GregBBRD

No idea of what other things affect my camshaft "success". Maybe I was just lucky. I have made some changes to what I do with camshafts and lifters....in certain engines......but I did not specifically make these changes because of camshaft wear.

I have spent hours and hours with cam profiles and valve train weight. I do not "overspring" my engines. I also do not "underspring" my engines. I try to find valve springs that have the proper spring rate for what they are being asked to do. Some of the valve springs used, in these engines, are just silly....way too much spring pressure. However, the inverse is also true....some people are using springs that are too light for what they are doing.

Truthfully, there's so much to do, to make these cars "survive" and run better, I can't spend the time looking for solutions for problems that I don't see.

I'm still trying to find the solutions to "gross" issues that actively ruin these engines and vehicles, plus solve the problems/power limiting factors that "naturally occur" as the output of these engines gets higher.

BTW....If the "pressure" of a flat tappet cam exceeds 200,000 psi...none of the oils tested will work. One with 60,000psi isn't much different than one with 120,000psi, in a 200,000psi load. Either oil is going to have failed and there will be metal to metal contact.

ptuomov

Opinions vary on the effect of aftermarket additives. Here's some food for thought from my favorite oil tester "540 RAT". He measures a significant decline in wear protection when an aftermarket additive is added to an oil that already has an additive package. I am not saying that you should just believe this one expert, just I think that he's not conflicted as he's not trying to sell you anything (that I know of):

http://speedtalk.com/forum/viewtopic.php?f=1&t=34926

I am personally leaning towards the explanation that the dramatic increase in flat tappet camshaft failures (in typical hot-rod engines, not 928s) was caused mostly by cam profiles getting more aggressive (i.e., higher accelerations), real men running gazillion pound valve springs, and cheap off-shore lifters flooding the market. Surely, the emissions-mandated changes to oils may have contributed as well, but maybe that wasn't the main reason for the epidemic.

GregBBRD

And then there is a large group of people that think the government "mandated" the reduction of zinc and phosphorus to get rid of more of the older vehicles and make people buy new ones.

Of course, those same people think that the whole R-12 thing was about money....and actually had very little to do with the ozone.

And think that $5.00 a gallon gas isn't about the price of a barrel of oil.

Who really knows?

ptuomov

I agree. For my practical purposes, for cam lobe and flat tappet lifter lubrication, whatever works, works. It's a too complex of a process for me to understand.

Here are some of the difficulties that I've personally experienced trying to understand the camshaft wear in our engines:

In hydrodynamic lubrication, there's an oil wedge between the two sliding parts. In the case of cam lobe on a bucket lifter, exactly on which side of the cam lobe is that oil wedge?

At first, I was thinking well the cam rotates in one direction so surely the wedge is always on one side.

But then I thought, hey wait a second, the contact point of the cam lobe on the lifter starts at the center, then moves from the center to one end to meet and greet the cam lobe nose, then reverses and goes all the way to the other end to say good bye to the cam lobe nose, and then reverses again and comes back to the center. So the oil wedge is on one side most of the cam rotation, but some of the time actually on the other side.

Then I started thinking that since the contact point reverses direction, it must stop for an instant. If it is stopped for an instant, there is no oil wedge. "There is no spoon." If there is no oil wedge, then there is no hydrodynamic lubrication, at it's boundary metal to metal. The cam is surely going to die.

"There is no spoon?" Well how do these cams live in the first place? Well maybe the cam lives because the cam profile is designed such that it accelerates the lifter very aggressively when the contact point is moving fast but then dwells at a constant velocity at the point where the contact point reverses, so maybe we can keep the pressure low at the turning point of the contact point on the lifter.

At this point I had forgotten something. This still leaves the spring force pressing the lifter on the cam lobe at the point where there is no wedge. Maybe they actually start decelerating the lifter as the contact point movement slows, stops, and reverses? And maybe they do just enough of that such that the profile deceleration almost cancels the spring pressure. That must work.

Ok, it doesn't work. The spring pressure is constant across rpms, while force equivalent of the deceleration increases with the rpm. Well maybe it works, a little bit. Let's make it so that the deceleration force almost cancels the spring pressure at the redline rpm. Now, this will still give some pressure at the time when there's no wedge at low rpms, but it will be better at high rpms.

