The old stalling when put in gear syndrome


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Sep 25, 2022
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I have been working on my 66 383 now for about two years, with short road trials for about year and a half. So, after my recent work on replacing the timing chain and gears, I had never seen anything like the chain slop in this one.....mainly from the plastic all gonium, prob. So, out with the old and in with the new, and new damper. So, knowing that the cam is now advanced plenty from where it was, I retard the distro before start. Starts and runs like a put all back and time for road trial. Before that, check timing and adjust. So, off I go. And in I come with this dreaded low idle in gear and rough run....did not die. Ok, begin checks. Found timing off for some reason, but that did not correct. After massive reading on multiple forums, including other mfrs, this is a common problem, that did not exist back in the day. Even seems to be present on newly rebuilt engines...not just pigs like mine. The route I have gone for now is to reduce idle down to just over 700, with drop to about 550 in gear.....was at 900 with drop to 600. So, listening, to those who have gone before, I am thinking throttle blades too far open, causing idle circuit screwup. Reduce down to the 700, and tune carb for lower rpm...minor leaning of the idle jets only so far. OK. SO, WTF over. I am writing to make one notation here, and that is that this problem was not evident prior TC change. And, this is not a distro timing issue because I am now about 5-6 degrees less advance to make up for the tight chain. But, but but.....there is another change, and that is cam timing. And yes, I did advance mine 2 degrees with Cloyes. But, I am wondering whether the cam advance may have an effect on this. AND, I do feel just a hint of idle roughness after the run and return, and after gunning a time or two gets better. So, I am going to pull the plugs and look for any that are having issues, and if so, go from Champ 12 to 14 to maybe help fouling a taste.....if I find some bad. Engine not bad when on the loud pedal, but the idle.......the idle, the worst of the worst conditions. And before anyone asks, I have limited this rebuilt distributor to 16 centrifugal, put in about 18 initial, and then am still playing with VA with some limits on it....but total is still way over 40 with VA, plenty of VA at idle. Just wondering in my case what changed to CAUSE this crap that did not exist with a worn out chain and gear.
First, which idle specs are you using? The factory idle speed specs from a FSM or somebody else's recommendations? Same with idle speed. ONLY CAP cars had idle speeds near what you mentioned, not federal cars.

In reality, the '66 383 2bbl timing specs are pretty good, as to total distributor advance and vac advance. Yes, if you look at part-throttle advance (about 2500rpm), both the centrifugal and vac adv working will result in total advance closer to 50-55 degrees advance, but at WOT, the vacuum will drop out leaving just the centrifugal + initial operational. The 36-40 degrees BTDC everybody talks about (for initial + centrifugal) is at WOT.

What were the issues with the original torque converter and what are the specs/application for the one you replaced it with? THAT is an issue as to the load the engine sees when in gear, which relates to hot base idle speed.

Having the idle speed too high (which you apparently do) CAN cause some issues with the off-idle activities and idle mixture adjustment as the transition ports can be flowing, too.

As to your cam sprocket advance, it should be 4 crankshaft degrees rather than 2, as 2 degrees at the cam results in 4 degrees on the crankshaft. That should NOT affect hot base timing settings . . . UNLESS the sprocket instructions mention such.

When the new torque converter was installed, with no other engine changes, and it went into gear harder and dropped the idle speed more, that should of been an indication something was "not right" and where the issue was. Presuming the cam is the OEM cam, as the timing set was original?

