got a problem guys. my 66 has an 86 model 350 in it with hei distributor. she will start right up and idle just fine but when i slowly rev it up it will start to stutter like its got a rev limiter, but when i unplug the vacuum advance she will smooth out and rev just fine and if i plug it back up it will start to stutter again. if i drive it with the advance unplugged it doesnt have any power at all so that aint gonna work lol. ive replaced my advance curve weights and springs and also replaced the diaghram that the vacuum line attaches too and its not fixed it yet. any ideas? i really hope so lol
what kind of vacuum do you have, ported or manifold? If it's manifold which is constant strait off the manifold it can make your vacuum advanced seem like it's working backwards. Ported vacuum is what you need. You can find this on the Carb. usually in the back or front of the Carb. there will be a vacuum port located just above the throttle butterfly's. This will give you vacuum only when you step on the gas and make your vacuum work properly. if you have any doubts which is which you can use a vacuum gauge to tell the difference.
ive got it on the ported, what has got me so confused is that i put a new double roller timing chain in like 6 months ago and it has run great since then and then all of a sudden like 3 days ago it started doin this crap, and know i had everything hooked up right cause it was running just fine. im stumped on this one
Have you put a timing light on it? I'd be curious to see what the timing jumps to when you first open the throttle. If the timing jumps passed 60 degrees, you may need to put a limiter on the vacuum advance.
ive not had a chance to put a timing light on it but ive got a friend bringing me another distributor over tommorow and im just gonna pop it in there and see if that helps any, if it does im just gonna buy me another distributor. been wantin a new on anyway and this will just give me an excuse to buy one
Just a suggestion.. You may want to throw the timing light on it before you go swapping distributors. You will need to set the timing after a swap, so why not do it before. It could be something very simple. dv
With the HEI distributors I think you are supposed to check the timing with the vacuum disconnected . http://www.73-87.com/7387garage/drivetrain/timing101s.htm Check out this article on ignition timing it says you need manifold vaccum with a canister when using HEI ignition.
That's true, but it's also a good idea to check the timing/agressiveness of the vacuum advance. I just went through this on a 406 ci build we did for my friend's '66 C-10 because we were getting a weird stumble upon tip-in on the dyno - he wanted us to use a no-name HEI distributor that he got for cheap. And, sure enough, the timing would snap to 60+ degrees as soon as the throttle opened. Unable to find one of those old Crane Cams vacuum advance limiters, we fabricated one from a stainless washer. With the limiter in place, we kept the vacuum advance timing to 46 degrees and the stumble went away. Hopefully, that's the case with jaybyrd66 and it's a quick fix.
good news, got another distributor today and popped it in there and she runs like a top now. never got a chance to put a light on it so i just eyeballed it and got it as close as i could in time and she purrs like a kitten and runs strong now
