Tuning ideas needed /200

[80Stang]

Well, got the engine running. Sure sounds cool but...

I had the rebuilt Autolite 2100 1.14 on it with jets whatever there were; checked today and they were 51s. That setup was running lean exept while idling, decelerating or while power valve was open. Power valve opens at 8 in/Hg, everything between 14 to 8 made the A/F meter show no lights at all as the A/F ratio sunk down out of the scale, lean side.

Inventory at home, found jet pair sizes 50, 51, 52, 54, and 68. Put the 54's in: does better, idles at two lights down from rich and the lean condition now starts at about 12-13 and the behaviour seems more reasonable. Idles down at 9 to 10.

I'm moving up to bigger jets as soon as I can find some. I'll also adjust more timing advance from the current 15,5 degrees in means to gain some more vacuum, but I'll avoid knock. Trying to find some powervalve that would open at upper in/Hg, maybe at 10 area.

Playing with timing and jets is not so tough, but who can say whats up with the stall that happens usually when I slow down for exemple from the high way to my home yard; the engine hesitates, shakes and finally dies unless I keep it running with gas pedal way down; this may happen too when I leave the engine idling for a while, won't take long after it starts running rough, vacuum drops and it stops. Then it is hard to get it running again, have to keep pedal to the metal and as soon as it fires it feels like running on less than all 6 for a while. Fuel level in the bowl maybe?

The meter is Autometer Sport Comp, the dizzy is '80 Duraspark currently set at 15.5 advanced, mech advance adds 10 degrees and vacuum diaphgram is attached. Just for background info. All the other bits and pieces of my setup can be found from my earlier post.

 

[Anonymous]

Sound's to me like the float level is to high.

 

[MustangSix]

I think you have the power valve just about right. You're on the right track and a slightly richer jet will help that main circuit. Just guessing, but something around a 62-64 should be about right.

You should be idling just on the rich side. Most engines do not like to idle at mixtures leaner than 14:1. At cruise, you should be at 14:1 or slightly leaner, and at full power you should be very rich.

I think you are very close now and a main jet adjustment will get you right where you need to be.

 

[80Stang]

I heard there is info available about hole sizes in Holley jets. Anybody knows of such info for Autolites?

Another wild idea, as a heard that in 4V applications people have used different sizes of jets in a pair. Considering Autolite 2V opens the butterflies in syncro and the plenum below the carb is open, would it mix enough the two different mixtures on the way to the chamber? Just thinking of mixing different sizes and assuming the result would be the close to the middle of the two; i.e. a pair with one 50 and one 68 would give roughly the same mixture to the chamber as two 59s. Just playing with the idea...

It may be hard to find jets for Autolites here, but I'm echoing the word around...

(plan B; maybe it's time to grap the dusty 350 Holley from the shelf and put it to work)

 

[MustangSix]

Or use a precision drill bit to open the existing jets. Drill, then carefully deburr.

 

[80Stang]

I assume plugs can't make it stall like that? It's got NGK/R APR6FS or something like that in it right now, which are equal to BSF82 but one step colder. The gap is now 0.040, I tried 0.060 first but it did not work.

The dizzy; being from an EGR setup and unmodified at the moment, I try to understand it. The weights give relatively low advance (10 degrees) and such engine has relied much on vacuum advance. We here got to consensus that it'd be better to change the weights to give 15, and restrict the vacuum diapgrams effect maybe by changing the whole unit to an adjustable version and make its effect weaker.

BTW, no overheating problems, and first impressions of MPG are around 20 already (unconfirmed).

 

[80Stang]

Thanks Big1 and MustangSix, you both were absolutely right. Progress today:

1. advanced basic timing to 18 degrees
2. found info from the web that Autolite jets are marked in a sensible way. The number on a jet represent its hole size in thousandths of an inch. So 54F is 0.054" and so on. I bought some drills and drilled one small 51F jet pair to 1.6mm, equal to jet size 63.
3. Found the inlet needle seat loose in the bowl, it allowed fuel to enter uncontrolled resulting in high fuel level. Did that, plus adjusted the level a little lower.
4. maxed the effect of accelerator pump

