Hi Adey,
If you recall, and as Steve previously advised, the early 330 R8 Box which you have factory fitted, has the weakest internals mainly the sunwheel tooth design & form, these Mk1 teeth can shear off easily when doing more sporty starts [worse with the addition torque of the 1400] also you will have hollow hardy spicer cross pieces within the universal joints housing the rubber stop at the halfshaft end.
These joints can be upgraded by disassembly and fitting solid hardy spicers which easily resolve the shattering problems, incidentally 8 out of 10 of my transaxle blow ups with std 330 boxes had shattered U/Js in the axle tube which then took out some teeth off the puny pinion gear, and or sheared sun wheels, breaking just where the shoulder is.
The R8Gordini solution was to keep the sunwheel tooth design, but they cleverly doubled the number of planet gears, but this itself revealed another issue with the cross pin and 2 shorter pins which would loose their rollpins and trepanne the box casing. Oddly enough the sun wheels were I think of a better quality material as they appear a bit shiny but they still snapped in half. Pat Bridger in the ex Goodwood, race car broke one in front of me as he left the start line at the Prescott La vie en Blue Hillclimb.
When I was pioneering the build of the first big Wheeler box in the 1980s using the R16 TL/TS 336 internals suitably modified this cured everything that had previously failed and I also had fitted solid U/J centres. locked in with grubscrews and Loctite bearing fit, these days internal circlip groove machining is the norm, making servicing the joints a lot easier. The joint kits were then BMW or Alfa or whatever.
The 336 diff ratio is 9x34 [ 3.777 ] not bad if you use 13" diameter wheels with low profile tyres.
A cheap and quick stop gap upgrade would be to find an R10 1289cc 4.125 later box [ like what your current bellhousing came from], this has strengthened planet gear teeth and a slightly taller 2nd gear ratio and bigger diameter crown wheel bolts, and bigger detent balls but thats all, fitting a pair of updated U/Js would give some insurance against the usual failures.
In period the R8G had the option of Factory homolgated upgraded pair of Group 2 U/Js solid centred with the halfshaft ends bored to receive the rubber bump stop My present South African 1135 Gordini came with drilled half shafts but no upgraded U/Js
When I later built the first 5 speed Wheeler big box, I used the internals sourced from the 385 R16TX box, and or 385 R5Gordini Atmo. these were fitted into the above but retained the R8G 353 5th housing and 5th synchro, and its factory gear selection, the diff ratio had now become shorter i.e.3.9, but R8G boxes are extremely rare and have always been expensive.
I would recommend that if you go down the big box solution then consider the 336/330 4 speed hybrid, a Quaife ATB is also available for this 10 bolt crownwheel found in the R16/R5G and is what I use in my current R8G Competition Car, but this very expensive diff is not necessary for road driving, the std R16 big 10 bolt open diff is beefed up everywhere and does not shed teeth or shear sunwheels.
I have built numerous boxes for my various competition use and for other Renault enthusiasts and I do not know of any failure to date.
These days exotic rear engined R8 / A110 boxes based around 353 5 speed boxes are available on line, with straight cut close ratio dog engagement gears and plate type LSD
but I read that they have their own problems, a friend hillclimbing in Spain with a Dauphine fitted with a 1550 Sacco unit has much to his understandable flustration, had 2 of these specialist these boxes fail on events.
The 330 Series Family of Factory Boxes appeared in later production and slightly altered in many FWD Renaults over the production decades, and as the particular model engine capacities are increased, they are suitably reinforced, mainly all in the final drive dept, i.e bigger diameter crown wheel and pinions with bigger bolts and bigger sun wheel splines, oddly the general bearing sizes seem to remain virtually the same , as do the synchro designs, but with some mods to the synchro baulk ring ramp angles.
I did once have a borrowed Hewland Mk8 5 speed cr/sc dog box from an R8 for evaluation a while back, this being based upon the VW beetle box , this particular box was converted to take R8 Swing Axles and the top mount, the idea was to learn about it and maybe utilise the gear clusters for our R8 boxes, The technical issues were just too much to resolve without a lot of machining saying that refurbished matched gear sets in pairs are cheap on ebay for the Hewland and ratio choices are good as well.
My 1951 4CV which was a loose build tribute copy of a works car, had an extremely rare Redele /Pons "Claude" 5 speed competition box with a helical geartrain but with dog engagement [a crash box] all 5 gears were fitted within the 4CV 3 speed die cast case with a 22mm spacer as well, as the original wide synchro hubs had been deleted, the final drive was a mountain ratio 4.9 .
When I first drove it to test the car I could change up OK through the gears but changing down and double declutching as well meant missed gears, not ideal in my book, so I made a mental note not to pursue the Hewland version any further. I suppose in period it was a hot transaxle to have in a 750cc 4CV.
The current Racing fraternity running the Formula Junior Cars race series which mainly run Dauphine Gordini gearboxes which is a named transmission in the Formula Rules Book, and which is similar to the above Claude box, were ringing me as they wanted to borrow my box to back engineer copies for their race cars-- Funny old World ! .
Cheers
Dave.
and ill keep a spare in the car for longer journeys just in case.
