RB30 balancer bolt RFT

[NZ-GTT]

My 26/30 is about ready to go in and I have been putting off torquing up the crank bolt to 400nm as recommended by Lewis engines on his website.

I started torquing it up in stages and the bolt reached it's yield at 350nm. After that it kept turning. Luckily I had a spare bolt and changed it out and this one torqued up to 400nm. That's Really F***en Tight! I used ARP lube on the first one and the second one went in dry but I assume there was still lube inside the crank. Any thoughts?

 

 

Edited February 27, 2020 by NZ-GTT

[Duncan]

I don't have the exact figures close but rb26 is different and much higher than rb25/20/30....if you are using the factory bolt, use the number from the workshop manual. 

[NZ-GTT]

The RB26 is 446 - 544NM for a M18 x 1.5 bolt which is more than the recommended for a grade 10.9 of that size. the rb30 has a M16 bolt with a recommended torque setting of 142-152NM which is less than that of a M16 grade 8.8 bolt. Seems a bit loose and I want to push this engine beyond what the Nissan factory intended. Should I leave it since it has achieved that torque or replace it with ARP?

[GTSBoy]

I was wondering why you were winding an RB30 bolt up to that torque and assumed that you were not using a stock bolt. Basically, exceeding the required (Nissan's spec) torque on that bolt by the margin that you have cannot be a very good idea. The torque is not just a function of the bolt but also what it is screwing into and the clamping surfaces that it has to load. It's no wonder that you f**ked the first one, and I'd be concerned that the second one is just simply too tight for the application. I'd get another one and do over again at a more moderate increase over the Nissan spec.

[NZ-GTT]

I was following the advise given here: http://www.lewisengines.com.au/rb-tech/  at the bottom of the page. He makes no mention of using an aftermarket bolt.

I'll get another bolt and do over again thanks. What do you consider a moderate increase?

[GTSBoy]

5 minutes ago, NZ-GTT said:

I'll get another bolt and do over again thanks. What do you consider a moderate increase?

No more than 20% I'd guess.

[GTSBoy]

6 minutes ago, NZ-GTT said:

I was following the advise given here: http://www.lewisengines.com.au/rb-tech/  at the bottom of the page.

Darren can always be wrong about numbers. Best to double check!

[NZ-GTT]

I've done more research. The torque specs given by Nissan for the RB26 match that of a grade 12.9 M18 x 1.5 bolt. Assuming that Nissan used the same grade on the RB25 & 30, the torque range for a M16 x 1.5 bolt is 300 - 380nm depending on the surface friction coefficient. I used ARP lube which changes the  coefficient even more. I've ordered an ARP bolt and will follow their recommendations. I've had a balancer come loose before and don't want a repeat.

Thanks for the advise.

[Duncan]

Good choice to replace it.

i'll bet nissan properly engineered the rb30 bolt and torque specs, and that a properly torqued factory bolt has never come undone. The problem comes in when timing belts etc get changed long after they'v'e left the factory.

[awoken]

On 29/02/2020 at 7:24 AM, NZ-GTT said:

I've done more research. The torque specs given by Nissan for the RB26 match that of a grade 12.9 M18 x 1.5 bolt. Assuming that Nissan used the same grade on the RB25 & 30, the torque range for a M16 x 1.5 bolt is 300 - 380nm depending on the surface friction coefficient. I used ARP lube which changes the  coefficient even more. I've ordered an ARP bolt and will follow their recommendations. I've had a balancer come loose before and don't want a repeat.

Thanks for the advise.

what arp bolt are u ordering the rb26 one ?? have u re tapped the 30 crank ??

[NZ-GTT]

Spool imports sell one for the RB25 & 30, no tapping required:

https://www.spoolimports.com/arp-nissan-rb25-rb30-harmonic-balancer-bolt