Pony Carb and DSII

[burnoutstang1]

Hi all,

Just got my new vaporizer carb in, man does that thing look spiffy. But I have a few questions regarding how it works with my DSII. The carb I ordered does have the SCV valve, and currently the vacuum advance to the DSII is not hooked up to anything. I had it running today and it ran great. When I tried to hook up the distributor vacuum advance the car would die. I figure I need to:

A. Block of the SCV valve
B. Block off the vacuum port on the carb

But then I'm at a loss. Why would the car die when hooking that hose up? Is the timing just advanced way too far?

 

[RyanCorpse]

Hey,

viewtopic.php?t=18841

That thread was mainly talking about how to plug up that hole with some epoxy.

 

[burnoutstang1]

Hey Ryan, thanks for the response. That was how I was planning to plug that hole, but the other questions have me more curious. Any ideas?

 

[jamyers]

It's easy as 1-2-3.
1. Put a vacuum cap on the SCV port on the carb, and leave the SCV intact but impotent.
2. With no vacuum to the distributor, set the initial advance (somewhere like 10-14 degrees, ymmv)
3. Run the distributor vacuum advance to anyplace that's seeing straight manifold vacuum.

And you're done with it.

 

[Frankenstang]

It's easy as 1-2-3.
1. Put a vacuum cap on the SCV port on the carb, and leave the SCV intact but impotent.
2. With no vacuum to the distributor, set the initial advance (somewhere like 10-14 degrees, ymmv)
3. Run the distributor vacuum advance to anyplace that's seeing straight manifold vacuum.

And you're done with it.

Exactly as jamyers said.
EDIT: The port on the side of the intake manifold (yellow arrow) "Might" makes a good source. Not sure what the preferred vacuum source for the DSII is.

AFAIK no need to plug/epoxy internal passages unless you're attempting to remove SCV permanently.
I got to quit after no. 2 with my mechanical/centrifugal only DP dizzy.
Good luck!

 

[burnoutstang1]

Thanks for the help guys, I really appreciate it. I gave this a shot, but as soon as I attempt to hook up the distributor to the vacuum source on the manifold the car dies and won't start. Does that mean I need to retard the initial timing a bit? How do I go about capping off the SCV without destroying it? I have another SCV I could just drop some super glue in then screw it in.

 

[Frankenstang]

and the port on the side of the intake manifold (yellow arrow) makes a good source.

opsie: I'm going to retract this statement (editing the post above in order not to further spread potentially wrong info). I actually do not know what vacuum source most are using for the DSII (maybe pcv...shrug, not sure...you might do a search).

But I'd still agree with jamyers that as long as you are not utilizing the original dizzy port for a vacuum source, you should be okay to just plug that load-o dizzy port feed (mine is plugged using a plumbing brass cap and teflon tape in the pic above, but note scv is still in place).

I just don't see where you'd need to epoxy the passages behind the scv or the scv itself unless you were trying to convert the load-o dizzy port feed on the side of the carb (the one I capped) to a typical 'ported' source...not sure.

Hopefully someone else will chime in with greater understanding of your particular issue.

 

[burnoutstang1]

I've read that any vacuum source should work for the distributor, but it seems to be killing it as soon as I hook it up. I'm thinking the initial advance is too much(distributor rotated too far counter clockwise). But I'm not really sure. Hopefully someone else is using a pony carb and dsII?

 

[jamyers]

I'll second Frankenstang's comments about plugging the SCV, as long as it's plugged and not in use, neither the carb nor the distributor will care about what the other one is doing (well, as far as the SCV advance is concerned).


Regarding your dying engine, let's get specific: what is the timing set at with the engine idling and vacuum plugged (this is the 'initial advance')? Anywhere between 4 and 14 degrees oughta work, I'll bet that 10-12 will be best by the time you're done.

