Balancer Woodruff Key Repair?

[CLEM0]

On 6/9/2022 at 1:41 PM, cyman said:

 

thank you for the prompt and comprehensive answers and solutions to my problem. the real problem is that this is a custom crankshaft(builder no longer offer it) made from a famous builder, in australia and then shipped to my country. so its a an rb26 stroker (2.9L) using an rb30 crankshaft. so first we have to remake the used crankshaft(i think the crankshaft is destroked and and with smaller counterweights). Machine shop will have to measure and  replicate the crankshaft.

in deed this rb storker was pushing like 900whp on an ati vibration dampener but we were unaware(naive) that the age of the dampener does matter(it was 10 years old when we first bought it, and used it as it seems to be good at the time of the build) also we used oem bolt and torque specs of that of an rb30. Buy the time we increased the power, soon enough we had this issue.

so to summarise it up, we need:

• an aftermarket balancer that will have very tight fit like Ross,
• after market timing gear like the Ross or RPR
• Nitto keyways

Do you think that using ARP crankbolt is good to be used just to be on the safe side? 

thank you.

Correct mate. The timing shield/washers as another poster suggested is nothing to do with the issue.

Plenty of other cars run a similar setup with washers and have no dramas or issues.

The only issue is badly made tolerances on Nissans part. Get a properly made balancer, get the snout repaired/crank replicated and make sure the snout is perfect. Balancer should not be possible to put on by hand/hammer. Correct tension and interference requires a pusher tool- if you don't use one- the balancer is too loose.

No other cars use slip on balancers really- besides Nissan for whatever reason. That little tiny gap may be nothing at low RPM- but that gap at 7,8,9,10k RPM or higher than stock power and driving etc is going to move the balancer, loosen the bolt, and either mince the crank snout, wack out the keyways, or- as in my case, do both!

Hopefully you get it sorted

Micrometer the balancer and the snout always!

Edited June 9, 2022 by CLEM0

[BK]

On 09/06/2022 at 3:38 PM, CLEM0 said:

Correct mate. The timing shield/washers as another poster suggested is nothing to do with the issue.

Plenty of other cars run a similar setup with washers and have no dramas or issues.

The only issue is badly made tolerances on Nissans part. Get a properly made balancer, get the snout repaired/crank replicated and make sure the snout is perfect. Balancer should not be possible to put on by hand/hammer. Correct tension and interference requires a pusher tool- if you don't use one- the balancer is too loose.

No other cars use slip on balancers really- besides Nissan for whatever reason. That little tiny gap may be nothing at low RPM- but that gap at 7,8,9,10k RPM or higher than stock power and driving etc is going to move the balancer, loosen the bolt, and either mince the crank snout, wack out the keyways, or- as in my case, do both!

Hopefully you get it sorted

Micrometer the balancer and the snout always!

No not correct at all regarding the shields. I suggest to go and have a talk to the guys at Ross as I have spoke at lengths with them over months about it. Sorry mate but the the factory washers and soft timing gear are THE biggest problem over the damper, It only takes a very small amount of compression on these back items and then no matter what damper you have it will work its way loose. The shields compress way before the any damper will as they are soft as shit, and is why they are listed as a not to be reused on disassembly item in the factory manual because they compress.

Even with balancer having an interference fit what do you think happens if the gear section and shields compress ? - the bolt comes loose. This is why Ross developed these only in the last 2 or so years as no one else picked up on it.

I personally destroyed a Ross damper keyway and bonding material on a 1000km old Ross balancer last year with a brand new factory RB26 bolt tensioned to around 470nm at over 800hp.

They replaced it under warranty luckily and now the entire assembly does not have one factory component bolted to the crankshaft.

[CLEM0]

On 6/9/2022 at 3:14 PM, BK said:

No not correct at all regarding the shields. I suggest to go and have a talk to the guys at Ross as I have spoke at lengths with them over months about it. Sorry mate but the the factory washers and soft timing gear are THE biggest problem over the damper, It only takes a very small amount of compression on these back items and then no matter what damper you have it will work its way loose. The shields compress way before the any damper will as they are soft as shit, and is why they are listed as a not to be reused on disassembly item in the factory manual because they compress.

Even with balancer having an interference fit what do you think happens if the gear section and shields compress ? - the bolt comes loose. This is why Ross developed these only in the last 2 or so years as no one else picked up on it.

I personally destroyed a Ross damper keyway and bonding material on a 1000km old Ross balancer last year with a brand new factory RB26 bolt tensioned to around 470nm at over 800hp.

They replaced it under warranty luckily and now the entire assembly does not have one factory component bolted to the crankshaft.

My apologies- I stand corrected.

I'd assume the loose balancer from OEM + bad washers is the bigger picture then.

Potentially yours failed from high bolt torque compressing the washer beyond necessary?

I just found it hard to be true as many cars use similiar washer on crank systems and have no dramas- and the washer is very thin as is- before any compression. I personally have 1 PRP one OEM.

Thanks for the info. Always happy to know more.

Edited June 9, 2022 by CLEM0

[BK]

On 09/06/2022 at 5:11 PM, CLEM0 said:

My apologies- I stand corrected.

I'd assume the loose balancer from OEM + bad washers is the bigger picture then.

Potentially yours failed from high bolt torque compressing the washer beyond necessary?

Thanks for the info. Always happy to know more.

Absolutely the correct RB26 tension at 450nm+ on the bolt makes the soft timing gear and washers / shield problem more pronounced, but at the end of the day the RBs all use the same lower timing gear arrangement.

On the white 32 RB26 we are doing the same setup right now after the blue car had this happen.

[White GTS-T]

Are people locking the flywheels when torquing these bolts up?

Or are they putting the vehicle in gear with the foot on the brake and putting all that torque through the clutch plate?

[BK]

On 09/06/2022 at 5:46 PM, White GTS-T said:

Are people locking the flywheels when torquing these bolts up?

Or are they putting the vehicle in gear with the foot on the brake and putting all that torque through the clutch plate?

Yep I do. I use one of my old RB starter motors that's been cut in half and welded locked, so I bolt that in place and get to 460 - 470nm torque quite easily with the 3/4" tension wrench. Doesn't move a mm when doing it in car.

How's everyone else locking their flywheels ?

[NZ-GTT]

I can't see any brakes holding anywhere near 400nm+ of torque. I did mine on the engine stand with the flywheel locked.
Look at the size of torque wrenches we are using to achieve that torque and go figure.

I personally can't see how an interference fit between the balancer and shaft would help, the clamping force comes from the bolt and areas that it compresses, the woodruff keys are there just to align timing marks for the cam pulley and balancer at TDC.

 

Edited June 9, 2022 by NZ-GTT

[BK]

On 09/06/2022 at 6:16 PM, NZ-GTT said:

personally can't see how an interference fit between the balancer and shaft would help, the clamping force comes from the bolt and areas that it compresses, the woodruff keys are there just to align timing marks for the cam pulley and balancer at TDC.

You are absolutely correct - keys are for timing alignment only and tension is provided by the bolt.

Admittedly some tighter tolerances I guess help with stuff not flopping around as much. The Ross stuff definitely is tighter, as the lower timing gear and balancers do not go on just by hand like the factory stuff.

[NZ-GTT]

The interference fit probably prevents water ingress too, I've  seen a few RB30 cranks with balancers and pulleys seized on.
Most of us don't keep our cars outside these days so not prone to ingress.