distributor advance
- Thread starter jcelk
- Start date
Omg, five pages of theory and no one has actually resolved anything. Every engine combo "Likes" a specific curve for spark timing. Sure if you have lots of money you can put the thing on a dyno and figure it out. But for us normal gearheads it's a seat of the pants thing, take it to the track and check your time slips. For a generic run-of-the-mill street car, just buy a good distributor and follow the manufacturers recommended setup.
Time, money, guessing and frustration.... or for $500, you can avoid all that, well, the time, guessing and frustration part and go with a Progression Ignition HEI distributor. No weights, no springs, no vacuum advance pod, programable at idle or on the fly with a host of other features, like going from carburation to EFI, people have to roll with the times and update at some point.
Back in the old days, when distributor "recalibration" machines where plentiful, now only a hand full exist if that, this would have been your best bet to recurve the weights and springs type without it being in the engine.
Hot Rod Article - https://www.hotrod.com/how-to/back-basics-recurve-hei-distributor/
Hot Rod Article - https://www.hotrod.com/how-to/back-basics-recurve-hei-distributor/
I saw one for sale on eBay recently and I found it beautiful like an old piece of art. It was affordable too.
i would buy a distributor tester if i found one that wasn;t to pricy those old sun machines were really cool looking and now i am having fun playing with this .. i have the time
i;m retired .thanks for all your input happy motoring guys
i;m retired .thanks for all your input happy motoring guys
I'd personally not bother to dyno-tune an engine. Do it real-world to dial it in. But that's JMO. Dyno tuning only gets you close, and you'll still be doing tweaks afterward. Guaranteed.
i put the distributor in yesterday and took it for a spin big improvement over the worn bushings and jammed weights like i had .. i made new bushings for the factory weights cleaned and greased the advance plate shaft and used the factory springs softer spring would make the weights advance at idle .changed the center weight to give me 24 deg mechanical advance and 10 deg of initial with ported vacuum kept the vacuum can that has 20 deg i noticed it loses 2 deg at cruising with my rear a 273 i;m going 60 mph at a around 2050 rpm the weights start at 900 rpm and is all in at 3100 rpm the orignal center weight would get me 27 deg all in thought that might be to high . question ? if anyone knows if i kept the weight that gives me 27 deg put initial at 5 deg hooked it to manifold vac with the can giving that would give me 20 deg = 25 deg at idle is that to much ? thanks everyone for your input i learned a lot can't wait till spring to get her on the road. merry christmas to all and to all happy motoring
I'm very happy things are going well and that you're having fun and enjoying your ride. If I understand your question correctly you'd like to try 5° advanced base timing and connect to manifold vacuum for 25° at idle- that's perfectly fine. And with mechanical advance added it sounds like you'd be around 52° which is not unheard of but is worth keeping an eye on. Detonation or preignition can be sneaky.
Starting with 5° isn't much, and I bet the engine would like even more base timing. However increasing that would put your total cruise timing (base + mechanical + vacuum) in a danger zone, especially with 27° of mechanical coming in. It may respond well to 12-14° initial + 20° of vacuum for 34° at idle but if you try that I believe you'll want less mechanical advance to avoid trouble when cruising.
option a is what i did 10 base 24 mechanical 20 vacuum .option b is 5 base 27 mechanical 20 vacuum option c would be 14 base i have weights that give 16 mechanical and 20 vacuum i don;t know if starting the engine would be a problem with 14 base and i don;t know which option would be better .it;s a lot more complcated than i originally thought.. being retired is great i have time to play and it was fun putting that engine and trans in last summer
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