Are there any performance changes? Does it have headers, Alum. manifold, bigger carb, etc? If not
why did you want to advance the cam timing?
OK, this is a lot. I had mentioned in another post that I would ask the friend trans builder about the OEM converter, which I did. He said, should be no problem, very stout converters. OK, this engine is stock, as far as I know, no converter, no cam changes. And, an interesting point on degrees of cam angle change by Cloyes....I put mine on 2A, and to be honest, not sure if that is cam or crank as you point out. My main issue is that when I went to the new cam drive, this issue began, and I am not saying that caused it, which it should not have, just dont know. Was not there before, and so far have not corrected it with what I have done to date with carb and distro settings. The singular point of contention I have is that when you advance the cam, you also advance the distro, meaning a timing change at the piston, so yes, it will affect timing setting, imo. Final point is timing settings. Book says 10 A for my engine, in the FSM. However, before all of this TC work, I timed to max until ping, and THEN it was 22 initial, and a lot above that. Now, I have it at 18 initial, and have not yet pushed that. I am not going by book, but by lots of opinions on pushing advance till ping, and also having to drop the centrifugal if you use more initial, which I have done for the moment, although I have cams for more timing if I want it in the distro. Anyway, this is an interesting problem, that seems yet to have no real answer, because our originals did not seem to exhibit this, and yet many do today???
The cam timing advance is to provide better low end torque, with retard providing better high rpm power. Mine is an old mouse, and I decided to advance a taste. They go up to about 12 each way on the new gears.
I know what advancing the cam timing does, I just don't think it is something I would do on a bone stock engine with miles on it.
What are your vacuum readings in the different rpms and driving conditions? What all did you take apart when you did the chain?
Unless it is Mousey Brown and a 427. Engine stock except for externals like water pump, shimmed oil pump relief, edelbrock and now the cam drive and damper. I have not taken vac readings, since had plenty at idle to pull the can, and had to back it down a taste. But, again, all of this is an idle issue, yes?
Have only done cursory vac checks around the carb.....not manifold. But again, seem to have plenty when working with vac cannister, and cut it back a bunch....tighten the spring and still get 15 degrees, at this point. But, should measure it. Just talked to Ray B about this. We talked mech advance at low speeds in the FSM tables.....and will get some at these low idle speeds. Also surprising to see the numbers in the AFB section, says idle should be 500.....aaaaargh. So, clearly my former 750 with changes up to 900 are off base. So, Ray suggested lower idle to maybe 650...or lower, then bring initial timing down to around 15, and test. I will do this and also today will go thru the plugs, looking for signs of foul, as I was having an uneven idle when in gear at about 500.....runs fine on the pedal. Will also go thru the idle jet adjust again as well with lower speeds....have already closed half turn when lowered from 850 down to current 700, so it does make a big difference.
Fwiw a vacuum leak won't mean you have no vacuum, otherwise you'd have a runaway diesel on your hands
Agree 100% on vacuum problems, and I need to do this check, in more depth. Because, that would exacerbate this problem. Today, after checking plugs, I replaced three that were darker than the other 5, but all were just sooty with tan ceramic....and no oil....a good thing. So idling much more gooderer. So, now at 650 rpm, quite a bit higher than FSM says at 500. Also went back thru timing which is currently at 18 plus 18 VA for about 36 at idle....yes may be a tat high, but engine loves it under high load, and comes off idle like a jet, very responsive. So, test drive a few miles to warm up, then romp, then as coming back into driveway, off the pedal, it dies.....cant handle the converter at that rpm.
So, I am going to continue with this game, and am still in the dark due to the black cloud. Oh, too, thanks to all above for pointers, and as I have been looking elsewhere, I have found some old points from Cbody67 that are appreciated. thanks all
You have VA tied to manifold vacuum not ported vacuum then?

I've rarely had OEM cam but 500rpm is low to me even if the fsm says so. 700-800 for me with RV cams. Lets the alt charge a bit better and water pump run a little faster at idle.
With the cam timing advanced, you may need to idle a little higher. 650-700 RPM is not excessive. You are also running on today's gas and not
what was available when the FSMs were written.
Never had any issues with FSM idle speeds. Maybe 50rpm more, but no more. Even the "small" factory a/c alternator did well at that lower speed. But then, too, with a Group 27 battery, a good bit of reserve.

Here's a proposal . . . put the vac advance at ported vac and put the hot base idle speed at 600rpm. This will put the transition ports and the throttle blades at a more "designed-for" position, which also means a bit more open. More air at idle might lessen the "stop" issues, possibly.

What were the application/specs of the replacement torque converter?

Is the carb. new or has it been rebuilt? Maybe the idle circuit is dirty or clogged. If that is the case then it could run good off idle but keep stalling when you stop. My friends 340 Cuda had that problem, and he had the idle very high, around 1200-1400 RPM. The carb. was an old Edelbrock 1406. About 12 years old. He replaced the carb. and it was idling around 650 RPM with the new one. Do you have another carb. you can switch to and see what happens?
With the cam timing advanced, you may need to idle a little higher. 650-700 RPM is not excessive. You are also running on today's gas and not
what was available when the FSMs were written.
Yes, current fuels are MORE volatile than the fuels the cars were designed with. Which means any air/fuel ratio should be more homogenized when it gets to the valve (prior to getting into the combustion chamber), For the same reason the fuel bowl can "dry out" after the engine sits, not running, for a week. Even with am OEM carb, it should work better at the lower idle speeds. On the two cars I was daily-driving when we first got RFG (oxygenate of 10%, split half and half between E10 and MTBE), I might have tweaked the idle mixtures on the two carbs just to ensure they are optimized, but no other significant reason to do so. When it became full E10, no difference. In other words, I did not experience many of the things others mentioned!

