Hydraulic roller race oil - what's it worth???

[DavidVizard-GFN]

Hydraulic Roller Oil – What’s it Worth?

Are a hydraulic roller lifters propensity to collapse fixable with just an oil change?

Text, Photos and Drawings,

By
David Vizard

This is another one of those oil tests – I don’t mind doing them but hate to publish them. Why? Because of all the hassle it inevitably generates by those that did not win the power race loudly defending their product. Let me tell you going into this there is far more to oils than meets the eye. Even really clever guys who make a career out of oil and lubrication research will tell you it is like trying to find the bottom of a bottomless pit. You learn more only to find there is more to learn. Here’s something I can say with a great deal of certainty. Oils have become so much better since I started racing back in the late 50’s that the performances we see now are out of site compared to 50 years ago – and progress continues. These days oils are becoming very application specific. For instance Joe Gibbs Racing spent a fortune on the development of an oil specifically to show best performance in a flat tappet Cup Car engine. Can we apply that old axiom “if it’s good enough for the likes of Tony Stewart’s $80,000 race engine it’s OK for my $6,000 Chevy Camero engine”? The answer, unless you are incredibly naive – is no!

So where are we going here? Let’s go back to the beginning of ’06. Nick Losito, our GFN karting guy, decided he would like to try his hand at racing a late model stocker at our near local track (Hickory). The class calls for one of two types of power – either from a ‘crate’ motor or a ‘built’ motor. The restrictions on the built motor were such that it was difficult to get much over 450 hp and the car had to carry a 100 lb ballast penalty if one was used.

The development of the UPM oil was based soley on Nick Losito’s need for speed at Hickory Speedway.
Photo Credit - chrisrevis.com

We decided to go the crate motor route here for two reasons. The first is we had a crate motor and secondly the Hickory track rules allow the crate motors to be rebuilt but not modified. Since our crate motor had seen considerable use it was somewhat down on power (and who knows – it may not have been that good to start with). However, going into this crate motor deal I knew we would be confronting some valve train issues that the stock roller cammed small block Chevy had. I voiced these the Nick’s dad, Don Losito, who, in addition to being the team owner was also our team engine builder.

The basic nut and bolts of the valve train problem is the hydraulic roller itself. At a certain point the combined side and vertical loading of the roller lifter will cause it to go into a rapid leakdown situation. When that happens the valve train dynamics just go to hell in a hand basket.

Hydraulic rollers, especially the OE style ones as shown here are very prone to collapsing when the loads from the combined forces of spring loads and rpm exceed a certain point. Where this occurs is dependant on the lifters hydraulic ‘stiffness’.

Hard though it is to believe I have seen as much 0.100 (one hundred thousandths) of lift disappear at the valve on Spintron tests. That much loss may well be a little more than typical but substantial loss of lift at higher rpm (starts at about 5500 rpm) is very common. Here we need to consider the variability of lifter collapse from one lifter to another. Because of manufacturing tolerances we can find lifters that will run to as high as 6500 and others that give up as low as 5000 rpm. Obviously the capability of one engines valve train compared to another will vary depending on the luck of the draw as far as lifter tolerances go. I had an ‘89 5.0 Mustang that would turn to 6500 stock (when the rev limiter was disabled that is) and a ‘90 that was all done at 5500!

So you can see that there is a problem with the lifters. My first move for our late model was to see if I could get a set of factory selected lifters with the lowest bleed down rate possible. Now here is an amazing thing. I spoke to the engineer who is supposedly in charge of lifter design – he was (or claimed to be) totally unaware of the collapse problem (what kind of business are we running here?). It became very apparent that we were on our own as far as any help in the lifter department was concerned.

About now I am sure that some of you are asking yourselves why would a hydraulic roller with the same internals as a hydraulic flat lifter be any different in terms of rpm capability. That’s a good question. When hydraulic lifters were about to be introduced I received a set from the manufactures and got Crane to whip up a hydraulic roller grind for me. I tested this in a pretty extensively modified 406 small block Chevy and the results were very disappointing. I suspected the lifters were collapsing mainly because I could not think what else it could be. This prompted a call to the lifter manufacture to get a box of lifters so I could select the hydraulically stiffest. It took 64 lifters to get 16 that were real stiff. Installing these raised the valve trains rpm limit from about 5400 to 5750 and brought up the power some 30 hp. That was better but still not good as this engine should have peaked at about 6000. At this point I wondered why the rollers were failing to hold up when an equally slow breed down rate in a flat tappet resulted in at least 1000 rpm more. This perplexed me for some time and the only conclusion I could come to is that the side loading peculiar to a roller lifter was the culprit. Take a look at the drawing Fig 1.

