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Renault gearbox to G-Car - is it possible


simonf

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Hi there,

Chats from the forum popped round at the weekend and we went for a thrash in his GT3 (which was proper by the way! :band: ) And i commented on how slick and positive his gearbox was. When i questioned from what parts bin it came from he replied "Its from a Renault 21" Well there must be hundreds of those rotting away in scrapyards so thats got me to thinkin' could I mate the same gearbox to my S3 turbo 2.2? I meen the engines look pretty well identical, allbeit that the GT3 had a different position of the wastegate and of course that lovelly chargecooler but everything else looked the same!

Has anybody attempted this? I have got to do my clutch this winter anyjow so thought if it was relatively straight forward i might as well do both together!

Your help as ever is greatly appreciated

Si

Edited by simonf

REHABS FOR QUITTERS!!

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It came up in a recent discussion, from memory the main points are. I think Simon350s started that topic, but could easily be wrong on that.

Brakes, you need to find a way to mount them/ fit later hub carriers

Gear change, you need to move to cable operated

Drive shafts, need to be swapped to later style

Mountings, swapped to later style

If you want to see the differences between the two, compare two cars (next Norfolk meet?).

Andy

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This has been raised a few time before, the simple answer is "it ain't simple)

Renault boxs that you will find in a scrap yard will have the wrong bell housing on them, Lotus made one to mate up to the 9xx engine.

So you really need a gearbox from a crashed car (unless you can find a bell housing somewhere), but you will also need :-

gearbox mounts

clutch

driveshafts

rear uprights with hubs

rear radius arms

rear disks

rear calipers

the rear brake pipes need re-routing

gear change linkage is totally different

exhaust mountings

the crank needs to be machined to accept a different spigot bearing

Plus a bunch of other stuff I have probably forgotten to mention.

And after all that you will then find that the rear wheels won't go on as they changed the bolt PCD between 'G' and 'S' cars and the offset will be all wrong.

Therefore it isn't a simple or cheap conversion, let alone getting hold of the parts.

Sorry to be the bearer of bad news.......................

Hilly

Edited by hilly

1981 S3 4.2 V8 6 speed (The Mutant)

Mutant V8 Conversion Thread

Knowledge is power .................... apparently.

 

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Ah right - that sounds like a bit of a chore! I was kind of hoping it would bolt straight on as i don't fancy chopping, welding, bending or bodging!! My gearbox isn't so bad as to require major work! But thanks anyway.

Def o see you at the next meet - is always nice to see a fellow G Car in an otherwise Stevens event!!

Si

Ps you got your rear valance back on yet?

REHABS FOR QUITTERS!!

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Ps you got your rear valance back on yet?

I see no rush for that, it's been off for the last 12 months +, so what's another year?

It's not even the right colour yet.

Re conversion, I'd written that assuming the use of a Renault box from an Esprit.

Andy

Edited by andydclements
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This has been raised a few time before, the simple answer is "it ain't simple)

Renault boxs that you will find in a scrap yard will have the wrong bell housing on them, Lotus made one to mate up to the 9xx engine.

So you really need a gearbox from a crashed car (unless you can find a bell housing somewhere), but you will also need :-

gearbox mounts

clutch

driveshafts

rear uprights with hubs

rear radius arms

rear disks

rear calipers

the rear brake pipes need re-routing

gear change linkage is totally different

exhaust mountings

the crank needs to be machined to accept a different spigot bearing

Plus a bunch of other stuff I have probably forgotten to mention.

And after all that you will then find that the rear wheels won't go on as they changed the bolt PCD between 'G' and 'S' cars and the offset will be all wrong.

Therefore it isn't a simple or cheap conversion, let alone getting hold of the parts.

Sorry to be the bearer of bad news.......................

Hilly

Cheers Hilly - I will give that one a SWERVE!!!

Si

Ps thats either a very good use of photoshop or you have horned an S4 4.2V8 into a G - CAR!!!!

If so....Holy crap i bet she is the fastest G Car around...I hope you ve done something to the anchors!!!!

REHABS FOR QUITTERS!!

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How feasible would it be to fix the current inboard discs etc to the Renault box ?

Keep off the straight and narrow

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Cheers Hilly - I will give that one a SWERVE!!!

Si

Ps thats either a very good use of photoshop or you have horned an S4 4.2V8 into a G - CAR!!!!

