Why Crane Cams Hydraulic Roller Lifters are Worth the Extra Cost!



As part of our continuing Product Development Program, Crane Cams’ product development team conducted an exhaustive series of evaluation tests aimed at finding areas of improvement for our hydraulic roller lifter family. We knew that the hydraulic mechanism has proven itself at 8400b RPM when used with a smooth operating rocker arm system such as the Crane Cams Shaft-Mount Rockers featuring the exclusive “polymer-matrix composite bearings,” but we decided to find out exactly how much abuse our hydraulic roller lifters could really take.



We initially decided to run a Spintron test simulating a typical offshore, “poker run” application, but extend the endurance time. Test parameters were as follows: .632” lift at the valve with a 248 degrees @ .050” lifter rise duration lobe; 1.7 rocker arms; 145# of seat pressure and 440# of open pressure; 5400 RPM constant test speed. The valve train was checked for wear every 10 hours and the engine was shut down every evening.



We ran this test profile for 50 hours, which is a target we use for marine applications. At the 50-hour point, everything looked good, so we decided to shoot for a total of 100 hours and continued the test. At 100 hours, everything still looked like it had after the first 10 hours! That was great and made us feel good about the lifters, but we wanted to “put a hurt” on the lifters and see how they held up.



We decided to increase the seat pressure to 175# and the open pressure to 535# to see how everything would hold up and see if we could “collapse” some lifters. We continued with the same cam lobe and the 5400 RPM continuous test speed. Engine oil was various types of 10W-30 oils. We decided to test various oils to see if there were any changes in noise, performance or wear. The engine continued to be inspected every 10 hours of operation. Everything continued to perform flawlessly. We started to hear a couple of seconds of lifter ticking upon start up, but that never lasted more than 2 or 3 seconds. After 20 hours, all of the lifters and cam lobes looked just as pristine as on our first inspection at the initial 10-hour mark.



We were happy with the 120 hours of abuse, but we weren’t seeing any wear, and this was starting to get boring. We pumped the seat pressure up to 205# and the open pressure went to 565#. We continued the same test speed of a constant 5400 RPM. There was no increase in the amount of lifter ticking after an overnight shutdown. Some would think that with 565# of open pressure working on at least 3 valves overnight that one would collapse, or at least take several seconds to “pump-up” on start up, but the ticking was very slight and went away after 2 to 3 seconds. The engine continued to run along happily for the next 20 hours! The inspection of parts was still showing everything pristine. At this point, we were extremely proud of the test results, but we still hadn’t put a “real hurt” on the lifters!



Note: There was still only very limited, slight “lifter tick” on start-up after an overnight stop. No evidence of hydraulic mechanism “collapse” was ever evident. We now had 140 hours of significant abuse on our valve train. If you consider that 5400 RPM in most any car in high gear will result in at least 120 MPH, our test valve train had just completed 16,800 miles at 5400 RPM.



To get more pressure, we had to change to taller springs. We set the seat pressure at 240# and the open pressure at 615#. These are the kind of pressures that are used with mechanical roller applications in “Sprint car racing” and “Drag racing.” We continued with the marine simulation at a constant 5400 RPM. After 8 hours, we started to hear an audible “tick.” We disassembled the engine for inspection and found that the lifters were still fine; we had started to lose a cam lobe. One hundred forty-eight (148) hours of testing at 5400 RPM had just ended. Twenty-eight hours had been completed with seat pressures exceeding 200# and open pressures exceeding 560#.



Further inspection revealed that we probably were getting some valve train separation, and the separation probably “wounded” the cam lobe. The valve train separation was probably the result of pushrod “flex” due to the high spring pressures placed on the hydraulic lifters. The whole purpose of the test was to run an entire valve train typical of components used with hydraulic roller lifters. We did not expect to be running spring seat pressures of 240# and open pressures of 615# on a hydraulic valve train! We will conduct this test again with pushrods typical of what would be used in a Sprint car or serious Drag car.



All in all, we are extremely pleased with the performance of Crane Cams hydraulic roller lifters. When you combine the RPM potential (which we have seen at the track with customers’ engines) with the extreme durability that this test confirmed; it is easy to see why serious performance engine builders demand Crane Cams hydraulic roller lifters and are willing to pay a little extra for them!



Additionally, this test “blew apart” most of the comments of “website tech experts” about how too much spring pressure will “collapse” a hydraulic lifter mechanism. It won’t collapse a “good hydraulic lifter mechanism.” All of the higher spring pressure tests were done with 10W-30 oils and 70# of oil pressure. We are extremely confident that the same results would occur with 5W-30 oil. Our next series of tests will confirm that, as well as some new “tricks we have up our sleeves.” We will stay in touch! Thanks for your business!