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Broken Rocker
https://www.ausmini.com/forums/viewtopic.php?f=2&t=97951		 Page 1 of 1
Author:  Wakka [ Thu Nov 15, 2018 6:10 am ]
Post subject:  Broken Rocker
Posted on the FB site, and copied here for those not using FB -

Caution.... this was a brand new rocker from a reputable supplier in the U.K., properly set up with correct push rod and valve springs. It lasted 50km before fracturing. There are signs of heat damage from the spot weld that seals an oil hole. Other rockers will be crack tested for any evidence of a production issue. M’while, whole set now replaced by a set of sintered rockers from a 90’s Mini. Working perfectly.

I will follow up when we get a response from the supplier
Author:  drmini in aust [ Thu Nov 15, 2018 7:07 am ]
Post subject:  Re: Broken Rocker
I suspect these so-called Minispares forged rockers are now cast iron. I had to machine the top of them on one set so the nuts sat flat. The shavings that came off were cast iron not steel.
I am a machinist, I know the difference.
Author:  Hobson [ Thu Nov 15, 2018 7:56 am ]
Post subject:  Re: Broken Rocker
drmini in aust wrote:
I suspect these so-called Minispares forged rockers are now cast iron. I had to machine the top of them on one set so the nuts sat flat. The shavings that came off were cast iron not steel.
I am a machinist, I know the difference.


Would it be a possibility that they could be labeled as "Chineseium" <not at all a politically correct term but political correctness offends me.
Author:  FNQ [ Thu Nov 15, 2018 9:25 am ]
Post subject:  Re: Broken Rocker
Not a good look when a rocker arm fails after 50k. Were these the 1.5 ratio? The photo or my interpretation of it may be misleading , but did you need rocker post spacers to correct the geometry? On the top photo, the arm with valve mostly compressed seems to be a bit eccentric to the pushrod and possibly causing additional force outside the anticipated ball/pushrod cup..... again it is probably the photo angle.... but just double check if you reinstall the new set. FWIW, i have run a forged set in a race motor for a few meets with no concerns, but my experience with aftermarket parts is that each batch can vary, although i would say for the most part the minispares uprated parts are usually good.
Author:  drmini in aust [ Thu Nov 15, 2018 11:47 am ]
Post subject:  Re: Broken Rocker
I can't see '1.5' marked near valve end of rocker, so they may be aftermarket std ratio (S replacement) rockers.
Unless mark is on the other side.....
And they look to have a shorter front arm than 1.5s.
Author:  Wakka [ Thu Nov 15, 2018 2:02 pm ]
Post subject:  Re: Broken Rocker
These are standard ratio rockers. Wear marks on the tips (after 50km!) indicate that they have not been properly hardened. Pics show what we interpret as seams from the mould. Product description on a website is - Forged cast type rocker with original ratio of close to 1.3 with adjusting screw and 1/2" af nut.. As noted fitment, etc. is correct and has been checked and rechecked. The sintered rockers held up during a dyno tune where the engine was run up to >6500 rpm in short bursts.
Author:  drmini in aust [ Thu Nov 15, 2018 4:27 pm ]
Post subject:  Re: Broken Rocker
Interesting they have 'cast' in the description now.
They don't make things like they used to. :x

Things are either forged steel OR cast (iron or steel), the processes are not the same.
Author:  Phil 850 [ Thu Nov 15, 2018 8:27 pm ]
Post subject:  Re: Broken Rocker
Maybe they meant forgery of a cast rocker :(
Author:  Ian_B [ Sun Nov 18, 2018 2:28 pm ]
Post subject:  Re: Broken Rocker
I had a set of original Keith Dodd .Gone now but they were very good
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