MopaR&D
Nerd Member
Damn son, what's the rest of your valvetrain setup? I thought hyd rollers got unstable after about 6400 RPM...
Magnum Roller Lifters
- Thread starter Jonnylightening
- Start date
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Damn son, what's the rest of your valvetrain setup? I thought hyd rollers got unstable after about 6400 RPM...
Jonnylightening
Well-Known Member
well it wasnt a lifter after all! it was a junk *** rocker!
Jonnylightening
Well-Known Member
Any collateral damage from that failure? Plus a bit of debris searching, at least You kicked up some useful info here anyhow.
mopowers
Well-Known Member
Thank you for the update.
Jonnylightening
Well-Known Member
hadnt really dug into the engine yet. the broken piece is MIA so im hoping it didnt fall in with my cam. Around the stud area I was seeing metal dust/chips so im gunna have to tear it down and clean. im just hoping nothing else is damaged. Definately wouldnt recommend those for anything.
Jonnylightening
Well-Known Member
I kinda feel bad about blaming the lifter. when I took the valve cover off I played with the lifters and that one had a lot of play so thats what I figured it was. Last night I actually took off my Rocker girdle as well and thats when I could see the rocker was cocked. Then I felt around and then noticed the sharp edge.
mopowers
Well-Known Member
Don't feel bad at all. At least you had the nuts to show us all what the problem was. Too many people start threads like this and don't ever report back. Hopefully you can get it all buttoned up and get it going again.
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Jonnylightening
Well-Known Member
Big thing now is which rockers to go with this time around?
JDMopar
Well-Known Member
You may be able to get small block Chevy rockers cheaper. Not saying cheap is good, but if you can get higher quality rockers for SBC cheaper....why not? I know several people who have used the SBC roller rockers on Magnum heads with good results. Maybe do a little research on the SBC rocker swap before plunking down mo money. Hopefully, the pieces of that busted rocker that are MIA got by the cam without causing any damage.
Dale Davies
Well-Known Member
Any id
ea what caused it to collapse. Possibly something got in the valve in the lifter that lets it bleed down rapidly. You would think that with 8k miles on it any crap would have come out long ago, but crazy crap happens. A bit of casting flash or sand, or a drill burr finally broke off.
Bobzilla
Well-Known Member
Check some of the remaining rocker arms to make sure they are not binding on the poly locks at full lift or when closed with the pushrods you currently have.
Also, can you post a picture or two of the other rocker arms on the engine. Curious how they look.
Jonnylightening
Well-Known Member
my heads were gone over by a reputable guy...there again not mentioning names. absolutely no binding whatsoever. everything was checked and gone over before they key was even turned the first time. Same rockers were in the engine for the 3 years ive had it now. Rockers I was sold from him were I believe procomp or PRW? (Chinese rebranded)
Jonnylightening
Well-Known Member
my car is currently at my buddies shop an hour away from me so soon as I get down there ill get more pictures and ill get the actual brand of rockers. They broke across the casting line. its not a straight clean break as you can see from the pick but it starts at the front of the casting line and ends at the back of the casting line. With the way the world is now it seems like almost everything you buy is **** quality.
[1] Doubt a Chebby rocker will work; the SBM rockers are very short.
[2] A lifter could still have caused this; if it pumped up, the posi lock or the stud may have made contact with the rocker body.
[3] Harland & Sharp rockers will break just like any other rocker if overloaded or faulty [ post #29 ]
[4] Check the underside of the rockers for contact between the stud & rocker slot, at full lift.
[2] A lifter could still have caused this; if it pumped up, the posi lock or the stud may have made contact with the rocker body.
[3] Harland & Sharp rockers will break just like any other rocker if overloaded or faulty [ post #29 ]
[4] Check the underside of the rockers for contact between the stud & rocker slot, at full lift.
TT5.9mag
Two atmospheres are better than one
Bobzilla
Well-Known Member
Completely understand, and no judgment here. Actually wondering if something has changed or moved since it was originally assembled. The picture you posted does not appear to show signs of binding until after the breakage occurred, so maybe just that rocker arm gave up after many cycles. Figured they were PRW and they are usually pretty reliable on this type of build.
montanaamps
Member
Harland Sharp.
I ran them on a set of stage 3 ported magnum cast iron 2.02 R/T heads just fine. 1.7:1 and 1.6:1 at different times with no issues, and I beat on this engine all the time very often seeing 7k rpm for years. Sold it and it's still going as far as I know.
I ran them on a set of stage 3 ported magnum cast iron 2.02 R/T heads just fine. 1.7:1 and 1.6:1 at different times with no issues, and I beat on this engine all the time very often seeing 7k rpm for years. Sold it and it's still going as far as I know.
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