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STROKER 6 CRANK


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#51 _oldjohnno_

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Posted 21 February 2010 - 10:42 AM

I've put a few pics up in the Members Projects section - the thread is called 202 Build. Like I said it's early days yet so not much to look at but I'll update it as I go.

#52 _beergut_

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Posted 21 February 2010 - 11:38 AM


so why bother with a 355 or 383 holden or chev bomber?
answer cubes and low down torque


Mate i think your question has been well answered by oldjohnno, but anyway, BECAUSE THE ROD RATIO WILL BE #@$^%& AND YOU CANT COMPARE A HOLDEN V8 OR A CHEV TO A HOLDEN 6!!!

You really would have to be an idiot to think you could compare them, no offense intended, just trying to clear things up a bit, i get along with you rather well most the time, but yeah, sometimes you say the darndest things.

Cheers.


bomber i think you took it out of context,
not comparing anything to anything
was just saying why you would do it
as in more cubes/low down tourqe same princbial as nearly any stroker motor
hey i know sfa bout a 202 i pefer/work on 308's rather than tempermental 202's

just to clear the air there's
no offence taken at all guys
i learn i f up people set me straight
all good lol

#53 _Drag lc_

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Posted 21 February 2010 - 06:10 PM

Yeah definitely more prominent with a red 202 crank than a black 202 crank, but I can assure you that neither are great! But the closer the crankpin is to the axis of the main journals, if nothing else changes, the better the balance factor.

Is yours a late model 202 crank? What balancer? I don't know what effect a flex plate & stally have (extra weight probably has some advantages). What do you rev it out to?


What are your experiances with these vibrations and the use of diffrent cranks?ie everything the same just a crank swap from red to counterweighted crank????in same engine ever done it?????

yes we have only eva used red crankes in the lc never used a counterweighted crank in it/powerbond balancer yes we have had 2 failures neither had been caused by anything to do with the type of crank used or vibrations.

#54 _sonic_injection_

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Posted 21 February 2010 - 06:18 PM

[quote name='greens nice' date='18 February 2010 - 06:48 PM' timestamp='1266482936' post='482906']
[quote name='Steve TPF' date='18 February 2010 - 03:56 PM' timestamp='1266472607' post='482841']
Found this on Ebay:
Holden 202 Knifedged stroker crank

Says: CRACKTESTED AND BALANCED HOLDEN KNIFEDGED 12 COUNTERWEIGHT STROKER CRANK ,3.375" STROKE
THE BEST STROKER AVAILABLE FOR YOUR HOLDEN 6.NEW 5.73"LONGER H BEAM CONRODS COMBINED WITH A KNIFEDGED STROKER CRANK PROVIDE A HIGH TORQUE AND FREE REVING ENGINE.ONE OF THESE STROKERS PUSHES OUR STREET REGISTERED FJ UTE TO A 13.40sec 1/4 MILE @100mph ON PUMP FUEL USING ONLY 6300RPM

Also:
SAVE $200 IF YOU EXCHANGE YOUR BLUE/ BLACK 3.3 CRANK IN GOOD CONDITION(must be less than.010 "undersize)

Doesn't say anything about supplying a ford crank for the job, so it sounds like an off-ground holden crank. Could be worth giving them a call.

[/quote]
you cant grind em .350 mate.

[quote name='greens nice' date='18 February 2010 - 06:48 PM' timestamp='1266482907' post='482906']
[quote name='Steve TPF' date='18 February 2010 - 03:56 PM' timestamp='1266472607' post='482841']
Found this on Ebay:
Holden 202 Knifedged stroker crank

Says: CRACKTESTED AND BALANCED HOLDEN KNIFEDGED 12 COUNTERWEIGHT STROKER CRANK ,3.375" STROKE
THE BEST STROKER AVAILABLE FOR YOUR HOLDEN 6.NEW 5.73"LONGER H BEAM CONRODS COMBINED WITH A KNIFEDGED STROKER CRANK PROVIDE A HIGH TORQUE AND FREE REVING ENGINE.ONE OF THESE STROKERS PUSHES OUR STREET REGISTERED FJ UTE TO A 13.40sec 1/4 MILE @100mph ON PUMP FUEL USING ONLY 6300RPM

