Hello, Matt,
quote:
Originally posted by merrill
for example, on the curve for 051 the movement on the cam maxes out at about 24 deg (BTDC??) however when one times the car the timing
is supposed to be 30 deg btdc at 3000 rpm.
Am in reading this incorrectly?
Matt
Austin Tx
66 230 sl - "white"
78 300 D - Blue
98 C230
Yes, your reading is correct.
The 051 curve shows max advance between 16 and 22 degrees.
The Good Doctor has confirmed this elsewhere on the site where he says that the max centrifugal advance on these distributors is around 20 degrees.
So, when you set the timing at 30 degrees btdc at 3000 rpm without vacuum, you will get idle speed timing at between 8 to 14 degrees btdc.
The vacuum curve shows max retard at between 8 and 14 degrees. So, when you reconnect vacuum, at idle the timing would move back to between tdc and atdc.
This is how it works on my 280SL with an 051. I set the timing at 30 degrees btdc at 3000 rpm and check that it retards when vacuum is reconnected. I dont lose too much sleep over how far back it retards.
We still do not have a good explanation as to why the timing needs to be atdc at all anyway.
I have never seen a 009 dizzy, only a 007 and I beleive the vacuum rod is not adjustable as the 051 is. Could you share some pictures of your 009? We could add them to the wike for future reference.
Above is my understanding of the issue.
Maybe others can chime in and correct me...
naj
68 280SL
