hey guys im in need of advice please as i have harmonics problem with my 202. ive recently finished restoring an lj torana and have now hit a snag of which im a lil confused about gettin over. i have had a few different opinions as to what to do and not what to do which always makes things worse.
problem - cant keep the flywheel on. no matter what ive done so far i either keep spitting fly wheel bolts or breaking them. i have done both blue and red lock tight. ive drilled head bolts and wired them together in pairs. yet i still keep breking them.
it is a worked 202, na and currently running 300 rwhp (dynoed) the motor has been balanced and blue printed 3 times over before the guys that built it were happy with her. im also running a fully rebuilt m20 box.
now from what ive been told by a couple of people is that i can redrill the flywheel bolts to 7/16 v8 arp pro bolts and that i can also put 4 3/8 dowles from the flywheel into the crankshaft to stop the vibrations. however i spoke to someone today that told me that i might throw out the balance and can do damage to the motor. can this actually happen?
so what im also asking is that how many other ppl have had this problem and if so how did you solve this. any info would be great.
cheers kris.
202 harmonics problem
Started by
_70rey_
, Mar 15 2010 08:13 PM
90 replies to this topic
#2
debkar
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Posted 15 March 2010 - 08:25 PM
Hi, running 2 dowels at the moment, always do in a decent revving red motor, have never had an issue since starting to do this many years ago,
These were fitted prior to balancing though
I use Holden flywheel bolts, not ARP,
Regards Simon
These were fitted prior to balancing though
I use Holden flywheel bolts, not ARP,
Regards Simon
Edited by debkar, 15 March 2010 - 08:28 PM.
#3
xu1kid
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Posted 15 March 2010 - 08:29 PM
whats been done to get 300 rwhp
#4
_70rey_
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Posted 15 March 2010 - 08:29 PM
hey mate thanks for the reply. yeah im a lil worried that if i put the 2 or even 4 dowles in a may have to re balance. dont really want to.
xu1kid... hmmm lets say she has seen a fair bit of work. enough to be a tough streeter but still enough left over so she is reliable.
xu1kid... hmmm lets say she has seen a fair bit of work. enough to be a tough streeter but still enough left over so she is reliable.
Edited by 70rey, 15 March 2010 - 08:31 PM.
#5
debkar
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Posted 15 March 2010 - 08:31 PM
hey mate thanks for the reply. yeah im a lil worried that if i put the 2 or even 4 dowles in a may have to re balance. dont really want to.
Hi, yes true, are you using ARP bolts? or Holden, I actually prefer the Holden ones,
I did say red motor, but I'm running black crank in red block. What crank are you running and what revs do you take it to?
Regards Simon
Edited by debkar, 15 March 2010 - 08:33 PM.
#6
_70rey_
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Posted 15 March 2010 - 08:32 PM
running arp pro bolts. apparently hold more torque pressure than holden ones. dont know if its true or not tho.
the engine revs out at 8200. can runs from 3200 to 7600 i believe maybe 7400 rpm. its a black motor im running
the engine revs out at 8200. can runs from 3200 to 7600 i believe maybe 7400 rpm. its a black motor im running
Edited by 70rey, 15 March 2010 - 08:34 PM.
#7
debkar
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Posted 15 March 2010 - 08:36 PM
running arp pro bolts. apparently hold more torque pressure than holden ones. dont know if its true or not tho.
Ah OK, I started with ARP, but I really think the Holden ones have more bolt head to flywheel contact area, just my opinion,
Regards Simon
running arp pro bolts. apparently hold more torque pressure than holden ones. dont know if its true or not tho.
the engine revs out at 8200. can runs from 3200 to 7600 i believe maybe 7400 rpm. its a black motor im running
mmm 8200, I don't ever see that , 6500 would be my upper limit,
#8
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Posted 15 March 2010 - 08:40 PM
theoretically , (if you do not want to pull the motor down to re balance it) you should be able to fit 2 dowels of equal weight exactly opposite each other and they should counter balance each other .balance would only go out if 1 dowel was fitted or if they are not dead opposite each other i would think...
#9
_70rey_
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Posted 15 March 2010 - 08:40 PM
na i haven ever reved her that high dont want to. highest is around the 6500 mark
thats what we were also thinking rob but with 4 dowles. as stated im a little worried to go ahead and do it to only have further problems and then have to re balance the motor again.
thats what we were also thinking rob but with 4 dowles. as stated im a little worried to go ahead and do it to only have further problems and then have to re balance the motor again.
Edited by 70rey, 15 March 2010 - 08:43 PM.
#10
rodomo
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Posted 15 March 2010 - 08:52 PM
My engine revs to 6 regularly, has seen 7 on occasion. Though the HP isn't huge.