Also:
SAVE $200 IF YOU EXCHANGE YOUR BLUE/ BLACK 3.3 CRANK IN GOOD CONDITION(must be less than.010 "undersize)

Doesn't say anything about supplying a ford crank for the job, so it sounds like an off-ground holden crank. Could be worth giving them a call.

nvm
[/quote]

Hi
I was offered the patterns 3 weeks ago. I declined the offer as they cranks retailed at $2000.00 10 years ago, It is Kit's Crank
regards
Brett
SONIC Injection

#55 Zook

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Posted 21 February 2010 - 11:04 PM

The balance factor on a standard 202 crank is woeful (that's why everyone is having huge vibration issues). Offset grind stroking them makes the balance factor even worse obviously


Except that you are not grinding a 202 crank. You are either using a new manufacture crank, or a Ford 221. It seems as though Holden didn't have much of a clue when they developed the 202. Can you explain this 'balance factor' thing to me, in your own words, not those from the first page of the google search I expect you'll now conduct, as seems to be your way.

#56 _oldjohnno_

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Posted 22 February 2010 - 06:10 AM

There are a couple of different conversations going on here. One is about the converted Ford and the Cullen cranks, and the other one that refers to the ebay ad that's been quoted is about offset-ground Holden 202 cranks.

#57 Heath

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Posted 22 February 2010 - 06:54 AM

Except that you are not grinding a 202 crank.

They mentioned offset grinding a 202 crank, I was responding to that.

It seems as though Holden didn't have much of a clue when they developed the 202. Can you explain this 'balance factor' thing to me, in your own words, not those from the first page of the google search I expect you'll now conduct, as seems to be your way.

Ahhhh... ok

My understanding of a balance factor is that a balance factor of 0 is where the counterweights balance the crank pins and nothing else

A negative B.F. is when the counterweights don't even balance the crank pins

A B.F. 0 and 1 is where the counterweights balance out the crank pins and some of the big end bearing & big end of the conrod mass (measure the big end and small end seperately because only one 'reciprocates').

A B.F. of 1 is where the counterweights balance the big end mass perfectly

A B.F. of over 1 is where there extra mass to compensate for other forces, I don't know much about that but it's not hugely common because in this area, you're normally approaching a pretty serious crankshaft mass

If you section a red Holden crank (3" or 3.25") into appropriate lengths, and support the main journals (say on smooth, horizontal rails), the thing will just roll until the crank pins are facing downwards (A crank with B.F: 0 will in perfect circumstances not settle upon any position). So they have a pretty significant Negative balance factor. It doesn't seem to be an issue until a bit above 5000rpm with a red 202 crank. It is less of a problem with the 3" crank, haven't seen it done with a fully counterweighted late model crank, and I don't really wanna cut mine up!

If someone has a blue/black 202 crank with #@$^%& bearing journals they wanna give me, I will do the test and see how that is!

#58 FastEHHolden

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Posted 22 February 2010 - 08:41 AM

http://cgi.ebay.com....e=STRK:MEWAX:IT

incase anyone was chasing one...very thin on the ground.

#59 enderwigginau

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Posted 22 February 2010 - 01:49 PM

Hi
I was offered the patterns 3 weeks ago. I declined the offer as they cranks retailed at $2000.00 10 years ago, It is Kit's Crank
regards
Brett
SONIC Injection


Brett they weren't $2000 ten years ago. They can only have changed to that in the last 5yrs. Before that, they were around $1300 incl GST.
Until someone starts selling billet stroker cranks then still think it would be a good business proposition - better would be all the manifold and injection moulds..........let me know when you can do those. Some is quite alot different to your gear. I don't think many appreciate how much better his manifolds were to most aftermarket stuff......

I never experienced and harmonics with a KC crank. I was using Starfire rods and Toyota pistons. What killed it was a dodgy piston clearance. Buckets of low down torque and it rev'd better that the 202 in my first hand experience. I do understand what is being said, and we did go to pains when it came to clearance work etc. On the 208 tow motor - big harmonic I could never get rid of.

