13 replies to this topic

[Stevo75]

Not sure if cross member is the correct terminology, but can anyone tell me if there is any difference between the front cross member (where the engine mounts) between a 4 cyl LH and an 8 cyl LH.

I.e. do I need to make any modifications to this member to fit a Holden V8 where previously a 1900 opel sat? Or is it just a case of using different engine mounts for the V8

[Dr Terry]

Yes, the cross-member is different between the 4-cyl & V8. The engine mount posts are completely different.

 

Having said that the 6-cyl cross-member which is the most common style, is the same as the V8 one.

 

Find yourself one from a 6-cyl & the job is done.

 

Dr Terry

[Stevo75]

Awesome. Thanks for that. Might be tricky tho. There are bugger all Torana parts for sale in NZ.

Is it much of a modification to the 4 cyl if I need to?

[Heath]

You could probably get someone to cut some mounts off a K-frame in Australia and send them across... welding them on is not awfully tricky, but they need to be the right distance apart from one another, and the right distance fore/aft.

 

Or you could make some new ones yourself... also not that tricky if you're handy with a welder. They don't need to look exactly like the original ones.

 

You can see what they look like here:

http://www.gmh-toran...hatch/?p=998467

 

Also, I think it is only the Opel 4cyl that has a different crossmember. I suspect the Starfire 4 is actually the same as 6cyl/V8, in-case you see a Starfire powered Sunbird sitting in a yard being wrecked.

[I'm a Red Motor fiend]

^^ I believe Heath is correct re the K-frames above.

[garth1976]

Heath is correct.

Starfire / 6 / 8 are all the same

The Opel was out on its own.

[dron]

Hi   You can get new weld on mounts, or at least you could 3 years ago when I built mine. Made in Adelaide and available on ebay compleate with engineering paperwork. May be wourth a look at the rod shop site to

[Stevo75]

Awesome info. Thanks guys. Yeah mine has the opel. I like the idea of the ones off eBay with the Eng info. That’ll definitely be worth a look if I get stuck.

Sunbird star fire crossmember is also good to know about.

I’m trying to join a few dots here, so apologies if I’ve made too many assumptions. If I sourced an entire sunbird front end crossmember (including top and bottom suspension arms) from a starfire or 6 cylinder would this have the RTS setup and same crossmember engine mounts as the LX V8 SLR. Joining dots a bit further (maybe well off now), but wouldn’t this be identical to the A9X for those parts.

Edited by Stevo75, 26 January 2022 - 10:21 AM.

[Heath]

It wouldn't be identical to an A9X at all, but it would be a fine starting point.

 

There's plenty of info on the best combination front end on this forum. A UC is close to ideal but needs the upper arm mounts re-drilled to the height of an LX RTS front end (free), better with an LH steering rack converted to solid mounted (you already own one, just make up some mounts), etc.

The UC steering arms and upper arms are the best ones from GM-H for cars without HQ stubs, the lower arms need less grinding to fit big bore shocks into them, etc.

[Stevo75]

Thanks Heath. Was there an ultimate front end post or something like that on this forum. I saw a few guys reference that but haven’t found it yet.

Just summarising what I took from your post.

1. Start with complete UC front end. (Are these the same for all UC’s?) There was mention that the starfire 4 cyl crossmember is the same as the 6 or 8 cyl. For my info are the bottom control arms and crossmember the same for the LH, LX and UC. I.e if I got stuck, could I use the cross member and lower control arms from my LH?

2. Re-drill for upper control arm (I take it this is just a simple measure down ‘x’ distance from existing and drill away).

3. Use my LH steering rack with solid mounts. (Is there any info on the dimensions and material for these?)

4. Should I use the HQ stubs?

5. Not quite sure I understand your last part. What steering arms and upper control arms should I use assuming I do use HQ stubs?

6. I’m guessing for calipers and disks, it’s best to go aftermarket. There seems to be some good gear around these days for reasonable $, instead of paying top $ for old tech HQ calipers and disks. Would that be a fair call.

Thanks heaps for the advise Heath. I know you’re probably sick of repeating yourself for some of this. Just tricky to find the right post sometimes and a lot of them I’ve seen, have a bit of debate on the better system without any consensus reached.

