Triumph Repair: crown wheel and gear, overdrive transmission, crown wheel

Question
Hi Jim, I have a 1972 spitfire IV the engine was replaced with a 1500 motor. and I still have a 4.11 rear end with a 4 speed trans. I am thinking of changing the crown and gear in my unit with a 3.63. Is this have to be done professionally. I love to wrench and haven't had to hire a mechanic in many years. I am just not sure if I would need special tools or special setting that have to be set. Or is it pretty straight forward? I need to do something right now 60 mph I am at 4000 rpms the car is always in high rpms. Will this make a difference? is it worth doing? Is the 3.89 going to have the same performance.. sorry for so many questions just need some advise before I spend all this cash.. Thanks Mark

Answer
Mark,

Unless you have a good tool setup replacing the ring and pinion yourself successfully isn't a viable option.

The 3.89 gearing was "stock" with the 1500.  You'd be happier on extended highway trips with the optional overdrive transmission.

You'll get similar highway results with a 3.63, but with loss of off the line performance.

I'd recommend finding someone in your local Triumph club with similar setups to what you're considering and seeing if you can cadge a test drive.   That'll be the best way of judging the differences.

Local clubs can be found on the VTR website (www.VTR.org), look under the "local Chapters" link.


Cheers,

Jim