My Street Demon install experience

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watchdoc

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So I gave up on the rebuilt Thermoquad and I purchased a new Street Demon 625. I had it up and running within a hour. I called Holley customer support and they sent me the new style Chrylser throttle stud for FREE. My throttle cable bracket didn't align with the street demon linkage. I solved the issue by drilling out the end of the throttle cable and putting it on the same side as the kickdown linkage. There doesn't seem to be any interference or binding this way. I used a tiny E clip to provide a stop between the kickdown and throttle cable.

Idles well around 800 rpm with my lumpy purple shaft cam and pulls about 15hg with the vacuum advance plugged. Throttle response is awesome and I had no issues with my air cleaner hitting the choke or clearance issues with the hood. More pics to follow.

I'm still adjusting the choke to get it to start on the first try. I wired it to the blue field wire on my dual field alternator.

I'm also only able to run about 5 degrees of initial timing at the moment without detonation. Could be old gas or wrong plugs or broken advance spring on the distributor.

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5 degree total timing? Or initial?

You might need to go up a jet or 2 in the primary if its pinging with the same timing setting as before.
 
MOPAROFFICIAL said:
5 degree total timing? Or initial?

You might need to go up a jet or 2 in the primary if its pinging with the same timing setting as before.
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Initial, this is a mild 340 with J heads and small port Weiand 8007 Action Plus spreadbore. I haven't driven the car much in the last 10 years so I'm gonna run this gas out and do some tuning before I speculate too much. I will report back how it's running. I'd be surprised if it needed larger jets.
 
watchdoc said:
Initial, this is a mild 340 with J heads and small port Weiand 8007 Action Plus spreadbore. I haven't driven the car much in the last 10 years so I'm gonna run this gas out and do some tuning before I speculate too much. I will report back how it's running. I'd be surprised if it needed larger jets.
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Good idea. Dont change anything then.
Maybe get some Lucas octane boost and pour the whole bottle in no matter if theres only 1/8 of a tank.

Cool. Let us know.
 
yellow rose said:
Why did you give up on the TQ?
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I couldn’t get it to idle or pull any vacuum. It was just dumping fuel and I don’t have any tuning or repair knowledge with them. I’m gonna send it back to the guy that rebuilt it to see if he can find the problem.
 
watchdoc said:
I couldn’t get it to idle or pull any vacuum. It was just dumping fuel and I don’t have any tuning or repair knowledge with them. I’m gonna send it back to the guy that rebuilt it to see if he can find the problem.
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sounds like the O-rings, or a needle seat, or terrible float setting, but I'm betting the o-rings
 
So I added 4 gallons of Shell V Power premium and a 15oz container of Lucas Octane boost and drove the car about half an hour. Detonation is gone and it pulls hard but I'm still only at 5 degrees initial. It's a 71 Dart with a 73 340 drivetrain.
 
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watchdoc said:
but I'm still only at 5 degrees initial.
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That may be what was intended for that distributor. Alot were intended for had low intial timing and quickly add advance just above idle.
If its a 'rebuilt' unit, then can't say what it was supposed to be. If its original, the tag number is the part number and can sometimes be looked up.

Two things to get a handle on what you have.
1. RPM of the initial timing. 5 deg BTC at 550 rpm and 5 deg BTC at 1100 rpm makes a huge diffence on the curve.
2. If you can, measure timing from the slowest rpm you can get it to run to as high as you can measure it. Measure every whatever is convenient. 250 rpm or every 2* increase. Either way will show the curve sufficiently to see what you have.
 
Mattax said:
That may be what was intended for that distributor. Alot were intended for had low intial timing and quickly add advance just above idle.
If its a 'rebuilt' unit, then can't say what it was supposed to be. If its original, the tag number is the part number and can sometimes be looked up.

Two things to get a handle on what you have.
1. RPM of the initial timing. 5 deg BTC at 550 rpm and 5 deg BTC at 1100 rpm makes a huge diffence on the curve.
2. If you can, measure timing from the slowest rpm you can get it to run to as high as you can measure it. Measure every whatever is convenient. 250 rpm or every 2* increase. Either way will show the curve sufficiently to see what you have.
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I was wondering how to plot the distributor curve. Do I just use the idle screw to set rpm? It currently idles at 800 in park and 750 in gear. Its gets pretty lumpy below 700. The distributor is the mopar performance distributor that came with the electronic ignition kit I purchased 25 years ago. I still have the box so I will check the advance specs.
 
