Diesel gearbox questions

[timmytheboy]

Hey dubbers I’m in the process of collect bits for a 02j conversion on the old diesel. Now my question is if I use a petrol gear box how will it effect the driving of the diesel? The hope is one day I’ll find the holy grail 16v and the box will be ready.

I’m not to concerned about power delivery mostly freeway cruzing. Is it the final drive that matters when looking for a box? It’s a 4 speed at the moment so it revs quiet high on the freeway.

Next question is will a g60 flywheel bolt up to a 1.5 diesel? I’d like to get the vr6 clutch and g60 flywheels in during the gearbox upgrade.

Also could someone please explained the 100mm axles to me simply the more I research the more confused I am. Can I use existing axles? Will I need 100mm cv joints and to change gearbox flanges to 100mm?

Cheers guys Any info would be great!

Tim.

[Bora Sport]

Typically the gearbox in a petrol car will be designed to give say 100kph at around or just over 3,000rpm. A diesel will be getting towards the upper end of its rev range at 3,000rpm. For example my diesel Octavia does 110kph at around 2,000 rpm. So in a nutshell if you use a typical petrol car gearbox a diesel will be undergeared. There are some petrol gearboxes from the early Golfs (4+E for example) that have relatively high gearing particularly in 5th gear that might suit. I'm pretty sure that will not apply to any of the modern gearboxes though.

Yes the final drive ratio is important. The lower the number numerically the more suited it will be for the diesel assuming the gear ratios are the same.

Sorry I can't help with the other questions.

[timmytheboy]

Thanks for the info.

Not sure if You know much about ratios but the box I’m looking at is a

02j EGU 3.300/1.944/1.308/1.029/0.837 FD 3.944

Going from a 4 speed 020 GC 3.400/1.940/1.290/0.970 FD 3.890

Will the extra gear help with keeping down revs?

Cheers

[sports racer]

Gearing will be slightly better at keeping the revs down if I worked this out right. With the 5 speed in top gear it will be 3.3 rotations of the motor for 1 rotation of the wheel (5th gear ratio x final drive ratio). For the 4 speed it's 3.7 rotations.

CV's come with either a 90mm flange plate (where they attach to the gearbox) or a 100mm flange. If the gearbox has 100mm you need the 100mm CV's to fit.

Cheers

Paul

[timmytheboy]

ok great thanks paul.

so with the cvs will the 100mm joint fit on the mk1 drive shaft? or will i need new shafts as ive read something about them being longer? is outer cv the same?

so last question guys if anyone know is will a g60 flywheel bolt to a mk1 1.5 diesel?

cheers, Tim.

[sports racer]

Give Peter Shelley (Canberra VW Centre in Newcastle) a call. 0414 573 485

Peter's forgotten more about MK1's than most people know.

[mnaussie]

Speaking from Experience, replacing the 4sp with a 5sp in a 1.5 is not going to get you much except a lot more shifting on the slightest incline. My 82 was great to drive with a 4sp but struggled above 100kph. I currently own a 79 in the states that had a 1.5 with factory 5sp, was OK but not ideal. On the hwy I would have to shift quite a bit on the slightest incline or headwind much better with the fresher 1.6 and even better with the 1.6 with turbo installed. The same sections of road with the 1.6 I no longer had to shift to just maintain speed. The 1.5 is a higher RPM engine than the 1.6 also

[AUC-05L]

I have a complete 020 5 speed conversion including new driveshatfs and clutch for sale. PM me if your interested.