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  #31 (permalink)  
Old 02-23-2013, 09:24 PM
Landshark928's Avatar
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Quote:
Originally Posted by MouseFink View Post
Engine Timing 101:

Regular production distributors have timing advance that starts at 700-900 RPM. The timing advance in distributors used in high performance engines starts at 1100-1200 RPM.

1.) Engines equipped with some high performance camshafts will not idle below 700 RPM.
2.) Since the centrifugal advance in a stock distributor starts at 700 RPM, you cannot set the initial timing.
3.) In order to lock down the initial timing in a engine e/w a high performance camshaft, you must have a distributor that starts the centrifugal (mechanical) advance at 1100-1200 RPM.

A distributor with a higher RPM centrifugal advance mechanism will allow you to turn the engine idle speed low enough so you can set the initial timing before the centrifugal advance starts. After the initial timing is locked by the distributor bolt, you can then turn the idle speed above 1100 RPM and observe the initial timing plus the centrifugal advance.

If your timing is 22 degrees BTDC, the initial timing is 12 degrees BTDC with 10 degrees timing advance in by 1200 RPM. .
Funny, my timing is set at 22* at idle. Idle is 1000rpms. When I drop the idle to 700rpms the timing stays at 22* When I raise it back to 1000rpms and the rev it, it starts to build after about 1200rpms and is all in by 3000rpms, 36* total. How did I do that? Cam is .660" lift, 253*@0.050" 110LSA 106ICL

Skip White HEI distributor with tuned springs, plates and plate stop. Maybe $50 in it total. Pretty easy to prevent advance below 1200rpms with a spring change and new plates.

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  #32 (permalink)  
Old 02-24-2013, 12:08 AM
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Bad tidings

Ok, got some problems, something went south and not sure what that is yet. Need some help here.

Started up the engine today to verify my new tach and AFT gauge installation and to describe that it ran terrible is an understatement.

I have made NO changes (other than these gauges) since last time it ran, which was excellent.
* First could not start it at all; could only get it to run for a little bit using ether. tapping the accelerator to give it gas was having no effect and eventually was just causing it to flood.
* We finally got it going, roughly, but then she ran rough and at very high RPM's of 1600-2000 (compared to where I left which was 850). Playing with the idle has eratic results; it either goes really high (2000) or stalls out.
* when it was running really high I dialed down the idle to get it to come down and then I got lots of backfiring and engine would stall around 1100.
* a very heavy fuel smell around the engine
* and the oddest of all, when I look at my timing light, which was hooked up and in RPM mode, it would every once in a while go to all zeros; which means no signal. So I think that means I'm not getting a spark to plug 1 (I only see all zeroes when I turn off the engine so this is definitely odd).
* fuel pressure gauge stayed where expected; between 6 and 8.

The last point makes me think my distributor went south but maybe the cylinder is flooded to the point where the spark plug can't fire?

I verified everything just to be sure (wires correct, no vacuum leaks, etc) and I disconnected all newly installed gauges to make sure there was nothing they were doing to interfere. What gets me is that nothing was changed since the last run otherwise I would focus on that area.

I do have my old distributor so I will be putting that one in to eliminate any potential distributor problem.

Any help and/or troubleshooting tips are much appreciated

Gary

Last edited by ggevaert; 02-24-2013 at 12:16 AM.
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  #33 (permalink)  
Old 03-09-2013, 10:00 AM
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Bad dizzy

Looks like the Dizzy went bad; dropped in another one I had sitting around and it ran again. Had to clean plugs as they were absolutely black; likely from the constant stop/starts in testing the dizzy. jeez.

Ordered a pertronix unit to replace bad dizzy.
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