Results:
- great enhancement in idle quality; idles pretty nice at 900-950 rpm and vacuum is at 11-12. The idle mixture screws are on-line again, previously the engine ran best the screws about all the way in (lean)...
- cruise vacuum near what it was with previous engine, 11-15 on flat roads, depending on vehicle speed and gear selected.
- vacuum is now overall better
- A/F ratio stays ok, no lean conditions. Normal value is little below rich area (2-3 lights below), both at idle and while driving. Idle is a light or two richer at the moment.
- power valve's effect don't show in the meter anymore (?). Smooth transition?
- encouraged to test WOT now as the mixture is way better - woooooshhhh!!! After 3000rpm things really start to open. Below 2500 I don't think it is much better than the previous engine, but after that it really roars. But there is torgue at lower rpms also, this cam is not as dead there as I expected
- A/F ratio won't go to rich area, not even at WOT. How come...should I try the 68 jets...

Problems:
- It still stalls after changing from higher speed roads to parking lot/stop lights or such. I thought this would have cured but surprisingly did not.
- need to get the choke working
- I borrowed a small round air cleaner due to hood clearance issues. I need to solve it soon, and I'm going to put in the Redline's product, that just adapts a tubing on top ot the carb and allows a free flowing cone element to be used somewhere else in the engine compartment

It's starting to show its teeth - and I like it.

 

[MustangSix]

Now you can start reading the plugs.

It may still be a little lean at idle and at WOT so a small amount of tuning is still needed. Try the 68 jets and see what happens. If you go too rich, then you know that your best jetting is between 63-68.

 

[Anonymous]

There still may be a vacuum issue as well. 11-15 is low. Perhap's there's a small leak ?

 

[MustangSix]

Some cams don't like PCV valves at idle. It acts like a big vacuum leak and that may be the source of the idle problem. Try plugging that to see if it helps idle quality and the transition to idle. If so, you may need to put a restrictor in the PCV line or possibly even eliminate it and replace it with another type of crankcase ventilation.

 

[80Stang]

Thanks friends, you covered some issues I was thinking of too.

Today it tried to stall in a few seconds almost allways when I had to let it idle or drive with very low rpms. I thought about a lean condition too even though it doesn't show in the meter - well, the stumbling begins, engine speed drops, vacuum drops below 8 and the power valve kicks in and so the meter shows stoichometric again but the engine keeps dying.

All I had time to do today was to try to adjust idle richer; screwed the idle screws one more round out. All it did was a lot worse idle.

I'll report if the problems are there after these procedures planned for tomorrow:
5. check for vacuum leaks
6. try the 68 jets
7. plug the hose to PCV and see what happens. I had it plugged before yesterday's progress and attached it again yesterday and it did nothing bad nor good
8. I'll read the plugs.
9. I can try standard Motorcraft BSF82 plugs. I have a new set available, and the previous engine ran very well with that plug type and using 0.050 gaps. The CR has not dramatically changed from the previous engine so why not they would work very well in this too (maybe from 9.2-9.3 range to 9.3-9.5). Just to be sure there is no hassle with plugs. BTW, '80 specs call for 0.048-0.052 gaps and I have way better spark now, 0.050 should be no problem to this engine.

Enough for one day, let's see tomorrow what happens. Thanks so far for bearing this tuning process with me, I appreciate it.

 

[80Stang]

5. checked with starter spray; no effect. I don't think there is a leak.
6. & 8. tried 68 jets. Runs like it did with drilled 63s, but I did not road test it as I checked the plugs first; they were all matt black coated so it ran rich already -> changed the jets back to 63 and yesterday to 1.5mm drilled jets (59). No effect on the A/F meter, I'm starting to be suspicious if the meter/sensor are working properly. Anyway, there is no lean bog like with 54s, so the best jet size maybe at 56-58 range (those sizes I don't have)
7. not tested yet with current config
9. put the Motorcraft BSF82 plugs in with 0.050 gaps. No worse, not noticeably better. Maybe slightly willing to keep running after I turn the engine off, but otherwise I'll keep on with these for now if they don't get worse - trust the originals!

Planned next steps:
10. timing to 20 advanced - current 18 = no knocking whatsoever
11. radical idle adjustments; I doubt the problem is due to extremely lean of rich condition or bad quality of the mixture:
12. try different venturi clusters; at least the 4100 has differently configured cluster, I'll check for the other 2100/1.14 and the 2100/1.21 to what they have. Anyway, this starts to be pretty hard core tuning and an area I don't understand of

We can quess how close it is that I try a Holley...

