bosch coil question. black blue red

[merrill]

so, when I replaced the old nasty coil on my 230 sl,  cheryl at K&K sold me a bosh red coil and a new ballast resister 1.8 with new condenser etc.

when I was looking at the mb service book for cars 71 to 77 for setting the dewll the book kept referencing the car having a bosh blue coil.

does a red coil affect settings?

Matt
Austin Tx
66 230 sl - "white"
78 300 D - Blue
98 C230

[JimVillers]

The coil does not affect the dwell.  The red coil requires a ballast, the blue coil does not need an exterior ballast.

Jim Villers
190SL, 230SL 5-Speed, 190E 2.3-16, MGB 5-Speed

[al_lieffring]

The coil that was originally installed on cars built 1969 and before was painted black.
On the USA model cars starting in 70 had the TSZ ignition system these cars had a blue coil, an amplifyer box a different distributor. and different dwell and timing settings.

Bosch replacement coils sold in the 70's were also blue in color, some had internal resistance others did not depending on the application they were made for.

The reference to a blue coil in the shop manual would have been a reference to the cars with a TSZ system, changing the coil doesn't require a different dwell setting, this is determined by the geometry of the distributor cam and the points,

Al Lieffring
66 230Sl
Jones'n for a new gas tank

[mdsalemi]

Matt,

If you really want to be confused, do a search on Google for Bosch Blue, Bosch Red, etc coils.  You'll be astounded at what you find.  there are plenty of blue coils made by Bosch--in Spain, Brazil and Mexico and goodness knows where else,  Some have resistance internally and some don't.  By trying to find out more last year, I only uncovered more...so when I went to a Pertronix ignition I went to a Pertronix coil.  That solved that issue!

Michael Salemi
1969 280SL
Signal Red 568G w/Black Leather (Restored)
President, International Stars Section
Mercedes-Benz Club of America

[Benz Dr.]

That's about right. The black coils are external resistance and the blue ones usually are not. 190SL's use a blue coil without a resistor but you can also find the black ones used as well.

Black coils are 13KV
Blue ones are about 18KV
Red coils are around 26KV and need a 1.9 ohm ballast resistor for our cars.

Dan Caron's
 SL Barn
benzbarn@ebtech.net
 slbarn.mbz.org
  1 877 661 6061