This drawing here shows the primary difference in the way a roller lifter is loaded compared to a flat tappet lifter. This side loading causes deformantion of the lifter body and a dramatic increase in the bleed-down rate.

What you see here are the forces involved as a roller lifter goes through it’s lift cycle. Note it suffers a high degree of side loading. The higher the pressure angle the higher this side loading gets. If the pressure angle becomes too great the lifter bores wear out really fast and the rollers fail. When the side loading exceeds a certain amount the deformation of the lifter body causes it to leak down really rapidly.

The lifter collapse phenomenon is familiar to many racers. For years those drag racers in the ‘stock’ divisions who are running Mustangs and the like have had to take steps to eliminate the effect of lifter collapse. The key toward achieving that is to adjust the lifters such that they bottom out and then back them off about 0.010 (ten thousandths). With a suitable spring this technique will allow as many as 7800 rpm to be achieved.

So if such an adjustment method works whey are we worrying about lifter collapse? Well here’s the kicker. It appears that some stock hydraulic valve trains can go into a mild resonance at certain rpm. When this happens the valve train suffers component separation. The hydraulic lifter than expands (pumps up) to take up that separation and this results in the valve being held just a few thousandths off the seat. Result – a sizable loss of hp. The stock division drag guys can get away with bottom adjusted lifters because the springs they use are much stiffer than stock and component separation is not an issue until way up in the rev range. When valve train component separation is an inevitability due to having stock springs, pushrods etc the situation changes. Here it becomes necessary to adjust the lifter so it has about 0.002 (2 thousandths) clearance at the top of the adjustment range so as to avoid ‘pump up’. Now the problem of lifter collapse becomes the #1 issue. Since the lifter cannot be adjusted to the bottom we need to find a way to make it less collapsible. This meant turning our attention to the oil itself.


Best Oil Blends – Often Not What You Think.

Some top quality oils are really good at cutting friction and wear but not so good at sealing between two closely situated surfaces (as we were to find out when we got to dyno testing). I remembered a while back talking to an Exxon oil physicist in England about blow by and emissions. In passing he happened to mention that they had experimented with some long chain polymers that produced a better seal between the lower face of a compression ring and the piston groove. Any improvement seen here would not only benefit new engines but older ones possibly having a little ring and groove wear. I don’t know where this went but the term ‘long chain polymer’ sort of stuck in mind. I called several oil companies about this and got no where. However, just by chance, it turned out that in my circle of friends I had one who personally knew a top oil physicist who was in the business of concocting custom blends for who and what ever. His credentials looked good as some of his clients were big time factory teams. The ‘long chain polymers’ triggered something here but I really cannot say for sure what but shortly there after we had some test oil blends to run in our crate motor mule.

Test Procedures.

Other than applying prodigious care over the test procedures the first move here was to be sure that we had a descent but random selection of roller lifters in the test engine. The next step was to see what variations might crop up with oils currently available off-the shelf in street and race blends. Some surprising results were seen here. I don’t intend to name brands because someone is sure to take it the wrong way and assume that because the oil concerned did not show well it must be a bad oil. Let me tell you this much.

Because the differences between some oils could be small Don, Dusty and Nick spent a lot of time tuning the engine for repeatability. Also aiding in this respect is the pre-conditioned air being fed to the engine. The air temperature is controlled to the correction factor temperature by a very large AC unit. This means our correction factors were very small thus minimizing errors from this quarter.

One of the best high dollar oils on the market showed a drop of no less than 9hp over one of the cheapest mineral oils available at K-Mart! In addition to that the difference between this low cost K-Mart available oil and some of the best hydraulic roller friendly off-the-shelf oils we could find was only about 2 hp. Something else we tested here might surprise you – a well known gooey ‘performance’ oil additive dropped a staggering 16 hp out of our test engine. I was amazed at that one as I was sure this additive’s ‘sticky’ texture would help seal up those lifters. What ever was going on here sure did tick off the engine.

