512 BBi Ignition Timing Spec?

Your 224/81 OM shows the "10 degrees @ 1000 RPM and 29 @ 5000 RPM" is correct. What is your "source" for the other information (both are very large amounts -- 38 deg at 5K RPM would be an even more unacceptable amount at 6K RPM)?
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FWIW, I use the timing curve above on my '83 BBi (note the error in the english translation for static timing). My timing is digitally controlled (mech advance is locked out, springs removed, etc.). I have knock sensors as well, so I can see that the engine is content with those numbers.

Side note, you can go higher in total advance (32 deg at 6300 RPM) without getting knock on pump gas, but I haven't really seen any benefit.

You might have seen different numbers in the workshop manual – which has numbers for the 365 and 512 BB.

 

18 ° at 1000 rpm? that is very high and strange to me. I know no engine with such a high number at idle

 

Unless that "Service Training" manual has a separate ignition section for each model, I'd guess that they just copied the 365GT4BB information (and only gave the high limit values). The OMs show three clearly different ignition maps/specifications for the three models. I will say that they made it very confusing in some of the text they use in the OMs (by not being clear about when they are talking about what's happening at the dist vs what's happening at the engine), but, fortunately, each has a dist advance vs dist RPM graph. My reading/translation of the OMs:

365GT4BB OM
static engine timing at idle = 16-18 deg BTDC
distributor advance at 2500 dist RPM = 10 deg of dist rotation
distributor advance at 3300 dist RPM = 13 deg of dist rotation
engine timing at 5000 RPM = 36-38 deg BTDC

BB512 OM
static engine timing at idle = 5 deg BTDC
distributor advance at 2500 dist RPM = 15 deg of dist rotation
distributor advance at 3200 dist RPM = 16 deg of dist rotation
engine timing at 5000 RPM = 35 deg BTDC

BB512i OM
static engine timing at idle = 10 deg BTDC
distributor advance at 2500 dist RPM = 9.5 deg of dist rotation
distributor advance at 3150 dist RPM = 11 deg of dist rotation
engine timing at 5000 RPM = 29 deg BTDC

 

Yes (as will be the valve event timing marks).

 

you are sure you still have the original flywheel in your car?

 

You can "confirm" the location of the marks on the flywheel relative to the PM1-6 mark by knowing (or counting) the total number of teeth on the flywheel (call this "Z") and then calculating 360/Z to get degrees per tooth and then counting the teeth from PM1-6 to any other mark.

 

Nerd alert!......I just counted 147 teeth on a BBi flywheel (FPN #118367). Approximately 2.449º /tooth

Someone want to confirm?

 

In the WSM for cat-equipped TR, they kindly put a note "Z=146" on the flywheel diagram (page D64), but it doesn't appear on the non-cat TR flywheel diagram (page D6). Are you sure that you didn't miscount by 1?

 

Absolutely n o t sure. I did count twice, but I went from a picture, and two of the quadrants were well in focus, and the other two, not-so-much.
Also,, the part number for a 512BBi flywheel is different. (118367-BBi Vs 123923-TR). Probably would be the same gears (?)

Thanks for checking

 

I don't know either for sure that they would be the same (and for doing this estimate it doesn't matter much). The flywheels are almost always different part numbers (even for different versions of the same model) because the ignition and valve event markings are different.

 

BTW

I observed that the 10º at idle was not the best for my BBi in terms of tip-in throttle response, and starting. I actually backed off a couple of degrees and found this improved. I put it back to 10º a couple of times and my observations were consistent.

What I am curious about but have not checked this is the 29º @ 5,000 rev point. Car runs very well.

YMMV / IMHO / FWIW

 

I've experimented between 0 and 15 static, and I find a little less than 10 "feels" a little better as well. That's also impacted by base idle and A/F (eg, retarding timing to compensate for too much idle air is a false positive that the car "likes" lower static timing). So if everything else is correct, anything between 5 and 10 deg seems to work pretty well (IMO).

I run between 5-12 deg at 1,000 (ECU automatically advances/retards timing to control idle speed), 22 at 2,000, 29 at 5,000, and 32 deg at 6,300+. No knock on pump gas.