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Are harmonics killing my engine?

Started by _jklumpp_ , May 14 2013 11:10 PM

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140 replies to this topic

#76 _Dansthemanow_

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Posted 19 November 2013 - 09:11 PM

you can always eliminate the water pump pulley with a davies raig electric water pump.They work fine.then you just worry about lining up the alternator.

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#77 warrenm

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Posted 19 November 2013 - 11:34 PM

That looks impressive.
Are you still running that dampener,and has it worked for you?
I noticed an earlier post u said going from a ultra light back up to a 8.6kg fly helped yours a lot.Did u still end up with the 8.6 coming loose?

I was using an 8.6kg & the wheel did come loose, but I have since fitted another counter weight crank that was balanced by a different company & I fitted the ATI balancer, I fitted a new clutch after breaking the drive straps on the pressure plate as well as a 10.6kg steel flywheel which is still in place. I used to have trouble keeping the "T" bolts that hold the rocker cover tight, 2 or 3 near #4 & #5 cylinder. Since the heavier flywheel & the ATI balancer were fitted they no come loose, so one or the other or both seem to have stopped this.

waz

there was some discussion with the guys last nite about building a damper from scratch as they have done this before. be he says's it's about a 1000 buck job. he wouldn't tell me what damper he used. but i clearly remember the one you built and was searching for it last night .

so you have to;

buy the damper

machine up the adaptor plate

knock off the timing mark and re weld up

tap the crank as a bolt to hold on balancer

make up new timing marks

extend the alternator bracket

no change to the water pump ?

no room for fan

there is a question i have here and it relates to the use of long and short water pump noses , i assume you have gone to the long nose to accommodate the extra balancer depth and thus no room for the fan left

G

I used the std 202 water pump, then made a new pulley.

Edited by warrenm, 19 November 2013 - 11:39 PM.

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#78 _Bluejinx202_

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Posted 20 November 2013 - 10:12 AM

I've been sitting back reading this thread, but nothing to offer as my engine is turned around and has a propellor running of the front where the h-balancer used to go. I've always been pretty casual bolting on my flywheel, a bit of lock tite and a normal ratchet and I'm away. I'm thinking that I must have the heaviest balancer in the world (the flywheel) and the other end has a constant dampener (the water) so I probably won't have these issues. Will I still have harmonic rev zones in different places to normal? Do guys running a flex plate and torque converter have the same problems?

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#79 rexy

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Posted 20 November 2013 - 11:08 AM

Has anyone tried the fluidamper style set up?

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#80 _Dansthemanow_

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Posted 20 November 2013 - 12:37 PM

Some of the guys running auto trans have had trouble chopping out flex plate bolt holes.But reinforcing around the bolt holes seems to fix that.
Another thing worth mentioning is that ATI can do custom balancers and i imagine would supply one tailored to a holden 6,for a price!

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#81 _Dansthemanow_

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Posted 20 November 2013 - 01:12 PM

I think the picture i am getting is once you go below standard weight flywheel,you have trouble.I noticed the xu1s were fitted with dowels a year after they lightened the fly to 19lbs.i think two guys on here have seemed to keep the stock weight wheel on.Even the 8.6kg may not be the wisest choice.
I think harmonic balancers are a black art.and the overall size/ weight is what most people look at.There are a lot of factors which effect the compatibility of a balancer.A lot of aftermarket balancers are not really tested,and designing one to suit a specific engine is probably outside the capability of a lot of aftermarket companies.ATI is probably one of the only companies that actually test their balancers on engines and measure the crank twist etc.If you were lookin at going custom,ATI is probably a good bet.

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#82 S pack

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Posted 21 November 2013 - 12:42 AM

I must be one of the lucky ones.

Balanced and blueprinted red 202 running a blue crank & rods, XU1 spec lightened flywheel (no dowels) and std red motor balancer.

Engine was built in 1987 and has had plenty of action above 6000 rpm and no flywheel problems.

