Hard starts after running

[TrailBeast]

Still not starting easy when warm after the 10 min sit. Ran out of time to play with it tonight. But so far so good.

That’s because all the things you have done are not solving the base symptom.
And it won’t, until you figure out how to keep the fuel from getting hot and filling the intake and any cylinders with open intake valves with fuel mist.
Gas fumes are heavier than air, and all that evaporating mist goes right down into the motor.
Then when you start cranking, more fuel from the idle circuit makes it worse.
In the end you’ll find that the simplest solution is to open the throttle till it fires up.

We can use insulators, heat blockers, return systems and non ethanol fuel, and some help.
Edelbrock type designs make that problem worse, as the fuel bowls are concentrated closer to the heat source.

Glad/hope you are enjoying learning everything you are in the process, but in the end you will remember these words, I guarantee it.

 

[Mattax]

So I do have a 727, tci shift kit, 2200ish stall (needs replaced). 3.73 gears. Had 36 degrees timing trimmed to all in at @ 2400rpm before carb idle procedure. After setting carb idle I'm sitting @ 31 degrees. So I will fix that when I'm happy with idle. Took it for a spin after setting carb idle, goes into drive smoother than before, about 100 rpm drop. Idle is nice, off throttle is responsive. Still not starting easy when warm after the 10 min sit. Ran out of time to play with it tonight. But so far so good.

Unless this is a drag race setup with no vacuum advance, 31 @ 2400 is too much.

OK A quick scan through your posts indicates you've got a 318 with a cam change, but not too radical.
Also that you may be using FBO's plate. If you want to use the FBO plate, then I can't help you. Follow what Don says and if it don't work out, you always have the option of doing it more like the factory and factory teams did.

The second link in the quote below is a great example of adjusting the advance to work as the engine will like it when using vacuum advance.

You've prob seen these but if not, I kindof spill the beans on shaping the curve here and with Rick as he works through and posts the effects of his changes here.

That quote comes from this thread, where TT5.9 also shows how more is not always better and similar in shape the timing is for a 5.9 Need some help with my timing curve.

Drag race focused, different story: Vacuum advance is not needed. Engine is run wide open, relatively cold, timing can be all in at low rpm as long as there is compensation for slew if running electronic ignition.

 

[Mattax]

@TrailBeast is applying logic. If base timing is actually anywhere from 0 to 16* BTDC, then its probably not causing the hard starts, and even up to 18 or 19* I would not expect that to be an issue.
Heat issues at start are probably not directly carb. Its either too much vaporization or too much liquid fuel in the intake. The latter can occur when vapor in the fuel line can't burp without pushing extra fuel into the bowls - overfilling them to the point they spill or drip out the boosters. The former is kindof the norm with an open system, and we just need to learn to manage it.

 

[Agent_Orange]

I really didn't mean to make this thread about me.

That being said, I agree that a new fuel filter with a bypass can only help things. I'm going to grab one next trip into town. Carb already has an insulated spacer.

And I don't plan on using the fbo plate for anything more than testing before I weld the t-bar.

 

[Agent_Orange]

Okay.. so quick timing question. These guys saying "all in by 2 grand" or "at the stall" that's only drag racing? And I actually want the curve that continues to pull slowly after 2700 or so? There is so much conflicting info out here.

I'm not 100% bought in to any theory... at the moment, this is where I stand. Setting the throttle plates and adjust the initial timing to get idle speed makes 100% sense to me. Wish I would have started there. And the heavy loop factory spring makes sense in order to get that continued long curve that comes in as the vac advance cuts out.

I'll get there. It's been a long summer, pulled the car out of storage after 10 years. Replaced brake system, upgraded entire front and rear suspension, opened transmission up 3 times, fixed brake and turn signal electrical issues, timing, now carb... I've been trying to hit issues on a safety, suspension, trans then engine time line. I've read so much this summer that I'm burning dim. But I was determined to get this car to a daily driver status by the end of summer.

Enough story.

 

[Mattax]

Okay.. so quick timing question. These guys saying "all in by 2 grand" or "at the stall" that's only drag racing? And I actually want the curve that continues to pull slowly after 2700 or so? There is so much conflicting info out here.