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watchdoc said:
I was wondering how to plot the distributor curve. Do I just use the idle screw to set rpm?
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If working alone, yes that's the easiest.
It currently idles at 800 in park and 750 in gear. Its gets pretty lumpy below 700. The distributor is the mopar performance distributor that came with the electronic ignition kit I purchased 25 years ago. I still have the box so I will check the advance specs.
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The instructions with the kit sortof get around the issues of different engine combos by advising to set timing at 2600 to 2800 rpm. Sometime later when MP had Mallory build the distributors, they changed it to something like 2500 rpm. (The Chrysler built version has a better advance.)

See which you have either instructionwise, or if need be, remove the distributor cap and rotor.
If the shaft is raw steel and spring attaches to a heavy weight, its a Chrysler advance.
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If the shaft is bronze color, and the spring attaches to thin sheet metal perch, its Mallory built.
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Its a completely different advance mechanism
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Any thoughts on changing to the cooler RC14YC plugs?
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Sure. I tend to think of RN9Y as basic 340 plug but sometimes too cold for street use and lower compression years/builds.
And RN12Y as pretty typical for 318/340/360 factory.
14 in my thinking is a hotter plug which I'd use if I saw fouling or if the FSM called for it.
 
This is the timing suggestions from the earlier instructions.
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The mallory unit has faster curve and generally needs tweaking.
 
So I've always set initial timing with the vacuum advance plugged. Do I plot the timing curve with the distributor vacuum advance plugged or connected?
 
watchdoc said:
So I've always set initial timing with the vacuum advance plugged. Do I plot the timing curve with the distributor vacuum advance plugged or connected?
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You're correct. Vacuum source is always plugged when setting and plotting timing and advance.
 
I just put a new one on my duster, still have not even started it up.
I need to run the wire to the choke, pia, because my car is currently in a storage building and I have to open the doors up all the way to get under the dash.
 
sireland67 said:
I just put a new one on my duster, still have not even started it up.
I need to run the wire to the choke, pia, because my car is currently in a storage building and I have to open the doors up all the way to get under the dash.
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Why wouldn't you just run a wire straight to the blue wire on the alternator?
 
watchdoc said:
Why wouldn't you just run a wire straight to the blue wire on the alternator?
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I have a one wire alternator on my duster.
I do have a re-set fuse under the dash with a key-on hot.
Just need to run the wire.
It is a 5 minute job at the house, but in a 10 ft wide storage building, I can only open the door of the car about 1/2 way, and the car has fresh paint.
I most likely will just wire the choke open and drive it home, this spring.
 
The one on my Duster is the second one I have bought.
I got one of the first ones that came out, and put it on my old truck.
It was reliable and trouble free like a hammer, sold the truck to my neighbor and he has not touched it.

8Umodb.jpg
 
So after previously reporting I thought it had Champion plugs, I pulled them today and they are Bosch Platinum 4327 plugs. They were all light brown with no soot.

I installed a fresh set of Autolite 65's which are a lil cooler than the 4327's. It runs and idles the same so far. I also plotted my advance curve from 750-2500rpm and the advance ranges from 5 degrees at idle up to 25 degrees at 2500rpm. That's as far as I could do go with idle screw. I'm gonna take it for a long drive tomorrow and try advancing the timing again and see how it does with better gas and different plugs.

So which plug is good to pull to get an idea of how the engine is running without pulling them all?

Also, here is the ignition kit I have. It originally came with the orange box ignition but I installed a chrome box at some point.

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I'd like to see more initial and I have no idea what you have for total, because you stopped at 2500. Unless that's where the advance stopped.

Also, if you get the timing curve corrected you'll likely see more heat in the plug. So I'd work on the distributor first and work from there.

5 intial is way too late for most anything, unless you a are working with an emissions ideal.
 
Ran 10 degrees initial this morning with no issues. Gonna try 15 tomorrow.

Choke adjustment still aludes me. Take 3-4 tries to get it started. It was 45 degrees this morning. What is the target rpm for fast idle?
 
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