RB26 Rocker Covers & Timing Cover Bolt Specs?

[God_Z_illa]

Hey everybody,

I was wondering if anyone can could please tell what the bolt specs are for RB26 Rocker Covers & Upper Timing Belt Cover as I'm looking at having custom titanium dress up bolts made, and I'm uncertain with the other posts I found online because of the conflicting answers, so I thought I'd just ask to be sure.

Thanks.

[Duncan]

Very very loose as the rubber bush and rubber seals take the pressure, you will need a tiny tiny torque wrench

[God_Z_illa]

Sorry Duncan I misworded what I said, what I meant by specs was the sizing of the bolts themselves. But your advice will come in handy when I'm at that stage.

[Duncan]

Sorry, that makes sense on re-reading, why would you want torque specs for a bolt of the wrong material?

It is a weird bolt

Cap head with Phillips drive

27mm total length

5mm at 7mm shank for the rubber bush to go through

20mm of M6 thread

2mm of narrower shaft, I guess that is to help with centring

[God_Z_illa]

Thanks Duncan that's a huge help, very much appreciated.

I hate to be a pain since you've already been helpful, but would happen to know anything about the timing belt cover bolts?

The only thing I could find out about them was their total length (including the head), the 3 long ones are 62mm while the 2 short ones are 28mm.

https://www.efisolutions.com.au/timing-cover-bolt-rb-vg-long-r31-r32-r33-r34-wc34

https://www.efisolutions.com.au/timing-cover-bolt-rb26-short-r32-r33-r34-awc34#:~:text=Size%3A 28mm long including the head.

 

[Duncan]

That won't be so quick and easy; I have a bunch of those bolts sitting around but don't know how many of which. The front and rear, upper and lower timing cover bolts are all over the place

I will be pulling the ex-race car engine apart sometime and can confirm exact specs then....but sometime has already by 5 months wait....

[Duncan]

Weird that they listed length including the head, bolt length is normally specified from the mounting surface/excluding the head

Here is the diagram at least for number and relative size. It's not complete though (strangely), there are at least 2 long bolts on the top front cover but only 1 is shown

This shows it a bit better

I'd guess 2 long bolts on top cover, 3 short on bottom cover + 2 short on top cover.

Kudos have kits of genuine bolts that might help identify number and length:

Lower timing case (3 of same): https://www.kudosmotorsports.com/catalog/lower-timing-case-fastener-suit-nissan-rb20de-rb20det-rb25de-rb25det-rb26dett-excluding-p-1388.html

upper timing case (2 long, 3 of  short) https://www.kudosmotorsports.com/catalog/upper-timing-case-fastener-suit-nissan-skyline-rb26dett-p-1387.html

Upper backing plate, these look easy but note 1 x 1 size and 3x a smaller size: https://www.kudosmotorsports.com/catalog/upper-timing-case-backing-plate-fastener-suit-nissan-skyline-rb26dett-p-1389.html

[Duncan]

Ah f**k it, it is a lovely starry night and 100m to the shed isn't that bad while it is still over 10o

Both long and short bolt have 8mm of M6 thread and an 8mm shaft.

Short bolt has 22mm under the head

Long bolt has 55mm under the head

The cap head is 6mm high but I don't think that matters

[TurboTapin]

All these parts can be purchased at your local Nissan dealership over here in Canada, is it not the same elsewhere?

[GTSBoy]

6 minutes ago, TurboTapin said:

All these parts can be purchased at your local Nissan dealership over here in Canada, is it not the same elsewhere?

He wants pretty titanium ones.

[Ben C34]

Be sure to send Duncan a cut of the profits when you start selling them.

[TurboTapin]

6 minutes ago, GTSBoy said:

He wants pretty titanium ones.

Oh.. right he did say that in his original post. I should read before commenting.

[God_Z_illa]

On 16/05/2023 at 7:12 PM, Duncan said:

Ah f**k it, it is a lovely starry night and 100m to the shed isn't that bad while it is still over 10o

Both long and short bolt have 8mm of M6 thread and an 8mm shaft.

Short bolt has 22mm under the head

Long bolt has 55mm under the head

The cap head is 6mm high but I don't think that matters

I'm sorry to have made you go to all that trouble, thank you again for going out of your way to help. I can't express my gratitude enough.

[God_Z_illa]

On 17/05/2023 at 10:47 AM, Ben C34 said:

Be sure to send Duncan a cut of the profits when you start selling them.

I have no intention to sell them. I've been going back and forth with a business that makes custom titanium hardware kits on request because I want my bolts to be anodised to a specific 50/50 colour scheme, however they've haven't yet made a kit for an RB26 before and told me I'd have to first provide them with the hardware sizing and quantities before they can give me a quote.