A long time ago, the trick of the day for hot rodder at the drag strip was to lock the vacuum advance plate, and have the mechanical advance all in as soon as possible. That worked pretty good with points and drag racing. The class racing guys of course aren't going to spill all their secrets...
As far as the conflicting info, yup. You'll have to decide for yourself which info comes from good sources with engineering, testing and applicable experience behind them.
I've not made any secret where my info comes from, or how I came around to relying of the sources that got me back on track.

for example

Back before electronic ignitions were the norm, a faster advance was considered a slight advantage in the 1/4 mile. A quarter mile was and is , run with the engine relativly cold. Often vac advance was locked out or removed (one more unneccessary variable for drag racing). Drag racing at that time was mostly class racing - Stock Eliminator.

I worked with a mechanical tech who played in that game. The secondary spring is needed for electronic ignition. He learned the hard way and passed it along to those of us who would listen.

Actually its not that big of a secret, but the magazine writers have never caught on. Read post #4

racingfuelsystems-Too much advance at light throttle?

What happens if there is too much timing advance under cruise or engine braking? Will there still be detonation? Will it simply misfire? I ask because

www.tapatalk.com

Here's a couple other guys who have run Stock Eliminator commenting on the subject. GTX John and 92b. What used to be done with dual points no longer applies with electronics even for drag racing.

lets revisit timing

@RustyRatRod @Mattax Exactly. Welding the inside , extending the springs into more tension.. ...wtf is he thinking.lol so we want a slow curve? Putting the spring under tension and into its max resistance..uh no thanks. The outside is where you would close it up. Tony is a pants shitter No. I...

www.forabodiesonly.com

Some observations here on Slew rate

Ignition box retard with RPM

I finally have a chance to check some of the various ignition boxes I have on hand to see how they retard with RPM. At the moment I have a MP orange box, an early 1980's gold box, a Mallory HyFire IV, Mallory HyFire V, Mallory HyFire VI digital, and a Mallory HyFire VII analog. Tonight I tested...

www.forabodiesonly.com

The other thing the long looped secondary spring does is allow the vacuum advance to come into play at part throttle.
If the secondary spring doesn't slow the advance, then there is too much timing at part throttle with vacuum advance. Or you have to compromise the vacuum advance.
You're driving for a couple hours at 50 - 55 mph and a adding a little throttle for a slight grade causes a gurgling (ping). I got to learn this the hard way. But feel free to try it out yourself. Really no harm. Just annoying and less efficient.

Large RPM and Vacuum drop when shifting from park to gear

So much misinformation. I think there's someone who needs to completely relearn what ported vacuum advance is all about. What a train wreck. To the OP, good luck!

www.forabodiesonly.com

 

[AJ/FormS]

IIRC you said you had a 2200ish stall. and 3.73 gears. That's gonna put a damper on how much timing you can run down there and still get to around 36*@ say 3400 rpm
That long-loop spring is only good for about 4>6* and some that I have tested took to 4000 rpm to be all in, with the stock weights. If you have a problem with detonation that can help, but mostly, that is unacceptable even in a 360.
I had a small selection of those long loopers, that I had accumulated over the decades, and so I rigged up a test-apparatus to weed out the late-bloomers, until I found one that seemed appropriate. It turned out to be just what I needed. Well I had to stretch it out a tad.
After that I just began installing the singles , one atta time, until I got what I thought would work. Each time, I had to generate a graph to see how it turned out, and to compare the current springs and weights, to the previous. Then began the roadtests...... for which, I had previously installed a dash-mounted, dial back, timing module, and with an on-board accelerometer, I was able to generate a pretty good theoretical timing curve to work against. By the end of the summer, I was reasonably pleased.

What I learned was this; at WOT;
3* short of ideal, from stall to 3600, is hardly noticeable. It's like less than 5hp max.
2* too much, when it causes detonation, you can feel it almost right away.
Therefore; if you can get the PowerTiming within a degree or two, and the stall-Timing even just close, but not too much,
Then, your engine will be happy. How it gets from stall to 3600, can be whatever; because the window, is very small, and in First gear, you scoot right thru it, and if you out-shift First at 5500, it will drop into Second at 3250, so just make sure, it doesn't detonate there..

At WOT
suppose your engine accepts 35* at 3400 rpm without detonation. and
suppose your stall rpm has to be less than 24*, and
suppose your T-slot sync ends up being 12*.
Your job is to connect those dots. So you gotta put the points on a graph. Then if they cannot be connected with a straight line, you have two choices;
1) run the 35* at 3400 and let the rest be what it will be. or
2) run a two stage curve, with the first curve connecting the Idle timing to the stall timing, then into the long-loop spring, ending as close to possible to your target of 35*@3400 rpm. Sometimes it is just not possible to do that with the parts you have. Sometimes, you have to make a compromise.
This is one of the reasons I like the 2800 stall convertor, it puts the stall rpm closer to what timing is achievable with factory distributor parts, and you don't hardly have to compromise .
Plus, you know, by 2800, the SBM is starting to make some half-decent torque, lol................................. which makes for a fun launch.

