[TR] TR4a ignition advance

[spamiam at comcast.net]

Thanks the the info.  This will help me make some decisions about the ignition system.

I am glad you clarified the crank vs dizzy RPM.  I had initially thought it was showing crank RPM, which seemed low to me.

The dizzy RPM makes better sense.

The 2-6-3 advance is surprisingly low, It would appear that the advance is nearly "Full" all the time, and it only adds 6 crank degrees anyway!

Most of the advance units I saw for other carbs were listed for rather more than that, but maxed out at higher vac levels.

The highest mechanical advance listed in the chart you gave was 18-22 crank degrees at  3200 crank RPM.  Should I assume this is the maximum mechanical advance, or will it go up some from there even further?

BTW, 4 static + 6 vacuum + 22 mechanical = 30 total degrees, or so it would appear.

Thanks!

-Tony

-------------- Original message -------------- 
From: Btmfdchn at aol.com 

In a message dated 9/21/2007 8:37:18 AM Pacific Daylight Time, spamiam at comcast.net writes:
Does anybody know the ignition advance information for the TR4A?

I know that stock static advance is 4 degrees BTDC, but what is the full vacuum advance?  What is the full mechanical advance?

Someone said to me that these engines can not tolerate all that much total advance (I.E. less than 30 degrees).  I would have expected that a total advance in the mid-30's would have been about right!

-Tony


Greetings...  The vac advance unit should be marked 2-6-3.  Advance starts at 2in of hg, all in at 6 in of hg with 3 degrees advance at the dizzy-6 at the crank.  Not much.  Centrifugal advance depends on what dizzy you've got.           TJ






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