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#83 _Dansthemanow_

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Posted 21 November 2013 - 09:24 PM

Interesting that not every engine gets the problem.
It also ocurred to me the effect of rev limiters on the crank.Mine is limited to 6400 and i hit the limiter a bit if im goin flat out.My old 192 never had rev limiter,but i revved that to about 6 1/2 k,ran the same alloy flywheel i got now.never came loose.A lot of guys are probably running msd or whatever with limiters.What happens to the crank when every second spark is cut off at high rpm.It probably does all manner of bizzare things.Mine has dual stage rev limit/rev cut.I shoild get rid of the limit and just hav the full spark cut at 6400.better to have no cylinders firing than half.That alone could explain a lot of cases of loose flywheels

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#84 _STRAIGHTLINEMICK_

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Posted 21 November 2013 - 09:52 PM

G'day blokes,

The flywheel issue is caused by harmonic vibrations in the crank .Imagine each power stroke making the crank twist and spring back x 6 cylinders x 6000rpm . The more power you make the worse the problem is, If you are making a decent amount of power and havn't modified the flywheel bolts and dowelled the crank then you will have this problem .The problem starts at the balancer (at about 100 rwhp) then moves to the rear at about 150 rwhp . The problem seems to be less in 3" stroke engines and doesnt seem to happen in a front engine digger , less weight ,less load ,less twist ,less harmonic vibration .

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#85 warrenm

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Posted 21 November 2013 - 10:49 PM

I wasn't having any issues at the track until I moved to slicks, so I needed a longer burnout to heat the tyres so I would hold the revs between 6000/6500. The cam at that time had max power at 6000, so I would change at 6000 & run through the traps at 6400/6500 which was no problem, but the revs were climbing through not holding, unlike the burnout.

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#86 _Agent 34_

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Posted 22 November 2013 - 07:25 PM

Ok,'

So we should go back to a base setting. Can the guys who do option 1 , 2 or 3 say so. only then can we get some base line settings. and then we can apply a factor of error on the weight of fly wheel or balancer. it;s only to narrow down the error margin and not argue about stuff. But the great thing about the forum is that we have different people doing different things which will equal out any error in approach.

1) balance , crank , rods pistons only

2) balance crank , rods , piston, balancer , fly wheel

3) line bore, balance crank, rods, balancer , fly wheel.

Lets assume that we are all running a blue black crank,

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#87 _Dansthemanow_

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Posted 22 November 2013 - 08:33 PM

Well my crank rods pistons and flywheel were all originally balanced.Only way they can go outa balance is if sonething bends.Mine still feels smooth so no immediate suspicions its out of balance.Remember the torsional vibration can not be eliminated by balancing.So theres some doubt balancing has much to do with it.could have but its not the main issue.Considering how many engines have this issue,you wouldnt think they were all out of balance or had bent cranks.
Personally im split between trying a new heavier steel flywheel,3.6kg romac balancer and locwired bolts, or pulling the crank to check it over and put 3 dowels,also with new steel flywheel.Hard decision.

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#88 warrenm

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Posted 23 November 2013 - 05:31 AM

Well my crank rods pistons and flywheel were all originally balanced.Only way they can go outa balance is if sonething bends.Mine still feels smooth so no immediate suspicions its out of balance.Remember the torsional vibration can not be eliminated by balancing.So theres some doubt balancing has much to do with it.could have but its not the main issue.Considering how many engines have this issue,you wouldnt think they were all out of balance or had bent cranks.
Personally im split between trying a new heavier steel flywheel,3.6kg romac balancer and locwired bolts, or pulling the crank to check it over and put 3 dowels,also with new steel flywheel.Hard decision.

Using a crank girdle & grout fill the block, adds mass to the block. The girdle can be added at any time but the grout is something that needs to be done before the engine is machined.