 

[Agent_Orange]

IIRC you said you had a 2200ish stall. and 3.73 gears. That's gonna put a damper on how much timing you can run down there and still get to around 36*@ say 3400 rpm
That long-loop spring is only good for about 4>6* and some that I have tested took to 4000 rpm to be all in, with the stock weights. If you have a problem with detonation that can help, but mostly, that is unacceptable even in a 360.
I had a small selection of those long loopers, that I had accumulated over the decades, and so I rigged up a test-apparatus to weed out the late-bloomers, until I found one that seemed appropriate. It turned out to be just what I needed. Well I had to stretch it out a tad.
After that I just began installing the singles , one atta time, until I got what I thought would work. Each time, I had to generate a graph to see how it turned out, and to compare the current springs and weights, to the previous. Then began the roadtests...... for which, I had previously installed a dash-mounted, dial back, timing module, and with an on-board accelerometer, I was able to generate a pretty good theoretical timing curve to work against. By the end of the summer, I was reasonably pleased.

What I learned was this; at WOT;
3* short of ideal, from stall to 3600, is hardly noticeable. It's like less than 5hp max.
2* too much, when it causes detonation, you can feel it almost right away.
Therefore; if you can get the PowerTiming within a degree or two, and the stall-Timing even just close, but not too much,
Then, your engine will be happy. How it gets from stall to 3600, can be whatever; because the window, is very small, and in First gear, you scoot right thru it, and if you out-shift First at 5500, it will drop into Second at 3250, so just make sure, it doesn't detonate there..

At WOT
suppose your engine accepts 35* at 3400 rpm without detonation. and
suppose your stall rpm has to be less than 24*, and
suppose your T-slot sync ends up being 12*.
Your job is to connect those dots. So you gotta put the points on a graph. Then if they cannot be connected with a straight line, you have two choices;
1) run the 35* at 3400 and let the rest be what it will be. or
2) run a two stage curve, with the first curve connecting the Idle timing to the stall timing, then into the long-loop spring, ending as close to possible to your target of 35*@3400 rpm. Sometimes it is just not possible to do that with the parts you have. Sometimes, you have to make a compromise.
This is one of the reasons I like the 2800 stall convertor, it puts the stall rpm closer to what timing is achievable with factory distributor parts, and you don't hardly have to compromise .
Plus, you know, by 2800, the SBM is starting to make some half-decent torque, lol................................. which makes for a fun launch.

That is fantastic information, and I appreciate the time you took to explain it clearly.


so after adjusting my transfer slots, my 318 is happy @ 14 initial @ 750rpm in park. So, I would want to set up my distributor with a spring that is light enough to quickly advance from idle (14*) to the 2200 stall (28*), at which point the long loop of the heavy spring reaches it's post and begins to slow the climb of advance out to 34* @ 3600rpm. Then adjust for as much vac advance without detonation.

What are the cons of running a converter with a stall that matches the cruise rpm? I live in the country and work is 25 minutes of 2 lane highway that I run at 2800-3000rpm, with the occasional pull from a stop sign or out of sweeping turns.

 

[AJ/FormS]

If I was in your situation with a low cylinder pressure 318, I would run at least a 2800, and 3.23s.
You'd get a similar hit off the line, a quieter ride, better fuel-economy, and possible even the same or similar zero to fifty ET, cuz the 3.23s will get you there without a gearchange.
3.23s will get you about 65=2700 with 26" tires at Zero-slip/perhaps 2800 with a 2800 Tc and 3>4% slip.

Oh wait, I already did this, lol. and loved it.

 

[Agent_Orange]

If I was in your situation with a low cylinder pressure 318, I would run at least a 2800, and 3.23s.
You'd get a similar hit off the line, a quieter ride, better fuel-economy, and possible even the same or similar zero to fifty ET, cuz the 3.23s will get you there without a gearchange.
3.23s will get you about 65=2700 with 26" tires at Zero-slip/perhaps 2800 with a 2800 Tc and 3>4% slip.

Oh wait, I already did this, lol. and loved it.

I'm not getting too carried away until I decide the future of this '69 340 in the garage. In the meantime, I'm learning as much as possible. My winter plans are, chassis stiffening, rear end spring perches, might change center section, maybe torque converter or transmission. Whichever is janked up. Both...

but right now it's timing and carb since I drive it as much as possible.