Technical Cast Iron SBC Rocker

Have a set of cast iron rockers that have roller trionions /no roller tip. Including pics.
I remember an article by Yunick that stated if the pushrod geo/length was right there was no advantage to a roller tip. ( I’ve used with and with out with out a problem.
Wondering if this is one off or something converted to get around a rule. Anyone for an idea ?

 

Many years ago, I bought a large box of aftermarket rocker arms for various engines because it had adjustable rockers for early Oldsmobile V8s in it, and it had a few of what you've got in the mix. No idea who made them, though.

 

I would think it would add a lot of weight to the valvetrain.

 

I would ***ume it would add weight. It had to be to get around a rule in my mind but I’ve never seen it before.
Some excellent machine work and someone that wasn’t afraid to try. I would not be afraid to use them in the least.
All my Chrysler hemis had prepped stockers.
Even my Donovan had no roller tips.
Never broke any. And that Donovan had springs that were as big chevelle coil springs. Lol

 

I’ll wind up using them probably on a little street engine but don’t think you could ever hurt one.

 

Can't get out to the shop, having surgery in a couple of days but they kind of look like some NOS Gotha rockers I have. I'll look when I get a chance

 

Just take care of you. Been under the knife before and more times than I’d like to admit. There is no such thing as minor surgery.

 

Yeah, while not for high rpm usage, should be fine for normal daily driving (not long freeway trips!).
Higher rpm driving, they will kill valve springs.

Mike

 

I go the opposite direction on Chevy rockers. I prefer roller tip stamped steel rockers over full rollers. They've always held up well for me, and they also fit under stock valve covers, even with poly locks.

 

Cast iron? Cast steel, maybe. Went looking for cast iron rocker arms and the interweb kept referring me right back to this thread. Only mention of it anywhere.

 

I've converted LS Rockers to work on a screw in stud before. First time I've seen a rocker like that one.

If the geometry is correct and shoe tip is just fine vs a roller. I've learned alot from Gary Patrick at Rocker Arms Unlimited, sharp dude!

 

Probably need to look up ductile iron rockers

 

Nick, you've been awfully quiet lately!
Anything to update on that 283?

 

I've been knee deep in Hilborn Injection stuff trying to get that side of my business up and going (Boss Fuel Injection). Have some patterns being made, prototyping a bunch of new parts for production runs, lots of reverse engineering, sourcing parts suppliers, making fixtures, etc, etc.... Never a dull moment!
283 still on the back burner for a little bit but I'm starting to get antsy!

 

LOL I got a set of crane roller rockers that have well over 150K on 'em. But I have seen roller rockers only go about 10K. I cannot attest if it is the luck of the draw or brand quality.

You are correct stamped steel rockers do not require extreme rocker covers. That lands in he plus column.

Back to the iron rockers if they were mine they would look really cool on the shelf in my shop. I like to keep my valve train light.

 

I just got a little information on them. They were indeed to beat a set of rules. No roller tip allowed. Nothing stamped or marked on them and they didn’t remember what they were ( name wise).
They decided to put a roller trionion in. Still a lot of work.
I've never had a stocker break except a bbc.
And I’ve even run some spretty stout springs on a sbc.
I am just curious as to what they originally started as.
I have put upwards of 35k on a set of used roller rockers and still not a problem yet.
Lighter is better.

 

LOL I run canted plug heads on an SBC I got here. The company said that I could run stock stamped rockers. Wrong. I broke so many rockers and studs in the first 10K that I got to where I could swap out on the side of the road as quick as i could change a tire. I maybe could have got by with long slot rockers.

I ended up with a set of roller rockers and never looked back.

Stamped rockers depend a lot on the rest of the valve train I think.

The iron rockers are cool. I got a set of McGurks on an Olds that resemble those. They are shaft rockers and it would not have been a big deal to put roller fulcrums in them and put them on an SBC. I think someone told me that they are ductile steel as opposed to iron but I have no way to verify that.

 

And Nicks has been trying to help me sort out one of my hilborn units that’s been stumping me.
I had for gotten he was elbow deep in a 283.
Any info to identify is helpful. I simply would like to know what they are. I know what they were on but I don’t think they started off as sbc. Lol

 

When I get a chance I am going to put an Harland sharp/comp com/and this one on the scales and just see. Now you guys went and did it. I gotta know

 

I had a broken rocker arm on a set of Ford D0VE heads, broke clean in 1/2. The look at the break sure looked like cast iron. Had that “white-ish” look to it. It struck me a odd, not sure really what it was made of, would cast steel break and not have any “pull” marks?

 

Here are the results. Kinda what you thought and yet not either.Sorry the data cardboard is upside down. I was in a hurry.

 

Fixed it, easier on the eyes this way-



And actually I’m surprised by the results.

 

Ok. I even looked through the inventory and found a Comp cams roller tip rocker with /with out fulcrum. 118 .5 with out pivot ball

 

Before I made roller rockers for my GMC 6 I had to replace valve guides every 2-3 years depending on how many times I raced. Factory valve lift is .375” and the reground Howard cam I used is .510”. The stock rocker, which a shaft mounted system, pushed the valve sideways enough to wear the guides. The rollers I made have roller tips and Torrington bearing on then shaft and I’ve never worn guides since.
SBC’s are notorious engines which wear guides and smoke on deceleration. Seams like a roller on a valve stem would be a good idea.

 

Just noticed you mentioned “made” twice. Care to share for a curious mind?

 

Also have this set of homemade rockers that came with the injection and Engle cam that I got for my prefect. They are in an isky box but look very close. They were made in a milling machine. The pivot trunnion is actually hardened steel. Oil grooved. No roller bearings. The tip end has a hardened steel insert that was threaded into the arm.
I actually put them on my 57 project. I will probably swap out another later style comp cams set I have but this guy put a lot of time. He actually made a spare also. There are 17. And if you look carefully you can see the small milling marks. The year was 69. And it came off of a jr fueled.

 

In the 60s I worked in a machine shop doing mostly head work. SBC heads usually had good valve guides while the inline 6 almost always needed guides . The valve train looked the same but the 6 had 1.75 rockers instead of 1.5.

 

I’ll take the rocker arm cover off the engine and post a photo. I have one extra right, left, and a stand as I made the stand hole .100” to the push rod side along with the rocker shaft holes.
My father was a precision machinist specializing in wind tunnel model parts for the aircraft industry. He opened his shop in 1948. I spent a lot of my preteen and teenage years in it. He died in 1963 when I was 19.
I am an industrial electrician by trade was helping out a machinist in his shop rewireing for 3 phase and showed him a blue print I had drawn for a roller rocker arms. This was in 1981. I asked him in exchange for my labor if I could use one of his Bridgeports to make the rockers. I made one cylinder set and a stand and he said I had to test fit them to a head to make sure they would work. They did.
I still had my regular job and did the work on the side at night and weekends. I came back one Saturday to keep machining the rest of them and he had made them all. I used Torrington bearings on a stock shaft that I had center less ground off .002” for the bearing clearance and Isky roller tips because they were on a pin with a clip.
I made a few design errors I would do slightly different today but at 78 I’ll never make any more. None have ever failed but the stock reground shaft did so I made a new one with a smaller rifle drilled hole, heat treated to the correct Rockwell and finished to the correct diameter again by having it center less ground. I made 2 .. to have an extra.

 

Awesome! My hat is off to you.