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Old 02-06-2020, 06:27 PM
bracurrie bracurrie is offline
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Join Date: Jul 2017
Posts: 187
Quote:
Originally Posted by Benz Dr. View Post
Seems like I'm trying to keep others from being confused and you sort of got caught up in the mix. lol

The main thing to remember is that vacuum retard is set to 0 degrees of advance at idle. On some engines with a 051 distributor, advance will start right off idle as soon as the throttle valve opens and vacuum falls off. With the 062 the vacuum portion of the distributor will remain at 0 until the switch over valve closes and then you will get 22 degrees of advance all at one time.
Below 2,200 RPM the switch over valve opens and the vacuum portion returns to 0. At 2,200 RPM the mechanical portion of your distributor will still be advanced fully and it will return to idle timing ( 3 ATDC ) at your idle speed.

MB did this so that they could have a larger overall timing advance curve. This unit has close to 42 degrees of timing available so that idle timing can go into ATDC and still have proper timing for higher RPM over 2,500.

A 051 distributor has 30 of advance and you have to set your idle timing to 8 degrees BTDC to obtain proper top end performance. There is no option to go into ATDC with a 051 because the engine would probably stall and have terrible performance.
While your 062 may, or may not be working, or work great, the initial concept was certainly interesting.
My 061 works fine. The retardation system is wonky, thus evaluating whether to go with out retardation, fix OE system or go with 123 ignition.

I just had no idea the Service Manual was so wrong. I was thinking that the mechanical advance was limited to ~20 degrees and the retard was good for ~20 degrees. So with an 061 if set at 10 degrees BTDC WO vacuum or 5 degrees ATDC w vacuum at idle then at 2200 RPM before speedswitch turns vacuum off timing ~5-10 BTDC then above 2500 RPM all at once retard of ~20 degrees is removed via two way switch and the result is ~38 BTDC. What I don't understand is where does the extra 8 degrees of advance come come from?

BTW what is the difference between an 061 and an 062 distributor? Service Manual says they are the same, but given other errors I wonder.
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