But why do we have to run much spring load in the first place? Well of course that's because otherwise the cam lobe loses control during the deceleration of the lifter and all the hell brakes loose. Well how about we decelerate the lifter really slowly. But in order to do that we have to accelerate the cam really fast so we have more time to decelerate it gently. But accelerating the cam profile quickly changes the degrees at which the contact point stops, so you're shooting at a moving target!? Luckily we know that we can get the maximum velocity by designing a pointy cam with quite flat flanks that has base circle radius plus the maximum lift close to the lifter radius, so that gives us a very fast acceleration to the maximum velocity!

Now I am thinking "Then you'll see, that it is not the spoon that bends, it is only yourself."

Until I tell all this to someone who actually designs cams and he says "They may have thought about it like that at some point in the 1940's, but probably not"

At this point, I had only tried to think about lubricating then God damn cam contact point, making power was not even considered.

The next logical step was to order Norton's "Cam Design and Manufacturing Handbook" from Amazon and begin by actually understanding the basics.

That was a while ago and I still don't understand the basics.

;-)

Mongo

The whole oil debate has me confused. I've been an avid user for Mobil 1 15w50 on these cars. According to Mobil Oil's site, the ZDDP content is 1300 PPM, but they also state the phosphorus content is 1200 PPM. They also indicate the phosphorus is an effective anti-wear compound for the motor.

So, should I NOT use Mobil 1?

http://www.mobiloil.com/USA-English/...duct_Guide.pdf

eijun

Mobil 1 15/50 + additive is ok (I think everyone says if your just using Mobil 1 15/50 by itself then your borderline)

Use the oils that people here recommend (a partial list which Greg recommends is in the first page)

Now trying to find the one which is the best for your car being each one is fickle, that you have to test yourself.

MainePorsche

I'm very happy with Mobil 1 for years. I add a zddp concentrate, for if it not a concentrate, you'd be adding quite a bit of 'junk' oil. With the Risoline I do note a difference. Others who have been in the car before and after my zddp use have commented as well. Half a bottle, or 5-6 oz. per oil change.

GregBBRD

And then you look at a late model Cup Car camshaft. They actually grind the "flanks" of the cams flat...so that there is no contact of the lobe until the very highest part of the cam touches the lifter. They are "missing" 1/2" of "lobe contact" (on both sides of the lobe) over a more conventional design....like in our 928 engines. That modification obviously increases the acceleration on the lifter and the resulting "pressure" between the two, but also reduces friction, over a large amount of the duration of the camshaft.

And, of course, how the oiling occurs is also affected.

Way beyond my little brain.

NoVector

Just another datapoint: my Blackstone oil analysis last November, Royal Purple 20/50

zinc = 1350
phosphorus = 1170
magnesium = 20
molybdenum = 122

I bought 2 bottles of the Torco ZEP but never used it after seeing the results...

ptuomov

Doesn't that 997 cup car engine have indexed lifters with a visibly convex contact patch? The convexity of the lifter surface makes up for the flatness of the lobe flank and the lobe lifter contact point still moves from center to side to opposite side back to center.

Mongo

The Rislone I bought does not look like that bottle. It is the basic engine treatment which supposedly gets rid of sludge and unclogs lifters. Again, is this okay to use with Mobil 1??? I know there is no ZDDP in this one...

GregBBRD

Camshafts just prior to that change. Flat tappets.

Sorry, not very current on my Cup Car stuff.

Andy Kay

As I said last year (post #4) I've been using Valvoline VR-1 20w-50 in my 911 for years. Next oil change the 928 will get VR-1 too!

ptuomov

Fresh off RAT's press:

http://speedtalk.com/forum/viewtopic...art=45#p437519

Re: Are my oil temps acceptable on the street?
by 540 RAT » Thu Jun 06, 2013 2:21 pm

As many know, I have an ongoing motor oil “Load Carrying Capacity/Film Strength” wear testing effort. This testing is a motor oil torture test that subjects oil to a friction test under load, in a controllable and repeatable manner, while the wear specimens are bathed in oil. This test is significantly more severe on the oil than is an actual running engine. That way you can see how different oils directly compare to each other, without having to wait for 100,000 miles to see what happened. It allows you to quickly determine outstanding oils from ordinary oils.

