I can't tell if it is just good karma from new ignition parts: pick-up; orange box; blaster 2 coil with new ballast resistor, and oh yeah, the GM silver spring, or the car is actually running a bit smother & stronger. The idle has been lowered about a hundred rpm to 900-850, and in gear to 600-550 rpm. Hard to tell with my ittie-bittie tack ticked off in 200 rpm increments. Idle adjustment screws turned in an additional full turn in plus a bit more. At "in gear idle" I keep thinking the engine will stall due to the lack of power pulses, but it still keeps ticking over, and responds well to feathering of the throttle with instant response when it is mashed to the floor.

I just went out to eat with a big group of friends down in Eastport (eastern most point in the US) were a surfer/hippy guy & gal make the most wonderful wood fired oven pizza, ribs, and smoked salmon dip. Sorry I digress, this was a fifty mile round trip at 50 to 60 mph all the way. The car with its new silver government motors distributer spring, seemed to be smother, and the exhaust note was not as loud as before all the modifications. Am I dreaming or has someone out there performed like changes and experienced the same results.

Additionally, the car is a bit more eager to lay twin patches than before. I performed this tire spinning test at the end of my 12% grade driveway on dead dry, and clean asphalt this afternoon. Several week before, I performed the same test in the same location, and more throttle was needed then to lay down a two foot long strip. So for what ever reason I guess I'm getting more torque to the rear wheels now.

_________________
67' Dart GT Convertible; the old Chrysler Corp.
82' LeBaron Convertible; the new Chrysler Corp
07' 300 C AWD; Now by Fiat, the old new Chrysler LLC

my 67 just got back to life after a monthish of sitting, feels good doesnt it?

she isn't a slant car but my 75 new yorker is coming out of a temporary retirement she goes better in the snow and ice than my truck does what arush it was to hear her come to life

_________________
Nothing beats a slant six
1987 D150

wjajr,

Sounds like the recurve was a good effort. The silver spring is keeping the governor weight from prematurely advancing so your getting more mechanical advance now when you want it.......

Many times a stock distributor is pretty sloppy and the weights are all ready partially out at idle, especially with the hotter cams that like to idle at a higher rpm.

When you do a recurve you get more power/torque early. The engine doesn't have to rev as hard for the same power. That is why it's quieter. It's just not working as hard. This recurve is working better with your mystery cam. It may take some more testing with other primary springs, but your getting closer to matching your cam.

Since the engine is not working as hard, you may get a little better mileage. Small things like valve lash, spark plug gap, idle mixture and vacuum advance pod tuning can make a big difference and felt in the seat of the pants driving. I know it sure make a difference on my engine.

Thanks for sharing the good report!

_________________
Aggressive Ted

http://cid-32f1e50ddb40a03c.photos.live ... %20Swinger


74 Swinger, 9.5 comp 254/.435 lift cam, 904, ram air, electric fans, 2.5" HP2 & FM70 ex, 1920 Holley#56jet, 2.76 8 3/4 Sure-Grip, 26" tires, 25+MPG

Thanks Ted, this all starting to slowly sink in. If I had a set of parameters to tune to, I can see where this would be easer than feeling the pulse, and reading the signs of the patient and treating as needed.

Yesterday it didn't look good for a dry Sunday. Now that this stupid tropical storm is blowing out of Eastern Maine tonight, Sunday we have a car show 100 miles or so north of here to attend. I will check fuel mileage on this excursion.

I have sent for the spring kit Charley Brooks is selling. Hopefully this kit will solve the rest of my drivability problems with the proper spring in place.When I get it, I will ask the following questions of you:

1. Static advance setting, idle rpm, and quality of idle. Presently below 1000 rpm the idle starts to lope, by 500 rpm it is very sporadic barely firing enough to stay running, but responds well to the slightest throttle input..

2. How many turns out should my vacuum a pot be set at, or how much advance should I be looking for.

3. When should the mechanical advance be starting to kick in above idle. I have a 2600 rpm stall converter, but is feels like it is hooking up around 19 to 2000 rpm.

4. Total static, mechanical, and vacuum advance at cruse speed once every thing is dialed in.

Now a few questions I would like to get straight in my head:

1. Explain torque out put, to timing advance. Or, in other words, less initial timing makes for more torque, or less torque, before mechanic advance kicks in at a given rpm?

2. I have observed that as one advances timing from TDC to BTDC idle rpm increases, and the lower the timing and idle the more the idle adjustment screws can be turned in. Presently I have a rolling idle between 900 & 1000, at a steady 12*. I'm guessing that flux in rpm is due to the cam over-lap and start of the lopping.

