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Replacing CD 150 in '69 Alpine

Bill Blue

Platinum Level Sponsor
I decided to quit messing around with small changes and went a full 1/64" to 3/32". No remarkable change, so upped the ante to 7/64". It woill now idle in 3rd gera at about 150 mv, touch the gas and it jumps up to .9mv. So just drilled the jet out to 1/8". Will probably test drive it tomorrow. Just how far does anyone think I should ride this horse? It's strange, the numbers have not changed, but the car pulls up my cruise hard pull hill more smoothly and a bit more power. So I see no reason to go back to a smaller jet. Maybe I've reached the point of response sensitivity.

Don, I've cut a shallow groove for the bowl vent and it butts up against flat aluminum, so that should not be a problem.

5th gear. Not the quickest, but the cheapest by far, DanR gave me a later series Volvo tranny with a J-Type O.D. attached. All I have to do is mate it up to an Alpine bell housing. The thing looks like it would be at home in a dump truck, Lots of cast iron - Dan estimated its weight at 100 pounds, about twice the weight of a T5.

Bill
 

husky drvr

Platinum Level Sponsor
Bill,

LOL - I was fairly sure you'd go that gearing route, in some form. I only made the suggestion in case you wanted to save a few man-months.

Have fun - but that's the whole point isn't it?
 

Bill Blue

Platinum Level Sponsor
Did a trial run with the .125" jet. Cruise voltage is in the high .8's, touching .9 sometimes. Voltage on the hill was in the .050-.075 range, an improvement. Was able to get it to idle on the intermediate jet, getting readings of about .1mv. Looks like its time to up the intermediate jet a step and drill the air jet out to .140". The magic should happen real soon.
Bill
 

Bill Blue

Platinum Level Sponsor
Bill,

LOL - I was fairly sure you'd go that gearing route, in some form. I only made the suggestion in case you wanted to save a few man-months.

Have fun - but that's the whole point isn't it?
Don, point me to where it would be more fun to run a stock (but foreign) Alpine transmission than a Volvo transmission.
Bill
 

Bill Blue

Platinum Level Sponsor
That run went well, but overall richer than the .125 run. I'm attributing that to the influence of the larger intermediate jet, further proof that it never shuts down. Now to do a .155 run.
Bill
 

husky drvr

Platinum Level Sponsor
Don, point me to where it would be more fun to run a stock (but foreign) Alpine transmission than a Volvo transmission.
Bill

Bill,

The question you want answered is "Do I think YOU get the most fun driving or working on your LBC's?"

Are you trying to get a dissertation on how different people derive enjoyment from different aspects of the same general hobby? o_O :D :rolleyes: Nope

After following your posts for two decades about the trials and tribulations of improving and maintaining your Rootesmobiles, it's probably as obvious to most members that no matter how much you like driving LBC's, YOU get more enjoyment "tinkering" to make unusual parts combinations work together to YOUR perceived satisfaction- and cost is just a small aspect. No matter how frustrating it is at times.

Not good or bad - just a bit "tilted" in a subset of "different". :)

Now, your logic about a "stock (but foreign)" seems a bit fuzzy because that trans/OD unit is no more foreign than the trans presently in your coupe - just different import dates. :p

Besides, about any transmission you decide might be usable is as foreign.

Rootes > UK

Volvo > Sweden

T5 > Mexico

MA5 / AR5 > by Aisin

NVG 1500 > USA

Getrag > Germany

So once again, Have fun - your fun,
 

Bill Blue

Platinum Level Sponsor
Doesn't the Volvo unit have a flange output instead of sliding the driveshaft coupling into the tail shaft housing?
Don't know. Dan pointed the to transmission and said "There it is." And we loaded it into the boot of the '69. It still is there as it is too heavy for me to remove. Our youngest son will be here for the weekend and we'll unload it and prolly check out the output shaft. Right now, all I know about is that it has a 1 1/16" input shaft and I think 10 splines.
Bill
 
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Bill Blue

Platinum Level Sponsor
I suddenly realized that all the air for the air bleed had to come in through the bowl vent. So I more than doubled my opening to the vent tunnel. Drilled the jet to 157" (long story) and took it for a trial. No noticeable change. In fact, the engine seemed to run richer for longer periods of time than the .140 run,

Now to do the .170". I think I go as high as .185" and if that does not do the trick, try a run with NO air jet. i.e., open hole in the casting.
 

