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Rocker assembly

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Rut

Rut

Obi Wan
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I may be in need of a rocker assembly for a 1275. I hope it's not the case, but I wanted to know if used or rebuilt ones were available.
Thanks, Rut
 
Hi Rut. I'd expect that used will be available, and Moss has the rocker shaft and wear parts. What is wrong with your existing one?
 
Just be sure to use the wide pad stuff with the 1275. Small bore rocker pads are narrower and have troubles lining up with the 1275 valve spacing. Rocker pads can be polished if just worn a little. Ground at a full service machine shop if badly worn. If you decide to go used, check around and see if people have some spare rockers or assemblies. I've got plenty of these if you want just a couple or a whole set. The main wear component is the shaft. Bushings next. Usually a new shaft makes things good again (other than the worn pads). Also if mixing complete assemblies, make sure you have the oil hole in the head lined up with one in the rocker pedestal. Things don't last long if they aren't getting oiled.

Mike Miller
 
Thanks for the replies...the existing assembly is the stamped steel style and a couple of the screw heads used for adjusting clearence are broken. Several of the lock nuts are partially rounded as well, and the assembly on the whole looks pretty bad. Considering what I'm trying to do with this car I don't think I need a high performance set-up, just a good stock one. The engine looks like Attila the Hun put it together!
Thanks, Rut
 
Ham-fisted PO's or hired wrenches. Not uncommon. These cars received scant respect from the time they left the dealership.
 
Well, it looks like I'm in the market for a complete rocker assembly and I prefer used or rebuilt in good condition. Should I get the stamped steel one like I currently have or look for the one that's cast or forged?
Thanks, Rut
 
Stick with the wide pad stamped steel. Found more of these closer to the advertised rocker ratios than the forged ones. Also, avoid the drilled adjuster screw ones if you can. I've had a couple of these break on me in a specific engine combination. The forged rockers have a bigger adjuster screw (5/16") by the way. The forged ones look neater. Just inspect the pads for stem wear into the curved pad portion.

Mike
 
Mike, thanks for the reply...I have a forged, later set, on the way in good condition. I'll inspect them and take them to my local machinist if I find wear. Upon installation I will rotate the shaft 180 degrees the minimize any potential wear as noted in previous posts. The engine is a rebuild and I have the machine shop invoice, but you can't tell it by looking. Way too many broken and maladjusted parts. BTW, how should I break the engine in? It's only been cranked on occasion to assess the rear oil leak and verify oil pressure.
Rut
 
Forged later set? Forged would have been early 1275 and Mini stuff. The steel stamped arms were more common after that as a cost savings and finally they went to sintered steel arms. Those sintered arms work but don't have a great reputation. They are the "later" arms. If that's what you purchased I'm sure they will work. If you want a set of the stamped steel arms for the 1275, Austin America engines are good donors as they have the wide contact pads.

What do you mean "rotate the shaft 180 degrees"? I may be confusing the engines I've tinkered with but I thought the A-series rocker shaft could only be installed one way. Regardless, if there is any wear on the shaft I would install a new one when you go to the trouble of replacing the rockers.
 
From what I understood I thought the forged rockers were later 1275 so I stand corrected. I have read and been told that the shaft can be rotated 180 degrees to put the wear on the top of the shaft vs on the bottom. That being said, do I have incorrect info? I want to do this correctly, but like everyone else I'm on a budget. Thoughts?
Thanks, Rut
 
The 12G1221 1275 Forged rockers were only on the 1967 engines. Pretty much just a single year, although I wouldn't wager that a few found their way onto engines in 1968. They are usually referred to as the "Cooper S" forged rockers.

The rocker shaft can be "rolled" 180 degrees and the non-worn side used for a little while. There are a few drawbacks to doing this. The shaft has to be drilled for the grub screw and then cleaned out. I'm not fond of drilling another grub screw hole opposite the existing one. Too much chance of breaking the rocker shaft with race valve spring tension. Maybe for a street engine it would work. I'll change grub screw locations and adjust rocker pedestal oil hole locations to get around this. Also, the location has to be marked so that the shaft doesn't get too much out of align fore or aft making either #1 or #8 rocker too tight between the cotter pin and the pedestal. Caution/Caution; make sure the oil holes line up on the #1 pedestal so everything gets oil flow.

HTH,
Mike Miller
 
Thanks for the very useful info! I've not seen the rocker assembly I purchased from a member on another forum, but was told that it is a forged set and in good condition. If it's not then lesson learned and I'll look elswhere, but I have no reason to believe it's anything but OK. I too would prefer not to roll the shaft and drill another hole. I will be very diligent when aligning the assembly and also make sure the hole is in the number 1 position. I currently have good oil flow with my current set up it's just beat to hel with broken bits and such. I would really like to meet the person that put this thing together or maybe the PO was as cheap as I am! Could the forged set have come off of another car like a Mini?
Thanks, Rut
 
The forged rockers could have come from a Mini or they could be aftermarket parts.

If you get the sintered arms on the set you purchased, there is nothing wrong with them for a street engine. They were used on the later A-series and A+ engines for years.

The stamped steel arms are also quite serviceable. Vizard discusses how to beef them up for use in performance engines.

You have lots of options.
 
When I started looking for replacements I requested forged thinking they would be a little stronger. What are sintered arms and what do they look like? I'm not familiar with the term.
Thanks, Rut
 
Sorry. Sintered is a process description based on the use of powdered metal. Metal powder is placed in a mold cavity/die and compressed at very high pressures and heat until the little bits of metal start to melt together. That melting/sticking process is called sintering. When the part is removed from the cavity it is typically in its final form with no additional machining required. Unlike cast parts, the surfaces are usually smooth but porous. A common item formed this way would be the oilite bronze bushings you find in generators and such.

The picture links below are for items on eBay at the moment. The links will become "dead" pretty soon.

The first is for a sintered arm. Note the different shape and heat treatment around the tip:
https://i4.ebayimg.com/07/i/001/1e/de/5e24_12.JPG

The link below is for a pressed steel set of arms. Note the wider contact pads for the valves. These would be from/for a 1275:
https://i.ebayimg.com/00/$(KGrHqUOKjkE1v7w!ogyBNnjnqUl3!~~_12.JPG

The last link is for an aftermarket forged arm. The factory parts are similar but a bit bulkier looking:
https://i.ebayimg.com/00/$(KGrHqYOKiYE2qmM30IjBNri4BHOnQ~~_12.JPG
 
Yep, the A+ sintered units work fine on street engine, just finished a motor where the customer supplied a set of those, got another set lying around here somehwere.
 
Thank you for the detailed info and the support. At my level of expertise you never know if you are doing the right thing, so it's good to hear that all are good to use. As I go thru this process I find that the knowledge base on this forum can really help keep you from screwing up...just ask first if in doubt.
Thanks again, Rut
 
I throw this FWIW, 99% of time on rocker arm assembly with some time on it, a new shaft will renew the fit on the rocker bushing to shaft, you woulld think that the bronze bushings in the rocker arms would wear out before the shaft, but this is hardly ever the case, it always the shaft wearing, I've built a bunch of these motors, literally a 100+, and in all of them I built, maybe two got new rocker arm bushings replaced, the rest all got shafts.
 
Hap, thanks for the info on the shaft. The current shaft on my car may be in good shape it's just the arms, nuts, and adjusters that look bad. It probably doesn't affect performance, but it makes me think it could be better. Can I use the shaft from my current pressed rocker on the forged one if it proves to be bad?
Thanks, Rut
 
Check price of new shaft, they were not expensive as I remember.
 
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