37 replies to this topic

[yel327]

Engage an Engineer before you decide on and pay for anything. Find out what it'll cost you - doing brakes tests isn't that cheap. Plus the Engineers fees. And find out what they require to go into the report. Like if you buy a used diff with no provenance who did the welding on it, it may not pass.

[claysummers]

Aren't the skylines 4 stud?

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[Bigfella237]

So I have another question in regard to stud patterns  ~ am I just being pendantic for wanting matching brakes and stud patterns LOL

Someone will no doubt correct me if I'm wrong but I have a vague recollection about something in the NCOP (or similar) that said you can't have different stud patterns on the same car?

 

I don't know why you'd do that anyway, if nothing else it means carrying two different spare wheels.

 

Totally agree about talking with an engineer before you do anything.

[kimbo]

OK ...had a meeting with an engineer today.  Bearing in mind I am in WA and there will be differences.  He says brakes no problem ...about $200 for brake test.   Stud patterns are OK to mix but why would you (my thoughts as well).   Best Borg Warner diffs for conversion are VL Commodore although he is saying that for ease of predrilling the axles which have 5 studs (R31 4 studs).  Max front tire width in WA is 245.  Anyhow will update as info become available.

[LJ RB30]

Just a small thing about the VL diff, they don’t have a drain plug ie you have to remove the backing plate to drain it, well the 2 I’ve had haven’t.
A VS diff does.
Not sure about models in between tho
& yes R31 skylines are 4 stud

[yel327]

Aren’t VL V8 diffs expensive? Might be worth costing getting a VR-VS diff and making it the width you want when you get the Torana mounts added. Then get axles made to suit with the stud pattern and centre bore you want. A pair of axles is maybe $800.

[Uncle Chop Chop]

First let's get the Torana and other early Holden PCD cleared up. GMH lists it as 5 x 4.24, this IS a typo. All aftermarket wheel makers list it as 5 x 4.25. Many years ago (probably 2004) I spoke to a person at ROH who confirmed that they get the blueprints from GMH, Ford etc and use those specs. They list it as 5 x 4.25, so that's what it is. 

 

For your hatch, I would use ( actually am going to use) Aussie Ford Falcon spec wheels for several reasons. The 5 x 4.5 stud pattern is very common. The studs are 1/2" UNF and VERY strong for a factory stud. In my 40 years in the tyre industry, I have seen countless cases of pre VE Commodore studs damaged and a fair few sets of 7/16" UNF as on the Toranas and HQ. I never saw a damaged Ford stud that couldn't be salvaged by using a flat file for a few seconds. The other reason is that they share the same centre bore as the HQ. Both are 71.5 mm. So you can run HQ 4 wheel discs (drilled to Ford pattern) and know the wheels will be centred properly on the discs without the need for troublesome hub locating rings. Plus the pre AU offset is +1/4", the HQ offset is +1/2". Torana offset is +32 mm while post AU Falcon is (generally) +36 mm. So you have choices in getting a wide range of offsets.

[RoyalPlum76SS]

Awesome ...how do you find road comfort with those profiles?  Bearable?   What diff are you running?  I think from memory a R31 Borg Warner is 1440 wide so might be able to be used without cutdown?

The Skyline diffs are a tad wider than standard LH/X diffs, actually they are 25 tads wider at 1465mm.

They are however, the closest in length of all the M75 M78 B/W diffs that are commonly available and used in Torry conversions.

If you don't want that diff length, then it, or pretty much anything else is going to need to be chopped to whatever diff length you decide upon. You don't need to source a (more expensive) VL diff, anything from VL to VS will be fine as a base to start a diff conversion.

[kimbo]

I have been reading through heaps of stuff here regarding fitting an HQ hub to a LX stub axle.  I will make a list below of what I understand and what I am not sure of.