If so....Holy crap i bet she is the fastest G Car around...I hope you ve done something to the anchors!!!!

Si

Your eyes are still working correctly, I have wedged a 4.2 V8 and six speed box into a 'G'car.

I haven't finished it yet (I am bloody close) so haven't a clue have quick it is.

The brakes haven't been the only head ache, for the full details looky here Clicky

Hilly

1981 S3 4.2 V8 6 speed (The Mutant)

Mutant V8 Conversion Thread

Knowledge is power .................... apparently.

 

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Si

Your eyes are still working correctly, I have wedged a 4.2 V8 and six speed box into a 'G'car.

I haven't finished it yet (I am bloody close) so haven't a clue have quick it is.

The brakes haven't been the only head ache, for the full details looky here Clicky

Hilly

Hilly, i must say i am very impressed!! You have shoe horned quite possibly the nicest engine around into one of the prettiest cars around! And the Nett result one of the quickest cars around!

I would be very interested to know the performance specs if you could get the times down! I should imagine though you are going to have to go for some wider rubber coz the S4 and RS4's are four wheel drive with good reason! as my formula prooves

LB=Lightweight body

LE=Lightweight engine

RWD= rear wheel drive

BGFiAlEoT= bloody good fun if not a little expensive on tyres!

LB+LE+RWD=BGFiAlEot!!!!! :)

It took to Audi boffins years to work that one out!

Edited by simonf

REHABS FOR QUITTERS!!

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Thanks

No idea how fast it will be, shouldn't hang about though.

I plan to stick with the 245/45 17 T-1s Toyos at the back for the time being as the Esprit is a fair bit lighter than the Audis plus the weight is rear biased which should help with traction.

Also if I stick with what I have currently got it will help the gearbox not to break as the torque put through it will be limited by the grip of the rear tyres.

If I find I do have a problem of continually lighting up the rear tyres then I'll have to consider larger rims.

Hilly

1981 S3 4.2 V8 6 speed (The Mutant)

Mutant V8 Conversion Thread

Knowledge is power .................... apparently.

 

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Simon

If you're concerned about the quality of your gearchange I'd be looking at the linkages first. All the rose joints etc are prone to wear and there is such a long linkage that any wear will effect the quality of change. Relatively cheap and simple to do.

Regards

Mat

post-1-0302470001278592957.jpg

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Simon

If you're concerned about the quality of your gearchange I'd be looking at the linkages first. All the rose joints etc are prone to wear and there is such a long linkage that any wear will effect the quality of change. Relatively cheap and simple to do.

Ah ha....Yea thats probably an avenue worth exploring before fitting a completely different gearbox ha ha - But would the linkage be responsible for crunching synchrios with speedy gearchanges? or grinding in reverse when hot. I think my Master cylinder push rod may need adjusting however as i noticed what feels like about an inch of pedal travel before you are moving fluid. Failing that it could be master cylinder itself and failing that maybe clutch!

Can you adjust the mastercylinder rod from inside the car adopting the lotus position!?

I know i am going about this all a#se about t*t but Chats GT3's gearbox was so smooht it just got me thinking if the gearbox transplant was posible and not oo much trouble

REHABS FOR QUITTERS!!

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I think you can get an improvement with your SM gearbox by giving the whole system a bit of an overhaul as the SM box changes just as well as a UN1.

By the sounds of it you want to look at the following: -

1) The slave cylinder .

This needs adjustment as the clutch wears.

Check it has got the lock nut (sometimes it is missing) as it can work it's self out of adjustment if missing.

2) Change the clutch hydraulic fluid as it is probably past it's best by now.

3) The cross gate cable

You need to adjust this as it will stretch over time.

Look at the clevis joint where the cable meets the gearbox linkage as this is a wear point. I swapped this for a ball joint as it had a lot less play in it.

Also check the cross gate arm on the gearbox as this can need tightening up as well, any play here will make for a sloppy change.

4) Replace the red cluch hose.

This softens when the engine is hot and instead of pushing out the slave cylinder the hose expands, not a lot (is that Paul Daniels I hear in the back ground?), but enough to cause problems.

The stainless braided hose is about

Edited by hilly

1981 S3 4.2 V8 6 speed (The Mutant)

Mutant V8 Conversion Thread

Knowledge is power .................... apparently.

 

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I think you can get an improvement with your SM gearbox by giving the whole system a bit of an overhaul as the SM box changes just as well as a UN1.

