help with timing sticker

[autbot318i]

Been rearching through multiple forums and looking through the bent. manual for the proper timing on my 85 318i. on this sticker i found stuck on the pass. side of the car. saids 26 degrees BDTC At 4000 _+ 50 in neutral. im not sure what that means exactly. every where i've looked so far only saids top dead center TDC. whats the "B" for?
as for idle timing not required. there seems to be plenty of people with idle issues including me. is it because we adjust the idle thought IDV and dizzy?

so if someone can kindly explain what the ignition timing means...that will be great.

thanks all.

Eric

[Ceeker]

BTDC -Before Top Dead Center-The spark plug usually ignites the fuel/air mix slightly before the piston reach's its highest point, this position is known as Before Top Dead Center (BTDC) do a google search for definitions on...

The issue with rough idle is either not having the motor at BTDC and ign timing set up correctly; sometimes timing is retarded..(no not stupid) or advanced. Usually the timing is turned back too much.

I would follow what the sticker on the car says rather then any of the manuals. the car is the sure thing. :-)

hope this helps.

[autbot318i]

thank you for that! I will be replacing the chain, tension, gaskets, rail. So from what you are trying to say is that I do not line up the marks but instead time it to 26 degrees from the mark to get BTDC? hope i got that right.

lets say i get this timing right...at what point would i need to adjust the distributor?

I'm learning as i go with this M10. been spoiled with ECU handling everything in more modern cars, this is a real pleasure to have such informative people on the forum.

my friends and family all wondered why I sold my E46 for an E30. but you guys know why.

Thanks again.

Eric

[scottinAZ]

you will align the marks on the cam gear to get the static timing correct. you adjust the distributor to get the 28 BTDC for the spark timing

[autbot318i]

thanks Scottin