rebuilt engine from S+S.guys are good. Car drives me crazy.New Holley 1 bbl (Summit) has 2 stage power valve. The car sort of falls on face at about 3500-4 k RPM. Opened up carb, unbelievable,short and long screws in wrong place on jet block direct from Holley. no faith in them. Poor workmanship all over it.

DC ignition,set for about 32-33 centrifugal,which means almost 15 static; unknown vacuum but should not matter at WOT; runs same w/o vacuum line (plugged) --DC set up instructions for vacuum are something else. Why not just a degrees at " vacuum ballpark on that?

Anyway, excellent gas mileage almost 22, white tailpipe, a little bit of surging.Falls flat in top of 1st and 2nd too. 20 k miles like this. Seems lean at high RPM? i remember stock 225 Duster about 1970 parents had, pulled like hell until you did not want to go there. What is wrong? Is single stage power valve better? or more power valve sooner? expected "new carb" to be bolt on problem solver.One thing I found was little plastic power valve "pusher" that turns motion 90 degrees was so loose (worn holes - on hinge pin you cannot remove) that it hung up would not enter jet holes, had to carve a little with razor knife to let it swing in (QC> what is that? ) but seemed ok after mod.

Realize hot setups are out there but stock was not like this. Things OK otherwise.

Any suggestions for more oomph high up from 1 bbl? Thinking of raising gas level.. tired of AAAAAH at at on ramp

John,

Is this a 1920 Holley?

What #jet did they install in it? If you use a #60 jet it shouldn't be that bad......and pull hard. Some carbs came with real small jets. Mine came with a #54 and it acted like yours.....that was a bit too lean for today's fuel and cause the surging.

I prefer the dual plunger because of the healthy pump shot. Hopefully they didn't leave out the spring on the accelerator pump diaphragm.

Sounds like their quality control is not that good...

_________________
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!!! Makes lots of sense..mare main jet, mixture improves everywhere a little bit.Will look for 60 jet.Are all holley jets same # system, not specific to this carb?

should be more main jet!! mare jets are rare!

The ones the 1920 uses are the same as a 2 or 4 barrel Holley racing carb's. You can purchase them at the local auto parts.

_________________
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 looked at Summit Holley single bbl availability & they only list a remanufactured carb....not a New Holley. Is the quality issue as a result of a remanufacturer's problems?

It might help to check the wet float level to insure you got enough fuel for the heavy dump. My 65 Dart holley 1920 wet level spec is 27/32.

_________________
1965 Dart 110k, 225, Carter BBD Super Six, 2 1/4 single exh., sbp manual scarebird front disc, 7 1/4 rear 2.94 sure grip, 14 x 4.5 OEM wheels, 833 OD with hyd. throwout bearing, HEI, electric fan, ram air/heated air, Accusump. http://plymouthcarclub.com/

Hi Don, thanks. Carb came in Holley box, must be reman due to wear on hinge holes in power valve actuator part. I do not remember any distinction in cat listing at the time, but you are probably right. I think it was listed as 'replacement"

I am thinking now ; how can they use same power valve with two checks to push in, as they use with one check? has to be harder to push in, that impacts power valve vacuum rating . The two steps relates to lean emission calibration, and i DO know hinge pin holes are badly worn.makes me think power valve operation cannot be right with worn holes,or maybe it needs a specific different power valve or spring to account for two checks to push.

Thinking of finding 60's slant era one stage power valve Holley and rebuild, or try to do something about hinge pin holes and try 60 jet? ..I f anyone has a pulled 1 bbl single check (probably pre 70?) that ran well, here is a buyer.

The very thin hinge pin is a press fit into carb body; was looking how to get apart when i noticed jamming of actuator first time , does not look serviceable at rebuild at all. without making something..a thicker pin?

I think I have an early 70's carb, not exactly a peak era for MOPAR performance.

John,
My carbs have the same design. In fact I prefer the dual plunger design over the single. The new style power valves (black plastic top) and old style (metal top) have no problem pushing the two plungers in. In fact, I have used as many as 5 gaskets under it to shim the power valve up for delayed activation. Believe me they do dump and to the point where I get a heck of a wheel spin with a 2.76 Sure-Grip. I have had to to detune the power valve engagement to reduce the wheel spin.

You can buy new dual plungers from Joe's Carb Rebuild. For address look in the "Slanted Network". I have purchased several from them and they were all excellent quality molded pieces. I think they were only $2.00 each.