BTW the choke works and is pretty functinal what comes to adjustments, with a Holley electr. choke cup (original exhaust heat inlet plugged in the choke housing)

 

[Anonymous]

I would recommend trying wd40 type spray for checking for vac. leaks, will have the same result but a whole lot less flamable(safer if you get a backfire or arc). Also i would drop the gap down to 40-45 and see if that helps the idle as plugs get pretty hot at wider gaps. and raise the idle speed to 1000-1100 rpm. I got the impression this is a new rebuild on the engine? If so and the engine is still real tight it is going to create higher chamber temps which don't like hotter sparks and slow idle. Larger plug gaps work better with less advance and vice versa. a hotter spark and lots of advance can provide too much combustion before TDC and cause stalling and too much heat. Higher compression amplifies this.

 

[80Stang]

Thanks. I have less than easy highway 500 miles on the engine, and it was built with minimum bore clearance.

10. timing set to 20 advanced. Seems to work ok, drove it to town and back some 6 miles total
11. tested mixture screws about four rounds out - idles bad. The more in I screw the better it runs, well almost. The screws are now only 1/3 round out from the bottom so it should be lean. Noticed some kickbacks during the testdrive when I take my foot off the pedal, otherwise this setup is more eager to go than the previous 18 deg setup.

I had the NGK plugs gapped at 0.040, no noticeable difference. Now the timing is more advanced so I may test smaller gaps after I read the plugs tomorrow/day after.

The idle is around 1000-1100, at the moment I don't believe I could get it idle below 900 but it might be possible if all settings come up perfect some day.

 

[CZLN6]

Howdy Teppo and all:

I've really enjoyed your detailed reporting. I have a few ideas to add to the mix.
*Next time you have the 2100 off the engine, try loosening the butterflys slightly then open the throttle and allow it to snap closed a few times. Then retighten the butterflys. Sometimes on a rebuild the butterflys are not carefully seated. Given what happened with your needle seat it is possible. I've had this happen on both on 2100s and 2300s.

*The power valve on the Autolite 2100 is less than high quality and accuracy on vacuum ratings. Know that the Holley power valves are adaptable to Autolites and are more durable and slightly more accurate on vacuum ratings and actual openings. They also give you a wider range of vacuum rating options.

*The 1.14 was an early iteration of the 2100 and was replaced with the 1.08 to get a leaner, cleaner engine beginning in 1968. The 1.08 has a leaner idle circuit, transitions and main jetting. With the engine modifications you have you will be plesantly surprised when/if you move up to a 1.21, which is comparable to a Holley 350 in CFM, and even more tuneable. We made this change on Dennis' "Hot6T" 200 and the difference was eye popping!

*We have found no reliable source of info on booster cluster on Autolite 2100s. We have measured a bunch and can draw no conclusions. They seemed to have changed from year, engine, trans, vehicle application and EPA accomodations.

I'm hoping this info is useful to you. Keep up the good job of reporting.

Adios, David

 

[80Stang]

Great David, thanks for helping me out.

The butterflys I'll check next time, but I remember it was a presicion job to get it working smootly for the first place.

Next time may come soon if I check the 350 Holley for duty; got a handful of power valves for loan from a friend and a set of gaskets, so I should be able to make it run pretty easily, without the choke though. Same applies to the 500cfm Holley, needs gaskets. That would be R&R, it's got 50cc accelerator and so on.

Some more info: popped open all the Autolites I have, and all the booster clusters are marked different. The other 1.14 is rebuilt in the past and has been in use recently so it is clean from the inside, might be operational pretty easily. It's got a 7.5 power valve in it, found the markings on top of it. The 1.21 needs more work, as somebody has altered the links and I need to buy a rebuild kit for it. First I intended to use the rebuild kit for the 1.21, but 1.14 was more complete and easier to do. Fortunately that throttle linkage allows different kinds of carbs be attached just by shortening/lengthening the rod between the ball joints.

All the rebuild kits I used have been Hygrade; for a 1946-1V on the previous engine, the 4100 (not used on anything yet) and the 2100.