3. Presently there is about a 400 rpm drop from "in park" to "in gear". So 1000 in "P" drops to a loping 600 rpm which is really a rolling 500 to 700 to 500 rpm tick-over. Do I aim for lowest idle in gear that will let the engine stay running while stopped in traffic, or do I adjust for smoother idle "in park', and live with a higher "in gear" idle which tends for a bit harsher shift between P & D, or P & R?

_________________
67' Dart GT Convertible; the old Chrysler Corp.
82' LeBaron Convertible; the new Chrysler Corp
07' 300 C AWD; Now by Fiat, the old new Chrysler LLC

great great questions wjajr this is also the stage I am at. I too will be looki,ng for the answers.

I keep hearing about the vac pods that can be adjusted..are these after market stuff or just on newer cars..(mine is a 62')

There also must be a way to check the dist. springs besides putting some in and driving it around to see if it works..If not to hard to explain I would love to hear about it..(please use 1st to 2nd grade wordz please:)

_________________
Its so nice out side, I think I'll go lay under my car..

wjajr,
1. Valve lash for your mystery cam will have a big effect on tuning parameters. How noisy is the valve train now? Is it just the intakes that make the noise? or just the exhaust or is the whole valve train quiet? You may be able to adjust for a better quality idle. Not being there to listen to it makes it hard to tune. However, it sounds like your close on the valves if it will idle at 500 and be responsive to throttle. More seat time until you get a slight tick will steady the idle some. Since your at 12 degrees initial it should be very steady and responsive. More initial will only raise the idle.

2. Depending on the vacuum pod you have will determine how fast it kicks in. At zero turns out it will kick in as soon as the throttle plates are cracked open, if your plugged into the timed port. I like to run the VC-208 about 3 turns out so it kicks in a little slower and later. The key here with your cam, at idle you should be able to unplug and plug it back in with no difference to the idle. You want it to be neutral with no effect at idle.

3. 1200 to 1500 rpm

4. 52 to 55 degrees for best mileage. Over 55 degrees it will feel flat and sluggish, not responsive to throttle changes.

Next set

1. Less initial timing makes for less torque. The initial timing should match your pump shot so you get a nice strong hit.

2. Correct, it is a balance. If you could reduce overlap with more intake seat time on your valve lash you could run the mixture leaner as you mentioned. I wouldn't worry about getting it too low. The cam is fixed, we are just tuning around it.

3. No, don't go for the lowest idle. My idle is at 600-650 in gear and can idle there for hours in bad traffic. You want a good idle you don't have to worry about, and not pollute too much. Tune it for a smoother idle in gear but not by raising the idle too much with the idle screw, but by being sure the advance weights aren't engaging to early and the pod isn't kicking in too quick. Both can raise the idle too quickly or make the idle more erratic and that just makes the shift harsher.

Fine tuning
They key is to run a strong enough primary spring to keep the advance weight all the way in at idle and to tune the vacuum advance so it is dialed out for a nice steady idle. With a lopy cam this may be a little more difficult to do. You may need a slightly heavier spring. I like the longer (more coils) for the primary spring like the original MOPAR springs and the ones Charles sells in his kit. They control the advance weight much better for a smoother response. The shorter GM springs are more off and on, like a light switch when used in a MOPAR distributor. The MOPAR advance weights are much heavier than the GM weights and require more control. The short GM springs are fine when used with the light GM advance weights. For best driveability stick with the MOPAR springs.

Hope this helps......

_________________
Aggressive Ted

http://cid-32f1e50ddb40a03c.photos.live ... %20Swinger


74 Swinger, 9.5 comp 254/.435 lift cam, 904, ram air, electric fans, 2.5" HP2 & FM70 ex, 1920 Holley#56jet, 2.76 8 3/4 Sure-Grip, 26" tires, 25+MPG

Okea? (a little Dan lingo there) Lets winnow this tome down a bit Ted.

There is definite valve train clatter. Intake are backed off to 0.016" & exhaust 0.014. Frankly that racket drives me nuts, but experience has taught that this car won't idle worth a dam when set to factory specs.

I was shooting for 10 degrees BTDC, however as the "clamp-down" bolt is tightened, the timing creeps up a few degrees. I can't determine if this a result of worn distributor parts, or just a result of the clamp driving the distributor shaft deeper onto the cam thus advancing timing. I have checked for side play in the distributor, and there is none.



Pod is a 7-R, I can't cross match it to Dan's list of pods showing Start & Max advance parameters foe each. Mine is currently turned out one and a half turns+/-. Your VC-208 is listed as starting advance at 6" Hg / 10*, and 10*-12* at 9" to 11Hg. Tomorrow I shall recheck my readings and report back.

I have to revisit this one tomorrow; last time I checked vacuum advance was dipping in around 1600 rpm.

Also on tomorrow's list.
My job is to work all three variables, static, mechanical & vacuum advance, to have it start to kick in around 1200 to 1500, and not to exceed a total of 52 to 55 degrees at 2800 or so rpm. which is about 55 mph.


