Broken rocker arms two weekends in a row

[Bluecuda340]

I run a solid roller setup that is [email protected] and lift at the valve is around .665. I broke a HS intake rocker on my W2 setup on drag week 2021. I was cruising down the highway at 3500RPM and I heard it then it picked up a miss. I did not have a spare but our timing was good because we called HS, they put us through to Randy and he drove our rocker arms to UPS himself and had them at our hotel at 8AM the next morning.

I really didn't look anything over until a month or more after I fixed it at the holiday inn. It appears the shaft had extreme wear and it eventually bound up and broke the rocker arm. The bearings were in fine shape but the shaft was pretty worn. I also found the same shaft wear on the other side of the engine, oddly enough both shafts were worn the most CLOSEST to where the oil enters, that one is a head scratcher for me. I sent the worn shafts and broken pieces to HS and they replaced them under warranty. Now I carry a shaft, both intake rockers, and an exhaust rocker as spares.

How does your adjuster look? HS only likes for 1-2 threads to stick out, if you had more than that I could see it adding stress.

I zip tied the bearings over the oil holes and drove it 45 minutes to the hotel on 7 cylinders.

 

[rumblefish360]

I've been on their websites looking at what each offers for small block mopar W2/W5 heads. T&D has a nice set up but it requires machining the heads and modifying the oiling system to feed through the push rods and I really don't want to go through all of that expense coupled with the cost of the rocker set up. Jesel's also require machining of the heads. The gentleman who I bought the Arrow from this past spring, and also the engine builder, is a machinist by trade and he tested the broken rockers and found no fretting or stress fractures in the aluminum. So that information, coupled with speaking with Randy, Jr. at Harland Sharp, indicates that these rockers are probably at the end of their service life. There's been a lot of questions about spring pressure, 655, and cam lift, .685. Both of those specs are well within the tolerance of these HS rockers. So long story short, got a set of new exhaust rockers to replace the ones currently on the engine to finish out the last 3 or 4 weeks of the season up here in Maine, then during the winter come up with a new plan.

Thanks Les. I appreciate the time and response.

 

[Les Gibson]

Do you pull or back off the rocker shafts during the off season?

I've only owned this car since April. But I do back off the rocker shafts over the winter to take pressure off of the valve springs.

 

[Les Gibson]

I run a solid roller setup that is [email protected] and lift at the valve is around .665. I broke a HS intake rocker on my W2 setup on drag week 2021. I was cruising down the highway at 3500RPM and I heard it then it picked up a miss. I did not have a spare but our timing was good because we called HS, they put us through to Randy and he drove our rocker arms to UPS himself and had them at our hotel at 8AM the next morning.

I really didn't look anything over until a month or more after I fixed it at the holiday inn. It appears the shaft had extreme wear and it eventually bound up and broke the rocker arm. The bearings were in fine shape but the shaft was pretty worn. I also found the same shaft wear on the other side of the engine, oddly enough both shafts were worn the most CLOSEST to where the oil enters, that one is a head scratcher for me. I sent the worn shafts and broken pieces to HS and they replaced them under warranty. Now I carry a shaft, both intake rockers, and an exhaust rocker as spares.

How does your adjuster look? HS only likes for 1-2 threads to stick out, if you had more than that I could see it adding stress.

I zip tied the bearings over the oil holes and drove it 45 minutes to the hotel on 7 cylinders.

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Adjusters looked fine, about 1 and a half threads showing past the rocker arm.

 

[Mr. Sinister]

I've only owned this car since April. But I do back off the rocker shafts over the winter to take pressure off of the valve springs.

I was told that by my engine builder.

 

[pittsburghracer]

I guess what got me started on not backing them off was when I bought my house in 1984 I had a one car garage in the house. I always thought if my car was start ready if there was a fire I could quickly get it out. When I built my shop the practice continued because I never saw any harm from not doing it. Like I said my last set were technically 6 years old with a .650 solid lifter cam. And my present build it over three years old with a .650 lift roller cam. If I saw a maintenance issue from not backing them off I would back them off.

 

[Mr. Sinister]

I guess what got me started on not backing them off was when I bought my house in 1984 I had a one car garage in the house. I always thought if my car was start ready if there was a fire I could quickly get it out. When I built my shop the practice continued because I never saw any harm from not doing it. Like I said my last set were technically 6 years old with a .650 solid lifter cam. And my present build it over three years old with a .650 lift roller cam. If I saw a maintenance issue from not backing them off I would back them off.

Do you start it during the off season? That would make a difference.

 

[pittsburghracer]

Do you start it during the off season? That would make a difference.

Absolutely not with alcohol.

 

[Inertia]

I rotate the race engines a 1/2 revolution, a few times thru the winter, cuz my engines don't have rockers that back off .(Toyota OHC)

 

[RustyRatRod]

I'm with you, I've never seen a rocker arm break like these have. I wish I still had the Norris stainless steel roller rockers that were on my old W2 Dart. But I didn't have a spare set of rockers to swap them out with when I sold that car so the new owner is all set in that regard!

Last I read, Norris was still making them but out of his small home garage.

