23 replies to this topic

[stormduck]

I have a set of pressed steel rockers that came with a 12G295 casting i recently purchased. Someone on ebay is selling a set claiming them to be 1.5:1. Does anyone know if they were set, or did they produce different versions? If so how do i find out? I assumed they would be 1.25:1??

Also, the pieces of metal that push against the valve tops are so worn down the adjusting nuts can't go any further! Are these easily replaceable? And is it really worth using this old set, or the newer sintered set that came as standard with the 998?

[Bungle]

i thought standard rockers were 1.25:1

[Jammy]

Standard rockers are 1.25, but standard rockers are pressed steel. I thought the pressed steel rockers were Cooper, which may mean they are a different ratio?

[Woody]

You used to be able to buy a set of offset bushes to fit to standard rockers and posts to make then high lift , so in theory it is possable

[Guess-Works.com]

If it wernt so cold in the garage I'd go measure some !

[DaveCoxon]

small-bore pressed rockers ANDlarger-bore pressed rockers ANDcooper s forged rockers AND all other sintered / pre A+ rockers are around 1.25. Offset bushing gives around 1.3 at the VERY most.

They are not 1.5 if pressed steel.

And if they're worn that much - or even 1/4 of that much, then they're bin fodder.


You can't go much wrong with the sintered rocker assembly for a stock or semi-modded motor. Despite rumours of them breaking, I've never met anyone who has (without other influences).

[miniboo]

I had bid on some pressed steel rockers that might! have been cooper s on ebay.

The seller says they are 1:5 ratio but now i have cancelled my bid as i dont think they are.

Heres the link: http://cgi.ebay.co.u...item=4591793050

[Dan]

Cooper S forged rockers are 1.27 (now there's pedantic for you!)

I personally don't rate sintered rockers, they are strong and last forever but they don't retain the same ratio throughout the range of movement and put a lot of side loading on the valves. I tend to use Cooper S forged rockers myself, they are still available (as reproduction) and quite cheap.

[DaveCoxon]

oops!

[DaveCoxon]

They look like they've been sat outside for a few years, then wire-brushed clean for Ebay.
Look at the third, fourth fifth rockers from the right - the thwo 'halves' have separated - probably because rust has formed and swelled down the centre.

I don't believe they're even 1275 rockers; small-bore ones more likely.






Dan - kinda agree with you - but you can't knock the Sintered units for being pretty good enough (in the value stakes) for the £0 or so that they cost!

[Madmax]

i just randomly came across them on ebay and on inspection i didnt think everything looked quite right either....hmm!

[stormduck]

They are the rockers that made me think about this. How do you measure them to find out for sure? And GW i really dont blame you for not wanting to enter the garage in this temp!

My items are the same as in the pic, and are from a small bore 12G295. So chances are the fella is wrong as advertising them as 1.5:1 ratio?

DaveCoxon - So the 'feet' (i can't think of a better name for them) that hit the valves cannot be seperated from the rockers, and therefore can't be replaced? So the shaft is more than likely worn, so the only thing salvageable are the pedestools (Spelling!?) ?? Yeehar.

Looks like i'm going to need to get a new set of rockers made up. I'm hoping to get a 998 with between 50-60bhp at the fly - hardly f1 performance but hopefully it'll shift the little tin can at decent rate of knots. Based on this what do you folks think would be the best rocker set up (i'm spending out on getting a 12G295 unleaded seated, new valves and guides) - a set of the sintered items? I really need to look at prices as it's got to be as low as poss.

[benjamin]

sintered rockers have the worst ratio of all ratio of about 1.21:1

cooper s forged have a ratio of 1.22:1

pressed steel small bore ones (have a round pad) 1.23:1

pressed steel 1275 (have oval pad) 1.27:1

[dklawson]

Dan, not to contradict you but my understanding is the same as benjamin's that the original forged "S" rockers were 1.22 (but not very consistent at that). Keith Calver says that the replacement forged arms are a full 1.23 and very consistent.

I bought a set of pressed steel arms to modify for offset bushes. As stated, the ratio can't be moved too far... unless you MAKE bushes for the arms and bore the stampings also. I started such a set and got them 90% done and tabled the project. From memory, the stock bushing is 0.688" in OD and I bored my arms out to accept custom bushings 0.722" OD. This allowed me to move the fulcrum/pivot hole in the arm by enough to get a ratio close to 1.4 However, as I mentioned, I never completed the set to try them.

When buying used, I've been told the best set to look for (if you don't buy performance parts) are the pressed arms off a 1275cc unit from an Austin America (or whatever variants you had that were the 1275cc replacements for the MG-1100).

[DaveCoxon]

They are the rockers that made me think about this. How do you measure them to find out for sure? And GW i really dont blame you for not wanting to enter the garage in this temp!

My items are the same as in the pic, and are from a small bore 12G295. So chances are the fella is wrong as advertising them as 1.5:1 ratio?

DaveCoxon - So the 'feet' (i can't think of a better name for them) that hit the valves cannot be seperated from the rockers, and therefore can't be replaced? So the shaft is more than likely worn, so the only thing salvageable are the pedestools (Spelling!?) ?? Yeehar.

Looks like i'm going to need to get a new set of rockers made up. I'm hoping to get a 998 with between 50-60bhp at the fly - hardly f1 performance but hopefully it'll shift the little tin can at decent rate of knots. Based on this what do you folks think would be the best rocker set up (i'm spending out on getting a 12G295 unleaded seated, new valves and guides) - a set of the sintered items? I really need to look at prices as it's got to be as low as poss.

The rockers in the advert are definately in the 1.25 range. If yours look like that, then they are in the 1.25 range.

If the feet are goosed, then they're bin fodder. Even if the feet were good and the shaft was goosed, chances are the bushes would be worn - which given the prices and arse of fitting new bushes, means they're worth naff-all basically.

If i were you - I'd find a set of sintered rockers from a 998 metro and start with them, then spend your money elsewhere. Whilst this talk of 1.21 and 1.24 clearly shows the sintered units AREN'T the best - the reality is that for the £100 a set of 'minispares' s rockers will cost - that money would be best spent elsewhere to achieve more power - eg, a SW5 cam, Rolling road setup, maniflow (rather than budget) LCB, custom dizzy, etc, etc.

That's my 2p worth...