With out using the throttle plate adjustment screw I need to get idle to a point that it settles in at 600+/- rpm by turning the distributor and hoping that the in park idle is not excessive. Than from that point, adjust the vacuum advance so as not to exceed 52 to 55 degrees at cruse which in my car is running 2650 rpm to 3100 rpm. Mechanical is what it is, but the tip-in rpm can be selected by tuning with the primary spring. This is good some numbers to shoot for!

Now to sit tight until the spring shipment arrives....

As a side note; I took the now, "award (I got a 1st. place in convertible category) winning" yellow 1967 GT to a car show today, a 200 mile round trip. The car ran well; I could feel when the mechanical advanced kicked in. On the way up to the show, the local old car nuts I hang with, less one old slowpoke, ram-rodded it all the way. I had to run 55 to 85 mph the whole way. This is not very conducive to good fuel economy, but recorded 19.2 mpg for the round trip.

The car pulls real strong from 55 to 85 at WOT (let off at this point), and is responsive to light part throttle in the 45 to 60 mph range, the car is willing to move the Speedo needle effortlessly.

_________________
67' Dart GT Convertible; the old Chrysler Corp.
82' LeBaron Convertible; the new Chrysler Corp
07' 300 C AWD; Now by Fiat, the old new Chrysler LLC

wjajr,

Some more thoughts......
As you have found the factory spec (.010 and .020) won't work with your mystery cam. Can you isolate if their is any noise coming from the exhaust valves? I would think that you could run them much looser than .014 to avoid burning a valve. They need some seat time to cool. This would help with the torque and steady the idle.

I understand running the intakes super loose to reduce the overlap effect and help steady the idle. If you loosen up the exhaust since they grow so much, maybe you could tighten the intakes .002 or so and still not loose idle quality and maybe improve it and loose some of the clatter. Do the valve lash with the engine hot and running so you know what is happening real-time.
For what it's worth mine likes to do the same thing. I set it for ten, tighten it and it always comes out at 12. No big deal......
Your pod will give you 14 degrees more advance. The key is to test it with the timing light pulling the line off and plugging it then checking the timing at the same time then plugging it back in. There should be no change in timing. If there is, unscrew the pod another turn. My VC-208 provides 22 degrees so I have to run it 3 turns out to keep it from coming on too soon and raising the idle.

You should be checking the mechanical advance as well, not just vacuum advance. We know your at 12 degrees initial and 14 degrees vacuum for 26 degrees. How much mechanical advance are you getting?
Good!
Refresh my memory, what governor are you using? Hopefully a 15R so you can get to 55 degrees with out too much work.


Thanks!

_________________
Aggressive Ted

http://cid-32f1e50ddb40a03c.photos.live ... %20Swinger


74 Swinger, 9.5 comp 254/.435 lift cam, 904, ram air, electric fans, 2.5" HP2 & FM70 ex, 1920 Holley#56jet, 2.76 8 3/4 Sure-Grip, 26" tires, 25+MPG

11 R governor.

Would the sum of these devices plus initial be: 12* + 14* + 22* = 48* degrees? If so looks as if I'm off a bit.

Next Q:
Initial is initial, it is set, always there. Aiming for 22* mechanical tip in at 1500 to 1600 rpm less 3* +/- the secondary spring holds back until 2800 rpm or so. Leaving vacuum advance to move up and down depending on signal from carburetor. There is a question coming soon, just have to think out loud for a bit.... As throttle is opened, depending on how much, the engine automatically retards up to 14 degrees based on that signal, and advances fully once engine is up to cruse speed when high vacuum returns. What is the optimal power advance degree value less vacuum advance contribution? Is this what I'm really looking for?

My 390 is a vacuum pig, sits near 9" to 12" Hg. under light throttle with easy dips to 4" (powere valve of 3.5), dead zero at WOT, and 15" to 17" at level cruse. Would a different vacuum pod be to my benefit?

_________________
67' Dart GT Convertible; the old Chrysler Corp.
82' LeBaron Convertible; the new Chrysler Corp
07' 300 C AWD; Now by Fiat, the old new Chrysler LLC

wjajr,
Yes, but not bad. You could make it up by going to a 11R vacuum pod like the VC-208 or VC-239. 12 + 22 = 34 degrees plus another 22 from the pod would give you 56 degrees, so your in the ball park. Make sure the pod arm is stamped with a 11R if you want the best mileage.
You want 30 to 32 degrees as soon as you can for the most punch and torque. Drag racers settle on 28 - 30 degrees and do not go over 32. Any more and the engine goes flat or pings.