Shannon Boal

Platinum Level Sponsor
Nobody could be more thorough than you..... That carb is giving very strange results. I tried to find tech info on it, but cannot remember the model, or type. Also, can you supply info on your o2 setup? O2 numbers below 0.1 volts would give little power, and might spit back in the intake from lean missfire (or slow burn with flame still burning when intake opens next time around)... I wonder if you have one problem, or multiple problems.
I suddenly realized that all the air for the air bleed had to come in through the bowl vent. So I more than doubled my opening to the vent tunnel. Drilled the jet to 157" (long story) and took it for a trial. No noticeable change. In fact, the engine seemed to run richer for longer periods of time than the .140 run,

Now to do the .170". I think I go as high as .185" and if that does not do the trick, try a run with NO air jet. i.e., open hole in the casting.
 

Bill Blue

Platinum Level Sponsor
Enlarged the bowl vent a lot. Drilled the jet to .170" No change. Still likes to cruise at .9mv. I can get it to idle in low gear at low speed. Runs in the 200+ mv range. As throttle is increased, mv. goes up gradually, but then jumps from 600mv to 900mv. Don't know the rpm's involved (tach quit), but I guess they are in the 1500 range run the jump occurs. I'm thinking it is time to remove the air jet. Maybe drop the main jet to .047" and maybe increasing the intermediate to the next step, about .033".

On a slightly different note, I wonder about the main jet opening to the air flow. It sticks up into the flow about 3/16". Would taking it down to 1/8" decrease the onset of the main circuit?
Bill
 

Bill Blue

Platinum Level Sponsor
Nobody could be more thorough than you..... That carb is giving very strange results. I tried to find tech info on it, but cannot remember the model, or type. Also, can you supply info on your o2 setup? O2 numbers below 0.1 volts would give little power, and might spit back in the intake from lean missfire (or slow burn with flame still burning when intake opens next time around)... I wonder if you have one problem, or multiple problems.
Shannon, the carb is a clone of the S&S "Shorty" Super E.
MY O2 setup is a 4 wire narrow band read by a cheapy Harbor Freight multimeter. The sensor is mounted in a section of 2" pipe so the the sensor is located almost dead center in the pipe. The pipe extends about an inch beyond the sensor. I think it gives pretty accurate data. It can instantly jump several hundred mv. either up or down and seldom gives steady numbers. Oh yes, the heater is fed "juice" from a cigarette lighter socket, via a wires running out the drivers window and to the sensor.

I don't get misfire when the readings are in the 70's or higher, even on a pretty hard pull. Having said that, power is down, but enough is generated to increase speed on the test hill.

I'm wondering if I have maxed out the air circuitry cast into the carb body, as there has been no change from .140 to 170 and there is no reason to think enlarging the jet would have any effect.. My current thoughts are to block off the main jet and tune the intermediate without the main interfering. Damn, I wish I did not live on a State Highway. Additional problem : Where would I go from there? It seems obvious that any enrichment from the main jet would kick in almost immediately, then drop out of sight at the first real need for additional fuel, exactly as it does now.

Bill
 

Bill Blue

Platinum Level Sponsor
I think I have solved the problem, even have photos, but of course the computer upgraded and now I cannot see how to upload them once selected.

So here is my best explanation. The main fuel jet delivers fuel via a short tube that extends into the throat of the carb. There is a step in the O.D. of the delivery tube. When the tube is tightened, the step is forced against the body of the carb. The problem lies in the arrangement of "stuff". The air supply terminates on the bowl side of the carb. The jet delivers fuel on the air side of the carb. No obvious way for the air to get past the step. I'm going to make a spacer that will allow the jet assembly to tighten at the bottom of the carb body, allowing air to pass past the step and into the throat.

