP) compound used for anti-wear in engine oils. And as everyone knows, with the reduction in ZDDP cam mfgr's have claimed increased rates of cam failures. Personally, I think the fear is exaggerated, and that there is likely more to the story than just reduced levels of ZDDP (I expect that a good number of failed cams had insufficent hardening procedures completed, and the cam grinder just blamed the oil rather than accept the blame), but a colleague of mine that has worked very close with NHRA drag racers for several decades says it's not just urban legend, that there is definitely a connection between reduced levels of ZDDP and failed flat tappet cams. This guy has worked with the best of the best (multi-time National Champions), I respect his experience.

So what to use? What about diesel engine oils?

In the old days diesel engine oils contained very high levels of what's known as Sulphated Ash. That's because older diesel fuel contained very high levels of sulphur, which caused the formation of some serious acidic conditions in the oil that had to be neutralized by the oil. Additives used to neutralize acids added to the SA content. And high levels of SA are known to result in excessive piston deposits. So HD Diesel engine oils were not a good choice for gasoline engines, because of the SA levels. But modern emissions reg's limit the sulphur content in diesel fuel to just 15 parts per million. And with the reduced levels of sulphur in the fuel, SA content can come down. Current HD Diesel engine oil specs call for SA level of no more than 1% max. So the fear of piston deposits from SA in diesel engine oils is pretty much a thing of the past. In fact, one of the tests oils must pass in order to receive API licensing is a measurement of piston deposits in an engine run on a test stand.

Now, with the reduced levels of SA, ZDDP levels have had to come down, but they are still well above 1000 ppm, I typically see zinc levels of around 1200 - 1300 ppm in most HD diesel engine oils. And, along with the zinc I also see a growing trend toward increased levels of boron and also moly, which both add to the anti-wear properties of the oil.

Diesel engine oils have other benefits, they are formulated to resist oxidation, which is the main limiting factor in the service life of lubricating oil. So they provide long service life and resist the formation of lacquer and varnish and sludge. And they are well fortified with detergents, so they clean up older engines and keep new engines clean. They resist foaming well. They are kind to seals and keep them pliable, helping to prevent leaks. And the viscosity grades are just about right for these older engines, which were designed to run on straight 30 and 40 grade oils. So a 10W30 or 15w40 viscosity grade is just about perfect. And they are readily available at most every auto parts store, Walmart, and truck stops all over the country. And they are reasonably priced.

If they aren't perfect, and I don't claim they are, they are pretty damn good, and IMO they make the most sense in older flat tappet cam engines; and that is what I use in my older engines. IMO they will work well for >90% of hot rod engines out there and may only be insufficient in those with seriously aggressive cams with very high lift lobes with very quick ramps, and very high pressure valve springs. Those cams are not very practical on the street and in reality they are few and far between. At any cruise night or show and shine or poker run I've even been too I've only ever seen a small handful of cars set up like that. Most of us run much more reasonable cams on the street. Even those with "street & strip" cars. Dedicated strip cars, that's a different story.

What about true Racing Motor Oil? True racing motor oils do not contain a lot of detergents or other additives, they are intended for short term use, only for 1 event, and then they are drained and replaced. So they aren't ideal for street use. Some companies may label an oil as a racing motor oil, and then sell it for use on the street, and in these cases the oil is probably not a true racing motor oil, there may be nothing special about it at all except for the name. I don't know. If you're using one, why not contact the company and ask for a technical data sheet on the oil, and then send a sample off to be analyzed and see what the additive content is. Send me a sample and I'll have it analyzed and post the results here on the HAMB.

And finally what about aftermarket zinc additives? I'm not a fan of self blending of lubricants. ZDDP anti-wear additives are surface acting chemicals, they contain molecules with a polar head and oil soluble tail, they are attracted to the metallic surfaces on an engine and plate themselves out to provide a protective layer. But there are other surface acting chemicals in the oil, detergents and anti-rust additives and lubricity additives, and they all are attracted to the metal surfaces too. So every motor oil out there is a careful blend of additives that work well together. Then you come along and add in some unknown compounds and you have no idea how they work with the additives already blended in the oil. IMO it's just not good practice. Buy a good quality oil to begin with and don't add anything to it is my advice. Let it work as it was engineered to work.

Sorry for the long winded post, I hope it doesn't bore you to tears and somebody finds it helpful.