Quote:
Originally Posted by 61ragtop
Yes I too noticed that last bit about the "dither".
My vac at idle is a solid 17'' Hg with the extra timing from the vac adv on manifold and was only 10-12''HG on the ported vac. When I get the top end put back together and she is running I will re check it.
I will also use a long hose and check the vac readings while I drive. What driving situations should I be ovserving the vac readings and Should I do this on both vac ports? I will also map out my curve too. All I know is i have 35* all in by 3100. I will map it as you described and see what I have though.
Re ignition box, I am guessing the Digital 6A will suit my needs just fine? With the auto trans I shouldn't need a rev limiter that the 6AL has? I do plan to go to fuel injection in the future, will the 6A be fine with that too?
What is a good way/sign to find out what the engine likes as the initial timing?
Here is where I am at now......
16 inital no vac adv hooked up
35 total no vac adv
27 initial with vac adv hooked to manifold vac at idle
44 total with vac adv all in by 3000rpm in neutral no load
The 35* total was set by my engine shop that dynod the engine but not in the car.
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Okay - I'll try to respond -- while watching James May tour the Champagne region of France on BBC...
The reason for checking your vacuum and writing it down -- is so that when you are in your driveway -- you can duplicate that vacuum (using a hand vac pump) to see what the timing is with that "amount". Obviously there is no way to tell what your timing is while driving... and a "real" vacuum number can really only be created under load (can't really get a good number in neutral just revving the motor).... We'll get to that when you get there.
The above is why people choose to do this stuff on a chassis dyno.... you can stuff a sniffer up the exhaust... use a vacuum gauge.... and check the timing all while just hanging out. You can also use the sniffer to see what effect your changes are making etc. Otherwise -- we're just kind of "hunting" for what works.
A quick story -- I 'made' a buddy with a new '32 Ford go to a dyno -- after I fooled with it and got it as good as I could... it still smelled pig fat to me... and while it ran way better after I set a few things - I was able to convince him that this would be money well spent. So at the dyno - owned by a friend of mine that is a genius with a carburetor.... I was saying to Alex (the owner) that I thought it was pig fat etc. Turns out it was lean and he had to put in larger jets... he found 7 or 8 hp... but there was something else "wrong" with the carb that only someone like him would notice - so he fixed that - and I can tell you that the "drivability" went up about 50%... it was under $300 and the smile on my buddies face was worth $500.
Now -- to even attempt to answer how you'd know what the motor wants/likes in a forum... is impossible. It's something a guy learns after doing a zillion or more tuneups etc. You just know when you're on the right track by listening to the engine - watching how vibrates (or not)... and on and on. Sorry. I just can't answer that one... AND I will say.... that while a guy can fiddle fool and get things much better.... you will only really know for sure if you're on a dyno.
RE: MSD box -- 6A or AL -- either way. If you don't need the limiter then there's no need. They will both work fine with EFI.
Make sure your coil is up to the task of MSD (Multiple Spark Discharge) It should be but it's worth checking to make sure. The MSD only multi sparks up to about 3000 rpms I think.
35* is about right for a total. Again - that all "depends". My new Smeding 383 with EFI and aluminum heads is set at 34* with 10* initial. My 406 with EFI and aluminum heads runs 36* total and 18* initial. Neither of them use vacuum advance...
Your settings are in the ballpark of what I would expect - but that doesn't make them right or wrong. There are so many variables - heads - compression/cylinder pressure - cam - etc.