Broke a pushrod, looking for advice

[1 Wild R/T]

Rocker doesn't look to bad, it looks like the pushrod wasn't to long, who made the pushrods?

 

[BSB67]

Pics below. This was on the intake of cylinder 5.

View attachment 1150333 View attachment 1150334 View attachment 1150335 View attachment 1150336 View attachment 1150337 View attachment 1150338

Is that a dent in the valve cover? Was it caused by the rocker adjuster hitting the cover or something else?

Engine is over reved, lifter pumps up, rocker contacts valve cover, push rod cup breaks, maybe.

You'll want to do a compression test and a leak down test on #5 before you put it back together.

 

[7t500]

Rocker doesn't look to bad, it looks like the pushrod wasn't to long, who made the pushrods?

Pushrods were Mancini Racing cut-to-length which were cut down by my friend and I on his lathe. It's possible I made an error but the nagging thought in the back of my head is that I had intermittent lifter noise and wonder if it was that lifter... plunger collapsed, lifter bounced off the head, and the cup broke off because the pushrod was exerted to a sideways force but is designed to handle compressive force and not shear force.

 

[7t500]

Is that a dent in the valve cover? Was it caused by the rocker adjuster hitting the cover or something else?

Engine is over reved, lifter pumps up, rocker contacts valve cover, push rod cup breaks, maybe.

You'll want to do a compression test and a leak down test on #5 before you put it back together.

Yes, dent in valve cover. The engine was at cruising RPMS, roughly 2500 RPM, definitely not overreved. It looks to me like the pushrod hit the valve cover.

Compression test is definitely a good call tho.

 

[BSB67]

Yes, dent in valve cover. The engine was at cruising RPMS, roughly 2500 RPM, definitely not overreved. It looks to me like the pushrod hit the valve cover.

Compression test is definitely a good call tho.

Check real close to determine the cause of the dent in the cover. It matters for identifying the root cause.

One scenerio is the rocker stopped when the lifter and pushrod were still trying to move. Either the rocker hit the valve cover, or the valve hit the piston, or 2) the pushrod was simply junk

 

[1 Wild R/T]

Pushrods were Mancini Racing cut-to-length which were cut down by my friend and I on his lathe. It's possible I made an error but the nagging thought in the back of my head is that I had intermittent lifter noise and wonder if it was that lifter... plunger collapsed, lifter bounced off the head, and the cup broke off because the pushrod was exerted to a sideways force but is designed to handle compressive force and not shear force.

I've seen cut to length pushrods fail before, at least 6-7 cars that I can think of, for no apparent reason... Not a fan, I'd put a set of Smith Bros in it & never look back...

 

[7t500]

I've seen cut to length pushrods fail before, at least 6-7 cars that I can think of, for no apparent reason... Not a fan, I'd put a set of Smith Bros in it & never look back...

Smith Bros is my top contender for replacements. Also considering swapping the ball on the rockers for cups. The the pushrods will be ball/ball, supposedly a better configuration then the ball/cup pushrods im running currently.

 

[1 Wild R/T]

Smith Bros is my top contender for replacements. Also considering swapping the ball on the rockers for cups. The the pushrods will be ball/ball, supposedly a better configuration then the ball/cup pushrods im running currently.

I've run both, I've never had a problem with cup style pushrods that are well made & the proper length.... Do what feels right but know that lots of guys ran the cups for many years & many miles with no problems....

 

[7t500]

Check real close to determine the cause of the dent in the cover. It matters for identifying the root cause.

One scenerio is the rocker stopped when the lifter and pushrod were still trying to move. Either the rocker hit the valve cover, or the valve hit the piston, or 2) the pushrod was simply junk

I double checked, the dent in the valve cover is absolutely from the pushrod. I'm at the point where I think it's either junk lifter or junk pushrod.

 

[7t500]

I've run both, I've never had a problem with cup style pushrods that are well made & the proper length.... Do what feels right but know that lots of guys ran the cups for many years & many miles with no problems....

