Alloy crank pulleys any good??? Options

[Dudleydaftdog]

Hey all, thinking about binning my lightweight alloy crankshaft pulley for the stock iron harmonically balanced pulley as my new builds got a crank seal leak and I'm thinking this might have somethin to do with it???

Is anybody running an alloy one without any probs? Got it from Fensport so I thought it would be the business but can't decide whether to revert back to OEM tommorow while I have it off.

Any experience or thoughts on them would be muchly appreciated : )

Thanks

Chris

[mkernz22]

I was looking into getting a lightweight pulley set, but after looking up reviews about lightweight ones, it isn't worth the issues it will cause.
It affects the oil pump because the stock pulley has a dampener on it to reduce the vibrations whereas the solid lightweight one doesn't.

It doesn't affect just the oil pump, but other areas of the engine as well.
Off an EVO forum:
"Originally Posted by GTREVO View Post
I have been an early user of underdrive pulleys for many years now but only learnt about the detrimental effects of harmonics in the 4G63 engine not too long ago.

Try replacing bearings every single race like I do and you will know that the problem lies more than just tolerances and balancing. Have been building 2.0 on the DSM's for years now and the inherent bearing problems but thank god I nitrided my cranks ( thus am able to save cranks even with worn out mains) and 2.3 strokers in my Evo 6 which kills absolutely every single mains running only 6 to 7 passes on a single event. And both makes over 700WHP. Both have not run harmonic balancers and without balance shafts. And yes, the engine DOES make a little more vibration without the balance shafts. Funny thing is that while the main bearings are worn out badly, the conrod bearings remain perfect, almost untouched....

Have recently completed a race on the stroker and will remove the main bearings shortly to compare previously on which I have ran no dampener and this time with the dampener. This will at least confirm some how on the effects of the dampener.

Am only relating my experiences with the harmonics that are killing the engine and I don't think Mitsubishi would be putting one on if it didn't need one...

If I recall in one of many early forums some long time ago, even Bushur runs the stock dampener and doesn't use pulleys...."

"Originally Posted by GTREVO View Post
Sorry for my late reply on my findings with my motor. Took it apart yesterday and the results are indeed very interesting. After running at over 8000 rpms on this stroker 2.3 motor and at 35 psi making 750 WHP/656 ft/ib WTQ, the bearings were in good reasonable condition and take note, this motor was run WITH a brand new stock Mitsubishi harmonic damper, crank pulley. I swear what I saw was surprising on what I revved the motor to ( 8500 rpm at times on the track). To add to the topic of balance shafts, this motor was built without balance shafts at all. The motor has seen done 40 dyno pulls and 10 full on passes down the track at the drags..

On my earlier post, I mentioned that the mains were worn right down to metal at a lower power level ( 670 WHP) and at less rpms at the track. This was on a brand new rebuilt motor with only 7 passes down the track and about 30 dyno pulls.

The above findings I found was on the same motor except that I replaced a set of brand new Clevites on it and the new Mitsubishi crank pulley and I was all ready to replace it again yesterday but hey there you go guys.... there is no dispute that the damper is there for a reason and for a very good reason in fact.... no more aluminium pulleys for me..."