 

[Mr. Sinister]

Last I read, Norris was still making them but out of his small home garage.

This is GREAT info!

 

[BVoelzke]

Indy rocker I broke a few years ago on my Indy headed R3 block 408 : 600 lift cam shifting at 6500 not a lot of spring pressure . Indy no longer offers the rockers I ended up buying a used set from a racer in Md an 8 hour round trip to get them. I damaged a few more after the repair but luckily had spares , I sold the motor after the crank cracked. I have since gone back to my ancient W2 heads on a 410 c.i. 360 block stroker with the old ductile iron non roller rockers I have ran for over 25 years without breakage or a problem

 

[Mr. Sinister]

Indy rocker

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Ouch!

 

[Andrew onorio]

Asking if anyone might have any thoughts on what might be causing this.
For consecutive weeks I've broken an exhaust rocker arm. Last week #4 exhaust rocker broke. This past Friday night #5 exhaust rocker broke. These are Harland Sharp rockers installed on Mopar Performance aluminum W5 heads. There's no oiling issue or clearance issues. I am told by the previous owner of my Arrow that these rockers are about 6 years old. Is this a case that they're just wore out and I need a new set or is there another reason. Appreciate any constructive thoughts.

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Valve interference? Boroscope the piston.

You talk about rocker arm life, but then I wonder how many dyno sessions or laps my Jessel rocker arms made in their life prior to me only using them 9 sec at a time. I actually had my Jessel rocker arms rebuilt during my engines downtime following our wheel stand episode.

 

[Nat]

all i know is any Alu equipment in construction hasto be inspected every 5 years Alu is not known for long life in highly stressed parts

 

[Dale Davies]

Asking if anyone might have any thoughts on what might be causing this.
For consecutive weeks I've broken an exhaust rocker arm. Last week #4 exhaust rocker broke. This past Friday night #5 exhaust rocker broke. These are Harland Sharp rockers installed on Mopar Performance aluminum W5 heads. There's no oiling issue or clearance issues. I am told by the previous owner of my Arrow that these rockers are about 6 years old. Is this a case that they're just wore out and I need a new set or is there another reason. Appreciate any constructive thoughts.

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Aluminium does not have the fatigue resistance steels have. With stiff springs and higher RPM for drag racing, you are probably experiencing fatigue failures. IMHO if you continue to replace one rocker when one breaks, you will continue to experience weekly failures.
Top fuel teams replace Al con rods and pistons regularly for just such a reason. Blown alcohol guys buy the used parts to run at significant saving to them, and they do not stress them as much. They get a number of runs out of them and switch them out before they fail. By then they are pretty much wall art.
PM proceedure would say replace the Al rockers at about 100 runs or switch to steel rockers that have higher fatigue life.

 

[RustyRatRod]

Indy rocker I broke a few years ago on my Indy headed R3 block 408 : 600 lift cam shifting at 6500 not a lot of spring pressure . Indy no longer offers the rockers I ended up buying a used set from a racer in Md an 8 hour round trip to get them. I damaged a few more after the repair but luckily had spares , I sold the motor after the crank cracked. I have since gone back to my ancient W2 heads on a 410 c.i. 360 block stroker with the old ductile iron non roller rockers I have ran for over 25 years without breakage or a problem

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I believe I would stick with tried and true old school.

 

[RustyRatRod]

Valve interference? Boroscope the piston.

That or some other valve train interference was my initial thought. He says no.

 

[famous bob]

I guess what got me started on not backing them off was when I bought my house in 1984 I had a one car garage in the house. I always thought if my car was start ready if there was a fire I could quickly get it out. When I built my shop the practice continued because I never saw any harm from not doing it. Like I said my last set were technically 6 years old with a .650 solid lifter cam. And my present build it over three years old with a .650 lift roller cam. If I saw a maintenance issue from not backing them off I would back them off.

If I DONT RUN MY ENGINE FOR A LONG WHILE , FOR SOME REASON , i will just roll the engine over with a big ratchet and 1 1/4'' socket every month..

 

[furrystump]

I have a friend that works for a company that makes very high end springs for a bunch of very different applications. He has always told me two things kill a spring that is appropriate for how you are using it. Heat and number of cycles. Sitting in a compressed state doesn’t do a thing to them.

 

[Mr. Sinister]

Does he make keepers and retainers too?

I have a friend that works for a company that makes very high end springs for a bunch of very different applications. He has always told me two things kill a spring that is appropriate for how you are using it. Heat and number of cycles. Sitting in a compressed state doesn’t do a thing to them.

 

[pittsburghracer]

Does he make keepers and retainers too?

Why??? Do you think the keepers and retainers are going bad.

 

[Mr. Sinister]

Why??? Do you think the keepers and retainers are going bad.

I recently saw a retainer split in half.

 

[pittsburghracer]

I recently saw a retainer split in half.

And that was from sitting all winter. Lol

 

[Bluecuda340]

At some point you have draw the line. For one the keepers and retainers are always under pressure, and with the mentality that the keepers could go bad from sitting all winter you should probably back off your head bolts, rod bolts, etc.