Timing question

[mirose]

Quick question...

Mass flo suggests 12-14 BTDC for best timing...But interestingly, that isn't the timing that sounds the best. Believe it or not, more like 18-20 btdc sounds sweet. Do I ignore the fact that the sound is better at 18-20 and go with spec? And what I mean by "sound better" is that the idle smooths out...rpm's go up around 100 and there is less of that grumbling sound of a low-idle engine.

I guess to some degree I LIKE that low grumbling sound...but I am just checking in with you smarter folks.

thanks - Michael

[Olli]

Total timing is far more critical than initial. If your engine likes 18-20 at idle, fine, but you need to make sure that now your total hasn't exceed 32-34. Most engine builders don't even mention initial, just total timing.

Olli

[JKleiner]

When using the Ford EEC-IV you are supposed to set timing to ~12-14 with the SPOUT removed. This takes the computer out of the loop. When you reinstall the SPOUT the ECU takes control of timing. If you are attempting to set it with the SPOUT installed you are doing it improperly and the ECU is getting confused trying to compensate which would explain why it sounds happiest at ~18-20 (about where the computer will put it at idle).

Jeff

[mirose]

Originally Posted by Olli

Total timing is far more critical than initial. If your engine likes 18-20 at idle, fine, but you need to make sure that now your total hasn't exceed 32-34. Most engine builders don't even mention initial, just total timing.

Olli

Ok, I'll have to research this. I was not even aware of two different kinds of timing. Thanks for the info.

Originally Posted by JKleiner

When using the Ford EEC-IV you are supposed to set timing to ~12-14 with the SPOUT removed. This takes the computer out of the loop. When you reinstall the SPOUT the ECU takes control of timing. If you are attempting to set it with the SPOUT installed you are doing it improperly and the ECU is getting confused trying to compensate which would explain why it sounds happiest at ~18-20 (about where the computer will put it at idle).

Jeff

Thanks Jeff. I did set my timing with the SPOUT removed. And yes, after I put the SPOUT back in the ECU did adjust things a bit and the engine sounds somewhat happier with the ECU in charge. I have had very little in the way of engine issues. Starts right up, has never quit on me and seems to run great. I was doing my first "checkup" of the car now that I have my first 100+ miles on it. Among other things I checked that all of my engine bolts were tight (intake, header, valve cover etc) I checked all of my major bolts and connections. Followed my fuel and brake lines and checked for leaks and finally double checked the timing on the engine just to be sure the dizzy hadn't wiggled or spun at all.

So there is nothing "wrong" that I am trying to fix here. It was part of a 100 mile "checkup" that I came up with the question. I guess my ear is so used to my daily driver that idles at a whisper with almost no vibration that having a grumbling, shaking, loud engine is a bit foreign to me. My instinct was that finding the LEAST grumbling and shaking would be the "best" setpoint for the timing, even though it didnt jibe with what the manufacturer was suggesting.

-Michael

[Olli]

Initial + advance= total @ X rpm

That is a very basic definition of total timing.

I'm not sure how the EEC controls advance.

Olli