Olin, to me it seems your sparks are firing much too late. 8deg @ 1,000rpm is
way too late, I'd say this would mean around 0deg @ 600rpm (or 0deg static). As
far as I know your engine should have a static timing of 12-15deg BTDC.
An increase of 10-12 deg per 1,000rpms is ok in this rpm range, increasing
slower from about 2,300 rpms on, when the tension of the second spring cuts in.
No increase above 4,000 rpms.
I figured the following timing:
24deg @ 1,000 rpm
37deg @ 2,000 rpm
41deg @ 2,300 rpm (second spring cuts in)
43deg @ 3,000 rpm
45deg @ 4,000 rpm
As fuel has not gotten better (lead wise) from the early days on, I would set
static timing a bit later than 15deg, though I've set mine to 15 deg and
haven't experienced any pinging since then, but I use a distributor without vac
advance.
All deg and rpm in this mail are crankshaft related.
Eric BT7
Heinsberg/Germany
I first want to thank everyone for taking the time to contact me about the
advancing/pinging/ and overheating issues i am having. With that said, I
have had some suggestions as to what the timing advance should be at known
rpms and to also check fuel mixture.
Here is what I started with when I rechecked the timing, vacuum
disconnected. My vibration damper only has 50 increments (marked with a
marker), so I am guessing somewhat. I used to have an adjustable dial
timing light, but that is missing. I still need to have someone at the
wheel to hold the throttle to 3000 and 4000 rpm so I can get more data
points, but this is what I have for now.
150 BTDC @1000 rpm
250 BTDC @2000 rpm
This is now what I have after adjustments, vacuum disconnected:
around 80 BTDC @1000 rpm
200 BTDC @2000 rpm
It looks like I am increasing 10-12 crank degrees/1000 rpm on the primary
spring. Because the 1000 rpm settings are influenced by centrifugal
springs, I would say that the static timing initially was ok.
I am not anxious to change the needles just yet. I am going to continue to
chart some more timing numbers to try and develop a curve. Getting the car
to idle at 600 so I can get minimal influence from the springs will be a
challenge.
I welcome any comments to the above, if you can make anything out of the
limited data above.
Regards,
Olin Brimberry
Raleigh, NC
62 BT7
______________________________________________________________________
This email has been scanned by the MessageLabs Email Security System.
For more information please visit http://www.messagelabs.com/email
______________________________________________________________________
|