Well guys, I readjusted the lash to 0.026â€￾ exhaust, and 0.018â€￾ intake, and adjusted the idle mixture. Screws went in a ¼ to ½

In gear idle @ 550 rpm vacuum got a little bit noiser going from 0-5â€￾ Hg fluttering needle, to 0-7â€￾ Hg fluttering needle. However it has dropped about 50 rpm from 600…

Park idle @ 1000 rpm was 10-11â€￾ Hg, now a fairly solid 11â€￾ Hg

1800 rpm was 15-16â€￾ Hg, now solid 16â€￾ hg.

Compression cylinders 1-6 @ old setting 0.012â€￾ & 0.021â€￾:
140; 145; 145; 140; 145; 145

Compression cylinders 1-6, a@ new lash 0.018â€￾ & 0.026â€￾
150; 151; 160; 145; 150; 150. I don’t know why #3 jumped up so much.

I have noticed a little roughness in the idle ( a little hitch in its getty-up you might say, and it is coming from the last three or right exhaust pipe) since that noisy lifter incident a few weeks ago, which just happened to involve number 4, the only cylinder lower than the others. I wonder if perhaps it got burnt?

Before compression test, I took a two mile run to re-warm the engine after supper & lash adjustment. The plugs still look real good, perhaps a bit leaner looking especially for #1. #4 color looked to be right on the money.

Now I’ll sit tight until the jets & plugger-upper arrive.

Car show tomorrow just twenty miles down the road, so I get a chance to see how she runs.

_________________
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

Bill,

Now that is some fine tuning! Good luck at the show.

_________________
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

Ted:
[quote]Good luck at the show.[/quote]

We had some rain this morning which cut out all the trailer queens, and fair weather show people. A wet morning makes for a small gathering, good for old featherless bipeds with less than concourse quality cars to place. The old Dart fetched a third place in “Best of the sixtiesâ€￾.

There was only one other Mopar at the show, a real nice 1956 Coronet that got a first place in “Best of the Fiftiesâ€￾.

The car ran real nice all the way down to the show, and back. The engine seams to like the new lash settings. Engine sounds a bit smother, and more willing to fire up & run from a cold start. After running for half an hour, it settled right down and idled without any throttle feathering.

Previously it sometimes would not want to idle down in gear after running in the 3000 rpm range for a while when coming to a stop sign, and sometimes would stall. A quick throttle blip or two would generally straighten it out until it settled down.

Hopefully this jetting up, and elimination of the enrichment circuit, will reduce this intermittent stalling problem.

_________________
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

The power valve plug and #57 jets are installed replacing #51 jets, and 2.5â€￾ Hg power valve in the old 390 Holley.

Here is the poop on the new state of tune:

1. Idle screws in an additional ½ to 3/4th turn, still have 3/23â€￾ drill holes in throttle plates.

2. 1000 rpm idle in park vacuum up one inch to a steady 12â€￾ HG.

3. 900 rpm idle in “Pâ€￾ generating 8â€￾-12â€￾Hg fluttering neddle.

4. 600 rpm in gear idle moved flutter up 3â€￾ so it is now 3â€￾-9â€￾ Hg.

5. Lope has subsided a bit in gear.

6. Cruse at 1800 rpm pulling 18â€￾ hg up 1 -1 ½ “.

7. Hard to quantify this, but off line punch is less aggressive, and cruse throttle response is less exciting. Over all this engine is needing that big gulp from the power valve while at WOT.

8. Still will burn rubber power braking, but not as much. Engine just dose not seam to be as lively.

9. Back spin is unbelievable in park @ 1050 rpm, nill in gear at 600 rpm.

So, do I:
1. keep the #57 jets, fill holes.

2. go up a few more jet sizes, and keep the holes?
.
3. yank out the plug & replace with a 1â€￾ Hg Power valve, as opposed to the previous 2.5â€￾ hg valve, and keep holes?

4. Just go back to original tune?

Confused Maineac

_________________
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

Seems to me a 1" pwr valve will be about the same as a plug, and will be fluttery. I'd go up 2-3 jet sizes and retest with the plug. If it's worse, go down 2-3 jet sizes and retest.

