Bent Pushrods on a rebuilt 318

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Deceus

Deceus

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Was having issues with crankcase pressure even though I was running a breather and PCV with good vacuum. Started doing a leak-down test and noticed six of my pushrods were noticeably bent. A couple things to note:

-There's only 180 miles on the motor
-I'm not running a particularly big cam. (Comp XE262)
-I'm running all new everything that was matched to the cam. (springs/lifters, etc)
-There's no sign of any contact on the pistons and they have some decent reliefs (KB167s)
-Only six bent and they all bent about the same. 8 would've made more sense since I could blame the intake or exhaust side.
-Aside from seeping oil out of a few weakpoints the motor seemed to be running strong.

Here's a vid I happen to take before really digging in.



8B35oZT.jpg


I'm about to tear off the intake and take a look at the condition of the cam and lifters but I wanted to get a few ideas about what happened here. The only theory I have currently is that my pushrods were a hair short and managed to bounce out of the groove in the rockers. That would certainly cause them to bind and bend. Everything else I think of would've effected more or less than 6 rockers or done some damage to my valves/pistons but the leakdown test came back good. 2 of the cylinders got poor readings but were good when I gave the engine another rotation so the rings may not be full seated in them yet but the valves are good.
 
That's ticking pretty bad in the video, your push rod length doesn't seem to be correct. You need to check for pre-load on those stock rocker arms. I have also seen stamped rockers bend from too much spring pressure. 65'
 
Your rocker shafts are not installed correctly. The oiling holes should be down and towards the valve tip. I would correct that first thing.
 
As many as you have bent I'm thinking retainer to guide clearance. I've seen stock heads that run out of room @.460ish. Pull the lifters
 
.470 lift you shouldn't have a problem with the retainer hitting the valve seal.
Did you check how much room you have ? I have seen stranger things!
 
JFLN said:
Your rocker shafts are not installed correctly. The oiling holes should be down and towards the valve tip. I would correct that first thing.
Click to expand...

I knew something didn't look right about those rockers! Spin those shafts 180 deg.
 
exhaust valves were dragging in guides and seizing up from lack of oil to valve stems with the shafts on upside down. you may still have a problem if you burned the guides also not much oil coming out the oiling holes only on 1 rocker arm may improve with shafts on right, you may have started premature ware on cam and lifters if guides were seizing up bad.
 
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I'm going to go with the above post ^^^^^ and add if you broke the engine in with the timing retarded you could have stuck the exhaust guides and bent the pushrods.

I've seen it way too many times. Too little total on break in will kill way more parts that having 50* total.
 
yellow rose said:
I'm going to go with the above post ^^^^^ and add if you broke the engine in with the timing retarded you could have stuck the exhaust guides and bent the pushrods.

I've seen it way too many times. Too little total on break in will kill way more parts that having 50* total.
Click to expand...

Which I think is what I did and am going through now at the engine shop. I’m learning some good stuff in this thread. Hope you figure it out.
 
With the shafts upside down, the rocker system is starved. Of the 5 mounting holes along the bottom of the shaft, the 2nd and 4th mounting holes are larger than the rest to let oil come up through the 2nd pedestal from the left on each head and go into the center of the shaft. All of the mounting holes on the top are just barely large enough for the rocker studs, and with the shafts upside down, those small holes cut off most of the oil flow into the rocker shafts. You can see no oil coming from the forward 3 pairs of rocker shafts holes; there should be a dribble from each one.

The idea of something seizing due to lack of oil, like the exhaust guides as suggested above, sure seems like a good possibility.
 
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Ok... looking at the vid...you will have to start over ... hate to say that.
Check everything good.. cam, lifters, valve guides, valve seals, even check the springs. Double check everything.. you don't want to do it all over again.
Was cam degreed?
What I recommend doing is running adjustable roller rockers. This is only a recommendation but if you're going to twist the engine any significant RPM this is what I suggest. I had a 273 with a smallish cam and was running down the interstate when all of a sudden my engine started running poorly. Got it home and removed the valve covers. Push rod had punched through the stamped steel rocker. I knew then I was NOT a fan of stamped rockers. Maybe for 100% stock cam but not for any higher lift cam. Replaced that rocker and drove if for awhile until I installed a 360.

