crank damper???
Turbo Mini Forums

need some advice for something an engine i'm going to be running until i can get the turbo engine re-built

for those of you that went to the rolling road day in lincoln you would have seen my 1380, it did quite well considering it was up against some turbo motors. Its an old A-series MED engine, early 90's and was only used for a year and is still quite fresh, its basically fast road spec, and pulled 67bhp at the wheels.

anyway i've been sorting out a couple of bits on the engine so its ready to go into my new car, gearbox gasket, gasket on transfer casing, drilling out breather on transfer casing as it was from a mini 1000 and had no breather etc, and put the one off my metro turbo engine on. Clutch seal etc.

i noticed that the crank pulley isn't a damper pulley, its just a plain pulley, is this a big deal? i was wondering if I could fit the damper pulley off my metro turbo engine?

your thoughts please?

The idea of a crank dmaper is to ballance to the load of the flywheel...

so in theory they are a very good idea... not seen an a-series without one to be honest!

Alex

AlexF

i'm guessing only the 's' engine ran a damper on the original a-series? then it was standard equipment on a+?

does it seem a good idea to fit the crank damper i already have to the 1380?

To be honest mate i wouldnt bother as the crank assembly was balanced wasnt it?

If you change the damper then it wont be any more, if it isnt broke dont fix it

yeah full rotating assembly was balanced

must admit i did wonder if the pulley would be a balanced item

i leave it as it is then!!

I would think it's worth fitting one. The "crank damper" is, as it's name suggests, a "damper". It basically helps absorb harmonic vibrations from the crank. It's worth fitting one, especially if the engines a bit of a "revver".

Phil.

WWW.TURBO-MINI.COM

It would need to be balanced after though right?

Would of thought if its been balanced well then you should be ok without the damper.



Only my opinion mind!

it helps with twisting not just balance!

alex

AlexF

From what I've found out, (including a nasty experience of an undamped crank at 8000 rpm)
The there is an issue with the way in which a standing wave can be induced into the crank by the firing phase - if you are not using a centre main strap, this can hammer the centre main bearings into the block/strap, or in very extreme cases break the flywheel taper and then (if you are even more unlucky and break the keyway or have a crap keyway or no locktab!) unscrew the flywheel, to varying effect.

See http://www.ximphony.org/moron.html for some photos of the results!

The hammering is generally caused by crap balancing, but - it doesnt take much to induce the wave, and adding an unbalanced plain pulley can do this.

I seem to remember that the early cooper S pulley was balanced to the crank (along with everything else).

Just on the safe side i've fitted an A+ type crank damper (yes I know its heavy) on every engine that I've run at high-ish revs, and never had a problem (at least with the ones i've built!).

Just check that the rubber in the sandwich (its visible as a small groove) is in good condition, and perhaps even balance it is you feel inclined.

Note that you will require a spacer between the water pump and the water pump pulley if you are using a mini type part (with the bypass hose). If you use a metro type pump, you wont need a spacer.

Anyone care to confirm the above?

Cheers,
Edwin

I totally agree with you neXTGen, however I've never used one and never had a problem so far.

Wil

Fastest 998 mini in the world? 13.05 1/4 mile 106mph

My last engine never had one and was fine, used to regulary go round to 7k+ when it ran the 45 with 286.

If i was building a fresh engine then i would but one thats done a fair few miles is obviously fine without it.

More weight, less speed!

more weight???


its harldy anything and its nice and close to the axis of the crank so has very little effect in terms of inertia!

alex

AlexF

i'll see about putting it on then, providing its in good shape

cheers!

you can also get ones that fit to the a series damper. Noticed them the other day in my minispares catalogue.

I know we're not talking a lot alex but every little helps lol!!

lol...

but at the enpense of your engine holding together is madness...

try a diet.. I know my car would be fatser if I lost a few kgs!! hehehe

alex

AlexF

Already trying that one! lol!

Its actually working too! Carrying 2 cylinder head to the post office at dinner worked aswell!!

Alex, you're not obsessing enough about weight. Yes, we could all lose a few pounds instead of putting lighter parts on the car. But like me and Iain (and others) you can do both and go commando and get your hair cut etc. ect.

Wil

Fastest 998 mini in the world? 13.05 1/4 mile 106mph

Wonder how much lighter id be if i just painted my clothes on?!

End of the day anything however small all adds up

LOL no wil thats the point I am getting at....

I wouldn't leave off a crank damper to save weight!!!

I would however remove most things from my car... inlcuduing running a light cage instead of a proper one, I think I'm obsessed enough

Infact I lightened the flywheel for weight saving

alex

AlexF