On the pin that holds them, if they are worn badly, just drill it out and press in new piano wire or you could try another economizer body. If the pins are cast in yours, try dressing them with a file to straighten them out.
I have also drilled/reamed the plastic plunger so they swivel easier.

_________________
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, that is exactly the area I am struggling with..NICE POST! thank you. Wheelspin w 2.76 is impressive as hell.

No way here, but hopeful.

Obviously, you are 'into this" !
What are you running for initial advance, rate /amount of centrifugal (max total) and vacuum? I have out of box DC Performance Slant setup,
running about 32 total, but have nagging feeling too much too soon.
Seems all in by under 3 grand or so, but timing marks seem funky, jumps around a bit .
DC distributor brand new wiped upper bearing sleeve, no lube, dry from factory!!! fixed that, but does not say much for care in doing those. I rebuilt two more dart distributors,with Mr gasket and then, later, springs from someone on this site, followed his advice, but have not installed them.

New ign parts will fit in old housing with oil cup onside,in fact that is a better quality housing.
I won't even get into nylon gear fits and end play dance.

Thanks again for sharing valuable info,
John

John,

How old is your engine? Sometimes a little slop in the chain can cause the marks to move around and not using ported vacuum can cause the marks to move around. Be sure your using ported vacuum and plug it good when tuning so the advance is out of the picture.

My curve is posted under the Engine FAQ, Timing Curve/Recurve Info, Ted's Curve.
Click on the link above mine and down load the spread sheet and over type my values in the orange block. The green blocks are automatically generated. Select graph at the bottom to see how your curve looks.

I run 12 degrees initial, and 20 degrees mechanical, vacuum advance doesn't count when you stomp on it since it's out of the equation, but I run a VC-208 11R can for 22 degrees. I see 52-54 degrees on the light at 2500 rpm. I get a couple of extra degrees right there since the big spring is stretching a little. It stays locked down after 2650 rpms on up.

The porting and extra compression I had done during the rebuild really improves the off idle torque. I also advanced the cam 4 degrees for even more torque. The POD is tuned 3 turns out so it doesn't come on right away. See Doc's instructions, page 4.
I am using a stock red 340 primary spring like the green one in "Bigslant6fans" MOPAR Spring Kit. The spring post is rotated all the way out to take out slop and keep it tight. Secondary post is rotated all the way in with a long looped extra long secondary spring.

My 1920 pump shot hole is drilled out ever so slightly and the pump shot linkage is tight, no slop and set for max throw. With healthy shot of gas and max timing at the same time, it's pretty easy to bust loose both P225 60's.

_________________
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 again Ted. I did not realize one spring is where the action is, more or less; so one spring controls to, in your case to about 2600, then it picks up second so it sort of stops it cold at that point, per your setup? what specifically is 2nd spring w loop from? does it make any sense ..? or can you tie down..? 2nd part, if i am following you correctly. Say a stop in slot? It seemed while I was working on it , both are in parallel ,actually, but you are saying loop in 2nd spring lets first spring control it all till loop gap is taken up, then it starts on second? ? from that view, loop is critical to fast advance climb stopping at ~ 2600? .Small advance way up due to #2 probably does not matter? So why mess with a second spring at all ? Mr gasket kit did not have any loops, if I recall correctly, must be all screwed up, unless TWO half as light springs bottom at ~ same time in parallel? = shorter slots on DC then stops it .

Any idea what DC setup was?

Ordered 60 and 66 jets, new plastic arm from Joe's will carefully check fuel level, get max accel squirt. Above you mention big squirt from dual plunger? You mean dual power valve jets, and dual checks, not a plunger? plunger reminds me of accell pump shot,don't want to mix up words... Plastic 90 degree thing with prongs is actually a check valve actuator?

It HAS to take a little more force to depress two check valve springs...maybe it is slight compared to spring on power valve balanced against vacuum? But PV calibration has to change a little.not sure if it is that critical in any event.

3-4 degree Bouncy timing might be two light springs, loop aspect not right.

Thanks for help and clear explanations,Ted!

John,

That small light spring lets the weights swing out rather quickly at low rpm to around 2500 or so rpm, at which time the large spring takes up the task of controlling the weight’s travel for an additional 3 degrees of advance.

Because of the stoutness of that long loop spring, the last three degrees of advance dials in slowly and stops without a bounce. Without the long loop spring, the weights would slam into the end of the slot, bounce back a bit, bottom out again and hopefully settle. The result makes the timing run up & down, or flutter, a few degrees until the next big rpm change when it starts all over again.

