Broken pushrod

[Adam]

I started my Challenger and saw it had no oil pressure. I immediately shut it down. I checked a few things, sender wire, etc.. I pulled the valve covers and found the problem. A pushrod had broken and fell out. The lifter was way up, almost out of the bore... Fortunately the lifter looked undamaged. I have ordered 3/8 diameter, oiling, .080 pushrods and new rockers. (they looked fine but have many miles on them).

I've seen bent pushrods plenty of times, but never seen one break in half..

 

[budascuda]

That s wild how one half is almost perfectly straight. You must have caught it just in time, some folks would have reved it up for half an hour to see if they can bring up the oil pressure! Lol
Good Luck Adam.

 

[Adam]

That s wild how one half is almost perfectly straight. You must have caught it just in time, some folks would have reved it up for half an hour to see if they can bring up the oil pressure! Lol
Good Luck Adam.

Yeah, weird... defective maybe... at least all the pieces are accounted for.

 

[Chryco Psycho]

I have seen them break like that before , probably 50 years old & fatigued

 

[Adam]

I have seen them break like that before , probably 50 years old & fatigued

I'm pretty sure these are after market, I don't remember the source.. anyway, it doesn't pay to go cheap..

Edit: I looked these up. Melling 323.

 

[DetMatt1]

I wouldn’t think that would’ve happened under normal circumstance, have you got a sticky valve?

 

[Adam]

I wouldn’t think that would’ve happened under normal circumstance, have you got a sticky valve?

Maybe. I will look into that. Thanks

 

[moparlee]

Maybe. I will look into that. Thanks

I had one bend after a re-build during break-in. Turned out the valve guide was too tight and the valve hung up.

 

[Steve340]

What is the wall thickness of the tube?

 

[moparleo]

It must be an optical illusion but the bent rod looks longer than the straight one.
They don't fail like that for no reason. I would find out why before I ran it again. Aftermarket rods might mean previous head work possibly mill work. I would get an adjustable pushrod to measure what the length they should be before getting replacements. Adjustable pushrods are very cheap and very handy when doing any block/cam/head work that might effect the length.

 

[fasjac]

Yeah, weird... defective maybe... at least all the pieces are accounted for.

Have not seen a break before either, only bent push ones. But, that’s only a few for me. Interesting. Glad all the pieces are accounted for.

 

[Adam]

What is the wall thickness of the tube?

.060, I believe.

 

[Steve340]

At 0.060" they may not be up to the job.

 

[chargerdon]

I may be wrong, but on a small block i do not understand why a broken push rod would cause zero oil pressure. On the small blocks the oil does NOT go thru the push rod anyways. You might have more problems than that !!!

 

[Adam]

It's a 440, but either way when the lifter gets pushed out of the bore, the oil pressure will be reduced by a lot.. my lifter was sitting, cocked, at the top of the bore, so the lifter oil passage was wide open.

 

[fasjac]

It's a 440, but either way when the lifter gets pushed out of the bore, the oil pressure will be reduced by a lot.. my lifter was sitting, cocked, at the top of the bore, so the lifter oil passage was wide open.

II was reading an article somewhere about a reputable engine builder adjusting the roller rockers on a hydraulic roller cam. He is adjusting the hydraulic lifters way down. Like almost becoming a solid lifter. His fuss/point was on the big block mopars, the lifter bore was too shallow. Especially with higher lift cams. Maybe some of you have heard that before. I have not.

 

[budascuda]

II was reading an article somewhere about a reputable engine builder adjusting the roller rockers on a hydraulic roller cam. He is adjusting the hydraulic lifters way down. Like almost becoming a solid lifter. His fuss/point was on the big block mopars, the lifter bore was too shallow. Especially with higher lift cams. Maybe some of you have heard that before. I have not.

It makes good sense, very interestingl