I’ve re-tested a dozen of those oils at a higher temperature to get a better idea of how various oil types perform over a wider range of temperatures. The oils chosen this time consist of:

*** 10 different brands
*** 6 low zinc (below 1,000 ppm) oils
*** 6 high zinc (above 1,000 ppm) oils
*** Viscosities ranging from 5W20 to 20W50
*** 8 full synthetic oils
*** 3 conventional dino oils
*** 1 semi-synthetic oil
*** 6 Racing/High Performance oils
*** 6 Modern API certified oils
*** 6 Low detergent (less than 2.0 “detergent/zinc” ratio) oils
*** 6 High detergent (2.0 or higher “detergent/zinc” ratio) oils

Here are those 12 oils, ranked by their test result capabilities at 230*F:


1. 5W30 Pennzoil Ultra, API SM (synthetic)
115,612 psi “load carrying capacity”

2. 10W30 Lucas Racing Only (synthetic)
106,505 psi “load carrying capacity” (8% below no. 1)

3. 5W30 Mobil 1, API SN (synthetic)
105,875 psi “load carrying capacity” (8% below no. 1)

4. 5W50 Motorcraft, API SN (synthetic)
103,517 psi “load carrying capacity” (10% below no. 1)

5. 10W30 Valvoline VR1 Racing Oil silver bottle (conventional)
103,505 psi “load carrying capacity” (10% below no. 1)

6. 5W20 Castrol Edge w/Titanium, API SN (synthetic)
99,983 psi “load carrying capacity” (14% below no. 1)

7. 20W50 Castrol GTX, API SN (conventional)
96,514 psi “load carrying capacity” (17% below no. 1)

8. 10W30 Joe Gibbs XP3 NASCAR Racing Oil (synthetic)
95,543 psi “load carrying capacity” (17% below no. 1)

9. 5W30 Castrol GTX, API SN (conventional)
95,392 psi “load carrying capacity” (17% below no. 1)

10. 10W30 Amsoil Z-Rod Oil (synthetic)
95,360 psi “load carrying capacity” (18% below no. 1)

11. 5W30 Royal Purple XPR (synthetic)
74,860 psi “load carrying capacity” (35% below no. 1)

12. 0W30 Brad Penn, Penn Grade 1 (semi-synthetic)
71,377 psi “load carrying capacity” (38% below no. 1)


Of these 12 oils, the top 10 were in the over 90,000 psi “OUTSTANDING PROTECTION CATEGORY”. And the last 2 were in the 60,000 to 75,000 psi “MODEST PROTECTION CATEGORY”. None of these oils were BAD oils, it’s just that some provided a higher margin of safety than others, regarding wear protection. Now let’s take a look at how things changed at a higher temperature.

Capability ranking at 275*F:

1. 5W30 Pennzoil Ultra, API SM = 97,955 psi (dropped 15% from its 230* value)

2. 5W30 Mobil 1, API SN = 96,323 psi (dropped 9% from its 230* value)
(2% below no. 1 here at 275*)

3. 10W30 Lucas Racing Only = 95,996 psi (dropped 10% from its 230* value)
(2% below no. 1 here at 275*)

4. 5W50 Motorcraft, API SN = 92,545 psi (dropped 11% from its 230* value)
(6% below no. 1 here at 275*)

5. 10W30 Amsoil Z-Rod Oil = 91,351 psi (dropped ONLY 4% from its 230* value)
(7% below no. 1 here at 275*)

6. 20W50 Castrol GTX, API SN = 85,815 psi (dropped 11% from its 230* value)
(12% below no. 1 here at 275*)

7. 5W20 Castrol Edge w/Titanium, API SN = 84,584 psi (dropped 15% from its 230* value)
(14% below no. 1 here at 275*)

8. 10W30 Joe Gibbs XP3 NASCAR Racing Oil = 80,957 psi (dropped 15% from its 230* value)
(17% below no. 1 here at 275*)

9. 5W30 Castrol GTX, API SN = 80,957 psi (dropped 15% from its 230* value)
(17% below no. 1 here at 275*)
NOTE: This is not a typo here, number 8 and 9 here just happened to have the same size wear scar, thus the same psi value.