When I first got my car it had only one light spring, no long loop spring. The car was used for drag racing, and saw mostly WOT & high rpm. When I tried to tame it for street use a few years ago, the timing would flutter around a few degrees, making it hard to tune timing, carburetor, and idle.

He walked me through a long saga of re-curve on my uppity engine. It only took about ten thousand words, and ten threads, but I got it right! Some of that conversation is posted under “Engine’sâ€￾ “Sticky: FAQ.â€￾

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

Thanks Bill!
Your distributor recurve was a challenge due to the "mystery" cam.....

John,


Correct! Actually it slows down the advance at 2400 and the big looped spring stretches a little to 2600 rpm.


Doc showed posted a picture of some springs and one that he likes which I found in 383's, 400's and 440's. It has about 8 turns and extra long loop. It is pretty stout and acts like a stop. Just like if you were running a 9R or 10R governor.
Yes.
Yes.
When using the governor from my 74 which is a 15R the slots are very long. I didn't want to weld them up to shorten them so I used the 440 long looped spring instead. Remember in 74 they set the initial timing at zero degrees. I have found that the SL6 is very sluggish at zero degrees, something fine for our grand parents..... One day when visiting Joe at Joe's Carb Rebuild I was telling him what a slug my stock slant 6 was and how it loved to ping......He said to crank the initial up to 16 degrees. I said your crazy........he said try it and I bet it won't ping. So I did and was hooked. Then I contacted Doc and started my distributor recurving adventure. Today we have quite a lot of data in the Recurve Instructions Sticky from various folks.
Right, to use those springs they rely on the length of the slot as a stop.
No, maybe others can answer your question. If I were to guess, it might be a 9R governor.
The dual plunger power valve is what I was referring to. Yes, the dual power valve jets/check balls. When you mash the throttle the accelerator pump puts out a real healthy squirt and then the vacuum drops to zero causing the power valve to drop down and engage both check balls and dropping another load of gas..........breaking both tires loose. If you jet up to about a #66 jet or larger you can keep them both spinning.
A single vs a dual 90 degree plunger arm is twice as much gas. With the other mods during the rebuild (compression, porting, etc) I found this very simple little carb once tuned can really surprise you. It is very responsive up to 90 mph, 3500 rpm. After that it reaches max flow of air down the throat and the limitation of what ever jet you installed and both check balls being pushed in. You can tune the 1920 Economaster from very lean (#56) to very, very rich (#66). After the rebuild my SL6 feels as powerful as a 318 when using a #60 jet.

_________________
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

Once again a big thank you, Ted, for an outstandingly clear explanation. good guys on this site! helping each other is job 1!

As an aside , and by way of a little contribution, spent a lot of time dancing with 97 MOPAR/ JEEP FI on AMC 45 year old design 4.0 six.Damn good engine, up there with slant,have had 4 of them in various flavors since 62; This one has 275 k, zero oil into it, 10 k miles each time, Mobil one. Even an aluminum one showed up in a 59 rambler wagon.. always landed on me, in daily drivers, not that I wanted them.

Anyway, REALLY got into 97 JEEP/MOPAR EFI. That is a very simple system; a special MOPAR 97 FI book exists describes its algorithms and sensors in total. I am an EE , loved the book. i think i could put it easily on slant ; biggest issue would be flywheel tone wheel. . Motorola based 16 bit CPU 's
Why i bring this up is 2 great troubleshooting things to share i discovered hard way. 1) gauges and vehicle information center are driven from serial line from PCM. If gauges go crazy, or zero, you have a simple power issue with PCM, either 12V or!!! #2) "no Response"= Diagnostic routine,long and complex, looks that 5V is at each sensor; but a short inside a sensor goes away (!) when you unplug that sensor, it tests OK at plug from computer. (5v is there, then) . They are grouped in 3's or 4's,each group on its own 5v, a short on any 5v sensor line kills all CPU output, gauges go to zero. PCM is not harmed by short (thank you mother MOPAR!) This condition, at end of MOPAR diagnostic tells you to buy new PCM>!!! 500$ Almost did but instead found short at flywheel sensor caused by sheet metal shield cutting into wire.shorted 5V FYI! Look at gauges, think about it first. manuals say nothing about gauges, but many guys w late mopars will tell you "Gauges went crazy when it died" Gas tank sensor goes into computer, not to gauge.oil temp and volts, too. Gas should read before starting if PCM is working.

I do not think diagnostic addresses shorted 5V very well, if at all!!!, we found by noting 5v went away at one sensor (TPS) when 2nd one in group (Flywheel) was plugged in =.accident! =500 still in pocket.