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Thread: VE 4CW crankshaft max load

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Posts: 71-80 of 80
2011-08-03 13:24:13
#71
Originally Posted by P10
Last 3 motors i have built
N/A race motors

1st 8 c/w ballanced no lightening, did approx 20 races, no issues

2nd 4 C/W ballanced no lightening, approx 15 races, ran bearings after oil pickup fractured and broke off. no issues up to that time

3rd 8 c/w Ballanced, knife edged ran bearings after 3 meetings

Im going to knife edge a 4C/W for my next turbo motor, its going to be pulled down every 3 meetings any way and bearings are cheap.


now the 3rd is alarming, how many laps per meeting did your run? what is max rev? coz im thinking of going balanced and knifed edged 8cw
2011-08-04 00:42:53
#72
it was 3 meetings, 3 practice 7-8 laps each, 3 qual 4-6 laps each, 5 x 10 lap races and 2 x 12 lap races

Ran bearing 2 laps into 2nd race 3rd meeting. No apparant reason, same sump, oil, cooler, and track as the other motors...
2011-08-04 01:12:06
#73
On my drag car am making over 600 on a 4cw crank.
2011-08-04 09:39:39
#74
I'm running a knife edged 4cw. I'm back on the OEM crank pulley just for peace of mind.
2011-08-05 11:39:33
#75
Originally Posted by P10
it was 3 meetings, 3 practice 7-8 laps each, 3 qual 4-6 laps each, 5 x 10 lap races and 2 x 12 lap races

Ran bearing 2 laps into 2nd race 3rd meeting. No apparant reason, same sump, oil, cooler, and track as the other motors...


thanks! it seems bearinglife islonger on drag due to less time on high rpms

Originally Posted by Doctor
I'm running a knife edged 4cw. I'm back on the OEM crank pulley just for peace of mind.


tthat makes sense
2011-08-08 11:20:41
#76
Extra crankshaft weight hammers the bearings. We dont have mitsu motors that run 3 degrees of ignition timing. We run 20+ degrees turbo and 30 degrees N/A..thats a shitload more bearing crush.
2011-08-09 20:24:28
#77
Originally Posted by Autech
Extra crankshaft weight hammers the bearings. We dont have mitsu motors that run 3 degrees of ignition timing. We run 20+ degrees turbo and 30 degrees N/A..thats a shitload more bearing crush.


no it doesnt
2012-02-10 02:48:08
#78
With the SR20 I suspect windage reduction is another strong reason why the counterweights were reduced and the girdle removed. There were a series of engineering changes to reduce windage issues.
2012-02-13 10:10:08
#79
Originally Posted by Autech
Doctor G

Running a 4cw has no unreliable affects.

Those that have been expressed - eg bearing lofe - vibration - are not true.



Autech,

You have absolutely no idea what you are talking about, and it shows with every post. There are so many false statements you are making I cannot ignore it anymore.

Originally Posted by Autech

4cw has less mass and hence ptoentially can trasnfer more energy to the flywheel.


This quote above would make any moderately educated person cringe. Even complete with multiple grammatical errors.

I don't even care to explain to you why you are so wrong and clearly you have poor understanding of crankshaft dynamics, but to others who are reading this thread, Miko is pretty darn close.

A crank has more then one important aspect when it is designed. Each of these cranks are "balanced". Each deal with inertial forces differently. Each has a different moment of inertia. The 8cw crank will provide less bearing wear which everyone on this forum seems so concerned about. The 4cw is of poorer design, but works for our DD purposes.

Hell I have seen weed-whacker engines with a bearing support on only ONE side of the crank....you would be surprised of the ignorance out there today.

Walker


Originally Posted by Autech
Extra crankshaft weight hammers the bearings. We dont have mitsu motors that run 3 degrees of ignition timing. We run 20+ degrees turbo and 30 degrees N/A..thats a shitload more bearing crush.


Ok small edit, I just read this.....BAHAHAHAHHAHA where do you get this stuff man?!

I MUST know where is this "mitsu" "motor", because if you know of an engine requiring only 3deg btdc for peak power I want one, that is better then F1, in fact that actually defies the known flame speeds of any fuel we have today.
Last edited by Dudeman258 on 2012-02-13 at 10-36-25.
2012-02-13 10:31:51
#80
Originally Posted by Denismo
subscribed

it is the "theory of the mechanics"

the second and the odd order harmonics are the worst

because we have the increased load in the resonance points. in the resonance point we have the summ of few periods POTENTIAL energy : it is the result of few periods of the kinetic energy.


Denismo, you really only need be worried about the 1st and 2nd order harmonics, when dealing with crank/rod assembly.

Do you have anymore information on this "theory of the mechanics"?

Walker
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