This lot will get the gearchange to like it came out of the factory and is much less hassle than putting a different gearbox on the car.

Hilly

Thanks hilly, very helpful

Well that my bank holiday weekend taken care of! Wonder what the wife's up to :thumbsup:

Simon

REHABS FOR QUITTERS!!

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Andy,

My gearbox change needs some attention, particularly the bushes in the mechanism.

Where would you advise going for the parts ?

Keep off the straight and narrow

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Andy,

My gearbox change needs some attention, particularly the bushes in the mechanism.

Where would you advise going for the parts ?

I'd happily say SJ sports cars, although I think they're the same price as from a Lotus dealer (good reason to go to Strattons, could possibly be there by Tuesday if you order tomorrow.

I need some door seals, so we could do a combined order (P&P on yours is going to get lost in mine). If you want a parts list i can send one through so you can look at which you need. Or you could call Steve / who ever else and they'll probably know by heart which ones you're most lilely to need.

Andy

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I'd happily say SJ sports cars, although I think they're the same price as from a Lotus dealer (good reason to go to Strattons, could possibly be there by Tuesday if you order tomorrow.

I need some door seals, so we could do a combined order (P&P on yours is going to get lost in mine). If you want a parts list i can send one through so you can look at which you need. Or you could call Steve / who ever else and they'll probably know by heart which ones you're most lilely to need.

Andy

Would you send that please Andy .. is it possible to attach it to a PM ??

Keep off the straight and narrow

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How feasible would it be to fix the current inboard discs etc to the Renault box ?

I have no choice on my project but to consider the UN1 unless I want to spend a fortune on an RBT ZF transaxle. With tuning to about 320hp.. the SM box would not last... hence my project conversion to UN1

The SM box output flanges are about 75mm wider than the UN1.. I decided that the OE IB brakes were not going to work well, so on my conversion to a UN1 I have conceptualized an inboard brake system to match the UN1 using aftermarket components. That way I can retain the wheel assy and links. The drive shafts need to be longer for the UN1. Mid 80's BMW 5 series shafts are the ones to use, unless you get custom ones made.

I have all the conversion parts in hand, and have Mike Rodriques on this forum to thank for all his valuable input.

If you set no goals you shall surely reach them..

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I have no choice on my project but to consider the UN1 unless I want to spend a fortune on an RBT ZF transaxle. With tuning to about 320hp.. the SM box would not last... hence my project conversion to UN1

The SM box output flanges are about 75mm wider than the UN1.. I decided that the OE IB brakes were not going to work well, so on my conversion to a UN1 I have conceptualized an inboard brake system to match the UN1 using aftermarket components. That way I can retain the wheel assy and links. The drive shafts need to be longer for the UN1. Mid 80's BMW 5 series shafts are the ones to use, unless you get custom ones made.

I have all the conversion parts in hand, and have Mike Rodriques on this forum to thank for all his valuable input.

Photos please Jan!

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Definitely interested in photos and any more details :thumbup:

How does the Renualt box compare with the Citroen with regard to length, and therefore position of the driveshafts ?

Edited by Nifty

Keep off the straight and narrow

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  • 3 weeks later...
Definitely interested in photos and any more details :whistle:

How does the Renualt box compare with the Citroen with regard to length, and therefore position of the driveshafts ?

I dont have any pix but Mike R has pix of his conversion..he is on this forum at times.

The driveshafts sit about 25mm further back and the tail of the GB reguires mods to the rear parcel shelf and muffler config... also linkage assy was improved on Mikes project.

If you set no goals you shall surely reach them..

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  • 2 weeks later...
Andy,

My gearbox change needs some attention, particularly the bushes in the mechanism.

Where would you advise going for the parts ?

Hi there - i have rebuilt the box in my S2 that i use for racing. It's a perfectly good box and feels really positive but i have shortened the throw to make it a bit quicker. If you rebuild the box the bearings come out to about 800 quid and the synchro rings just arent easily got.

Not bothered about selling them but have 2 really good spare boxes and one for spares if you run into any bother.

cheers

Simon

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Thanks Simon.

At present I'm only going to tackle the linkage and bushes.

Once I decide on whether I'm going to do any major engine mods/changes then I'll reconsider the gearbox issues/options.

Cheers,

Nifty.

Keep off the straight and narrow

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