Reinforce /make stronger a car gearbox

[hotponyshoes]

So I've taken in consideration an option .
Custom build one.
To adapt the original gearbox to the engine I'd have to laser cut an adapter plate ,then skimmed to make it perfectly flat and parallel.
Because of the bell housing which requires mods too ,cut parts etc.
Being this project a rally car,it will be always under load,stresses etc
My idea is to build the new housing out of steel ,yes more weight but an initial disadvantage can be considered a bigger advantage.
It's placed right in the center line of the car longitudinally , and at floor level.
This would surely increase weight but , it will make an huge difference in matter of weight distribution and center of gravity of the car itself
Mid rear so it will be less prone to roll over in my head.
View attachment 388903
This part in the middle is what contain the differential
I believe it would be possible to make it ,line bore for the shaft put .
And drive the diff using the output shaft from a FCA group modern 5 speed transmission (obviously modifying it) .
Also the diff from the same transmission so modern axles can be used "solving" several problems
I should take a modern gearbox, a 126 gearbox dismantle both study both and make it fit "together"
Unfortunately rules Don't allow me to cut the original car frame otherwise engine and gearbox would sit in the car as in a normal FWD car but moved to the rear which would be ideal.
This idea involves custom built input output shafts, gear housing, and modern stronger gear train from OEM.
It's hard to understand I guess but it works in my head

I don't know if you need to go as far as laser cutting and skimming.
I've seen bell housing adapters made by people just drilling a ring of holes and cutting it out with a jigsaw.
A decent bit of billet should be flat enough for that job as supplied. I bet if you could accurately measure the angle between the original belhousing face and the input shaft it won't be 100% from the factory anyway..

 

[hotponyshoes]

I've got some big sheets of alloy billet here, I'll measure one up if you like and see how flat they are as they come

 

[Memmeddu]

What I've discovered is that here in Italy it's not possible to make and drive what I want.
Rules continuously change , and becomes every day harder and harder to accomplish this goal.
I'm pretty negative about .
Till few years ago was possible to build little group b looking cars
Nowadays not anymore .
The car I chosen itself has to be revolutionised to do that .
Way easier to build a tubular frame and put a fiberglass shell on it .
Unfortunately even this option is not an option because it has to be registered.
The only way is to turbocharge the original engine add electronics , put a roll bar ,disc brakes ,fly on handbrake , racing seats an belts and a pedal box.
I don't want to compete with it never wanted to win just having fun and get better driving.

 

[bricol]

You can redesign the gearbox, remake the internals from special steels, modify tooth profiles, change bearings, use super duper oils - all can be done, as we've done it working with some experienced gear people for an industrial machine gearbox that had to have certain ratios, and fit in a specified space, or it would not work. Was not cheap.

And what happens when you break something? You fit the spare you had the forethought, and had the budget, to make at the same time as all the original components.

But what happens the next time something fails . . . ?

You can spend all your budget, half your life making the perfect competition car . . . or you could have spent the last decade enjoying thrashing a club spec car, with spares available everywhere, even the local breakers yard, having a whale of a time . . . just saying . . .

 

[8ob]

Don't discount using another transmissions internals, a friend that raced a Marcos used Ford internal gear sets in a Volvo casing to circumnavigate racing class /rules.
I made a casting to use a g50 porsche gear set in my own bell/diff housing for a transaxle on a project. That corrected otherwise impossible driveshaft angles (flipped diff) and allowed the use of a full size flywheel/clutch combo. A fair bit of work but worth the grief.

Bob

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Vs this which would have had to run upside down.

 

[PhillipM]

Remember the first time you started mentioning all this and I said do the bare minimum to a stock one and go racing first otherwise you're going to spend 10 years and £20,000 in the garage for a car you might not like or are even to race by then?
Yea, still that.

That's an interesting one though 8ob, what was that for? Looks like it'd work for us...

