More dizzy questions - 45D

[chrisryder]

After thinking of getting an electronic 25D for Borris and being informed a 45D would be better, I've just had the brilliant idea of fitting my electronic 25D off Bluey onto Borris, and fit a shiny new 45D onto Bluey in return.

Bluey's currently running a 1098 with 1275 head, LCB and HS4. I presume from my previous thread that a 45D will be better than anything else as it's 'a more modern dizzy', i'm just concerned about getting the advance right.

I already struggle with pinking, despite the compression seeming fairly low (done a test). Upon fitting the head I had to drastically retard the ignition timing to alleviate pinking.

Will any 45D do? Is there a certain one to look out for that'll be better than others?

[Alec]

Hello Chris,

I'm not convinced that a more modern distributor is neccesarily better. For example the Lucas distributor on my 1948 Ferguson tractor has a ball bearing as the upper spindle bearing, so when it wears fitting a new bearing is an easy repair and restores the distributor to near new condition again. The 25D series has the useful micrometer adjustment of the timing, very handy for fine tuning.

Selecting a distributor for your non standard engine probably will need some information from someone else who has done the same modifications. Ideally it needs a rolling road session but there should be sufficient information out there. When you say you have significantly retarded the timing, what sort of figure are you talking about?

Alec

[myminor1969]

Hi I have a 45d from Simonbbc fitted with a Lucas Gold sports coil on a 1098cc. I initially timed up as standard 6deg BTDC @ 600 RPM. Car runs fine much smoother but a little flat on accelleration. Just Advance the timing to make sure it doesn't pick under load.
PS the vacuum is push-on type I just used a small piece of tube pushed over the end of original metal vacuum pipe.

[chrisryder]

i've no idea what figure i'm currently at, no real way of accurately telling.

there were several (a dozen?) full turns of the micrometer until i ran out of adjustment then still had to rotate the dizzy body back too!

[Alec]

Hello Chris,

doing a static timing test will tell you that.

Alec

[bmcecosse]

Sure the vacuum advance is working ?? It's entirely up to you which dizzy you pick - but I fancy that when Lucas designed the 45 D they aimed to reduce manufacturing costs - and hopefully also to try to eliminate some of the failings of the 25D. Hence the larger diameter cap to separate the contacts slightly more to minimise tracking - and no doubt better engineered advance mechanism. And yes - they dropped the micrometer adjuster - saves people fiddling with things they don't understand..........and saves on cost.

[dalebrignall]

chris i have a 45d with lumatronic electronic ignition it runs fine ,no problems at all .