With my big roller I've been using K-Motion springs with a 1.55 diameter for several years. I've never had to replace any of them. I did have one or two rockers break due to the amount of grinding that had to be done. I also did have one rocker shaft break, probably due to a combination of spring pressure and fatigue (it was 5 years old). I DID try to get Mike T/A to warranty the shaft but he asked me how many motors did I blow up with that shaft on them. I said "five or six, what's your point?" :laugh: He said "Go Scratch" . BTW Jim W, Scotty used Jesel individual pairs on his Stg-4 motor (the one that ran 7.68). Later, Doug.
Roller? I know this is a little late but you have to watch out for the cam digging into the front of the block. Just like running a bronze distributor gear. I thought i did something wrong but other people have had the same problem. I caught mine earily and cleaned it up and did a "fix "for it but its something you'll never see untill its too late. Rollers I would consider the last resort for that last bit of power. Very $$$$. i would also recommend playing with flat tappets until you find the perfect grind then swap to a roller if you still feel the need. But thats how I'd do it if I started over again. Unless, of coarse you have money just falling out of your pockets. My expense putting a roller in my race car is almost $3000.00 :jd: I think you could spend that money somewhere else and make up the 20-40 HP. Not to mention the headache involve.
[ Now what would be really nice!!!!! Is if the new blocks (T/As or Bureks) would be made to use the BB Chrysler lifter diameter. The larger lifter diameter would allow us to grind some solid lifter cams that would compare to our present day rollers. Take Care [/QUOTE] John, Actually, that is an option on our block, larger diameter lifters, oh , the cam profiles that we could run. Jim Burek p.a.e. enterprises
mushroom style lifters, you guys should check that out . used in early rover v8 engines in formula 5000
Know of an 800+ HP engine that had a solid roller cam break the roller rockers(new).Not too long ago.Grinding for clearnace could weaken them. Also saw a non roller hyd cam engine running T/A 1125 Springs over a period of time that had a push rod go right through the rocker and break, the rest of the roller rocker openings that slide on the shaft were starting to go oval !!!the one failed from going oval and finally cracke and broke on the bottom This with no grinding and only an 1125 spring.This motor also had at least 10 years of use.Did replace the rockers on this motor and running OK again lucky nothing else broke !!! Springs checked out fine with correct heights & open and closed seat pressures and checked for no coil bind.Roller Rockers DO wear out and weaken over time and should be inspected and replaced as needed.
http://www.sierranevada.edu/people/chris/5-48.html The MUSHROOM lifter is a derivative design of the mechanical lifter. This is a design which takes advantage of the wider contact face to facilitate a broader and steeper cam lobe, thus allowing a higher rate of valve lift (velocity).