Lou

_________________
Home of Slant6-powered fun machines since 1988

My vote is for #60 jets and the plug.......leave the holes....for now.

You know that mystery cam is sure sending some wild signals.....noted on your vacuum gauge.
I am thinking a little more valve lash might help as well.......just a thought.

It is tempting to put a bolt in them (as an experiment) to see if it would run. But it is better to have them shut with a small hole as needed.

_________________
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

Ted,

Plugging the holes is no big deal, I just solder them up. Done it before. I’m thinking that perhaps there is a little too much air at idle now that that power valve is not dumping fuel with a syncopated beat of the vacuum gage…

I’ll first try a set of #60 jets, hopefully the local speed shop has a pair. Will these larger jets give back some of the lost power on the highway?

Any ideas why Olympic class back spin is occurring at 1000 rpm shut down, where previous to this change, the engine would stop with perhaps one little half hearted kick at that speed?

_________________
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

Bill,

For that to happen it has to be getting some fuel somewhere. Are you sure that there isn't too high of float level to where it's pulling a little extra in on shut off. Maybe through the air bleeds or up the metering block? I would be tempted to run the float a little on the low side. Is there a possibility that there may be that much unburned fuel with your mystery cam?

The 60's should give you a nice fat cruise.

_________________
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

Ted,

Could be float level, I did have that portion of the carburetor off & sitting on the bench. After spewing out all those questions in that last post and then shutting down for the night, float level did cross my mind as a cause for that run on problem, but I just crashed and burned on the couch.

This morning I found the refrigerator, new in March, had puked water all over the floor, and everything in it defrosted, all before one sip of coffee. I don’t deal with these sorts of morning up-sets too well. Sink pig & trash guy are making out well with this. Now to determine if the compressor has failed, or the freezer door got left ajar, as something is running, and all the lights come on when opening door…

I came here to gather my thoughts, reflect, and choke down my urge to call Sears and rip’em a new one.

Later today I’ll give the float a quick check, run to town for a set of 60’s, deal with that damn ice box, and rake some more rocks preparing for new lawn.

Stay tuned,

Bill

_________________
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

Bummer! on the fridge....
Just a thought.......is the back spin as bad when the engine is cold? or just when it's hot?
I am wondering if once the engine has been driven some distance, if the carb is getting too hot and percolating combined with a high float level may cause some excess fuel burping on shut off.
If so, I wonder if you need to make a heat shield for your carb (like mine) and use a thick rubber gasket to help isolate it?

_________________
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

Ted: Hard to say if the fuel is percolating. I don’t generally smell gas after shut down, so if there is a bit of fuel getting by and down the intake, it can’t be much.

There is that hydronic hot spot under the carburetor that I retro fit to the Clifford manifold, so there is heat under the carburetor, but not like the exhaust manifold would pump into those castings on a stock set-up.

This morning I checked the float level on both fuel bowls, and the level was below the hole. I than started her up, and reset the levels. By the time that adjustment was completed the engine reached operating temperature, and an in park idle of 900 rpm., and shut down was a non back spin event.

I have had my rock vaccination for the day.

It is looking like some damn fool did not fully close one of the doors on the refrigerator last night, I wonder who he might be, which had I gone grazing after supper, as is my usual MO, I could have closed it…

_________________
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

Ted,

Number 60 jets now installed. An immediate difference in idle quality on start up, smoother & lower at “in parkâ€￾ rpm. The idle circuit was still tuned to the 57 jets.

Could it be lower idle may be due to richer mixture? Exhaust pipes are a nice shade of black, previously they were not as dark.

I was able to turn in Idle Mixture screws almost one full turn.

Here is the second shovel of poop with #60 jet:

Park Idle readings
1. 850 rpm throttle plate full closed vacuum 6â€￾ to 10â€￾ Hg fluttering.