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#89 _STRAIGHTLINEMICK_

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Posted 23 November 2013 - 11:35 AM

Ok Agent 34 , i do option 2 and check the crank tunnel is in line with a straight edge and feeler guage ,then torque each cap and measure the tunnels in 3 places . Remember the harmonic vibration cannot be stopped ,or lessened , just have to make the combination hang together by balancer and flywheel selection,a retaining bolt for the balancer ,machining flywheel and crank faces ,upgrading to 7/16 bolts and dowelling . Also there is a crude but easy old school fix that i still use because it just Works .That is to cover all threads ,under bolt heads ,flywheel and crank faces with the long curing Araldite ,torque it up ,release and torque it up again to the ARP bolt torque value , wipe the excess and let it cure .

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#90 _Dansthemanow_

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Posted 23 November 2013 - 03:21 PM

So you reckon the high strength araldite with the standard size bolts might work if the harmonics are kept under reasonable control?

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#91 _STRAIGHTLINEMICK_

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Posted 23 November 2013 - 10:35 PM

So you reckon the high strength araldite with the standard size bolts might work if the harmonics are kept under reasonable control?

It might work for a while but the 3/8 botls dont have enough clamp force if you are making decent power. If you are not using slicks then the the larger bolts and no dowel seems to work.

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#92 _STRAIGHTLINEMICK_

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Posted 23 November 2013 - 10:47 PM

I've been sitting back reading this thread, but nothing to offer as my engine is turned around and has a propellor running of the front where the h-balancer used to go. I've always been pretty casual bolting on my flywheel, a bit of lock tite and a normal ratchet and I'm away. I'm thinking that I must have the heaviest balancer in the world (the flywheel) and the other end has a constant dampener (the water) so I probably won't have these issues. Will I still have harmonic rev zones in different places to normal? Do guys running a flex plate and torque converter have the same problems?

Yep ,I'm using an auto in this car and still had the problem, the flexplate bolts came loose and it tore the centre out of the stock flexplate.I was pulling the trans out after every race meeting untill it was sorted .

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#93 warrenm

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Posted 24 November 2013 - 06:57 AM

x2 for Araldite.

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#94 _Dansthemanow_

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Posted 24 November 2013 - 02:24 PM

For me swapping from ally to steel flywheel might overcome it,especially with the araldite.Theres 2 reasons an ally wheel is more prone to come loose.Due to expansion rate,it is probably a loose fit on the flange by the time it heats up.
Also.again due to the difference in expansion rate to the steel crank,changes in temp produce "tension" at the interface of crank and flywheel.This means the joint will slip once a high torque is applied.once it has slipped,the tension is releived untill the temperature changes,and the process repeats untill the bolts work loose.

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#95 _Dansthemanow_

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Posted 24 November 2013 - 02:32 PM

That last effect can be compared to a car tyre.It can transmit a lot of torque if there is minimal sideways loading.Once you corner hard and the tyre has a lot of lateral loading,you will slide if you apply a lot of torque.
The flywheel expanding pushes outwards at the interface,then you apply twisting force and it slips.

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#96 _Dansthemanow_

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Posted 24 November 2013 - 04:41 PM

Ive also found that not only holden 6s suffer from loose flywheels.Although its not as common,even toyota 2jz and bmw sixes can sometimes have chronic loosening of the flywheel.One guy on a supra forum had his come loose 5 times after using red loctite on the bolts.Its just inherent for inline 6s.Too much twist in the long crank.

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#97 greens nice

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Posted 24 November 2013 - 08:02 PM

I have a 7 1/4 inch fluidampr and hub to suit a holden 6 if you are interested Dan.

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#98 _Dansthemanow_

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Posted 24 November 2013 - 09:57 PM

Hmm.certainly worth a look.Send some pics my way.

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#99 warrenm

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Posted 25 November 2013 - 06:13 AM

Ive also found that not only holden 6s suffer from loose flywheels.Although its not as common,even toyota 2jz and bmw sixes can sometimes have chronic loosening of the flywheel.One guy on a supra forum had his come loose 5 times after using red loctite on the bolts.Its just inherent for inline 6s.Too much twist in the long crank.

The 635 BMW's touring cars that raced here in the early 80's also had the same issue, also the 6 cyl Chrysler can have some issues.