Samvada Posted February 16, 2021 Share Posted February 16, 2021 Hi, Pulled the cam and lifters from my em7-300. The rollers are all chewed up. Cam not so bad. Anybody have experience with this? Please help identify the cause. Attached photo. thanks, paul Quote Link to comment https://www.bigmacktrucks.com/topic/65927-em7-300-lifter-roller-failure-cause/ Share on other sites More sharing options...
fjh Posted February 16, 2021 Share Posted February 16, 2021 t This here is not uncommon just happens ! 2 Quote Link to comment https://www.bigmacktrucks.com/topic/65927-em7-300-lifter-roller-failure-cause/#findComment-469103 Share on other sites More sharing options...
Joey Mack Posted February 16, 2021 Share Posted February 16, 2021 Very common problem... I think mack says the roller, stops rolling, and that's the result.. after you get it fixed, adjust the valves according to Mack spec.. also if you have engine brakes (690 Jacobs) buy A 215SB321 reset screw kit for the rockers and bridges. Jojo 1 Quote Link to comment https://www.bigmacktrucks.com/topic/65927-em7-300-lifter-roller-failure-cause/#findComment-469107 Share on other sites More sharing options...
terry Posted February 17, 2021 Share Posted February 17, 2021 I'm sure they are a hardened surface after, a bunch of miles the hardened part flakes off, just like wheel bearings will do. terry 1 Quote Link to comment https://www.bigmacktrucks.com/topic/65927-em7-300-lifter-roller-failure-cause/#findComment-469115 Share on other sites More sharing options...
Joey Mack Posted February 17, 2021 Share Posted February 17, 2021 Yes sir... Thats true, the brass axle gets a flat spot that messes with the roller. What amazes me is when I do a cam job on an E-tech that runs.. (crappy but runs) and I pull lifters out that are so worn out the roller is gone and it's riding on the yoke of the lifter, and it didnt'nt drop a valve , bend a pushrod, or any other major damage.. 🤔 1 Quote Link to comment https://www.bigmacktrucks.com/topic/65927-em7-300-lifter-roller-failure-cause/#findComment-469119 Share on other sites More sharing options...
Miami Cossack Posted February 17, 2021 Share Posted February 17, 2021 We've become so used to those roller tappets that we take them for granted. People seem to feel they will last forever, and they seem to, but it doesn't take much to make one fail when you think about it. That roller just has to stop rolling and that's it. Doesn't take much to cause enough friction to jam it up. There is a life expectancy for those bearing in there and a tiny little particle of crud or some heat and once the roller starts to rotate slower than the cam and it builds up the heat it won't take long Quote Link to comment https://www.bigmacktrucks.com/topic/65927-em7-300-lifter-roller-failure-cause/#findComment-469122 Share on other sites More sharing options...
fjh Posted February 17, 2021 Share Posted February 17, 2021 They when to a ceramic roller and spring loaded push tubes that seemed to help lots ! How ever they did not do it to all engines! Quote Link to comment https://www.bigmacktrucks.com/topic/65927-em7-300-lifter-roller-failure-cause/#findComment-469124 Share on other sites More sharing options...
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