10. 10W30 Valvoline VR1 Racing Oil, silver bottle = 75,116 psi (dropped 27% from its 230* value)
(23% below no. 1 here at 275*)

11. 0W30 Brad Penn, Penn Grade 1 = 68,768 psi (dropped ONLY 4% from its 230* value)
(30% below no. 1 here at 275*)

12. 5W30 Royal Purple XPR = 66,664 psi (dropped 11% from its 230* value)
(32% below no. 1 here at 275*)

As expected, the capability psi values dropped as the oils got hotter and thinner. But for most of the oils, the drop was not enormous. And the average psi drop for the whole group of 12 oils, was only about 12% from their 230* values.

You can see, there was some shuffling of the ranking order, but the original top 10, are still in the top 10. And there was no indication of the presence of slow burn zinc (requires more heat and load to become effective) that may have helped the low performing high zinc oils, do better at higher temps.

But, since engines oil won’t typically be running at just 230*F or at just 275*F, it makes the most sense to average the values from the relatively cool low temp and the relatively hot high temp, to arrive at values in the middle. This will provide a more real world reference overall.

The “average” capability ranking from 230*F and 275*F combined:

1. 5W30 Pennzoil Ultra, API SM (synthetic)
106,784 psi “load carrying capacity”
zinc = 806 ppm
total detergent = 3387 ppm
detergent ppm/zinc ppm ratio = 4.2, the higher this number, the higher the proportion of detergent, which can have the potential to try and clean away zinc

2. 10W30 Lucas Racing Only (synthetic)
NOT SUITABLE FOR STREET USE
101,251 psi “load carrying capacity” (5% below no. 1)
zinc = 2642 ppm
total detergent = 2943 ppm
detergent ppm/zinc ppm ratio = 1.1

3. 5W30 Mobil 1, API SN (synthetic)
101,099 psi “load carrying capacity” (5% below no. 1)
zinc = 801 ppm
total detergent = 1489 ppm
detergent ppm/zinc ppm ratio = 1.9

4. 5W50 Motorcraft, API SN (synthetic)
98,031 psi “load carrying capacity” (8% below no. 1)
zinc = 606 ppm
total detergent = 2005 ppm
detergent ppm/zinc ppm ratio = 3.3

5. 10W30 Amsoil Z-Rod Oil (synthetic)
93,356 psi “load carrying capacity” (13% below no. 1)
zinc = 1431 ppm
total detergent = 2927 ppm
detergent ppm/zinc ppm ratio =2.0

6. 5W20 Castrol Edge w/Titanium, API SN (synthetic)
92,284 psi “load carrying capacity” (14% below no. 1)
zinc = 1042 ppm
total detergent = 1952 ppm
detergent ppm/zinc ppm ratio = 1.9

7. 20W50 Castrol GTX, API SN (conventional)
91,165 psi “load carrying capacity” (15% below no. 1)
zinc = 610 ppm
total detergent = 2599 ppm
detergent ppm/zinc ppm ratio = 4.3

8. 10W30 Valvoline VR1 Racing Oil silver bottle (conventional)
89,311 psi “load carrying capacity” (16% below no. 1)
zinc = 1472 ppm
total detergent = 2787 ppm
detergent ppm/zinc ppm ratio = 1.9

9. 10W30 Joe Gibbs XP3 NASCAR Racing Oil (synthetic)
NOT SUITABLE FOR STREET USE
88,250 psi “load carrying capacity” (17% below no. 1)
zinc = 743 ppm
total detergent = 620 ppm
detergent ppm/zinc ppm ratio = .8

10. 5W30 Castrol GTX, API SN (conventional)
88,175 psi “load carrying capacity” (17% below no. 1)
zinc = 830 ppm
total detergent = 2648 ppm
detergent ppm/zinc ppm ratio = 3.2