IMM Engines is building me 408 stroker engine and I'm not going to use the stock pedestal rockers (magnum)... I'm going roller rockers. LOL... I don't like pedestal type rockers either.
First and foremost contact Mike at B3racing. Mike is a very nice guy and he went out of his way on answering my questions. He's a member on here and he sold me a set of PRW roller rockers. They aren't the best in the world but not the worst either. No needle bearing is the ones I use. He also sold me a geometry kit in which that set the rocker tips dead center of the valves with a narrow rub pattern. It does make a difference.

Make sure you got the shafts turned correctly this time.... lol. When I have the shafts bare in hand I hold them up and look at the oiling holes and make sure they are pointed down the furtherest they can go. I might be a crazy but even though the holes are pointed down the holes are not drilled center of the shafts. After I have confirmed that I take a grinder wheel and zip a very small notch in the top of the rocker shaft which is facing forward of the engine. That way I know that I will not mistakenly turn them backwards.
Keep us posted .. I don't mind helping.
 
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Did you run 100% fresh fuel? No old gas?
 
Pulled the intake. None of the lobes on the cam looked completely flat. Probably going to have to invest in a dial indicator to make sure I'm still getting the right amount of lift. Was never really too confident in how the valvetrain went together but I was with 2 other people that have built a few engines. I suppose this is what I get for spending so much on an engine and then cheaping out of rockers.

MOA said:
Did you run 100% fresh fuel? No old gas?
Click to expand...

100% fresh everything. Tank, lines, pump, carb the whole damn car is practically new at this point.
 
So pop the heads off, check for bent valves, double check the cam specs, measure for new pushrods, install the shafts the right way, put new oil in and fire it up. Anything I'm missing?

Of course there's plan B where I sell everything I own and go with new aluminum heads, harland sharp rockers and a roller cam.
 
Deceus said:
So pop the heads off, check for bent valves, double check the cam specs, measure for new pushrods, install the shafts the right way, put new oil in and fire it up. Anything I'm missing?
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Yeah... throw those ******* stamped steel rockers in the trash! :poke:
 
Deceus said:
Yeah I've been eyeballing these: COMP Cams Pro Magnum Shaft Mount Roller Rocker Arms 1622-16
Click to expand...


Those are great rockers. But you still have to call Mike at B3 racing engines and have him fix you up with a set of his geometry correction shims. Use no other.


BTW, there is nothing wrong with the parts you have. Just to be blunt, I suspect that your issues are solely self inflicted. Shafts upside down, not enough timing on start up and who knows what else.

You can probably fix this with minimal cash and still have a good engine. If a lobe has gone flat I'd look at the pump and bearings. Better safe than sorry.
 
Of course it's self-inflicted. That's the beauty of doing things yourself lol.
 
Deceus said:
Yeah I've been eyeballing these: COMP Cams Pro Magnum Shaft Mount Roller Rocker Arms 1622-16
Click to expand...

I was going to go with those rockers however Mike at B3 recommended a 1.6 raito instead on my Edelbrock heads. I gained more lift using the 1.6... put me at .571/.576 If Comp made 1.6 in those rockers it would be really nice.
I didn't pay a fortune for the PRWs ... it wasn't $580...lol
Talk to Mike... you will be glad you did!
 
Look at the bottom of the lifters if they all look good the cam is most likely fine.
If you got a whipped lobe the lifter will be trashed.
 
brian6pac said:
Look at the bottom of the lifters if they all look good the cam is most likely fine.
If you got a whipped lobe the lifter will be trashed.
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Yeah I pulled them and looked. They didn't look too bad but I'd like to see the measurement for peace of mind.
 
Nothing wrong with stock rockers, been running them since 2012 with a .480 lift cam to 6 grand.......but i put mine on correctly.
 
There are notches in the ends of the shafts. They go down and to your left as you install them from the fenderside.
Make sure your pushrods are the right length , on the next go 'round, jus saying.
Ain't HotRodding grand!
 
You can have retainer to guide clearance at .450 lift in some instances. Don't take anything for granted. Check and verify everything.
 
Deceus said:
Of course it's self-inflicted. That's the beauty of doing things yourself lol.
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You have a good attitude. I find it always easier to forgive me own mistakes versus those made by others..... funny how that works LOL.
For your lift range, the stock stamped rockers can be made to work but are on the limit of their use IMHO. With a faster ramp cam like the XE's, there is more force on the rockers so that is another factor.
 
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