[Gmecm] flathead ford files?
David Allen
davida1
Sun Feb 3 23:07:23 UTC 2013
Hi Alan. The .bin I started with was from a Chevy small-block pickup truck.
There is no way around programming some different values into the .bin calibration for this to work. Fortunately, there are only a few critical things to get it to run. Once you get it to run, the rest can be tuned.
The "base pulse constant" is a factor in the ECM that matches all the fuel tables to the injector size and engine displacement values. If you change the injector size, or change the engine size (or both) you use this one to match everything together. There are math formulas you can use to calculate an "educated guess" BPW constant and the engine should be able to start and run good enough to make tuning tests.
The other one is the distributor reference angle. This is the amount of degrees before TDC, when the distributor trigger wheel sends a pulse to the HEI module. It allows the ECM to calculate actual advance "at the crank" in spite of the fact that the distributor is already advanced a few degrees.
This one is also easy to set. You need to get the engine running as good as possible at idle by tweaking the BPW constant and turning the distributor to manually change the advance. Find the point where the CRANKING UP advance is best. In other words, find the position of the distributor where the engine STARTS easiest without kicking back or backfiring. The ECM is not in control of advance during cranking, the position of the distributor is the only thing that sets the advance while cranking. So you adjust this one manually.
After you have the distributor adjusted for easiest starting, then you put that amount of degrees into the ECM distributor reference angle constant. The ECM will then subtract this amount of degrees from its timing calculation so that it is accurately displaying timing.
Then there is a maximum advance relative to reference. This is the maximum degrees of advance the ECM can ever add to the distributor's manually set advance. For instance, say you wanted your engine to have a LIMIT of 30 degrees advance (actual advance at crankshaft never more than 30). You have found out that 10 degrees of distributor timing makes for easiest cranking, so the distributor is set at 10 degrees. So you would put the 'maximum advance relative to reference' at 20. Then, no matter what the other timing tables calculated, the ECM will limit the timing to 30 or less.
If your engine has a stock camshaft in it, the "shape" of the fuel tables sould be close enough to run and tune the engine. If the cam is very radical, you may find that it wants to flood and load up at idle, which will require adjustments to the VE tables.
Hope this helps!
David
----- Original Message -----
From: alan mays
To: gmecm at diy-efi.org
Sent: Sunday, February 03, 2013 4:10 PM
Subject: Re: [Gmecm] flathead ford files?
Hey David thats impressive, me likee. Im thinking a little different though, Im scheming my own intake , Ive been talking to a foundry and am a pattern maker,
side saddle digital midgets-port injection, I wish i could be less cryptive but.....
propriatory until reality.
So how could a bin be built for a 38-48 or later, the only small V8 as i said is the rover/buick olds 215 3.5
--- On Sat, 2/2/13, David Allen <davida1 at hiwaay.net> wrote:
From: David Allen <davida1 at hiwaay.net>
Subject: Re: [Gmecm] flathead ford files?
To: gmecm at diy-efi.org
Date: Saturday, February 2, 2013, 6:21 PM
I have done this! Got a 1944 4.0L Ford / Lincoln flathead running under TBI with 1227747 ECM.
The car hasn't been tuned or driven yet because the clutch and brake pedals and shifter aren't ready. The manifold is a real work of art.
Some pictures are here:
The engine:
http://68.209.87.173/FlatheadEFI/11_07/Engine_11_07.jpg
Distributor:
http://68.209.87.173/FlatheadEFI/11_07/MVC-002Gann.JPG
TBI:
http://68.209.87.173/FlatheadEFI/11_07/MVC-005Gann.JPG
http://68.209.87.173/FlatheadEFI/11_07/MVC-006Gann.JPG
http://68.209.87.173/FlatheadEFI/11_07/MVC-015Gann.JPG
Electronics:
http://68.209.87.173/FlatheadEFI/MVC-015ann.JPG
The only problem is, the engine has an awful cam in it and I don't think it will ever run smooth unless this is replaced.
Sincerely,
David
----- Original Message -----
From: Adrian Flynn
To: gmecm at diy-efi.org
Sent: Saturday, February 02, 2013 4:01 PM
Subject: Re: [Gmecm] flathead ford files?
I don't know but it would be a favorite of mine as I have always loved the old "Flat Heads", first engines/cars I ever worked on.
Adrian
On Sat, Feb 2, 2013 at 4:57 PM, alan mays <truckeez at yahoo.com> wrote:
Hey with the nostalga craze, I wonder if anyone has done a old ford flathead using a gm computer--there are electronic distributors on the shelf for them. maybe something like a 3.5 rover hotwire system would be the closest, but yes im aware rover uses lucas stuff.
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