Black crank, Holden bolts, no dowels and I don't use Loctite.
How is the fit of the flywheel onto the crank spigot?
Black crank, Holden bolts, no dowels and I don't use Loctite.
How is the fit of the flywheel onto the crank spigot?
#11
_70rey_
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Posted 15 March 2010 - 08:58 PM
the flywheel is tight onto the crank. not loose at all.
#12
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Posted 15 March 2010 - 09:15 PM
what flywheel are you running?
#13
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Posted 15 March 2010 - 09:32 PM
I would dowel it if it's gonna see more than 6000rpm regularly. Not necessarily with a forged 3" crank but definitely any cast 3.250" one.
#14
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Posted 15 March 2010 - 09:34 PM
I would dowel it if it's gonna see more than 6000rpm regularly. Not necessarily with a forged 3" crank but definitely any cast 3.250" one.
what does that have to do with the price of eggs in china?
#15
_monaroman68_
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Posted 15 March 2010 - 10:19 PM
300hp dynoed luv to see the sheets and i hope its forced with something or a bit of giggle juice to see that. If not i will buy the thing off you.
#16
_clubspClubsportr8ortr8_
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Posted 15 March 2010 - 10:42 PM
Monaroman i am with you as Captain Nitrous is getting 420 flywheel with a very healthy shot of gas and my new engine being built by the same man who built that engine we might get over 300 flywheel naturally aspirated and my bill is just over $10000 with a little more to do.If the dyno sheet appears i will take 2nd dibs on the motor and also for what its worth go back to std holden flywheel bolts as that is all i am using with the new engine.
Jeff
Jeff
#17
_oldjohnno_
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Posted 16 March 2010 - 06:30 AM
Jeez you're a bloody sceptical lot. I've managed to get a hold of the dyno sheet and you can clearly see where the harmonics start to set in..
#18
Heath
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Posted 16 March 2010 - 07:34 AM
LMFAO OldJohnno
EVERYONE here chasing power, as far as I am aware (don't know everyones setup in and out but I think it is a fair assumption), has harmonic problems. It's just that a lot us don't spend much time at properly high rpm so we don't fully appreciate it.
Well I don't understand it well enough to explain the nature of the vibrations very well, but the counterweighting of a 202 crank makes it a lot more unhappy at 6000rpm!
I would dowel it if it's gonna see more than 6000rpm regularly. Not necessarily with a forged 3" crank but definitely any cast 3.250" one.
what does that have to do with the price of eggs in china?
EVERYONE here chasing power, as far as I am aware (don't know everyones setup in and out but I think it is a fair assumption), has harmonic problems. It's just that a lot us don't spend much time at properly high rpm so we don't fully appreciate it.
#19
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Posted 16 March 2010 - 08:58 AM
haha nice dyno sheet, why have a monster cam in it but dont rev it to the limit defeats the purpose it wouldnt pull the skin off a rice pudding down low and when it starts to pull hard your changing gears
#20
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Posted 16 March 2010 - 09:32 AM
Ive never (touch wood) experienced any flywheel trouble with my 202.
that said, as soon as I started spinning it harder (originally to about 5800, now to about 7k) I stepped up to a billet steel, explosion proof flywheel.
Seemed like the best idea for my legs/feet/toes
And after the last rebuild and full balance It spins to 7 freely (not much point going any further with my camshaft)
I cant say Id really trust a standard flywheel (not without a scatter shield anyway) especially when the lightweight ones are so cheap
that said, as soon as I started spinning it harder (originally to about 5800, now to about 7k) I stepped up to a billet steel, explosion proof flywheel.
Seemed like the best idea for my legs/feet/toes
And after the last rebuild and full balance It spins to 7 freely (not much point going any further with my camshaft)
I cant say Id really trust a standard flywheel (not without a scatter shield anyway) especially when the lightweight ones are so cheap
#21
_70rey_
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Posted 16 March 2010 - 11:39 AM
its not a standard flywheel it is a lightened heavy duty one. and for those who are wondering yes the engine had cost me alot of money and can garantee it has 300 rwhp with no giggle gas.
orangelj have you got your motor dowled at all? what flywheel bolts do you use?
orangelj have you got your motor dowled at all? what flywheel bolts do you use?
#22
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Posted 16 March 2010 - 12:21 PM
Standard holden ones.
I checked mine for warping/stretch with a thread indicator before using them though.
Bit of loctite and away I went.
When you say lightened Heavy duty you still mean a holden factory unit?
Yella Terra billet steel explosion proof flywheels are around the $300-$400 mark so cheap insurance.
My crank isnt dowelled, I sent my crank, rods, pistons, romac balancer, flywheel etc to the balancer.
Did you have the whole lot balanced or just the internals?
