NEED HELP Kinda fast 427 BB
Thread Starter
Racer
Joined: Feb 2010
Posts: 494
Likes: 0
From: Leominster MA
NEED HELP Kinda fast 427 BB
Ok this engine isnt in a vette (but you guys know i have one).
So im driving home and i heard the dreaded sound and thought i blew the motor. I pulled the valve covers to discover one of the lifters turned sideways and was totally off the pushrod. The 4 Rockers before that look dark like they werent getting oil (the spun one looked fine)
What do I do! I pulled the intake to see if there was anything elsei could find. One bent pushrod so far (on the worst looking rocker of all mind you)
This is a comp cam magnum, hyd flat lifters. 427 bb motor. Should i jsut put new lifters, pushrods and rockers? The cam from the lifter valley looks ok, should i pull that too or can I get away with the above?
While I have it apart im jsut gonna put a new intake, water pump etc not that it matters.
Any help would be appreciated. Anything I should look for? Motor isnt that old.
So im driving home and i heard the dreaded sound and thought i blew the motor. I pulled the valve covers to discover one of the lifters turned sideways and was totally off the pushrod. The 4 Rockers before that look dark like they werent getting oil (the spun one looked fine)
What do I do! I pulled the intake to see if there was anything elsei could find. One bent pushrod so far (on the worst looking rocker of all mind you)
This is a comp cam magnum, hyd flat lifters. 427 bb motor. Should i jsut put new lifters, pushrods and rockers? The cam from the lifter valley looks ok, should i pull that too or can I get away with the above?
While I have it apart im jsut gonna put a new intake, water pump etc not that it matters.
Any help would be appreciated. Anything I should look for? Motor isnt that old.
Race Director
Joined: Apr 2000
Posts: 17,676
Likes: 201
From: Who says "Nothing is impossible" ? I've been doing nothing for years.
Can't help you on the big block I'm just a little mouse motor builder but you came to the right place. From what I can tell there are a bunch of big block wizards on this forum 
Melting Slicks
Joined: Apr 2007
Posts: 3,189
Likes: 111
From: Tolland CT
A bent pushrod? Were you reving the motor a bit when this happened?
If not I'd wonder about valve timing, kind of sounds like a piston may have hit a valve causing the push rod to bend. Hope not. Wondering what else could cause a bent pushrod.
Stock timing chain or roller chain?
You had one rocker arm nut loosen enough to let the pushrod drop out?
How are the others?
Did the car still run at all ?
If not I'd wonder about valve timing, kind of sounds like a piston may have hit a valve causing the push rod to bend. Hope not. Wondering what else could cause a bent pushrod.
Stock timing chain or roller chain?
You had one rocker arm nut loosen enough to let the pushrod drop out?
How are the others?
Did the car still run at all ?
Thread Starter
Racer
Joined: Feb 2010
Posts: 494
Likes: 0
From: Leominster MA
Apparently so, few others seemed loose to me too. It ran, just not well, noisey and poppin through the carb too. I checked out the valves (from what i could see through the ports, have the intake off at this point) Don't seem like anything is bent from what i can tell.
Its weird cuz the one that " slipped " off , the pushrod is fine. its the first valve on that side that was bent. And it could have been bent before this who knows. The first four rockers look dis colored. Again might have been that way before i got it. Im not sure.
I think ive decided to just yank the entire cam put in a new one, lifters timing chain etc. See what happens i guess.
The previous owner thinks it was a comp cams magnum cam (no idea which one of course) the rockers are roller tip comp cams, 1.72 ratio.
Any recommendations? It sounded nice when it was running.
Head castings are 3964291 (1969 gm hi perf 109cc)
Block is 3916321 68 427
Its weird cuz the one that " slipped " off , the pushrod is fine. its the first valve on that side that was bent. And it could have been bent before this who knows. The first four rockers look dis colored. Again might have been that way before i got it. Im not sure.
I think ive decided to just yank the entire cam put in a new one, lifters timing chain etc. See what happens i guess.
The previous owner thinks it was a comp cams magnum cam (no idea which one of course) the rockers are roller tip comp cams, 1.72 ratio.
Any recommendations? It sounded nice when it was running.
Head castings are 3964291 (1969 gm hi perf 109cc)
Block is 3916321 68 427
Le Mans Master
Joined: Oct 2006
Posts: 7,123
Likes: 433
From: Gladstone MO
C3 of Year Finalist (appearance mods) 2019
Maybe the rocker nut backed off. If the locking feature loses it's stuff they will do that. Look at the condition of the rockers and the pivot *****. Any signs of heat and they should be replaced. If you're going to use them again, keep the ball and rocker paired up with their original counterparts, and if you need to replace any of them, move good ones from the intake valve to an exhaust position. GM says the intakes run a little cooler.
I agree with your replacing the cam and lifters together. New lifters on a used cam is not a good plan- I have done it and had a couple with no problem, and had a couple that the cam went away too.
I agree with your replacing the cam and lifters together. New lifters on a used cam is not a good plan- I have done it and had a couple with no problem, and had a couple that the cam went away too.
Instructor
Joined: Oct 2008
Posts: 187
Likes: 12
also if you ever plan on reusing stock type rocker arm nuts never ever use an impact
to remove them, the heat generated by doing so will destroy the holding power of the
interfearance type nut. Replace them all ! sounds like it just backed off
to remove them, the heat generated by doing so will destroy the holding power of the
interfearance type nut. Replace them all ! sounds like it just backed off
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Melting Slicks
Joined: Jan 2003
Posts: 2,877
Likes: 13
From: Doha
St. Jude Donor '08
I had the exact same thing happened to me, one rocker slipped off the pushrod (the pushrod's ball end broke off) and all other rockers looked very dark where the pivot ball is. These CC roller tips and their matching pushrods are junk, I threw them in the trash and got a Trick Flow roller rockers and pushrods, 1200 miles on them so far and they just work great.
Melting Slicks
Joined: Oct 2008
Posts: 2,154
Likes: 69
From: Regina Sk Canada
Sounds like you have an oiling issue to start with? Were the rockers blue, what did you all have done to the motor and how long ago was this? I imagine if you did a cam change, that new lifters would of been installed. Did you replace the valve springs to match the cam? As for the pushrods, are they 3/8 or 7/16. were they cleaned properly are checked for straightness? Who set the valve lash, was that done correctly. Lots of things to look at and consider. Now i would pull start by checking all the lifters for signs of wear, get a new set of performance 3/8 pushrods, put it together leaving the intake off and put a dial indicator on the pushrod end of each rocker and spin the motor over by hand check for valve lift to see if the cam is missing parts of any lobe? We did that when i whiped a cam in my 427.