Offset grind a 202 crank? Use BMW rods.......

Grant..

#60 _oldjohnno_

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Posted 22 February 2010 - 05:38 PM

My understanding of a balance factor is that a balance factor of 0 is where the counterweights balance the crank pins and nothing else


If you section a red Holden crank (3" or 3.25") into appropriate lengths, and support the main journals (say on smooth, horizontal rails), the thing will just roll until the crank pins are facing downwards (A crank with B.F: 0 will in perfect circumstances not settle upon any position). So they have a pretty significant Negative balance factor. It doesn't seem to be an issue until a bit above 5000rpm with a red 202 crank. It is less of a problem with the 3" crank, haven't seen it done with a fully counterweighted late model crank, and I don't really wanna cut mine up!

If someone has a blue/black 202 crank with #@$^%& bearing journals they wanna give me, I will do the test and see how that is!


Balance factors are usually expressed as a percentage, and the percentage refers to the proportion of reciprocating (in addition to all of the rotating weight) that is used to make up the bobweight.
The interesting thing about the late 202 cranks is that while every web is counterweighted, not every throw is the same. Cylinders 1 and 6 have quite a bit more counterweight than the rest (and actually this isn't all that uncommon, even on cranks that are only partly counterweighted. I think it helps control flex induced "wobble" at the ends of the shaft.) Cyls. 2 thru to 5 have lighter weights, and at first glance you would think this would create an out of balance condition but if you look a bit more closely at the centre four weights you'll notice they are tapered or wedge shaped (in opposing directions for the two pairs) and this has the effect of displacing or biasing the counterweight forces of these cylinders in a direction that cancels out the forces from 1 and 6. Of course it also has the effect of further reducing the effective balance factor for these 4 cylinders. It sounds like an odd way to do it - I think most people intuitively would treat the crank as 6 individual engines all balanced to the same factor and all in phase. No doubt the engineers had a good reason for designing it this way - it would tend to put a sort of a torsional pre-load on the crank that may help with TV issues.
I really can't agree about Holden being clueless when they designed the 202 - you have to remember they weren't designing a race engine. What they were aiming for was something that had sufficient power and emissions performance, was reliable, cheap to produce and could be based on an existing design. Considering the restraints placed on them I think they did well.

#61 Zook

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Posted 22 February 2010 - 08:58 PM

Thanks gents. I now know a little more than I did before. While I still think that a crank is either 'balanced' or it's not, and I had heard about different weights in different spots, to counter wind-up, if you will (or better still, Oldjohno's explanation), I had not heard of BF.

I'm still going with 'there's no substitute for cubic inches' though, and will build my stroker motor, give it a flogging, and if it blows up then so be it, I'll try something else.

#62 greens nice

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Posted 22 February 2010 - 09:25 PM

I'm still going with 'there's no substitute for cubic inches'


a decent rod/stroke ratio is good too Posted Image
i tend to think of 3 1/4 as the magic number for the stroke when it comes to holden sixes.
although ive seen a pretty quick altered with a stroker.

#63 Heath

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Posted 22 February 2010 - 09:34 PM

Can you explain this 'balance factor' thing to me, in your own words, not those from the first page of the google search I expect you'll now conduct, as seems to be your way.

Thanks gents. I now know a little more than I did before.

Douche.

#64 Zook

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Posted 24 February 2010 - 01:48 AM

So did you learn that firsthand, or just read about it?

#65 orangeLJ

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Posted 24 February 2010 - 08:19 AM

So did you learn that firsthand, or just read about it?


you do realise how stupid that sounds right?

How else is someone meant to learn things? Sure you can sit and play with cranks all day long, but at the end of the day, without that practical lesson being accompanied by some form of theory (ie. READING ABOUT IT) you dont learn squat.

f*ck dude. Get off Heaths back. Who gives a shit if he is copying and pasting (not saying he is or isnt here) if he is finding the correct or even semi-correct information then who gives two shits where it comes from?

