Silicon dampers are not as good as people make out. The silicon heats up from the movement and looses it's damping effect.
Blackstone years ago changed from a oil pressure damper to a silicon one and the engines all suffered various failures including broken cranks. The engines fitted with these dampers were showing bent cranks[deflection readings] and also failures or the cam shafts and gear drives.

They were replaced with the old style oil pressure type again , but Blackstone up graded the rubber one in the flywheel.
This design is now copied by all marine engine manufacturers. It uses a center rubber drive that is similar to a coupling drive rubber. It looks like a gear tooth on the inside and outside diameters. The outer of the damper is in two halves and is fitted to the inner/rubber and bolted into place. There are various compounds for the required frequency range of the engine.

There are coupling inserts available from industrial transmisson companies that would be suitable for a 2 piece mini damper.

Bottom line is ,do the torsional calcs for the engine and get a damper to suit.

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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

I have now experianced one of these balancers/dampers failing, it was on a mild street motor (only 1300cc) and lasted less than 12 months. It first sounded like a slipping alternator belt and then went "bang" which sounded like a radiator hose bursting without the smell of hot coolant, then the temp skyrocket.

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http://www.youtube.com/watch?v=nDMkVq1jRGU

Wow. After some serious reading on pages 1 and 2 I skipped to the end and hoped someone would just tell me "which damper to use". While I tip my hat to miniman and david r. guys... what's the best damper for a race car for < $500?

Speak to Lindsay @ mini's plus

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http://www.youtube.com/watch?v=nDMkVq1jRGU

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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.

Thats the one I was thinking about drmini in aust.

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http://www.youtube.com/watch?v=nDMkVq1jRGU

Both our Nb race motors have standard 40 year old BMC dampers fitted and they have never given trouble, ever. If you must upgrade from a std ballancer then i suggest using a Cooper S type.

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Have a Nice Day.
If already having a nice day please disregard.

You should give Lindsay or Graham a call they will tell you all about them......they do the job quite well when compared to/with a cooper S balancer when tested on the same engine.

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http://www.youtube.com/watch?v=nDMkVq1jRGU

Standard 1275 1 piece balancers are OK for the road but are now NLA new from UK.
Don't throw old ones out when the rubber cracks, Ross Tuffbond in Blacktown NSW can recondition them. They also make new ones I hear.

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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.

Yeah well collectively they're building my engine... i've divided between a good A+ damper, MED one or the one lindsay/gr recommends, which looks like a bling!ed 2-piece S damper. Honestly, I think an accusump may be better insurance on a race engine than a $400 damper - as long as it's balanced and is good rubber, should do the trick.

All this talk about torsion, twisting, vibrations and imbalances... the theory is great but tests don't lie. Apart from falling off or shattering, the differences may be hard to measure 'damper effectiveness' on race day.

I put it to someone to do a vibration test in a dyno-setup at 4000 - 5000 rpms comparing a few of 'em... get some cold hard facts. We're not talking about extra hp here really, more longevity.

The best std ones are the mk1 balancers but aparently this is the next best option since they are becoming harder to find. The Harmonic vibrations between 4 & 5,000 rpm in a 1275 are at its greatest and given a race engine usually spends most of its either side of this its not such a problem but for a road car at freeway and highway speeds (100 - 110 km/h) the engine rpms are between 3,600 and 4,400 which is its most damaging due to the excessive harmonics caused at these engine speeds.
If you have a mk1 balancer with good rubber I'd say use it just make sure its all balanced prior to installation.

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http://www.youtube.com/watch?v=nDMkVq1jRGU

smiling simon,

I don't know the state of play, or the rules, for racing Minis in Oz. That said, I still don't think that Accusumps are truly worthwhile UNLESS you are one of those who places a lot of store in getting a race engine up to good oil pressure before the engine is fired up.

If you are concerned about low/no oil pressure while cornering, I think that this is a nonexistent problem for most racing Minis. For example, the Mini Miglias in England race on very sticky 10 inch slicks on 7 inch rims. The Miglias also run state of the art shocks, front and rear swaybars and some run improved geometry that raises the roll center amongst other things. It's most likely true that Miglias have the most grip of any steel shelled Mini with 10 inch tires in the world. In spite of generating serious g-forces while cornering, the use of Accusumps is either extremely rare or nonexistent. Based upon this, I doubt that any lesser racing Mini require Accusumps to preserve oil pressure while cornering.

If you think you're going to lose an oil hose or filter or experience some other major gusher of an oil leak, then an Accusump may save your engine.

For these reasons, I think that any money spent on an Accusump is probably better spent elsewhere.

I'd be interested in hearing opposing opinions.

Got some good news friday arvo they warrantied my balancer . . . will be getting a report about the old one so that should be interesting reading

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