gearbox crossmember

[jarvo]

Hi all,

Looking for some advice.

The previous owner of my EK put in a motor and gearbox from a VH commodore. He cut up the gearbox crossmember and built his own to support the gearbox. I don't like the look of it and want to replace it with something more solid. Does anyone know of a shop i can buy a kit off the shelf? I also need the part that goes over the gearbox just under my new larger trans tunnel.

all help and advice appreciated

Cheers
Jarvo

[jarvo]

So ive trolled through other posts and it looks like you cant buy a kit off the shelf and i have to make one myself

I havent found a sticky yet or details how to make my own, so can some one point me in the right direction to which thread has step by step instructions?

Cheers
CJ

[Blacky]

To make the brace over the trans tunnel just make a cardboard template that sits against the floor and picks up your brace that has been cut away , then cut it out of 6mm plate - I need to do one this weekend so I might post up a how to ....

[rosco]

Jarvo - you are going to regret me answering this...

Do you have a MIG welder?

No, you can't buy a floor brace from any of the aftermarket suppliers, sorry...

Ok - let me know if you want me to chime in on this... I have lots of pix of what I did - after doing the rounds to fabricators.. they weren't interested in "one offs".. they would tool up to make 100 - but the cost was around the $2,500 mark - divide that by 100 and you end up with $250 each.... double that and it would pay for a MIG you could actually "use" .... not like the cheapo 4 setting units you find in Bunnings etc...

As Blacky states - you'll have to mark out and make a template of what you need.... I made one out of ply - and took this off to the fabricators.... coming back home each day with an even more disheartend result.

It was the sole reason I enrolled in a TAFE MIG welding course and purchased a better than average MIG...
I haven't looked back - and now also have an even more advanced TIG for panel work and aluminium/stainless etc..etc....

I made up my "arch" under the hump by purchasing some 2" x 1" rhs tube, cutting the overlap out with an angle grinder and MIG'ing it back together again. I did this until the arch was formed - then I made up the angled mounting plates to the floor cross-member and MIG'ed that to the floor cross-member.

For the transmission mount, I had previously had a Rares trans mount - which was a huge assembly that bolted through the floor and held up the transmission by sheer brute strength - it also re-enforced the removal of that factory floor member which ran under the transmission hump.

What an engineer will need you to do now - is to fit a chassis rail kit - there is an adjustable transmission mount which is bolted to each rail - you simply drill and fit it where your rear trans mount needs it.

There is also a tail-shaft hanger - which is also bolted between the rails - its purpose is to hold the spinning tailshaft captive should the uni joints fail and threaten the tail-shaft digging into the road and catapulting you into oblivion....

You might like to chase up CRS and see if the kit is still available.

As for the "arch" - you will have to either make one yourself, get a friend to help who has the equipment or have one made for you...

You will need an engineering certificate for insurance and registration purposes...

PM me if you need more - happy to show you what I did with mine....


frats,
Rosco

[jarvo]

Thanks guys.

Luckily enough for me my step dad is a boiler maker with 40+ years experience using a mig. Would be great to see step by step pics in how to fab these bits so i can show him.

I appreciate all the advice so thanks again.

We will hopefully tackle this in a week or 2

Cheers
Jarvo

[rosco]

Jarvo - I can't do this today - but I will post a couple of the end result - your Dad will be able to make one of these up for you... in the meantime, get your cardboard out and cut out something you want him to work from.
the hump arch base will be angled forwards at each side - so that it can be MIG'ed to the body frame.
You will need to make up an angled piece across the underside of your trans which can be bolted to and removed from the frame when pulling out gearboxes or motors etc....
On the removable bit - I welded my handbrake lever frame.... pix soon... not many, but between what you cut out and my pix - your Dad will easily get the idea of what's needed...

frats,
Rosco

[jarvo]

Cheers Rosco,

I will pass on the details to the old man. He is keen to give this a crack which is good

Jarvo

[rosco]

Hi Jarvo,
Just trawled through my pix - and only came up with one so far....

If you take a close look - you'll see the arch was made up by grinding out 3 faces of each cut then pulling it back together to eventually form the rounded arch - these were done about every 1".

The cross bar which looks like it runs along the bottom is actually the rear trans mount... it's located about 1 foot further back - but the pic give the illusion it's part of the arch - it's not.

You can see my attempt to create a removable flat section laying on the floor.. with the handbrake frame welded to it.
I might make another one of these later on - it looks pretty ordinary - but in the 31 years of use so far hasn't shown any signs of problem.

You can also see the lower ends of the arch where they are angled forwards to align with the body floor frame - just inside where the subframe bolts to. I left enough of the original frame to be able to beef up that area with rhs and MIG it in... the arch was then MIG'd to the new steel rhs - it was a lot easier to do it this way, rather than muck around trying to MIG the arch directly to the frame.

Pic... I'm still looking for more.. they might have been taken pre-digital.. and I have boxes and boxes of printed pix of this old bus to fish through and find the ones we want...



frats,
Rosco

[jarvo]

Thanks Heaps Rosco,

I will show my dad, i have also found a couple of pics from other threads of cross members so i have saved them to a zip drive, the only thing is i dont have the details of what was used, dimensions etc. He is pretty cluey so im hoping he will work it out just from the pics. (he has been building truck trailers for most his life so im sure he is capable)

[Devilrod]

We did something similar to Rosco. Basically curved a section of rectangular steel welded it up and welded it in. My crossmember was custom made to suit once the auto was in. I think there are pics on my build threads.

[jarvo]

Thanks DR,

I will check out your build and maybe do something similar

Cheers
CJ

[rosco]

CJ - I used 2" x 1" for the arch - and much the same for the vertical rhs to the body frame.

let me know if you want more...

frats,
Rosco

[Devilrod]

Here's mine we made...

This is from this thread.

http://www.fbekholden.com/forum/viewtop ... f=5&t=2425

[rosco]

Good work, Brett - that's pretty much what Rares gave me in '83 to mount the rear tranny.
When I cut out the big hole in the floor and took the "hump" section of the floor crossmember with the cut, I wasn't too happy about just having the tranny mount through the floor to hold it all together - although Rare's told me it was fine.

I had access to a stick welder and just couldn't help my self from making that horrible original upper and lower brace on each side of my hump.

When I came back to re-address the area some 14 years later - and had bought a MIG by then - I designed and made up the "ARCH" and lower bracket... I was a lot happier with the end result - which, incidentally - included the Rare's trans mount... which weighs probably twice that of the Arch I put together... my floor isn't going anywhere.

I did hear the odd "creak" from time to time with just he Rare's tranny mount... but now with the added arch and lower member - you could probably winch the whole car up on the arch alone.... F1 racing cars don't have the "Arch" I built... there's is mediocre compared to mine.....

frats,
Rosco

[Devilrod]

Rosco, mine was originally holding a supra 5 speed in another EK and was engineer approved with similar size flat plates as seen below on the inside of the car. No creaks or grains and worked really well.

One thing to keep in mind Jarvo is maintaining the right geometry when you make the mount and try not to have it hanging down too much.