11. 5W30 Royal Purple XPR (synthetic)
70,762 psi “load carrying capacity” (34% below no. 1)
zinc = 1421 ppm
total detergent = 3050 ppm
detergent ppm/zinc ppm ratio = 2.1

12. 0W30 Brad Penn, Penn Grade 1 (semi-synthetic)
70,073 psi “load carrying capacity” (34% below no. 1)
zinc = 1621 ppm
total detergent = 2939 ppm
detergent ppm/zinc ppm ratio = 1.8 (only 43% of the detergent concentration of no. 1)

Looking at these 230*F and 275*F combined “average values”, you can see the following:

*** Modern API certified oils ranked from number 1 to number 10
*** Racing/High Performance oils ranked from number 2 to number 12
*** High detergent oils ranked from number 1 to number 11
*** Low detergent oils ranked from number 2 to number 12
*** Synthetic oils ranked from number 1 to number 11
*** Conventional dino oils ranked from number 7 to number 10
*** Semi-synthetic oil ranked number 12
*** 20 wt type oil ranked number 6
*** 30 wt type oils ranked from number 1 to number 12
*** 50 wt type oils ranked from number 4 to number 7

So, it’s quite clear by looking at these results, that high zinc levels, high detergent levels, and heavy viscosities do NOT play any particular roll in how well a motor oil does or does not provide wear protection. The only thing that matters is the base oil and its additive package “as a whole”. Looking at zinc levels, detergent levels, and viscosities on an oil’s spec sheet, will NOT help you choose a motor oil that provides the best wear protection. If that is all you go by, you will be kidding yourself about how good any particular oil is.

And keep in mind that the oil industry is fully aware that there is alternate chemistry available besides zinc/phos, which can be used for extreme pressure wear protection, that is equal to or better than zinc/phos. And that alternate chemistry is just what they use to reduce the zinc/phos levels in modern API certified oils. So, you do NOT need to have high levels of zinc/phos in order to have outstanding wear protection, no matter how loud someone screams that you do. Because they simply do not know what they are talking about. That high zinc thinking is only a MYTH repeated a million times until everyone just "thinks" it's true. But, that MYTH has been BUSTED by real world "dynamic wear testing under load".

In spite of what many Racers, Hotrodders and Gearheads have been lead to believe, only “dynamic wear testing under load” can provide the necessary data to help you choose a motor oil that will truly provide the best wear protection. It’s the same type of idea where we dyno test engines to see how they truly perform, rather than just looking at their spec sheets.


SYNTHETIC VS CONVENTIONAL OILS

Some of the most commonly claimed benefits of synthetics are:
1. Synthetics provide a higher level of wear protection.
2. Synthetics can withstand higher temperatures before thermal breakdown begins.
3. Synthetics provide superior flow under extremely cold conditions.

So, let’s see how the real world testing above, supports those claims. The synthetics above did show some advantage regarding wear protection, but NOT by a large amount. The highest ranked conventional oil ranked 7th out of 12, but was only 15% below the highest ranked synthetic oil. And this conventional oil ranked higher than other synthetic and semi-synthetic oils.

This shows that you cannot automatically assume that a synthetic oil will provide the best wear protection just because it is synthetic. Wear protection depends on the oil and its additive package “as a whole”. And it’s the additive package that contains the extreme pressure protection components, not the oil itself. And again, only “dynamic wear testing under load” can provide the data to help you choose an oil that provides the best wear protection.

THERMAL BREAKDOWN

I also heated the oils and observed the temperature at which they started to vaporize/smoke, which indicates the onset of thermal breakdown. Thermal breakdown is the point at which the composition of the oil begins to change due to the temperature it’s exposed to.

The official test for this is called the NOACK Volatility Test. In this test, the oil is heated to 302* F for one hour. The lighter oil fractions will vaporize, leaving thicker and heavier oil, contributing to poor circulation, reduced fuel economy, increased oil consumption, increased wear and increased emissions. The test reports results in the percentage, by weight, lost due to "volatilization." Before July 1, 2001, 5W-30 motor oil in the United States could lose up to 22 percent of its weight and still be regarded as "passable." Now, with GF-4, the maximum NOACK volatility for API licensing is 15 percent. European standards limit high quality oils to a maximum of 13 percent loss.