• HQ hubs will replace Torana hubs straight up.
• HQ Disks will need to be machined to lower the diameter by 12mm.
• The flat face of the rotor will need to be machined from edge to center.
• If HQ calipers are fitted there might need to grinding to clear the lower wishbone.  Brake pads have to be ground down as well?
• Can standard Torana calipers expand wide enough or have the correct alignment to be used?

Sorry about this but there are lots of opinions and different ways folks approach this.  Some of the articles are also over 10 years old so maybe there is a new consensus :-)

 

Cheers guys

[yel327]

GMH did the above far simpler. By using HK to HZ disc stubs and then simply bolt on HQ-WB rotors with HQ or HX-HZ calipers. No rotor machining required. The hard thing is the steering arms. I did the above using UC steering arms and never had any issues, but people rave about bump steer which I never noticed on a street car. GMH did it using specific steering arms for both LH XU2/L34 and LX with A9X. Not sure if Harrop still make the A9X arms, if they do that is the easiest way in my opinion, you just need a pair of UC upper control arms as well. HZ calipers were machined to fit on A9X vehicles, but a combination of HX and UC calipers will fit without any mods. HQ fit as well but unless you find L34 calipers you will have the brake hose pointing down rather than up. I'd only do this if you want 4.75" PCD though. It'd be far easier to fit a Hoppers kit if you want Ford pattern, using something as simple as XF-XG rotors with a common caliper (like VS or whatever they use) on the Torana stubs and steering arms. I'm not sure what it is Hoppers use, this is what they had for HK when I looked. This way you can use off the shelf bits rather than requiring a custom rotor when you need to replace one.

[kimbo]

GMH did the above far simpler. By using HK to HZ disc stubs and then simply bolt on HQ-WB rotors with HQ or HX-HZ calipers. No rotor machining required. The hard thing is the steering arms. I did the above using UC steering arms and never had any issues, but people rave about bump steer which I never noticed on a street car. GMH did it using specific steering arms for both LH XU2/L34 and LX with A9X. Not sure if Harrop still make the A9X arms, if they do that is the easiest way in my opinion, you just need a pair of UC upper control arms as well. HZ calipers were machined to fit on A9X vehicles, but a combination of HX and UC calipers will fit without any mods. HQ fit as well but unless you find L34 calipers you will have the brake hose pointing down rather than up. I'd only do this if you want 4.75" PCD though. It'd be far easier to fit a Hoppers kit if you want Ford pattern, using something as simple as XF-XG rotors with a common caliper (like VS or whatever they use) on the Torana stubs and steering arms. I'm not sure what it is Hoppers use, this is what they had for HK when I looked. This way you can use off the shelf bits rather than requiring a custom rotor when you need to replace one.

 

The Hoppers kit is about $2k but you can have whatever stud pattern you like.  Its more than I wanted to spend for front brakes and studs but I might just have to bit the bullet :-)

[yel327]

I get that, but again you end up with custom rotors unless you use the stud pattern from the car the rotor was originally designed for. Do the sums of the HQ brake upgrade. By the time you get new rotors machined down, new bearings etc. Get calipers rebuilt. New brake lines etc. It is still going to be costly and, in the end, still probably requires Engineering. Probably the only way around the Engineering is to replicate LX with A9X, which means expensive Harrop steering arms. However, you will need Engineering for your diff, and if you intend running wheels wider than 7" and more than 1" bigger diameter than standard, you'll need Engineering for that. So, no biggie for the brakes. I think guys here have also been made to go through Engineering to put a V8 in an originally 6cyl Torana, so you may be up for it regardless whatever else you do.

[rexy]

The Hoppers kit is about $2k but you can have whatever stud pattern you like.  Its more than I wanted to spend for front brakes and studs but I might just have to bit the bullet :-)

 

 

Just get blank HQ discs and have them drilled to the stud pattern of Satan (F**D).

 

Cheaper to get new axles for whatever diff you use in F**D pattern than to buy a Hoppers kit.

 

Pity UPC aren’t still around - same stuff as Hoppers at half the price.