Good to know. Saves some headache from locating and swapping to rocker hardware. I at least know I have the right length currently... but will wait to verify until I determine if I am only doing cam/lifters or if I'm also doing heads...

 

[BSB67]

If it were mine, I would get longer pushrods. With that style of adjuster, I'd probably target zero adjuster threads showing.

 

[slimt]

Question about the pushrod. When the are resized or made to length , Are both ends shaped to fit? Or ? Ive never knew of such a thing.

 

[1 Wild R/T]

Question about the pushrod. When the are resized or made to length , Are both ends shaped to fit? Or ? Ive never knew of such a thing.

They are built to what you specify... Ball & Ball, Ball & Cup.... Ball radius, cup radius, oil through, no oil... Wall thickness, diameter... Length... You tell them what you need...

 

[moparedtn]

Yep, likely lifter failure, enough to allow the pushrod to go....well, where it shouldn't have.

 

[7t500]

If it were mine, I would get longer pushrods. With that style of adjuster, I'd probably target zero adjuster threads showing.

IIRC, the recommendations from the rocker manufacturer was to shoot for 2 threads showing beneath... I can dig up the information but I think that was recommended. May I ask why you'd shoot for 0 threads showing? Just not a recommendation I have heard prior.

 

[7t500]

They are built to what you specify... Ball & Ball, Ball & Cup.... Ball radius, cup radius, oil through, no oil... Wall thickness, diameter... Length... You tell them what you need...

Correct, I ordered cut-to-length pushrods since I had a buddy with a lathe. I had to order the correct ball and cup diameters for the lifters and rockers I am using.

 

[RemCharger]

Rocker doesn't look to bad, it looks like the pushrod wasn't to long, who made the pushrods?

Pushrods were Mancini Racing cut-to-length which were cut down by my friend and I on his lathe. It's possible I made an error but

I've seen cut to length pushrods fail before, at least 6-7 cars that I can think of, for no apparent reason... Not a fan, I'd put a set of Smith Bros in it & never look back...

Correct, I ordered cut-to-length pushrods since I had a buddy with a lathe.

I just gotta ask ...... did you or buddy with the lathe chamfer the hole before you pressed them together?
How hard (or easy) was it to press the cups in..

 

[beanhead]

IIRC, the recommendations from the rocker manufacturer was to shoot for 2 threads showing beneath... I can dig up the information but I think that was recommended. May I ask why you'd shoot for 0 threads showing? Just not a recommendation I have heard prior.

The less the adjuster protrudes, the less chance of breakage and the better it is for pushrod-side geometry during operation.
But...it's critical that the rocker can still squirt oil above the pushrod cup. A very smart Mopar specialist mentioned to me not to go strictly by thread exposure for this reason, so I rounded up some various types of aftermarket rockers and sho 'nuf..some rockers have a larger chamfered recess after the threads, oiling hole location/angle and adjusters vary... so on some if you don't have the adjuster out enough the oil will just be squirting on the side of the pushrod/cup and oil doesn't get into the cup where it's needed. In other words you 'ideally' want as little adjuster showing as possible that will still get oil to the cup.

 

[7t500]

The less the adjuster protrudes, the less chance of breakage and the better it is for pushrod-side geometry during operation.
But...it's critical that the rocker can still squirt oil above the pushrod cup. A very smart Mopar specialist mentioned to me not to go strictly by thread exposure for this reason, so I rounded up some various types of aftermarket rockers and sho 'nuf..some rockers have a larger chamfered recess after the threads, oiling hole location/angle and adjusters vary... so on some if you don't have the adjuster out enough the oil will just be squirting on the side of the pushrod/cup and oil doesn't get into the cup where it's needed. In other words you 'ideally' want as little adjuster showing as possible that will still get oil to the cup.

That's a great tidbit of information! I will have to look and see what mine looks like...

 

[7t500]

I just gotta ask ...... did you or buddy with the lathe chamfer the hole before you pressed them together?
How hard (or easy) was it to press the cups in..

We cleaned the ID with a drill bit and used the Mancini Racing pushrod assembly tool. They pressed in pretty well.