Basic Distributor set up and static ignition timing

Looks fine to me.

 

Pretty much the same way I did it back when I had points. It should start up OK and then you can fine tune it. Good luck

 

This is a topic close to my heart at the moment.

I have a Euro (UK) spec, dry sump, carb '76 GTB (2-valve) with a single distributor. This has two sets of points, one for each bank, and a concentric, double-ended rotor arm that serves one bank at the outer ring and the second bank on an inner ring of cap terminals. It does not have the R2 'retard' points required to meet US emission regulations.

I have puzzled hard and long over interpreting the manual instructions for setting the static timing. The text and diagrams seem to refer to DISTRIBUTOR timing, static being 6deg advance. To me this means 12deg at the crank but the timing flywheel timing marks conflict with this idea and suggest that its 6deg at the crank.

My point is that, when set up with static at 12deg, or even a bit more, the car goes one heck of a lot better that with 6degrees and there's no evidence of detonation (pre-ignition or 'pinking'). With 6deg it idles like a dog and is sluggish everywhere in the rev range.

I only ever feed it on 97/98 octane fuel with Castrol lead substitute additive and octane booster.

Any ideas on the correct interpretation gratefully received.

Paul

 

From what I know, having alot of advance movement in the lower rev range does help with part-throttle response and shouldn't cause detonation problems - especially if you're using high octane fuel. It's in the higher rev range where it's more critical and that you don't want too much advance.

Because you're advancing the distributor 6 degrees at idle (beyond the stock setting from 6 to 12 degrees), that 6 degrees will also be present at max advance too (stock is 34 degrees so it now will be 40 degrees). I can't say if this is a safe number, but with the very high octane you're using, you should be able to use that setting...

 

Thanks, that was my reasoning too.

If I can get someone to push the pedal for me I'm going to check the advance up the rev range to make sure that the curve is roughly what it should be and doesn't go wildly advanced at the top end. 40 degrees doesn't look too much compared to other tuned engines I've worked with. But of course they're all different and some will take the extra advance while others won't even look at it.

I have in my head a plan to go 3D mapped electronic ignition with a throttle position sensor, timed off a toothed crank pulley, possibly going to twin wasted spark coils and doing away with the distributor all together. My expectation is that, properly mapped, the improvement in power and drivability will be very significant.

 

"The text and diagrams seem to refer to DISTRIBUTOR timing,"

I guess with Ferrari anything is possible but I have never heard of an engine where the timing was based on distributer timing - it's based on crankshaft degrees prior to tdc for the piston. That's what the engine sees and that's what the spark is based upon.

6 degrees static is a fairly common number though I have seen engines that were happiest with as much as 14 degrees and the SAME exact engine in another car that wouldn't accept any more than 8-9 - both with max advance of 38 degrees.

 

Well, I haven't had time to run it up yet and do the check. Having found a bit of over-winter condensation 'moose' around the filler cap whilst doing an oil and filter change, I've currently got the dry sump oil tank out for cleaning so now would not be a good time! And, anyway, I've hidden the keys away, just in case I forget that there's no oil available to lube the engine.

I've had the dizzy to pieces and, as you say, its not like the Lucas units and its only the cam that turns with centrifugal advance, not the rotor arm. I've cleaned the weights and springs which, this time around, weren't at all sticky. Unlike the first time I did it when I thought some epoxy had got in there.

I got myself a second hand Snap-On digital timing light off ebay a month or two back so I should be able to measure pretty accurately once I get it all back together.

Paul