Engine: 2.1 Carb B21A: Converting to electronic ignition?

[scooters]

Originally Posted by Steve and his 244

Hi, thanks for the pic. That makes things a little easier now.

Ive only just set the timing on my car, but i'll double check it anyway after fitting the hotspark system just so I know its right (I have a strobe light)

By the way, you 79 245 was originally designed to run on 98 octane fuel with the timing set at 12 degrees BTDC. When 95 became the norm, volvos official recommended figure for running on 95 octane was 7 degrees BTDC.

Is it when it is a lower number BTDC that you have to worry about holes pistons etc or is it when its a bigger number?

Steve

Worth doing properly but I wouldn't be overtly worried. Jim, my new mobile mechanic who worked on the B21 for 15 years told me that the timing on the B21 is a pretty rudimentary affair, being a lazy enough engine at the best of times and you could usually get it to safe if not efficiant parameters with the test buld method! - the give away is the lack of play in the adjuster bolt on the dizzy - some cars have huge amounts - there isn't a lot to play with on the 244 B21 at all!

[pookie]

Advancing the ignition timing ( higher numbers ) increases the risk of pre-ignition. This can be heard as " pinking " and can cause damage to pistons if it is severe. Retarding the timing ( lower numbers ) prevents this.


Pookie