Last Sunday out for a cruise. Motor running great..just about 2 miles from home. Up through gears (not jammin) everything fine. Come to stop sign..up through gears..everything great..motor strong as usual
In fourth gear..about 45MPH..loud BANG..knocking. I idle to stop about 500ft.
I was thinking rocker came off. Towed car home..pulled valve cover. #6 exhaust rocker is off..cracked and broken. Rocker is tight but since it's broken it's jammed against next valve.
I rotated by hand..removed rocker..and pushrod. Pushrod height was about like all others. Stud is fine..threads good.
Today I bought a new rocker and pushrod.
Turned motor till intake was compressed..tightened rocker until still very loose. Rotated motor and watched rocker move correctly.
Brought engine to compressed #6 intake and tightened exhaust again..feeling for up/down motion and spinning pushrod in hand.
Turned motor on starter with HEI disconnected..watched rocker moving open close just as it should.
Brought it back to Intake compressed..small tighten on exhaust..though to leave looser..start then final 1/2 turn if necessary.
Start engine..pop through carb, Pull cover..rocker completely off..pushrod just barely above head surface.
Could I have collapsed lifter ? Or..perhaps lifter was damaged when rocker broke ?
Motor is GM crate short block 350 Gen I
Cam is 24502476
Lifters 5232720
Camel Hump 186 2.02/1.60
Everything knew except..ROCKERS
When I was building this..i blew a couple disks in my neck and back pitching (baseball) the shop I was using helped me. They finished assembling engine.
I just went through all my parts receipts..all new except no ROCKERS.
They do not look like less then 10K miles.
Cam was broken in correctly (shop does many Hot Rods and exotics).
So..
I know it could be rounded cam. It could be rocker metal fatigue that bent rod and damaged lifter.
I am going to pull intake..hopefully it's a lifter that just collapsed or bleed down and not a cam round. The HEI may not come out without hood coming off..and a real chore to re-align.
Given that the rocker was moving correctly just before motor started..I am guess lifter. I don't think a cam can round in 2 minutes of idling..as it was showing correct lift when rotated on starter.
Am I naive..just hoping and not thinking this. ?
This car gets about 3000 miles a year. On the day it blew it still accelerated like always..quiet motor..very strong. Oil pressure 60lbs..25-40lbs at idle.
Any ideas...before I pull it.
Trying to think positive..two kids in college..and money is limited (duh)..
Old guy not real happy at the moment
In fourth gear..about 45MPH..loud BANG..knocking. I idle to stop about 500ft.
I was thinking rocker came off. Towed car home..pulled valve cover. #6 exhaust rocker is off..cracked and broken. Rocker is tight but since it's broken it's jammed against next valve.
I rotated by hand..removed rocker..and pushrod. Pushrod height was about like all others. Stud is fine..threads good.
Today I bought a new rocker and pushrod.
Turned motor till intake was compressed..tightened rocker until still very loose. Rotated motor and watched rocker move correctly.
Brought engine to compressed #6 intake and tightened exhaust again..feeling for up/down motion and spinning pushrod in hand.
Turned motor on starter with HEI disconnected..watched rocker moving open close just as it should.
Brought it back to Intake compressed..small tighten on exhaust..though to leave looser..start then final 1/2 turn if necessary.
Start engine..pop through carb, Pull cover..rocker completely off..pushrod just barely above head surface.
Could I have collapsed lifter ? Or..perhaps lifter was damaged when rocker broke ?
Motor is GM crate short block 350 Gen I
Cam is 24502476
Lifters 5232720
Camel Hump 186 2.02/1.60
Everything knew except..ROCKERS
When I was building this..i blew a couple disks in my neck and back pitching (baseball) the shop I was using helped me. They finished assembling engine.
I just went through all my parts receipts..all new except no ROCKERS.
They do not look like less then 10K miles.
Cam was broken in correctly (shop does many Hot Rods and exotics).
So..
I know it could be rounded cam. It could be rocker metal fatigue that bent rod and damaged lifter.
I am going to pull intake..hopefully it's a lifter that just collapsed or bleed down and not a cam round. The HEI may not come out without hood coming off..and a real chore to re-align.
Given that the rocker was moving correctly just before motor started..I am guess lifter. I don't think a cam can round in 2 minutes of idling..as it was showing correct lift when rotated on starter.
Am I naive..just hoping and not thinking this. ?
This car gets about 3000 miles a year. On the day it blew it still accelerated like always..quiet motor..very strong. Oil pressure 60lbs..25-40lbs at idle.
Any ideas...before I pull it.
Trying to think positive..two kids in college..and money is limited (duh)..
Old guy not real happy at the moment