Scorpion Endurance Lifters
 

Does anyone have any experience with these lifters good or bad?

I've been using them for the pasted 15+ years. I've had them break at the fulcrum, but there is a life time guarantee on them which i can say that thay stand behind for sure . ive had 3 beak over the years . Always at the fulcrum which i have notice that now they made out of a better material and so far no breakage to date . My lift is .580 with 280 on the seat and its a street driven car ..

Are you referring to rockers arms, or the SR lifters made by Johnson with cast iron bodies that are called Scorpion’s?

Sorry, I meant to say the Scorpion Endurance Rocker Arms, not lifters

Well, THAT'S ironic.....I happened to be on here when your post appeared earlier today, Tim....after typing a short note and pics, I hit "submit reply".
Immediately after, I realized your subject line which referenced "lifters", and thought what a dumb-ass I'll be if I don't delete this.....so I did. Hahaha...

I've recently chosen the "race" series for my build over their "endurance" series. The engine is being built soon, so no RW experience yet.....I realized after buying that the endurance rocker weighs about .5 oz less than the race, which appear more massive and maybe robust? Dunno.

FWIW, Cliff doesn't like Scorpions for reasons I forget atm....I have CRS a lot.

Cliff posted a pic where the Scorpion rockers cracked near the valve wheel

Early ones where failure prone even in situations where a factory one would live forever.

Here is the pic mentioned. Tried them and like most of the roller rockers I've tested or tried over the years they failed. All but two were cracked when this engine was torn down for inspection.

The only roller rockers I've not had issues with (discounting the high end shaft mounted varieties) are Crane Gold Race, Harland Sharp, or Crower Enduro.

For at least 90 percent of these builds factory stamped steel rockers are more than adequate and NEVER put grooved rocker balls in them......FWIW.....
http://forums.maxperformanceinc.com/...1&d=1712492692

I did a search and found some failures but that was several years ago. As stated maybe they have improved the product and maybe they are more reliable now, or maybe I should just open up my wallet real wide and get the crowers. I have had good luck with Harland Sharps but I need 1.65's and I don't need 1.7's like some say they are.

Keep in mind, the way aluminum fatigues means that all aluminum rockers have a finite number of stress cycles before failure, no matter how well they're made. Fine for a race car that can change them out each season, maybe not for a car that gets driven often.

Even recently with in the last couple years, Bulter’s don’t recommend Scorpions on big roller cams.

Fatigue life of aluminum parts depends on the forces applied to those parts. There is a lot of lighter duty applications for aluminum rocker arms that the fatigue life is almost infinite. Different alloys effect the fatigue life, the forces on them does also. Some of my Harlan Sharp and Crane aluminum rocker arms are going on 30 years of service with roller cams. Seems like Scorpion (and some others I can think of also) have ever never figured out the correct aluminum alloy or engineering to maximize the fatigue life for their rocker designs.

I have those Endurance rockers in my recently build 400 engine with solid roller cam in it,
about 600 street driven miles with them, so far so good.

I’m at the point where the cost difference between Crower SS Enduro Rockers and any other rocker out there compared to the cost of the overall engine build is a decision that makes itself.

Well, thanks to this thread....I'm selling my Scorps and buying the Crower enduros....I had them on my last Lamnas, and I might as well put them on this one too. Gotta be able to sleep at night.

Bulter performance released their own 1.65 rocker arm series that has more clearance for bigger spring retainers. They look a lot like endurance Scorpion, says made by Scorpion.

https://butlerperformance.com/i-3164...tegory:1459691

That's really what it boils down to for me. As much as these engines cost these days to build them right and use top notch parts, it's not a hard decision to just put a good rocker arm on it. Budget might mean you just have to wait a little longer to get them but the biggest issue I've had is whether they are even on the shelf.

I would not waste my time with the Scorpions.
Maybe the new ones will pan out. Just let someone else find out and get back to us on that.
I was going to buy some Crower SS rockers. 800+ $ but talked myself into getting some Crower SS shafts. Jegs had them for 1540$ and went all in. Over 2K now !
Glad I did, no rocker worries for me. It was a pretty interesting setting them up. Not too bad, learned a few things.
I seem to collect Pontiac roller rockers like I collect Holley carbs. There I worse hobbies to have.
Someday I will sell a lot of stuff.

On my 2nd set of Scorpions covering over 10 years. 1st was the Race series on botha flat tappet hydraulic and later solids.
Currently going on 6 years with a set of 1.65 Endurance on a hybrid set up with 150 on the seats and 400 open.
Just checked them this past winter. Not a ton of miles but no issues with either.

Cliff, what was the year when you found these Scorpion rocker failures.

If you didn’t know, Scorpion makes the rockers arms for both Isky and Howard’s. Isky bodies are the endurance versions, Howard’s uses the race version. I think even Summit brand rockers are Scorpions. There are a lot of those rocker arms out there working fine. Some are being used in very big cams also.

I mentioned the alloy they use being different than most rockers in the earlier post, I doubt the weakness is from the alloy, it is more likely to do with the machining tolerance that alloy has for assembly. Most cheap rocker arms (like a Proform) are made of a easy to machine 6061 alloy. Then the better rocker arms, like Crower’s Aluminum rockers, Harlan Sharp or the older Cranes were made of a 2024 alloy that is almost twice as strong as the 6061, but still easy to machine and forgiving to assemble. Scorpion opted to use a 7000 series alloy, I don’t know which 7000 it is, but it is likely slightly stronger and lighter than 2024. The down side though is it is harder to machine and the tolerance for assembly is tighter. The body using that alloy can’t flex as much as a 2024 or 6061 when the bearings or pins are pressed in on assembly. I think most the Scorpion’s failure’s was because QC wasn’t high enough and the press fit of pins on the tips or the trunnion bearings were to tight. Then under even lighter loads that increased the strain on the rocker body. It ends up causing cracks at the higher pressure points thru the body.

If you want use them for a bigger cam and are still concerned about the strength of the body, I would maybe should consider sending them off and get them cryoed. Probably a good idea for any rocker seeing a lot of abuse.