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knife edged 202 cranks

Started by _uglybob_ , Feb 23 2009 08:59 PM

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24 replies to this topic

#1 _uglybob_

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Posted 23 February 2009 - 08:59 PM

hey guys just after some opinions on these cranks on ebay

http://cgi.ebay.com....1742.m153.l1262

need to get a new crank. are these worth the money or should i just use a red motor one, pretty sure i have a couple of those around.

any advice appreciated as always

cheers
ben

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#2 _SableMet7/73_

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Posted 23 February 2009 - 11:14 PM

Hows it going Ben,
been thinking of getting 1 of these to for a
while now but need to wait until funds allow
for progress on my build. I'll be watching this
thread to see what others reckon.

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#3 _gtrtorana_

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Posted 24 February 2009 - 06:48 AM

I thought about getting one for my engine when I built it but I figured that this crank would be better suited for constant high reving engines like speedway motors rather than street motors that are up and down the revs all the time.

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#4 _Drag lc_

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Posted 24 February 2009 - 07:07 AM

i have seen these for sale for some time but i was under the understanding that a proper knife edge? light weight crank,the counter weights had to look like a tear drop but i have never used one nor do i know anybody that has used one of these types of knife edge cranks but i thought machining them like this was not a good idea.they even do red motor ones i think :spit:

Get a Red Motor one Ben

Hayden

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#5 _82911_

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Posted 24 February 2009 - 07:35 AM

For drag racing = Red motor crank
For circuit racing = Blue/black crank
For street = your choice!
Those ebay cranks would look nice in a cabinet on top of the bar! :tease:

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#6 _clubspClubsportr8ortr8_

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Posted 24 February 2009 - 07:52 AM

Hi i enquired about 1 of those cranks but the price got to around $1000 by the time it had been recoed so you could use it then add $150 if you don't have an exchange + freight.There is another gentleman who sells holden 6 gear,the store is MER racing engines and i rang this company and still around $950 but no hidden costs other than that the ole red motor crank lasts forever.

Jeff

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#7 _2runa_

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Posted 24 February 2009 - 08:32 AM

I thought about getting one for my engine when I built it but I figured that this crank would be better suited for constant high reving engines like speedway motors rather than street motors that are up and down the revs all the time.

You are correct these are used in speedway alot, you can knife edge it yourself and have it balanced, this is also a common as a budget speedway mod.

Most of the guys that I know have ceramiced the top of the piston, valves/ports, headers etc, those who are prefoming well are up around the 220hp mark

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#8 _NZ Toranaman_

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Posted 24 February 2009 - 10:00 AM

I reckon they are great.

Or you could do what I did and taped up the journals and got out the angle grinder and did my own knife edge

I used a cutting disc and used a piece of wood shaped into a V for a guide then shaped it like a bow of a ship, I also removed all the daggy edges and the bulges off it and added a rounded back edge.

I then took it down to the local engine shop and got it balanced and ground ready for rebuild.

I think this is one of the reasons my engine is quick compared to the dollars spent on it.

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#9 _2runa_

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Posted 24 February 2009 - 10:49 AM

I reckon they are great.

Or you could do what I did and taped up the journals and got out the angle grinder and did my own knife edge

I used a cutting disc and used a piece of wood shaped into a V for a guide then shaped it like a bow of a ship, I also removed all the daggy edges and the bulges off it and added a rounded back edge.

I then took it down to the local engine shop and got it balanced and ground ready for rebuild.

I think this is one of the reasons my engine is quick compared to the dollars spent on it.

Your on to it ... 9" is better :spoton:

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#10 _Drag lc_

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Posted 24 February 2009 - 11:33 AM

nz toranaman,
do you have a pic of your crank when it was done?i gather you are talking about a counterweighted crank?.

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#11 _SableMet7/73_

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Posted 24 February 2009 - 12:44 PM

Budget constraints will probly decide it for me.
Picked a red crank with the least amount drilled
out of the counterweights & still on standard size
journals from the few I have. Machine shop gave
it back with only a polish required, said it was all
sweet.

Can someone encourage my laziness as I've got
manuals 1 imperial & the other metric & doing the
equasion would just give me a headache. Had a rough night.
Are Red crank rod journals the same size as Blue crank?
I was going to run Red crank, Blue rods in a Red block.
I really should just go mic them up myself I spose.

