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Time for some Basic Maintenance Now that we have reached the 175-200 run level with "Project 4-Link," it is time for some "Basic and Preventative Maintenance." The engine is running perfectly and shows no signs of any problems. We have had a fantastic early season so far. I won the IHRA Amalie Nationals in Cordova, IL in the Quick Rod (8.90) class. The next weekend I got to three cars at a local Summit Series S/Pro race and last Saturday my son, Andy, took the S/Pro title at Cedar Falls Raceway. The car is repeating within a hundredth run after run. So. . .what could be wrong? Four weeks ago I broke an intake rocker and I actually heard it break while I was idling in the staging lanes. I shut off and was not sure what it was. I started the engine and it sounded flat, plus the oil pressure went from 80 pounds to about 10 at idle. After I got my heart started again we towed it to the trailer where I found the broken rocker. I am really glad it broke then and not while I was doing a burnout or making a full run. This is where the difference between "basic" and "preventative" maintenance begins. The rocker arms on the Indy 440-1 cylinder heads are aluminum and therefore have a certain "life" to them due to fatigue. When I called Scott at Indy Cylinder Heads he summed it up pretty well with this comment: "If I had just broken an aluminum connecting rod, would I replace just the broken one or replace the entire set?" He was right, all the rockers were fatigued the same and probably would start failing. The cheapest insurance for me was to get an entire set and have 15 spares. I think it is a good plan for any car with a radical cam profile and springs that have 240 pounds of seat pressure and 600 pounds open pressure. There is a huge repetitive load on these rocker arms and the cold weather I raced in this spring probably contributed to their premature breakage. Next up is some preventative maintenance. I check the valve spring seat pressure after every weekend when I check the valve lash and inspect the components. The springs have started to read 210 to 225 pounds on the seat. When springs start to weaken they can do damage before they break. If the seat pressure is below spec it is hard on the roller lifters as they can "bounce" when the valves are closed and this is probably how roller lifters start to fail. This "bouncing" does damage to the lifter wheel or small needle bearings and eventually the lifter fails and it is major work to fix the resulting damage. I decided to replace the valve springs with the same springs it came
with from Indy Cylinder Head, K-Motion 950s. I installed them with the
heads on the car with the help of a DRC valve spring tool and some compressed
air in the cylinder to hold the valves up while I removed the spring
and retainer. After changing the springs, which took only about an hour,
I checked the seat pressure and it was back to 240 to 250 pounds on
the seat. I think I will rest easier knowing I have done my best to
keep the valvetrain in one piece by doing some mid-season maintenance. |
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