500 (Classic) 500D 126 transplant

[TheSlowlane]

Hi I have 500D 1963 model with suicide doors and want to put a 650 niki 126 engine and gearbox I know these fit the latter 500's but do the drive shafts etc fit into the 500D as the holes in the chassis look small and I don't want to by a engine and gear box and find it does not fit I can but a complete niki car so would have every thing need if it fits has any one done this conversion
Regards Ray

 

[Damon500]

Hi Ray,
There are several ways of approaching this conversion with varying degrees of cost and durability- all will require partial disassembly of the transaxle to remove the diff and change axles- here are 3 options starting with the best (and dearest) and working back..
1) Fit a set of 500R axles and flanges to your transaxle- these are the same diameter as the Niki ones but shorter. You will also need a set of 500F rear suspension arms and drive couplings. Niki Arms won't work as they are too wide and the wheels will stick out of the arches.
2) Fit a conversion kit with 500R axles and flanges modified to suit 500D drive couplings- these are available from suppliers such as axel gerstl and will work well on a moderately driven vehicle with a standard 650 engine. Make sure your drive couplings are in good condition as they won't last too long with this conversion.
3) Fit the 500D axles into the niki diff with Niki cross pins pressed in and spacers on the inner drive blocks to take up the clearance. This is a temporary solution that would only be contemplated if your 500D driveshafts and flanges are in exceptional condition and you intend to drive the car very lightly- the flanges and splines will strip rapidly and driveshafts can snap completely so I only suggest this option with extreme caution.
It is definitely worth doing the 650 conversion- I have travelled in excess of 70,000km in my daily driver 500Fs with 650 conversions - they have been extremely reliable and keep pace with the traffic.

 

[AlekNedelchev]

Let me know if you need any advice on the matter or if you need any of the parts for the conversion.