Breaking rocker arms
Posted: Sat Aug 26, 2017 12:04 am
Hi everyone,
After a bit of advice if anyone may be able to help, so about 12monts ago I broke a rocker on inlet #4 initially I thought it had happened because the lashcap may have come off somehow and the pushrods become in contact with the rocker itself not the locating cup. Anyway thought no more of it and replaced the rocker and upgraded pushrods to manton series 5 and all seemed fine.... untill last week when the rocker on inlet #3 did pretty much exactly the same. 12months seems along time but the car has only covered probably 3-400 miles. I have checked for coilbind and there seems to be plenty of clearance on both inner and outer springs and there Is nothing contacting through the stroke of the arm. Did i just get unlucky and get a bad batch of forgings? I only just remembered after looking at the pics but on one of them you can see where it looks like the oil hole has broken through the side just next to the adjusting screw- this was the one that let go last week.
Engine spec is 2276 turbo efi. Street eliminator heads. Vw650 springs. Fk8 cam, manton series 5 pushrods, cb forged 1:4 rockers.
This is first rocker that let go This is pic I took at time of first rocker breaking showing small hole in forging. This is latest breakage. Note this is the above rocker with hole in it These are latest snappage
After a bit of advice if anyone may be able to help, so about 12monts ago I broke a rocker on inlet #4 initially I thought it had happened because the lashcap may have come off somehow and the pushrods become in contact with the rocker itself not the locating cup. Anyway thought no more of it and replaced the rocker and upgraded pushrods to manton series 5 and all seemed fine.... untill last week when the rocker on inlet #3 did pretty much exactly the same. 12months seems along time but the car has only covered probably 3-400 miles. I have checked for coilbind and there seems to be plenty of clearance on both inner and outer springs and there Is nothing contacting through the stroke of the arm. Did i just get unlucky and get a bad batch of forgings? I only just remembered after looking at the pics but on one of them you can see where it looks like the oil hole has broken through the side just next to the adjusting screw- this was the one that let go last week.
Engine spec is 2276 turbo efi. Street eliminator heads. Vw650 springs. Fk8 cam, manton series 5 pushrods, cb forged 1:4 rockers.
This is first rocker that let go This is pic I took at time of first rocker breaking showing small hole in forging. This is latest breakage. Note this is the above rocker with hole in it These are latest snappage