This takes time.

 

[BIGREDRASA]

There's an old mechanics' saying: "If you thinks the problem is carburetion, it's probably ignition, and vice-versa."
Have you checked out your advance? The high initial advance settings with no pinging lead me to think you may not be getting any vacuum and/or centrifugal advance. With the low vacuum readings you have, your vacuum advance may need to be changed. You've not stated what kind of advance readings you're getting at the different vacuum and RPM readings. Is your vacuum advance diaphragm the kind that has a screw-in nipple, or the kind that has the two halves crimped together?

 

[Anonymous]

What bigred said.
20* initial timing is way too high for everyday driving, I had some problems with my 144 which traced down to a rotted diaphram in the vacum advance valve. It was actually working backwards due to the wierd position it was assuming. The light should appear to rotate towards the driver side as you rev it up. It looked good under the timing light --- at first -then i realized it was retarding instad of advancing under accel. also make sure you are using the proper vacum port for your dizzy, have had wierd stuff happen on (usually chevy small blocks) on later model carbs with multiple ports on intake or carb as some are set up for different flow characteristics.
Also make sure that you don't have a vacum leak somewhere that you arn't noticing like on you aircleaner or at mounting screw areas not near your carb.
1 more thing, you mentioned "lean bog" usually bogging is a rich reaction and surging(not wanting to hold a steady rpm) a lean condition. and you said that you are down to 1/3rd on the mixture screw- another sign of rich. Restarting requires holding throttle to the floor another sign of rich. You may need to remove clean and reinstall your o2 sensor as when they get covered with soot they will give false readings.
Have seen more than 1 occasion where a similar condition finally got traced to a clogged or too small air filter. Air filters have the same effect as a choke to varying degrees.
Eventually you will find the problem and it may amase you what a simple little thing it is and that you jumped through alot of hoops that were unneccessary to get there. This happens to EVERYBODY more often than we want to remember.

 

[80Stang]

Gosh you got into the same issue as a friend of mine, the ignition. BIGREDRASA and danwagon, here is some info:

Last time I checked dizzys output was on the previous engine. The Duraspark has centrifugal advance that is adjustable to 10 or 15 degrees - it is set to 10 at the moment. The vacuum diahpram is non-adjustable and worked aggressively but it was about a year ago when these were measured. We have been thinking of changing to 15 and restricting the vacuum some amount somehow. An adjustable diaphram is on the purchase list. I'll measure the timing curve and vacuum readings but it may take a few days to find the time to do it.

Vacuum leaks I can double check.

Lean bog - I meant more like surging; the AF meter showed stoich readings at about 13 inHG and again at 8 and below (power valve in action), in between the meter went totally lean and the engine hesitated real bad. That was with 54 jets and smaller, now I have about 59s and that problem is not present anymore.

The mixture screws are only 1/3 round open. Now the engine starts right away if things are ok, but the "problem" can be ON and it needs a lot of throttle to start up, runs very rough for some time (with throttle way down) and starts to pull strong after it wakes up...

Air filter - I don't believe that is the problem. I had one 10" open element universal type air filter there until the day before yesterday. It was 2" high and open all around, and I used a new element in it. I had to give it back so I fabbed up a filter housing from a junk VW on neigbours yard and put new element in it too. It is temporary solution until I get the Redline "iglu" to adapt a remote free flowing filter to business.

The problem is related to slow rpms somehow, idling or so. The engine pulls strong, torgue is there, it accelerates well and revs easily to 5500 rpms without hesitation (haven't tested higher)...I can drive slowly on 2nd or 3rd gear at 1500rpms forever if I wish, I drive to work 35 miles one way at 55MPH/2300rpm/12inHG with no problems and so on. The problems may occur as soon as I slow down from the highway to city traffic - slow turns, traffic lights, parking lots...

I'll draw the timing/vacuum curves and write more info as soon as I can get to it. Tomorrow I have a business trip and the engine is going to see 200+ more easy miles.

Sorry it is hard to explain but I try to give as much info as possible 'cause I appreciate everybody's ideas to fix the problem. Thanks for reading and responding!

 

[BIGREDRASA]

One other thing. Are you running an EGR valve? Have you checked it for leakage?