Here are the approximate observed temperatures at which the various oils started to vaporize/smoke, which indicated the onset of thermal breakdown:

5W30 Pennzoil Ultra, API SM = 280*

5W30 Mobil 1, API SN = 265*

10W30 Lucas Racing Only = 290*

5W50 Motorcraft, API SN = 275*

10W30 Amsoil Z-Rod Oil = 300*, the BEST in this test

20W50 Castrol GTX, API SN = 275*

5W20 Castrol Edge w/Titanium, API SN = 280*

10W30 Joe Gibbs XP3 NASCAR Racing Oil = 280*

5W30 Castrol GTX, API SN = 280*

10W30 Valvoline VR1 Racing Oil, silver bottle = 260*, the WORST in this test

0W30 Brad Penn, Penn Grade 1 = 280*

5W30 Royal Purple XPR = 285*


Here are the “averages” for the onset of thermal breakdown with these 12 oils:

Full synthetic oils = 282*

Semi-synthetic oil = 280*

Conventional dino oils = 272*

These observations are perfectly consistent with the NOACK Volatility Test that is performed at 302*F. Oils have to be vaporizing/smoking by 300* in order to perform this official test. For the oils tested above, certain specific oils did show a significant difference, such as the synthetic Amsoil Z-Rod oil which had a 40* advantage over the conventional Valvoline VR1 Racing Oil.

But, as for overall averages, there was only a 10* difference between synthetic and conventional oils. So, the real world observation here does NOT support common internet oil info claims about synthetic oils having an unbelievably high temperature capability compared to conventional oil.

Don’t believe everything you read on the internet about motor oil. Because there is a lot of misinformation floating around, that has often been repeated over and over without any proof to back it up. Most sources never ever do any independent testing at all, they just repeat what others have already written. And it doesn’t matter how many times, different sources repeat the same wrong information, it will never magically become true.

The above info also makes a good case for running an effective oil cooler setup, if one is needed to keep the oil safely below the threshold of thermal breakdown. But you may also need an oil cooler thermostat as part of that type of setup as well, so that the oil doesn’t end up too cool. You should keep oil temps above 212*F to keep the normal engine condensation quickly boiled off, rather than just slowly evaporated off. You don’t want to allow slowly evaporating water to have the chance to mix in with the oil and dilute it. Oil can only be thinned out by becoming diluted with coolant/water or fuel. And oil can only get thicker by getting overheated and vaporizing its lighter components. So, an ideal temperature range for most motor oils in general, would be between 215*F and 260*F. You get the idea, not too cold, not too hot, just right.

I did not test the cold flow capability of synthetic oils here. So, that claim’s validity remains to be seen. But I did perform one last test here, and that was testing at 325*F, to see what wear protection capability still exists during extreme heating conditions. I selected the highest ranked low zinc oil, 5W30 Pennzoil Ultra, API SM and the highest ranked high zinc oil, 10W30 Lucas Racing Only. Even though they were both vaporizing/smoking a lot at this temperature, here are the results at 325*F:

1. 5W30 Pennzoil Ultra, API SM
98,329 psi “load carrying capacity” (essentially no change from its 275* value)

2. 10W30 Lucas Racing Only
97,561 psi “load carrying capacity” (essentially no change from its 275* value)

As you can see, their load carrying capacity leveled off and stayed approximately the same between 275* and 325*. So, it is comforting to know that you don’t run into dangerously low wear protection if and when you end up with overheated oil at some point. But of course the oil will have already run into thermal breakdown and should be changed as soon as possible.

At the end of the day, there are many outstanding motor oils available. And now you have even more oil performance data to consider. So, making an educated choice to suit your needs should not be too difficult.

540 RAT
Member:
SAE (Society of Automotive Engineers)

MainePorsche

I use the 3x Risoline concentrate for its zddp. I use Techron for a cleaner and MMO for a pump cleaner and lubricant. I am aware of the cat issue with to much zinc, but one has to be a judge of using a zinc additive judiciously versus overdoing it. I like my results over two years with the small amount that I add infrequently.