#66 Heath

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Posted 24 February 2010 - 12:53 PM

I learnt about the system, found out the method. I had a cast iron 3" stroke crank in my shed and the journals were rusty so I decided to sacrifice the crank for some research/learning. Me and my friend sectioned it up, did the tests I briefly explained above and discussed ways to alter the counterweights with positive benefits, made some prototypes and we've definitely got somewhere, but there is a significant amount of work involved in developing it obviously. Long story short with modifications to a forged 3" stroke crank you can do a lot with balancing, haven't done it with a 3.25" crank or anything yet. So yeah I obviously didn't design the system of balance factors, just a system that is already out there.

When you learnt about physics, did you make the principles up yourself? Or did you copy the existing physics principles that someone else had come up with?

Call me lazy, but there's no point in re-inventing the wheel when there is plenty of information already out there

Now are you going to stop being a Posted Image douche?

#67 TerrA LX

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Posted 24 February 2010 - 01:19 PM

On that question about breathing capacity of V8 heads....whats the bore centres of a red 6 compared to a v8? has someone got a v8 and a red6 head gasket in the shed to lay over each other? I'm have a crazy and very economical thought.


My old boss used to tell me stories of when they were doing the 70's falcons they used to chop up cleveland heads, section them together and fit them to 250 blocks, went like the clappers but kept cracking them.

#68 xu1kid

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Posted 24 February 2010 - 02:14 PM

haha nice one heath

#69 Zook

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Posted 24 February 2010 - 03:40 PM

Oops, sorry guys, didn't mean to hit a 'wet behind the ears, generation Y' nerve. Get some time up!

Edited by Zook, 24 February 2010 - 03:41 PM.


#70 Zook

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Posted 24 February 2010 - 04:00 PM

I can't edit the post above any more. But to build on my reply, and to back track a bit...I was pretty happy when Heath tried to find me a squiggly wire for my LX - showed himself to be a good guy. WRT the current thread...what I tried to do by saying thanks to Heath (and OldJohnno) was to say 'OK, so I may have been a little premature in my estimation of Heath's knowledge' (about crank balancing, either in theory or practice), like an apology (for those that are having trouble keeping up, including Heath, Orange and pretend XU-1). Anyway, he came on with the name calling, which I don't give a shit about. And here we are...

Edited by Zook, 24 February 2010 - 04:01 PM.


#71 Heath

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Posted 24 February 2010 - 04:50 PM

Why did you jump to the conclusion that I was an idiot? And why did you try and make me out to be an idiot? If you thought I was talking about stuff I don't have any grasp on, maybe you could just PM me telling me to stop talking shit, rather than trying to make everyone go "yeah watch this dumbarse try and explain himself here"

I got photos of all this stuff I did and I was going to post them up, I thought people would be really interested in it but stuff that I'm not going to. If you don't wanna hear what other people have to say then why go on a forum mate? This kinda shit makes me so hesitant to post anything good.

What do I have to do to gain credibility on this forum?

Edited by Heath, 24 February 2010 - 04:53 PM.


#72 _Drag lc_

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Posted 24 February 2010 - 05:38 PM

This kinda shit makes me so hesitant to post anything good.


yep heath i know that feeling all to well after what happened in on of my threads the other day.

#73 _Bomber Watson_

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Posted 24 February 2010 - 05:44 PM

What do I have to do to gain credibility on this forum?


Start roundhouse kicking the Richard Craniums that have been showing up to the chin, then unleash a flurry of uppercuts to there fore heads will go alright mate.

Cheers.

#74 _oldjohnno_

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Posted 24 February 2010 - 06:28 PM

What do I have to do to gain credibility on this forum?


Nothing - as far as I'm concerned you already have it. And I'd guess 99% or so of the forum regulars would agree.

I'd like to see the pics of your crank experiments; if you don't want to post them could you PM them?

#75 Steve TPF

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Posted 24 February 2010 - 06:54 PM

I've been following this thread with a good deal of interest, and I'd love to hear more about 202 cranks and the pros/cons of strokers. If anyone has some hard info (dyno figures, results of personal tests, opinion of a professional engine builder etc.) please share.

Zook, it doesn't matter if the info is cut-and-paste, if it's accurate and informative I want to hear about it.





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