MTFCA Forum

The inevitable happened, my repaired rocker arm stand cracked along the weld. The repair was original to the car when I bought it. I'm soliciting opinions and help. My options as I see them:
Leave it broke, where' s anything going to go? The bolt is hold down the cracked end I can't see the valve/pushrod action moving it? Not planning on "red lining" the engine.
Find a club member who may have an extra surplus to their needs (could use two)
Find a club member who can repair the repair. Have no idea what "rod" was used to make the original repair. Or someone else whose capable
Find a club member who can make new. Or someone else who is capable. I've attached a CAD drawing I did "years" ago in anticipation.
Thanks

I sure would not leave it as-is
It looks like a simple enough part to fabricate and would not be surprised if someone doesn't have spares or a pattern. Even made from solid would not be too big a job, frankly.

I had new stands machined for my BB from T-6 block aluminum then line bored 25 years ago - didn't cost that much.

Joseph, If you need It welded I have a Process for welding cast Iron. It Is called spray welding. I just repaired a broken part for a Duesenberg car that was irreplaceable. The weld Is as strong as the parent metal and does not leave any stress as conventional welding does. My opinion would be to make new ones and I could do that at a small cost. I have a 16K sq ft shop with any kind of equipment you could emagion, Both conventional and CNC. Bill

Bill I've sent you a PM. Thanks

Joe if you can't get that fixed I may have one and can check tomorrow, later afternoon.

John prefer an unbroken original over attempting to repair this one. It would be great if you had one. Thanks

Bill Crosby

could you aim me to a website regarding this welding process? I'm not having much luck. I am acquainted with plasma spray of various materials (and that's what my searches are all producing) but have never heard of spray welding...would like to learn more...thank you

Scott, I didn't find much on the process that I use, There are many versions available that are good for high volume, such as Plasma, Arc and Gas spray. I have both high volume like a gas Metco P5 and low volume, hand held Gas torch for small individual jobs like a broken ear on a carb or a broken cast iron part big or small, It Is great for repairing freeze cracked blocks and heads. I have repaired Bronze Carbs with good success with bronze powder.

It uses very fine powders. I stock upwards of 30 different cast iron, steel and hard facing alloys, along with many aluminum, copper and bronze Powders. There are hundreds of alloys.

I did find a web site that has good general info ( https://weldguru.com/OLDSITE/spray-welding.html ) but not a lot of detailed technical Info.

I learned 40 years ago from a Metco Field Instructor who had a wealth of knowledge.

It Is not used for GP welding. A good Mig, Tig or Gas welding setup Is a lot more useful for the average or above average welder.

I had a customer who Hired me to weld 2 Chevy 500 CI blocks together to make a V16. That one was very expensive but very cool.

I could send or post pictures if you would like to see the equipment. I could also show the process If that would be helpful.

It has It's applications and Is appropriate for some situations.

If you want to call and talk about this or other subjects, my # Is 585-671-5959 After noon Is best.

Bill

Bill

your response and offer is most generous. Many thanks! I am not likely to become involved in this but am always very interested in technology and this was a new one on me. My experience with plasma was with AL2O3 plasma-sprayed onto Beryllium and then ground and lapped into a bearing surface. Very tough stuff! Also have experience building up metal for regrinding bearings, but that was not my equipment either.

Again, thank you for the detailed response.

Thanks for all the help. It is indeed a simple part and more than likely I'll have one made. I've had a number of people offering. I am still holding out hope that someone may have an original laying around surplus to their needs. I've attached a copy of pictures that might help you identify that "mysterious" rocker arm stand sitting on your shelf and a way to get the post back to the top. Thanks again

If you do not find one quickly, I'd send to Bill Crosby. I firmly believe you will be happy with the result.

THEN, to NOT simply clamp the shaft. I have to believe that for longevity's sake, there needs to be a stack of peelable brass shims in that slot so that the stud can be torqued against a non-resisting surface! I have never seen this part and am equally unacquainted with speed equipment, but can say without hesitation that if this was originally designed to not to be used with a shim pack, then this is a pi$$-poor design for anything that is going to be tightened beyond finger tight.

Once repaired, I would treat all other rocker shaft stands thusly as well.

Scott interesting observation, couldn't the same be said for the manner in which the Model T Ford connecting rod and piston pin are held tight? I think the failure is a combination of poor design (not enough meat and wrong material choice.) Thanks Bill and I are trading emails and drawing back and forth, machining a new one is definitely the way to go)

Joseph

actually, the stresses are quite different between a connecting rod wrist pin clamp and your standoff, though I think you make a cogent observation in bringing it up.

Your standoff suffers from terribly insignificant flexure area just after the very stiff beam-type cross section of the one bolt hole and the clamping bolt hole. There is no area to spread the stress across the circumference being clamped. It throws all the stress into a very short bending moment right at the bolt hole (and that's of course where it cracked). Cast Iron in particular doesn't like this (is probably Maleable Iron but not much better). Steel might survive, but I'd bet that whole design would benefit from packing material like I had mentioned, or redesigned with a significant rib across the entire top to spread stress across a MUCH greater area, since you cannot make the mounting points more flexible (nor would you want to).

The connecting rod is designed such that the material wants to wrap around the diameter of the pin and stretch which is a very strong and widely spread out stress, and in fact, there is no beam designed into it (the flexure area) and is almost purely a tension stress over a hoop, with no concentrated bending moment.

see if you can visualize what I'm saying by comparing a rod with the face-on shot of your standoff...now if the beam of the connecting rod ran all the way up the right side of this picture and stiffened the hoop of the wrist pin clamp, you'd have exactly the situation you are experiencing and these things would have failed constantly:

I'm no engineer, but I wholeheartedly agree with Scott. Just from a seat of the pants/school of hard knocks education. Dave

Thanks Scott, not disagreeing (I'm not a fan of "virtual" communications), just using this as a learning opportunity.

Joe sorry I didn't find any original stand in the parts I just got. RAJO shafts, rockers, bolts, a set of machined blocks that are stands but no originals.

John I've sent you an email. I would have an interest in the machined rocker arm stands. Thanks

Just a follow-up to my original posts. After most leads on making new or having originals went dry, I made my own. Material the right thickness was purchased from McMaster Carr, a 22mm drill bit from Ebay. Fortunately I have a large heavy duty floor drill press that did just fine. Having an original to copy was a tremendous help. So approx. $100 later I have a set of 4. Thanks everyone for their advice and help.