In the 1990s, in the back of the Chevron website, was a full section devoted to "new gasolines". It mentioned the "hot restart" could result in extended crank times compared to earlier Chevron fuels, plus some other things. In reality, I experienced none of that in my area (DFW, TX), which is one of the EPA Ozone Non-Attainment areas. Later, in the back of the Exxon and Mobil website, I discovered USA maps of which fuel blends were in which areas of the country . . . MANY MORE than every suspected. Therefore, with these different blends, I know that my experiences here might not be what others have experienced in other parts of the nation. Something like 13 different fuel blends!

Is the carb. new or has it been rebuilt? Maybe the idle circuit is dirty or clogged. If that is the case then it could run good off idle but keep stalling when you stop. My friends 340 Cuda had that problem, and he had the idle very high, around 1200-1400 RPM. The carb. was an old Edelbrock 1406. About 12 years old. He replaced the carb. and it was idling around 650 RPM with the new one. Do you have another carb. you can switch to and see what happens?
n my '80 Newport 360 BBD 2bbl, the reason it was traded-in was that once it got off of the fast idle cam, it would not idle. Multiple efforts to fix it had failed. On the main system, it ran fine. Even when at 60mph, coasting to an off-ramp, the engine would die. It would always re-start, but I had to keep the idle speed manually elevated with my right foot.

My diagnosis was "no idle fuel", although decreasing the size of the idle air bleed on the venturi cluster could make fuel drip from the venturis. FINALLY, I found a spec for "Low Speed Jet". I dsid not know where that was, so I searched my library of FSMs to look for it. The spec size was listed in the carb specs in the FSM. Finally, I found where it was . . . at the bottom of the brass idle feed tube, but not at "the bottom", being up in it a little bit.

When I found that, I pulled the venturi cluster out and started to probe the hole with a bent-wire spark plug gap gauge. Starting small, the hole there increased in size with each probe. Hard deposits were blocking it! Then, a trip to a hobby shop for a twist drill and an assortment of bits. I used the hand twist drill and bits to enlarge the "Low Speed Jet" hole until I "got brass". I flushed the tube with spray carb cleaner and re-installed. Problem fixed.

When I first went through the carb, I sprayed carb cleaner into those idle tubes. They appeared "open", as they flowed cleaner through them. So I deemed them good. As soon as the carb cleaner (in the tube) was used up, the engine died.

Just my experiences,
Great comments and technical points. Note.....I am on the stock engine, trans and converter....prob never removed, but unknown for sure. I have a new Edelbrock AVS since I could not find the right size accel pump, even from Mikes, for this carb....AFB had many sizes pumps. And yes, I am very familiar with idle some carbs, esp in motorcycles. But often there are three sizes and then sometimes an air jet replaceable too.....sometimes just drilled in. Air jets are built into the inlet section of the carb and port air to those nasty little small ports around the throttle plates, when used....brass and come out. So, after recommendations, today I used propane to look for leaks....found none, But, But I am now confused on the PCV valve. Mine is screaming open at idle, and dont see how the idle can be controlled in this case. But, the design sites say that even at idle some small vacuum is at the valve and some air will flow...will increase with reduced vac at higher speed and load in the intake. That makes sense. But, I have never asked my dumb self about how much air should be entering the intake thru PCV, because I have never had this idle issue before. Now, I suspect a bad, although fairly new PCV, and too much air coming in at this idle condition that is crap. And, Cbody.....I will try the ported vac on the carb, and see what we see, just for grins. Thanks again for the pointers....driving the old guy nutz. Just got back from two several hour stints on friends machine.....just quit, no spark. So, after hours of testing, come to learn that the japanese engine, Mitsi, has points with just spring load on the wire coming to them. And, the wire terminal was contacting the points frame and grounding out....just the mismatch of one small nylon washer, I think. Black cloud overhead, as usual.