I checked mine for warping/stretch with a thread indicator before using them though.
Bit of loctite and away I went.
When you say lightened Heavy duty you still mean a holden factory unit?
Yella Terra billet steel explosion proof flywheels are around the $300-$400 mark so cheap insurance.
My crank isnt dowelled, I sent my crank, rods, pistons, romac balancer, flywheel etc to the balancer.
Did you have the whole lot balanced or just the internals?
#23
_oldjohnno_
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Posted 16 March 2010 - 01:25 PM
I think you should focus your attention more on controlling the vibration rather than just trying to keep the flywheel on. Even if you do get it to stay on I'm pretty sure that such severe vibration would just break something else.
Controlling the vibration on a Holden six requires pretty much the same steps as you'd follow with any engine. Firstly you'd want to run the lightest possible pistons and rods. Anything you can do to reduce the reciprocating mass in particular (eg. taper wall pins) will have a huge effect. A longer rod ratio also helps a lot though I doubt you'd want to change that now.
Next you'd need a much bigger and more effective harmonic balancer. It has to fit very tightly to work properly. Most balancers have a resonating frequency of their own and if it coincides with a resonant frequency of the crank then things turn to shit very very quickly. The bottom line is that if you're gonna spin it up then you need to be prepared to test a few different balancers to find the one that works best with your engine and rev range.
Also consider a heavy main girdle. It won't really do anything to stop the vibration directly but because the little Holden block is so light it wants to buzz along with the crank, and the heavy girdle might help dampen things down a little.
Don't get too distracted by the whole "balancing" business. When your builder tells you he's balanced your engine to within 1/2 gram it doesn't necessarily mean much. All it really means it that you can spin it up in the balancing machine without either or both ends wanting to jump out onto the floor. Your balancer can say it's "balanced" to within .000000001 grams, but that doesn't guarantee that certain areas of the crank aren't subjected to absolutely massive loads while the engine is spun up, due to the way the weights and counterweights are distributed along the shaft. What I'm saying is if your piston/rod weights match, and the assembly spins up ok on the machine, don't be too concerned with an inch/oz here or there. It's the least of your worries.
Definitely use a steel flywheel, for safety sake if nothing else.
A question for you guys: has anyone here had severe vibration problems with an automatic equipped engine? I've had flywheels come loose etc. but never had any dramas with flexplates or their bolts.. Makes you wonder whether the convertor isn't a pretty good damper in itself, and that in turn makes me wonder whether some sort of dampening elements on a manual flywheel would be of benefit?
Controlling the vibration on a Holden six requires pretty much the same steps as you'd follow with any engine. Firstly you'd want to run the lightest possible pistons and rods. Anything you can do to reduce the reciprocating mass in particular (eg. taper wall pins) will have a huge effect. A longer rod ratio also helps a lot though I doubt you'd want to change that now.
Next you'd need a much bigger and more effective harmonic balancer. It has to fit very tightly to work properly. Most balancers have a resonating frequency of their own and if it coincides with a resonant frequency of the crank then things turn to shit very very quickly. The bottom line is that if you're gonna spin it up then you need to be prepared to test a few different balancers to find the one that works best with your engine and rev range.
Also consider a heavy main girdle. It won't really do anything to stop the vibration directly but because the little Holden block is so light it wants to buzz along with the crank, and the heavy girdle might help dampen things down a little.
Don't get too distracted by the whole "balancing" business. When your builder tells you he's balanced your engine to within 1/2 gram it doesn't necessarily mean much. All it really means it that you can spin it up in the balancing machine without either or both ends wanting to jump out onto the floor. Your balancer can say it's "balanced" to within .000000001 grams, but that doesn't guarantee that certain areas of the crank aren't subjected to absolutely massive loads while the engine is spun up, due to the way the weights and counterweights are distributed along the shaft. What I'm saying is if your piston/rod weights match, and the assembly spins up ok on the machine, don't be too concerned with an inch/oz here or there. It's the least of your worries.
Definitely use a steel flywheel, for safety sake if nothing else.
A question for you guys: has anyone here had severe vibration problems with an automatic equipped engine? I've had flywheels come loose etc. but never had any dramas with flexplates or their bolts.. Makes you wonder whether the convertor isn't a pretty good damper in itself, and that in turn makes me wonder whether some sort of dampening elements on a manual flywheel would be of benefit?
#24
Heath
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Posted 16 March 2010 - 01:44 PM
Makes you wonder about how good it is having a lightweight flywheel on a Holden 6 is...
Edited by Heath, 16 March 2010 - 01:47 PM.
#25
_NZ Toranaman_
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Posted 16 March 2010 - 02:33 PM
I am about to fix this problem myself in the next week or 2 with another simple fix.
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