[LXCHEV]

I love my old school HQ stubs/disks/calipers (which is essentially A9X). Super basic, cheap as chips, and nothing exotic what-so-ever, but works great for a street cruiser.

 

Mind you - if I had a clean slate (and a little bit of cash), I'd take a good look at the new Hoppers Stoppers brakes. I believe they retain the standard Torana stub axles. The calipers certainly add a bit of bling.

[ls2lxhatch]

You will find some pictures here.

https://ls2lxhatch.com/suspension.htm

[Heath]

I have written it out a bunch of times, but I had a quick search and couldn't find it.
 
1. Start with complete UC front end. (Are these the same for all UC’s?) There was mention that the starfire 4 cyl crossmember is the same as the 6 or 8 cyl. For my info are the bottom control arms and crossmember the same for the LH, LX and UC. I.e if I got stuck, could I use the cross member and lower control arms from my LH?
1: You can start with a UC front end, all UC front ends are the same, or the same enough. In fact all LH-UC K-frames are basically identical. The bottom control arms on LH's are thicker, LH's and LX's have a small round shock hole which needs to be made much bigger for proper shocks. All of the parts are interchangeable.

2. Re-drill for upper control arm (I take it this is just a simple measure down ‘x’ distance from existing and drill away).
2: Yeah you just re-drill those upper control arm mount holes as low down as you can. Simple as.
http://www.gmh-toran...hatch/?p=764147

3. Use my LH steering rack with solid mounts. (Is there any info on the dimensions and material for these?)
3: Just make some ally bushes. I found that the crossmember was not "straight" enough for the steering rack to be simply solid mounted (when I did the bolts up, it distorted the rack so it did not move freely), so a little rubber pad behind each aluminium bush took up the slight misalignment and made the rack function freely:
http://www.gmh-toran...hatch/?p=765781
If you're a big softie and you like lighter steering, you can use the UC rack which is already solid mounted. There is not a big difference but if we are talking "ultimate" then it would be a solid mounted LH rack for sure.
 
4. Should I use the HQ stubs?
4: If you prefer the idea of full-sized Holden brakes compared to what's an offer nowadays, sure. They are a little bit of a 'drop stub' also, but no huge advantage either way.
But no, you should use Torana stubs otherwise. All Torana stubs are the same unless your car is an A9X or has a drum brake front end.
If you are going to make your own custom brake package, just use Torana stubs I reckon.

5. Not quite sure I understand your last part. What steering arms and upper control arms should I use assuming I do use HQ stubs?
5: The best upper arms and steering arms for a normal Torana with normal Torana stubs are UC ones.
The UC upper arms have an offset upper balljoint (it sits further aft in the car) and this allows you to run better steering geometry by having more positive castor. This is critical for making a Torana street car drive well.
The UC steering arms are slightly longer than LH/LX (not ideal) but they have a better toe curve (AKA Bump Steer) for a car with positive castor. Maaaaybe A9X steering arms are a benefit with loads of castor, still on Torana stubs, but I am not sure of that. UC steering arms are a safe choice and not very expensive.
 
6. I’m guessing for calipers and disks, it’s best to go aftermarket. There seems to be some good gear around these days for reasonable $, instead of paying top $ for old tech HQ calipers and disks. Would that be a fair call.
6: Yeah, that's a fair call. I don't know of that many brake kits but there are a few and they are fine.
The normal "Hoppers" kit is all OEM brake parts (ignoring the hubs), so it's not "aftermarket" like a Harrop/Wilwood/AP/Brembo etc. package that you could piece together - the Hoppers kit is like if someone handy went to a wrecker and figured out a bunch of OEM parts that fit together and work nicely. I would take that option over HQ brakes, probably.
Hoppers have some kind of flashy 4 pot caliper that they can offer, but nearly all of their kits I've seen are an OEM sliding caliper. They aren't brake porn, but they're effective brakes for a street car, no doubt.

[Stevo75]

Thanks heaps Heath.

Yeah I know you must get tired of reiterating the set up. I know I had seen the ultimate front end post quite a few years ago but buggered if I could find it last night.

What you’ve posted here is nice and clear tho. I know what I’m looking for now.

Off to put the word out for parts. I’ve been in touch with a guy who has a lead on a 6 cyl UC in a paddock, so I’ll chase that.

Cheers

Steve