boostedteg

hey guys, im sure someone one here knows what they are doing with ignition timig on a 350, heres the problem, its a 79 block in an 86 blazer, just bought a new edelbrock carb, hopefully putting that on tomorrow sometime but im pretty sure the ignition timing is off because when i start it up cold, starts up fine, but when i start it up hot, starter drags real bad, loosened the distributor and turned it a little, now starts up great but feels sluggish to me, it also doesnt have the timing mark tab on the timing chain cover so i went to buy one for an 8 inch balancer which is what it measured, and it doesnt fit, im curious if theres is anyone on here that knows their shit about 350s, that can help get this ignition timing set, im willing to pay, i dont care to take it to a shop because i could do it myself eventually, but i dont feel like paying an arm and a leg to get it done, any comments, please pm me so we can discuss it, thanks guys

Fabrik8

Ah, the joys of carb'd engines. Wait, what's a carburetor?

It starts well when cold, which is good. That means the carb probably works pretty well and is in good enough condition. I'm guessing that the hot start problem is probably due to one of two things: Either the mixture is too rich, which wouldn't necessarily cause the same problems when cold because of the higher air density, OR you're getting too much heat into the carb or the fuel system. Do you have a carb spacer/insulator between the manifold and the carb? Also, are your fuel lines routed somewhere close to the exhaust or someplace else where they can heatsoak while the engine is off? You might try insulating the fuel lines or changing where they're routed. If I remember correctly, most hot start problems with carbs come from fuel boiling or vapor lock problems, or just an overly rich setup.
Do you have an electric choke or something similar that could be malfunctioning?

I'm not entirely sure that the timing has anything to do with your problem, I think it's just fooling you by correcting a problem caused by something else. That's assuming of course that it's set correctly at the moment. Timing for cold and hot starts should be the same, because there isn't really any way to change the timing between the two. So yeah, the timing should be checked just to be thorough. Even if that's not the problem it would be good to know that the timing is set correctly so you're getting the best performance.

Oh, and how aggressive are the cams? And what you you mean about the starter dragging, is it not disengaging properly?

boostedteg

dam, sounds like your exactly what i was lookinf for, yes it has an electric choke, and im assuming its functioning properly, im also assuming the cam is stock, also what i mean when i say starter is dragging im just refering to the motor, when it gets to operating temp, it turns over extremely slow, but like i said, i messed with the timing and it doesnt do that at all anymore, but now its sluggish, it doesnt feel like it has the power it should, also hpoefull the carb will be out of the question when this new carb goes on, any other comments would be greatly appreciated, thanks again man

Fabrik8

Well, I think changing the timing has probably corrected the hot start problem but it sounds like the timing that works for starting isn't the timing that works for running.

The starter sounds like it's getting heat soak really bad. That's the first thing that I would fix, because that is going to be a problem regardless of what other things are wrong and will really affect decent starting performance.

So get a nice new (and modern!) starter, get the timing set to where it should be, and then see how it goes. I'd try those first before you put the new carb on. There isn't anything wrong with putting a new carb on, but you don't really learn anything about what or where the problem was if you just make a bunch of changes all at once. I think you'll find that a better starter really helps a lot though, and then the proper timing and the nice new carb will make everything gravy.

I haven't touched a carb'd engine in probably close to 15 years, probably since I was in high school or just after. I'm going off of memory, I'll freely admit that.. Just thought I'd throw that out there, just do you don't think I'm an expert on carb'd engines. That was my official advice disclaimer.
I work for an ECU company if that puts it in context.

boostedteg

haha thanks man for the help. i will try that and see what happens