After a lot of testing and when all the oil and gas fumes had cleared, we elected to use Mobil 1 as our baseline because it was both good and consistent. Over the years Mobil 1 has earned a reputation such that it has become the yardstick by which other oil blenders judge their success.

With all the circuits re-jetable the Holley HP series race carb was calibrated to best power mixture throughout the rev range used.

After running surprisingly few test blends through our engine our tame oil physicist appeared to squarely nail the issue. Take a look at the following chart for the results. These numbers, the product of averaging a number of consistent runs, shows the differences involved.

Here are some hard numbers to study. A major point of interest is the difference of almost 11 hp between two top grade oils from big name oil manufactures (yellow and green columns). What this means is you could be buying an oil that, in all other respects, is top-of-the-line but fails in the area of roller lifter seal up. The UPM oil addresses that problem. The results are as per the red column.

The following graph however gives a better guide to the form of the improvements seen. Note how there is little difference between the two curves until some critical point where collapse sets in.

What we see here are the curves from the previous chart. The tests start at these higher RPM’s because that is the rev range used for a crate motor during racing. At lower RPM the differences one oil to another progressively become less. This is as expected because at lower engine speeds there is less side loading on the lifters so leakage is not such a problem.

We had a number of crate motor late model cars try this oil at Hickory. The good news was that most of them said it made enough difference that they could feel it. The bad news is since they could feel the difference and knew it worked they also felt there was no need to dyno test. As a result we got zero dyno feedback from these users.


Built Engine Tests.

Although this hydraulic/crate motor oil might well be a racers edge for a crate motor powered circle track car or an otherwise stock street motor with a roller cam it needs to be asked what it might do in a hydraulic roller equipped modified motor. In such a motor the reality of lifter pump up is minute compared to lifter collapse.

Here is one of our hopped up test engines. This particular engine had a well specced and otherwise tweaked hydraulic roller valve train and as such it would turn to 6500 rpm. Even so some significant bleed down must have been occurring starting at a little over 6000 rpm. Use of the UPM oil resulted in 4 more peak hp (6300 rpm) and 7 more at 65000.

Using a hydraulic roller equipped test engine that we had already managed to get to 6500 rpm with, we dumped a fresh fill of Mobil 1 and refilled with the hydraulic/crate oil. No change in output was seen on this engine until about 6000 rpm. At peak power (6300 rpm) the output rose by 4 hp at 6500 the difference was 7 hp. From these results I concluded that even with our well developed valve train adjusted using the standard ¼ turn into the lifter travel that collapse was just beginning to happen. By fixing, at least to a point, the lifter collapse at these rpm the power rose.

Street Use and Power Gains

Can this oil be used in street applications sure – it might not get EPA approval because it has a few trace additives they don’t like but that said there is no downside for the user. As for the power gains end users are likely to see this will vary from one engine to another depending on the lifter leakdown situation. Some engines out there may gain very little but the number of vehicles that fall into that category could well be small. At the other end of the scale there may be a few engines with lifters built on a Friday afternoon when it was a question of – to hell with tolerances I want to go home! Such an engine could pick up as much as 16 hp! Also worth noting is that a lot of LS1/6 style engines have had a problem with the odd leaky/noisy lifter. My truck did. The UPM oil’s sealing capability is just the sort of fix for this problem that is about an easy a job to do as they come. Just pour it in!

So where do we go from here? The bottom line is that all these tests led to Don announcing that his company, Ultra Pro Machining, was now in the business of developing and selling high performance oils.

Available only in gallon containers this UPM oil should be high on your list to consider for a quieter and more effective hydraulic roller valve train.

If you want some call Ultra Pro Machining on 704-392-9955 or visit their web site for this and other products in their extensive line at UltraProMachining

[BlackCat13]

David and all contributors,
Thanks so much for this entire site and all the wonderful stuff appearing here.

After 40 years I am being stimulated and challenged in my thinking and learning things that had never really crossed my mind before.

thanks
BC13