Thread: Broke Comp Cam promagmun rocker

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Most of my BBC experance is with marine builds. Most of the time number 7 cyl fails, next most often is number 8 cyl. So this was in the back of my mind, was one of these cylinders were it failed. Usally a valve hits a piston with little evidence as to why. Have my thoughts about it.

High load conditions with a solid roller is an issue initself as many of the valve train componets need checked and replaced more often.

Originally Posted by turbo2256b

Most of my BBC experance is with marine builds. Most of the time number 7 cyl fails, next most often is number 8 cyl. So this was in the back of my mind, was one of these cylinders were it failed. Usally a valve hits a piston with little evidence as to why. Have my thoughts about it.

High load conditions with a solid roller is an issue initself as many of the valve train componets need checked and replaced more often.

well yes and no i not trying to get in a pissing contest with you. as i do not know who you are so i give you the benefit of the doubt. in that i do not know how many offsore engine you built . i built some marine blower engines and built many carb marine engines. i was a dealer in hi rent off shore used bbc big chief parts.blocks other parts. and the hi HP merc stuff many HD cranes ,and t&D .jesel stuff has past threw my hand over the years .along with many delwest valves. crower Hippo liftes. jesel bowtie all were soild roller engines with very good hold out not many if any number 8 rockers that i ever seen fail they were very good about number them. i been building engine and machining engines for many years. had many bbc with 700+. sold rollers that been street/strip. blower and turbo bbc Nos. been doing then for over 30 years .the hold out on parts as very good .. lifters so/so at low RPM no oil . but that was before hippo.old comp roller rocker and lifters were not very good for that use . as for 7 hole that is was with a 4/7 swap cam ? to say that 7an 8 fails it is common for the rod bearings to fail on some guys engines .but over the years just when you think you seen a pattern to failure . i seen just as many in other location as well .i seen fail. if you have any spin-tron testing or if you can tell me its harmonics. i like to see the test .like spring rate what spring . what cam lobe number.core size .base circle.fire order of cam .belt or chain timing set or gear if so 3 gear or 4 . valve alloy stain less . titanium. inconel ? many years ago i was told by one of the bigger builders of race off shore boat engine to never use steel body roller rocker arms in boat engines