I'd unhook the vacuum advance and plug the manifold so you don't have a leak. Then start it, set the initial advance to 8 or 10 degrees (being conservative). Then double-check both the idle speed and idle mixture screws on the carb, shooting for the smoothest idle at 650-700 rpm in neutral. THEN I'd hook up the distributor vacuum advance to the port in the intake manifold right below the carb. The idle speed should jump up a good bit as the additional ignition advance comes in. If it's dying, then look for a vacuum leak at the distributor diaphragm, or something funky going on inside the distributor (like the base plate flopping around, or maybe the cap and rotor ailgnment is out of whack somehow.)

Once you get it sorted out so that the additional vacuum advance helps the engine instead of killing it, then you can go back and reset the carb idle speed and mixture screws with the vacuum hooked up.

THEN you'll probably want to take a closer look at that distributor and find out exactly what timing curve is built into it, and whether or not you want to mess with recurving it.

 

[burnoutstang1]

Thanks for the thorough response. I'll give it a shot this weekend and let you know the results.

 

[burnoutstang1]

Okay, so I'm home this weekend and I gave this a shot. With the scv plugged, the vacuum port in the carb plugged and the manifold vacuum plugged, I can 't seem to get the car started. I tried hooking up the distributor to the port on the manifold but same result. As soon as I unhook the vacuum from the manifold and leave it open, the car starts up and runs fine. Distributor is pointing to between cylinder 5&6 per pony carbs instructions. Any ideas?

 

[FalconSedanDelivery]

The Vacuum canister is allowing too much advance ( as I've posted numerous times a Recurved Dist has much more than replace this spring and bend a tab ) Your canister may be adjustable / damaged , etc, send me a pic of the Dist and I can sheld more light .

 

[burnoutstang1]

I don't recall having ever recurved my distributor. I just ordered a standard reman and installed it that way. I'm assuming just a picture with the cap off?

 

[FalconSedanDelivery]

yep , i can tell by seeing it if its adjustable , ttyl

 

[burnoutstang1]

Okay, I'll have to take them this weekend when I'm home again. So there's something inside that's adjustable and out of whack? How do I go about fixing that? If its an issue with the distributor, why is it that when plug the vacuum hole in the manifold with my finger the engine dies as well?

 

[FalconSedanDelivery]

Better start at the begining ( verifiey TDC) then check it against the timing marks , do that and we can go from there

 

[burnoutstang1]

How do you verify TDC without using the timing marks? I seem to recall something about removing the spark plugs...

 

[ludwig]

Do a search for 'TDC' or 'find TDC'. This comes up about every two or three weeks.

There are maybe four different methods and they have been covered extensively. But yes, they all involve the removal of at least one spark plug, namely the first one. The rest are for convenience since it makes the engine easier to turn over by hand without five compression cycles to pull through.

 

[jamyers]

...With the scv plugged, the vacuum port in the carb plugged and the manifold vacuum plugged, I can 't seem to get the car started. I tried hooking up the distributor to the port on the manifold but same result. As soon as I unhook the vacuum from the manifold and leave it open, the car starts up and runs fine. ...

Whoa, wait a minute before you start tearing into the distributor. You've got something else going on there - that's the opposite of a vacuum leak! If the engine wants more air than what's going through the carb, then the carb is too rich somewhere - choke sticking shut, mixture screw out WAY too far, float too high, something.

BUT before you tear into anything, [edit: adter you verify tdc and the timing marks] start it up with that vacuum port open and the engine idling, put a timing light on it and find out what the initial timing is. Should be something between 4-10 degrees for a decent beginning point. "between #4 and 5 cylinders" isn't a timing setting at all, you need the actual number.

The starting point for the idle mix screw is lightly bottomed out (all the way in - but DON'T force it), then back it our 1.5 or 2 turns.

Starting point for the idle speed screw is something like 2 turns in past contact with the throttle. This one's not as big a deal as the idle mix screw.



You need to get it to start and idle with all of the vacuum ports plugged up first, then move on to other stuff.

 

[burnoutstang1]

That was my suspicion, but I wanted to see what you guys thought. Let me get my timing light on it this weekend (after making sure I've got the right TDC), plug up all the holes, and get it idling. It's a brand new pony carb, but maybe the idle screw is out too far. Then we'll start tackling the distibutor after that.