Krismc
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| posted on 14/5/06 at 05:06 PM |
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lightend crank pully??
I have a lightend flywheel and ive been offered a lightened (aly) crank pully! will i recieve any benefits and will my engine be ok with both these
on!
Built, Ivaed, Drove and now Sold - 2011 MNR VORTX RT+ 2000cc Zetec on R1 Throttle boddies.
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flak monkey
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| posted on 14/5/06 at 05:21 PM |
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Crank pulley had little effect on the rotational inertia of the system due to its small diameter.
Up to you if you want to fit it. You cant see it when it is on there anyway 
Benefits are negligable and the engine will be fine with or without it.
Sera
http://www.motosera.com
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Krismc
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| posted on 14/5/06 at 05:25 PM |
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well i wont bother then!!
cheers for that mate
Built, Ivaed, Drove and now Sold - 2011 MNR VORTX RT+ 2000cc Zetec on R1 Throttle boddies.
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ned
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| posted on 14/5/06 at 09:05 PM |
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i have one (ally front pulley) but unecessary expense really, unless you're lightening and balancing the whole crank, flywheel and clutch as i
have but still negligable unless you want every last hp out of it.
Ned.
ps mine is also a smaller diameter so it actually has even less effect when spinning as flakmonkey says, but it also reduces the charge to the
alternator
beware, I've got yellow skin
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MikeRJ
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| posted on 14/5/06 at 09:24 PM |
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If the oringal crank pulley contained a crank damper and the shiny new one doesn't then one of the differences you may notice is shorter
crankshaft life!
[Edited on 14/5/06 by MikeRJ]
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02GF74
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| posted on 15/5/06 at 09:01 AM |
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quote:
Originally posted by MikeRJ
If the oringal crank pulley contained a crank damper and the shiny new one doesn't then one of the differences you may notice is shorter
crankshaft life!
[Edited on 14/5/06 by MikeRJ]
how come?
my understanding, wrong it may be, is that is reduces shock to the drive belt.
as for fitting it, there a no increaes in power, just like when fitting a lightened fly wheel; the difference having less mass to spin up to speed
meaqns the engine will reach that speed quicker.
unless it is free or less than £5, don't bother.
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MikeRJ
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| posted on 15/5/06 at 10:34 AM |
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quote:
Originally posted by 02GF74
my understanding, wrong it may be, is that is reduces shock to the drive belt.
No, a belt drive has inherent shock/vibration absorbtion, no need for any other damping. The crank damper is so-called because it is used to dampen
torsional vibrations in the crankshaft.
As with all components the crank has a natural resonant frequency, and once the engine speed hits that frequency the amplitude of the vibrations can
increase significantly which can dramaticly shorten the fatigue life of the crank. It can also reduce power as the cylinders furthest from the cam
drive (belt/chain or gears) will be seeing timing variations as the crank twists.
Generaly, the longer the crankshaft, the worse the problem becomes.
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NS Dev
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| posted on 15/5/06 at 10:59 AM |
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Quite right!!!!!!!!
Torsional vibration on the crank is very severe!!!
one of the common problems on the vauxhall xe engine is shattering the oil pump inner gear which sits on two flats on the crank nose.
This happens if the locking bolt that pinches the gear against the shoulder on the crank comes loose, then the torsional vibrations chafes then
shatters the gear!!
If you want a demo of the effect, try holding onto an extension bar on an air impact wrench. That's what the engine crank is going through
basically!
Retro RWD is the way forward...........automotive fabrication, car restoration, sheetmetal work, engine conversion
retro car restoration and tuning
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