Timing - Was Jetting Change

[brianstj]

I decided to start a new thread so the interesting discussions on the carb function is not diverted in the original...

So on the timing - I have the little sticker under the hood (not Tii) that instructs to set at 25 BTDC @ 2700 RPM, with vacuum advance disconnected and plugged of course. I am all for setting up the "ball in the hole" at 1500 RPM and giving it a go, but I have a couple questions on that.

1. Curious on how this spec superceeded the spec on the underhood sticker?

2. Is this a "catch all" setting for all carb'd cars, regardless of modification?

3. I have a Getrag 245 with 215mm flywheel from a 1980 320i - are the marks in the hole going to be the same?

Thanks!

[Guest Anonymous]

Per my quickest available resource (Haynes), 25 degrees @ 2000 rpm "with emission control and air pump." All models "except 2002ti and 2002 tii= 25degrees @ 1400 rpm. I think Haynes felt that pushing the recommended recommendations just a little couldn't hurt. Obviously, there are a great deal of variations between models, distributors offered and recommended specs.

If you or your engine start to ping like crazy after the suggested modification, go back to the sticker specs. What year and trans was your car originally? In other words, to what year, trans and State did the sticker originally apply?

Good luck.

[c.d.iesel]

1. Curious on how this spec superceeded the spec on the underhood sticker? = that 'spec' if for emission

control compliance, slightly retarded

to contribute to slightly lower Co/Hc

exhaust readings The 1,500rpm setting is for a

non-emission compliant (read Euro), giving better

performance, but the car will still test with passing

readings at any State Inspection Center - provided

of course all other settings are optimum - not molested

carb jetting, worn cam timing, poor compression,

gasoline fouled motor oil, and other emission control

device malfunctions/leaks - like from the EGR, Air

Injection systems. Remember 30 + years of

screwdriver-poking, nutstripping hacks can make

these cars so out of wack it's depressing.

The 2,500 rpm timing setting is for the tii injection

pump and it's fuel delivery 'curve', and it's throttle

response time - the tii will not be happy with the more

advance setting of 1,500 rpm like a carb motor will.

Trust me.

2. Is this a "catch all" setting for all carb'd cars,

regardless of modification? = YES

3. I have a Getrag 245 with 215mm flywheel from a 1980 320i - are the marks in the hole going to be the same? = your on your own on that one - sorry

[brianstj]

OK - so what number of degrees does the "ball in the hole" @ 1500 RPM correspond to? Just in case the 5 speed trans/flywheel combination is not compatible with the 2002 timing marks, I can use the adjustable timing light on the crank pulley to get the right setting if I know the number to shoot for.

Thanks!

[c.d.iesel]

25 degrees @ 1,500 rpm

and 60 degrees of dwell if your using points