Any help appreciated
Cheers J

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#12 _uglybob_

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Posted 24 February 2009 - 12:55 PM

oki doks so im definantly not getting one of the ebay ones, pretty expensive bar orniment wouldnt you say greg?
so if you say red for drags / blue for circuit, how would you prep both cranks for those specific tasks? (as in counter weight machining and stuff)

yeh pretty sure i will hayden is that what you are using? i think iv still got the steel one that i got with the 179 block that im using now ill have to go dig it up.

just one more question, on that ceramic coating on the piston, what is there to gain out of doing this?? i was thinking about doing it while i have the motor apart this time. would probably help alot if nitrous was to be used yeh?

thanks for the help
ben

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#13 _Drag lc_

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Posted 24 February 2009 - 03:11 PM

sablemet7/73,
yes i beleive that the b/end journal size is the same

Ben, yes we are using a std red crank. if you use the steel crank wont it be smaller ci than 202?.

Hayden

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#14 Heath

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Posted 24 February 2009 - 03:14 PM

Or you could do what I did and taped up the journals and got out the angle grinder and did my own knife edge

I used a cutting disc and used a piece of wood shaped into a V for a guide then shaped it like a bow of a ship, I also removed all the daggy edges and the bulges off it and added a rounded back edge.

I then took it down to the local engine shop and got it balanced and ground ready for rebuild.

lol this is something I never expected to read on here. If you just used the angle grinder, the finish would be pretty bad for collecting stresses, right? Or does that not really matter a huge amount?

Do you have any photos? Removing the daggy edges and stuff is something that I can see myself doing, but actually shaping it is kinda an overwhelming exercise in my mind. Wanna elaborate on the whole process?

You didn't mention that in your list of motor mods hehe, are there some other backyard mods we should hear about too? hehe

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#15 _NZ Toranaman_

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Posted 24 February 2009 - 03:30 PM

I added some pics on my thread with the 13.5 second run.

I also included the cam specs so you can see its not some wild beast as well

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#16 _why-psi_

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Posted 24 February 2009 - 06:46 PM

you'd probably lose a bit of torque with this crank but gain acceleration

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#17 Heath

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Posted 25 February 2009 - 03:38 PM

Are you just factoring in the difference in weight? Because I would argue otherwise. Even in the 'low RPM range', the crank is still flying through dense atmospheric conditions [i]bloooody[/b] quickly. I'm not sure the weight would make that great a difference; or nothing that you couldn't compensate for with a heavy flywheel anyway

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#18 _why-psi_

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Posted 25 February 2009 - 04:23 PM

yes. less weight less inertia meand it can be slowed easier. a heavy flywheel would defeat the purpose of havine a lightend knife edged crank in the first place

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#19 N/A-PWR

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Posted 04 February 2013 - 02:50 AM

Hi All,
Yep, that's what we want, less torque and more acceleration - lightened flywheel, extra strong clutch and a light LC/ LJ Body. Dave I

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#20 _STRAIGHTLINEMICK_

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Posted 04 February 2013 - 07:34 PM

G'day blokes, I do the knifedged cranks that you see on ebay.I have built these engines for over 20 yrs and only sell parts that I know will work.The knifedged crank will accelerate quicker than a stock blue crank and about the same as a red crank but without much of the vibration that these engines suffer from. This vibration spits balancers and flywheels ,undoes sump bolts and cracks blocks in extreme cases.I have used one of these cranks in my fj for 6 yrs of drag racing and street driving without a problem.
But in the end the choice is yours.

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#21 N/A-PWR

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Name:Dave I
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Posted 04 February 2013 - 09:59 PM

The knifedged crank will accelerate quicker than a stock blue crank and about the same as a red crank.

Hi Mick,
Great to know and do you have a knifed steel crank for a 202 Mate. Dave I

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#22 _STRAIGHTLINEMICK_

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Posted 05 February 2013 - 04:49 PM

Hi Mick,
Great to know and do you have a knifed steel crank for a 202 Mate. Dave I

No steel 12 counterweight cranks are available and not usually required but you can have one made for 4-5 grand from Ivan Tigh

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#23 N/A-PWR

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Name:Dave I
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Posted 06 February 2013 - 03:50 AM

No steel 12 counterweight cranks are available and not usually required but you can have one made for 4-5 grand from Ivan Tigh

Damn,
For the Life of a 5 'G' crank we better have the Blue one - thanks Mick. Dave I

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#24 N/A-PWR

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Posted 12 July 2015 - 07:18 PM

Hey Mick,

do you still have this crank for $399:-

http://www.ebay.com....=p2047675.l2557

G'day blokes, I do the knifedged cranks that you see on ebay.I have built these engines for over 20 yrs and only sell parts that I know will work.The knifedged crank will accelerate quicker than a stock blue crank and about the same as a red crank but without much of the vibration that these engines suffer from. This vibration spits balancers and flywheels ,undoes sump bolts and cracks blocks in extreme cases.I have used one of these cranks in my fj for 6 yrs of drag racing and street driving without a problem.
But in the end the choice is yours.