I recently heard about a broken Mini crank that broke while being raced in a fairly mild 1275 engine. At the same time, it was found that the Romac damper being run on the engine showed signs of impending failure as the "plastic" material that separates the two metallic components of the damper assembly was breaking up and protruding outside of its space where it is tightly jammed between the two damper "halves".

I would like to hear from anyone who has had problems with Romac dampers on either road or race Mini engines. Thanks.

I've never used one but have heard of failures. I'd go the new MED 'S' Damper kit:

http://www.med-engineering.co.uk/catego ... cat_id=126

I checked my Romac damper last weekend, still all good.
It's on a heavily worked 1430cc that sees 7800rpm on track.
Was fitted on the 28/5/09

Don't know what the life expectancy is, but the old original steel balancer was absolutely rooted. This is the lightweight steel/alloy version.

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Too many cars, and too little time.

I just bought one of these

http://www.minis.com.au/minis/catalog/product_info.php?cPath=21_47&products_id=912

and they have GR's blessing as well.

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Member VMCI #19

I'd go withTuffbond - they guarantee their process for life

8. ROSS TUFFBOND warrants the Tuffbond bonding of the dampener ring to the inner hub of the balancer for life, to the original purchaser only; however the warranty is void if the balancer has been machined, damaged or modified in any way from its original specifications.

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David L


My greatest fear in life is that when I die my wife will sell my Mini and tools for the price I told her I paid for them!

One would go nice on my spare S balancer centre...

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DrMini- 1970 wasaMatic 1360, Mk1S crank, 86.6HP (ATW) =~125 @ crank, 45 Dellorto (38 chokes), RE282 sprint cam, 1.5 rockers, 11.0:1 C/R.

Hi Doc,

do you know who in the UK makes that damper? It's cheap enough.

Sorry no I don't know, but GR would.

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DrMini- 1970 wasaMatic 1360, Mk1S crank, 86.6HP (ATW) =~125 @ crank, 45 Dellorto (38 chokes), RE282 sprint cam, 1.5 rockers, 11.0:1 C/R.

The ROMAC one is identical to the Swiftune unit : http://www.swiftune.com/Product/365/steelalloy-crank-damper.aspx
but ROMAC is cheaper in Aus.

The SH Engineering units start at 250GBP !!! http://www.shengineering.co.uk/pcmcrankdamper.aspx

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Too many cars, and too little time.

Yes - I had a failure on my Nb race car.....
Rev limiter set at 8000 rpm - but aim at 7500 general max.....

Brand new -
1 day testing at Wakefield Park.... running in engine...
1 day practice at Eastern Creek..... lock bolt came loose.... (probably installation fault )

1/2 lap qualifying - lock bolt came off - balancer failed as per your description - presumable due to misalignment and sideways forces .. luckily pulled in before complete failure.

Replaced with another new one.... with long cap head bolt http://www.minispares.com/Product.aspx?ty=pb&pid=37968 and plenty of loctiite...

So far so good - all OK after 1 qualifying, 1 short race, 1 crash a month ago at Oran Park
and 1 practice, 1 qualifying and 4 races at Oran Park this weekend gone....
Still have to do all post race checks - but kept checking over the weekend and looked OK.

But long term will be looking at the alternatives as shown (weren't available when replacing last one in a hurry )

thanks to you all for your replies.

I have never used a Romac or a Ross but the one thing I have found over the years is to get dampers balanced by someone you trust.
I have never had one out of the box that didn't need re-setting.
I have never had one fail after it was re-set.

Morris,

what do you mean by "reset". Do you mean balanced? A damper should be balanced along with the entire rotating assembly(crank, flywheel, backplate, diaphragm, etc.)

thats good until you use the clutch, then the back plate and pressure plate moves and the whole thing goes out of balance.
All engines have a torsonal vibration and the damper is there to smooth out the peaks in vibration. With a mini engine the out of balance forces exceed max. vibration frequency [node point] and when the clutch is used at a critical rpm then the crank flexes and creates minute stress cracks. Do this enough times and BANG!!!!

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Research is the difference between speculation and investment. Anyone who copys some one else will always be second
www.minisprintgt.com

How are they "set"?