90 replies to this topic

[FastEHHolden]

You're going to weld it on?

[rodomo]

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

Try Holden bolts, nothing to lose?
And this ^ ^ ^ is good reasoning.

I don't know if I would trust oldjohnno's advise too much.................................he makes thing up.

Edited by rodomo, 16 March 2010 - 05:39 PM.

[greens nice]

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?

hi Johnno, a mate has a fc with a 6/71 blown 202 and turbo 350, and hes shaking flexplates.

[warrenm]

Red crank, blue rods, 6kg Yella terra flywheel, 7/16" ARP bolts with Loctite Super bearing mount, PowerBond balancer & engine spins to 7000 quite often.

[greens nice]

hi Johnno, a mate has a fc with a 6/71 blown 202 and turbo 350, and hes shaking flexplates.

Interesting. Do you know what rev range he's running Kev?

it goes to 7500 i think

this is the car

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Edited by greens nice, 17 March 2010 - 12:05 PM.

[greens nice]

Why didn't the Holden dealer team have this problem ? if they did how did they solve it ?

they wouldnt tell us their secrets even if they did, they were probably using cast iron flywheels anyways.
i wonder how harrop and jim rowly fixed the problem, they were both using steel flywheels

[piquet]

Now this come from experience with a flywheel coming loose too often in another car. We did almost all that you ahve done and found out that the crankshaft was cracked in No6 B/E journal and not far from falling apart with major consequences.

Before you go to doing more radical things get under the car and before you pull everything apart put a dial indicator on the outer clutch face of the flywheel and get a mate to turn it over slowly by hand and check the run out in the flywheel. (Take the plugs out first it will be easier to turn over)
There are specs in the workshop manuals as to what the runout tolerances are but for what you are doing it should be absolutely minimal.


If the run out is excessive it could be one of two things either a warped flywheel or a bent/cracked crankshaft.

Once the runout has been determined
pull the flywheel off take it to the engine builder and get him to check it for warpness/bend.
being an ultra lightweight flywheel there is every chance that this could be warped due to high revs and heat.

If the flywheel is ok then it is further in the engine.
Next is to check the end of the crank for run out

If there is any/too much runout in the crank then that will be what is causing the bolts to break/loosen.
The cause may not be that it is out of balance but the fact that it is either bent or cracked.

I would suspect no 6 B/E journal allowing the flange end of the crank to bend if the problem is in the crankshaft

cheers
peter

[LJ RB30]

Now this come from experience with a flywheel coming loose too often in another car. We did almost all that you ahve done and found out that the crankshaft was cracked in No6 B/E journal and not far from falling apart with major consequences.

Before you go to doing more radical things get under the car and before you pull everything apart put a dial indicator on the outer clutch face of the flywheel and get a mate to turn it over slowly by hand and check the run out in the flywheel. (Take the plugs out first it will be easier to turn over)
There are specs in the workshop manuals as to what the runout tolerances are but for what you are doing it should be absolutely minimal.


If the run out is excessive it could be one of two things either a warped flywheel or a bent/cracked crankshaft.

Once the runout has been determined
pull the flywheel off take it to the engine builder and get him to check it for warpness/bend.
being an ultra lightweight flywheel there is every chance that this could be warped due to high revs and heat.

If the flywheel is ok then it is further in the engine.
Next is to check the end of the crank for run out


If there is any/too much runout in the crank then that will be what is causing the bolts to break/loosen.
The cause may not be that it is out of balance but the fact that it is either bent or cracked.

I would suspect no 6 B/E journal allowing the flange end of the crank to bend if the problem is in the crankshaft

cheers
peter

Mine did exactly that, huge crack in no6 bigend when I pulled it out, so I thought meh Ill give it a hit with a hammer, to my shock 5 hits and the crank was in 2. Scary s**t considering I was just turning it 7500rpm the day before I pulled it out. The main tell tale was not only the dial gauge on the flywheel face, but the rear main started to leak excessivly.

I got a counter weighted red crank (a bloke made a few 25+ years ago) in a 202. Before i got it , it was in a mates XU1 that revved hard but he had alot of trouble keeping clutches & flywheels from coming loose. After many attempts he gave up & put a standard crank in it. The crank sat in another mates shed for many years till i got it, when i had my engine balanced (by Paul England i think in Melbourne) i was told the flywheel had 20 thou runout at the flywheel outer. This was put down to the welding of the counter weights & only grinding the main & big end journals but not the rear flange. Had it fixed & revved the crap out of it for a few years with no clutch/flywheel problems (20 years ago mine you). The motor is still intact as i built it ( now back in the same XU1) So this would have similar symptoms as a cracked crank but mine was fixable.

[Heath]

Do you know what builder/workshop did the crank for it? Not interested in tracking them down but I am curious

[LJ RB30]

Do you know what builder/workshop did the crank for it? Not interested in tracking them down but I am curious

If it's my crank you want to know about, it was done by a bloke at the Bendigo Ordanace factory (ADI) & i think Luigi Coombes of Luigi's head shop was involved (when he was in Bendigo, he's been in Perth for 20+ years)