 

[Memmeddu]

Remember the first time you started mentioning all this and I said do the bare minimum to a stock one and go racing first otherwise you're going to spend 10 years and £20,000 in the garage for a car you might not like or are even to race by then?
Yea, still that.

That's an interesting one though 8ob, what was that for? Looks like it'd work for us...

Yes I remember and came out tremendously true .
I think I would directly left the project.
It's exhausting my mental energies
If will happen as stock as possible with serious improvement on what's most important (brakes, suspension, engine reliability)

 

[stuvy]

Remember the first time you started mentioning all this and I said do the bare minimum to a stock one and go racing first otherwise you're going to spend 10 years and £20,000 in the garage for a car you might not like or are even to race by then?
Yea, still that.

That's an interesting one though 8ob, what was that for? Looks like it'd work for us...

Yes I remember and came out tremendously true .
I think I would directly left the project.
It's exhausting my mental energies
If will happen as stock as possible with serious improvement on what's most important (brakes, suspension, engine reliability)

Build it up, get used to it then make it faster

I raced in the RGB championship and guys would turn up with winnebagos, race shuttles and a£100k race car and run brand new tyres each 20 minute race

Then be struggling to be in the top 10

All the time beaten by someone that didn’t take it seriously and would just have fun in a home built car

 

[PhillipM]

Same with ours, some of the top boys have 1-2 spare cars too!
All to plod around in the mud for a plastic trophy.

 

[minimutly]

Same with ours, some of the top boys have 1-2 spare cars too!
All to plod around in the mud for a plastic trophy.

Same as National Autograss has gone - £20 to £30k cars, plus anything up to £100k mohos, no prize money, tin trophy at the end of the year. Wife told me to get real years ago - competing against people with their own businesses, putting everything they could and more down against tax, buying engines, cars etc. I built everything, engine, gearbox, car, even trailer, and at one time converted a van to campervan to tow it.
You need a lot of money, a lot of time, orboth...

 

[PhillipM]

There must be 10 cars at 100k+ now in safaris, and a lot more at 60-70k area, plus 50-100k motorhomes (some teams bring 2-3!), etc.
Insane how much money has poured into some stuff lately. And yes, you're right, so many using them as business and tax writeoffs on the sly, always been bad for that, a lot worse these days.

 

[8ob]

There must be 10 cars at 100k+ now in safaris, and a lot more at 60-70k area, plus 50-100k motorhomes (some teams bring 2-3!), etc.
Insane how much money has poured into some stuff lately. And yes, you're right, so many using them as business and tax writeoffs on the sly, always been bad for that, a lot worse these days.

Not hard to get to that either, transaxles alone can be 10k-15k and a half sensible V8 can run to 25k. I built up that g50 above for a mid engined car with a V8, that box can hang on to 600hp without any issues, used to be able to find them for about £1,500 but they seem to have doubled now. The alternative at the time was this https://shop.quaife.co.uk/shop/gearboxes/h-pattern/synchromesh/qbe62g/

Bob

 

[PhillipM]

Yes, I had a G50 box for the buggy once but it just didn't make sense to try to make it work as stock, ended up on the Master transaxle instead.

 

[minimutly]

Yes, I had a G50 box for the buggy once but it just didn't make sense to try to make it work as stock, ended up on the Master transaxle instead.

Master?

 

[PhillipM]

Renault Master. UN1/UN5

 

[minimutly]

Renault Master. UN1/UN5

Is that related to the Renault 30 box?

 

[Memmeddu]

Made research
The original engine is capable of 90HP fully forged with upgraded carb and custom head .
The gearbox is always the same and there are no particular upgrades for it.
So I believe it can handle more hp than what I imagined.
And this explains the whole lot of engine swaps in Poland.
To modify the original engine you have to spend at least
800 euros for the cylinder + forged pistons and H Conrods
1200 for the head
300 for the crankshaft
And other 600 for the oil system.
The engine is famous for its reliability and strength
Swap the engine it's just 200 Euros