2. 900 rpm throttle plate off stop vacuum 6â€￾ to 10â€￾ Hg. less flutter. 57 jet produced 8â€￾ to 12â€￾ Hg

3. 950 rpm 10â€￾Hg quivering needle

4. 1000 rpm 11â€￾ Hg steady needle. 57 jet produced steady 12â€￾ Hg

5. 1050 rpm 12â€￾ hg steady needle

In Gear Idle based on 1000 rpm Park idle:

1. 550 rpm; floating up & down 50 rpm due to lope, vacuum 1â€￾ to 9â€￾ Hg. flutter; average of about 4â€￾ Hg.

2. 600 rpm adjusted with idle speed screw vacuum 1â€￾ to 9â€￾Hg flutter. 57 jet produced vacuum 3â€￾ to 9â€￾ Hg flutter.

When idled down to 500 to 600 in gear, engine has pronounced rocking motion in step with lope as before any changes were made. With 60 jets this rocking abates at a lower rpm than when the original 51 jet & 2.5 power valve were in place.

The engine is much more willing to go at cruse than with #57 jets, also shift point is restored to a higher rpm, where it was with 51 jet & 2.5 power valve. Also less exhaust racket with the 60 jets. A stronger feel at all rpm.

Red Neck Dynamometer indicated that there is defiantly more rear wheel Hp than with 51 jet, closer to where it was whit 51 jet & 2.5 Power Valve. Without using my fishing ruler, I can’t say for sure if the 60 jet is stronger than the 51 & 2.5 PV .

1000 rpm is defiantly a sweet spot with this cam, vacuum gage needle settles down, lope is noticeable, but engine is not rocking in its cradle like it was possessed.

Almost forgot, after tuning in the garage, temperature gage had moved up to a warmer place. Went for a 3 or 4 mile ride to cool it off, and it only gave a half hearted kick back at shut-down.

Before the cool down ride, carburetor and manifold were very warm to the touch, so you may have something with that fuel percolation theory. Looks as if there must be some fuel being forced out into the manifold at shut-down.

One more observation:

This carburetor has only one air bleed per primary barrel, and two bleeds for each secondary. The inboard locations for a bleed on the primary side don’t look as if they were plugged after manufacture. Is this normal for a 390?


[img]http://i294.photobucket.com/albums/mm87/wjajr/Dart%20Engine/100_1265.jpg[/img]

_________________
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

Good work!


Yes
On this style yes...the racing version no. They figure one bleed on the primary side is all you need for the street. They are trying to be more economical with this carb.

I was curious how hot the carb got and if you could comfortably hold your hand on it after a long haul. With a deflector mine stays luke warm.

When I am working on the motor at idle, etc....and it gets hot, the electric fan is sure nice to have!

_________________
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

Ted, after a tune session with idle at 550 to 1000 rpm, with out side temperature in the mid 80’s here today, that carburetor was hot. I have a good tolerance for heat on my hand, and I wasn’t leaving it there for long. It was hot. The old factory fan dose not move much air at idle.

Maybe I’ll get an electric fan with all the fixins in my stock’in come Christmas … I should think that factory fan must suck up some hp at 3000 rpm and above so it would be a good up-grade. Besides that old fan is nosy when spun up.

I’m going to review your musings on mufflers & tail pipes, I have had it with the racket. I want to keep the duel exhaust, and the chrome 340 stile tips just because it looks cool. The song is pure nasty, just too loud, and way too much drone.

Thanks for the help
Bill

_________________
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

Bill,

You may not want to run a muffler and a resonator like I do, it's almost too quiet.
You might want to try these folks since your entering the car in a lot of shows.
http://www.accurateltd.com They have the stock traditional mufflers with a quality sound.

My setup is much quieter running a long body MagnaFlow with a 2.5" core and a 22" long 2" diameter resonator.
My set up is quieter than a stock SL6 car with the stock pipe.
I am running 2.25" most of the way over the axle then into a 2" diameter resonator.

I have a friend that has a set of Hooker Aero Chamber mufflers. They sure are nice as duals. About half the noise of the FlowMaster 40's and no drone or rasp.

_________________
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