Case in point: When my son talked me into drag racing the car this year, and as long as I kept my foot to the floor the vacuum advance could not kick in and it pulled/accelerated very consistently for a #56 jet. One time I let my foot up before crossing the finish line and the engine went flat from too much timing from the vacuum pod kicking in. I am at 12 degrees initial plus 20 degrees mechanical for a 32 degree total. The engine never made it much past 2800 rpm for a 70 mph run at 19.3 seconds. Not bad for the posi spinning both wheels off the line and weighing in a 3600 lbs and a tranny and torque stock converter with 405,000 miles on it.
Its a vacuum pig because the valve lash for your cam is not spot on and the overlap is very high until you reach the magic rpm where it starts coming into tune. The cruise vacuum sounds reasonable. I cruise between 15 and 19" at 50 mph, 2000 rpm. Light throttle on hills is 9 to 15 depending on speed and rpm. With 3600 lbs and 2.76 gears I need to keep it at 2500 rpm for best vacuum on a hill. That is with 2.25" single exhaust pipe to a Thrush Muffler and and 2.25" out except the last 30" is 2" pipe. With long primaries on the headers you could get better low end vacuum numbers.

_________________
Aggressive Ted

http://cid-32f1e50ddb40a03c.photos.live ... %20Swinger


74 Swinger, 9.5 comp 254/.435 lift cam, 904, ram air, electric fans, 2.5" HP2 & FM70 ex, 1920 Holley#56jet, 2.76 8 3/4 Sure-Grip, 26" tires, 25+MPG

I have not found a big difference in gas mileage between high 40s and mid 50s total advance. 55 is a number I've seen Ehrenberg give for V8's, which require more advance than a 225 in general.

I agree that loosening the valve lash or advancing the cam some will bring your vacuum readings up and likely your mileage too. Too tight lash can really kill idle quality and mileage.

30 deg full mech advance is really as high as I would go for max power at WOT on any kind of performance engine. You really start losing power fast when you go with more mech advance than that, even by 2-4 deg. I have gained a whole second in the 1/4 by simply retarding my timing during one day of drag tuning.

Lou

_________________
Home of Slant6-powered fun machines since 1988

Ted.

I'll aim for 32 degrees by dropping initial back to 10 BTDC which will give me 32 degrees. I don't think I can go bellow 10* and still have the engine idle in gear with out stalling. If I have to, I can always fill in the governor slots to limit the advance a few degrees. I found a chart somewhere that tells how much to fill per degree reduction, hopefully I can relocate it...

I'll order up a VC-208 and give it a few turns out with the Allen wrench to land in that tip-in 1500 rpm sweet zone. Perhaps the springs & all will show up soon so I can get this clam bake going.

I have noticed that with the timing dialed back to 12*, feathering the throttle is a lot easer to control without the timing jumping.

I'll recheck the valve lash, and back off the exhaust a bit more for more seat time. Did you say an additional 0.02" for a total of 0.024"?


The idle smoothes out at around 1000 rpm. How dose one go about setting the lash to "Spot On" SWAG-it, and keep SWAGGING until the vacuum gage says OK enough? Or, is there some tried & true tribe ritual one has to follow?

I'll perform another vacuum study to create a base line before any valve lash adjustments, as well as a timing vs. rpm chart. Got my engineering & design hat on for a day or two more, busy with setting grades, laying out foundation, and scribbling up an electrical plan for the new house so it will be a few days before I get to the study.

_________________
67' Dart GT Convertible; the old Chrysler Corp.
82' LeBaron Convertible; the new Chrysler Corp
07' 300 C AWD; Now by Fiat, the old new Chrysler LLC

For lash, I usually run them loose (start with 0.024/0.030") and listen for valve noise. Then start lashing them down in 0.002" increments until when the engine is HOT (210+ deg) the idle quality gets worse compared to a cold or medium-warm engine. This assumes carb and other stuff will let it idle nicely at all temps with loose valves. Valve noise should be a lot less or gone at this setting.

I don't trust any cam grinder's lash recommendations, and have ended up either below and above their specs depending on the cam.

Lou

_________________
Home of Slant6-powered fun machines since 1988

wjajr,
Don't do that, just use a stiff long looped secondary spring. That will stop the advance.
I was worried about the exhaust valve lash at .014 as you quoted. That is a sure bet for a burnt valve over time. Set them as Lou suggested. By doing the lash while the engine is running you can tell where the lash ramp starts by trying various feeler gauges. "Spot on" would mean there would be little to no noise hot and the vacuum gauge will verify it with high values.

_________________
Aggressive Ted

http://cid-32f1e50ddb40a03c.photos.live ... %20Swinger


74 Swinger, 9.5 comp 254/.435 lift cam, 904, ram air, electric fans, 2.5" HP2 & FM70 ex, 1920 Holley#56jet, 2.76 8 3/4 Sure-Grip, 26" tires, 25+MPG