[Shiny]

To your point about strength of the Scorpions, the location of the cracks in Cliff's photo seems unexpected. I wouldn't expect tension loads there, which I associate with risk for cracking.

Why would they crack there? Bearing failure and then weirdness? Other design weakness in the bearing support "arms"?

Is this a common failure mode in other brands?

Mike

[PAUL K]

We had a recently rebuilt Pontiac engine come through our shop with Scorpion rocker arms and a HFT cam. I think seven of the rocker bodies were cracked around the front side of the trunnion area. The worse part of the deal was Scorpions unwillingness to help resolve the issue. The tech at Scorpion didn't seem to the the cracked rocker bodies were an issue since they're rocker arms bodies have a lifetime warrenty. But insisted the rockers are sent back by the shop that originally installed them.... We put HS rocker arms on and called it a day.

Next issue we had was with a new set of 1.65 Scorpions that had excessive run out on the roller tips making it impossible to adjust lash. Over half the rocker arms had .003 or more of run out.

[indymanjoe]

so i called crower and they basically assemble them on demand. so mine should be here in a week. the guy that does it went on vacation last week. guess i rather get them after a vacation then before LOL

[rolling money pits]

Like HFT lifters….this thread has me worried.

I have Crower enduros, 1.6 believe, and HS “squares”, I think they are 1.52. Both obtained 2004/2005, is that far enough back that I should be OK, or at least have little to be concerned with?

[DaleO]

Originally Posted by Cliff R

Tried one set of Scorpion full roller rockers here and this is what we ended up with. 13 out of 16 cracked in exactly the same manner......and YES the engine was using higher springs pressure and a full "race" set-up. I've been chastised for using those rockers in that application but aren't we supposed to "upgrade" from stock rockers when we install solid roller camshafts, stronger valve springs and start spinning the engine past 6000rpms?........

Do you have side views of this rocker Cliff?

[Formulajones]

Originally Posted by rolling money pits

Like HFT lifters….this thread has me worried.

I have Crower enduros, 1.6 believe, and HS “squares”, I think they are 1.52. Both obtained 2004/2005, is that far enough back that I should be OK, or at least have little to be concerned with?

I wouldn't worry about either of those even if purchased today. Crower Enduro and Harland Sharp are far superior than a bunch of the other stuff on the market today, you'd be hard pressed to do any better for a conventional rocker arm system.

[Steve C.]

Here is a good track record for the Crower Enduro stainless steel rocker arms.

I bought a set with a 1.65 ratio in 1995 for a 560 hp 412 build that made peak power at 6400 rpm. Then these rocker arms were used on the next build in 1998 on a 600+ hp 462 that made peak power at 6400 rpm.
For the next engine build I upgraded to a T&D shaft rocker system. I later passed on these same Crower rocker arms to Cliff Ruggles who used them on his 455 in the 73 Ventura which is now sold.
I suspect they are still being used today.

.

[Formulajones]

I have a similar track record as Steve with the Enduros.

I used them on my BBC build around that same time frame, mid 90's. Started out with a hydraulic flat tappet. Ran that engine till around 2000. Decided I wanted more power and swapped to AFR heads and went roller with 275 lbs. seat pressure. Ran this combo for a couple years and decided on another cam change, this time a hydraulic roller and about 160lbs. seat pressure. Still using the same Enduro rockers and making just over 600hp, spinning the engine to 6500 rpm.

That same engine and the same rockers are still in the car to this day after more dragstrip runs than I can count and thousands of street miles. I haven't had a valve cover off of it in 20 years. I still jump in it today and drive it on 300-400 mile road trips and don't think twice about it.

Recently put an overdrive in it so I can go even further. Before that, all those years, I was driving it with 4.10's and spinning it 3000 rpm everywhere I went. So they haven't exactly been easy miles. It just keep on going.