View Single Post
Old 08-18-2011, 11:37 PM   #15
Jim/GA
Senior Member
 
Jim/GA's Avatar
 
Join Date: May 2010
Location: Young Harris, GA
Posts: 1,370
Default Re: Ok so a brand new radiator and it still runs hot

Quote:
Originally Posted by TinCup View Post
30degress of dwell at 2000rpm. About 5degrees retarded.
Now that you have given us some hard facts, I would say your point gap is too wide and your timing is retarded, even for a HC head.

People don't normally set their points on an A by dwell. But if I did, I would set it closer to 45 degrees, not 30. 30* is typical for an 8-cyl engine. Better to set by feeler gauge thickness of .017" to .020". After you do that, just for yucks, you could read out what the dwell is (for future reference). Dwell should not vary with RPM; if it does, you have a problem with your distributor. Always set point gap or dwell before timing.

Second, Henry timed these engines at TDC at the timing mark with the lever fully up. Full advance on the lever was 40 crank degrees of advance. You are starting out at -5 degrees and only advancing the lever 1/2 way, or 20 degrees, so your final advance is only ~15* BTDC. That is not enough. You should shoot for closer to 30*, which means if you are starting at 5* retarded, you need to advance the lever almost the full swing. Moving the lever all the way to the bottom of the quadrant would result in final timing of ~35* BTDC (perhaps a bit too much for the HC head, but try it and see what your temperature does -- you can always back it off a bit with the lever).

If you can tell us you are at 5 deg. retarded initially, then that means you have a timing light and scale on the engine. Good. Get the dwell set closer to 45* first, and then set the initial timing to where you want it. (Why not TDC, like Henry did?) Anyway, after doing that, start engine and see where you have to put the timing lever to get 30* of advance. That's where you want to run with it.
__________________
Jim Cannon
"Have a Model A day!"
  • Repair
  • Restore
  • Drive
  • Enjoy!
  • Join MAFCA
http://tinyurl.com/Join-MAFCA

Last edited by Jim/TX; 08-19-2011 at 07:20 AM.
Jim/GA is offline   Reply With Quote