Bill
 

Shannon Boal

Platinum Level Sponsor
Looking forward to seeing the photos, hopefully won't have to fix software issues first! Will research carb....
I think I have solved the problem, even have photos, but of course the computer upgraded and now I cannot see how to upload them once selected.

So here is my best explanation. The main fuel jet delivers fuel via a short tube that extends into the throat of the carb. There is a step in the O.D. of the delivery tube. When the tube is tightened, the step is forced against the body of the carb. The problem lies in the arrangement of "stuff". The air supply terminates on the bowl side of the carb. The jet delivers fuel on the air side of the carb. No obvious way for the air to get past the step. I'm going to make a spacer that will allow the jet assembly to tighten at the bottom of the carb body, allowing air to pass past the step and into the throat.

Bill
 

Bill Blue

Platinum Level Sponsor
Removing the main jet assembly sure was educational. I was mystified by the air bleed system, thinking the carb metered emulsified fuel and could not understand how emulsion air could have a big impact on richness. Not so, metered fuel is emulsified as it enters the airstream. Simplifies things! The air bleed simply allows air to be sucked into the airstream along with fuel. The jet regulates the amount of air (instead of fuel) that can be introduced, Now for a road test, I'm pretty sure it will run considerably leaner.

Bill
 

Shannon Boal

Platinum Level Sponsor
Yes! That mixing/ emulsifying thing with the dual curves programmed by the fuel and air jets is where the magic happens. I have read the S&S PDF, so I am behind, but can see where you are. Float settings are worth looking at as a source of lean-out on an uphill climb, but I don't feel lucky about that.
Removing the main jet assembly sure was educational. I was mystified by the air bleed system, thinking the carb metered emulsified fuel and could not understand how emulsion air could have a big impact on richness. Not so, metered fuel is emulsified as it enters the airstream. Simplifies things! The air bleed simply allows air to be sucked into the airstream along with fuel. The jet regulates the amount of air (instead of fuel) that can be introduced, Now for a road test, I'm pretty sure it will run considerably leaner.

Bill
 

Bill Blue

Platinum Level Sponsor
Yes! That mixing/ emulsifying thing with the dual curves programmed by the fuel and air jets is where the magic happens. I have read the S&S PDF, so I am behind, but can see where you are. Float settings are worth looking at as a source of lean-out on an uphill climb, but I don't feel lucky about that.
No, I've tried float levels high and low, no impact. Settled for something in between.
The really surprising thing about the emulsifying is where it happens. Right in the airstream. I thought they would have at least had air entering the main fuel tube so that the jet assembly would look somewhat like a Weber emulsifying jet. For a while I thought maybe I had an incompletely machines main air tube. Air entering the tube would work with the tube sealed from the airstream and I was ready to start drilling holes. But a search soon killed that thought.

Bill
 

Shannon Boal

Platinum Level Sponsor
I am just absorbing something you said months ago about this carb. The high speed system is more like their version of a full-power enrichment system. The "main" fuel in this might be expected to start metering at 1300-1600 RPM, but this is much higher, say 2500+. I guess it was not for cruise so much as full-bore. At this point, I think you could teach classes for the S&S tech people.....One loose thought, any chance of stray fuel coming from the cold-start-enrichment system?
No, I've tried float levels high and low, no impact. Settled for something in between.
The really surprising thing about the emulsifying is where it happens. Right in the airstream. I thought they would have at least had air entering the main fuel tube so that the jet assembly would look somewhat like a Weber emulsifying jet. For a while I thought maybe I had an incompletely machines main air tube. Air entering the tube would work with the tube sealed from the airstream and I was ready to start drilling holes. But a search soon killed that thought.

Bill
 

Bill Blue

Platinum Level Sponsor
Shannon, at this point the enrichment circuit is a mystery to me. All I know is that I cannot see any impact on the O2 meter when it is engaged at idle.
Bill
 

Shannon Boal

Platinum Level Sponsor
Well, that seems odd. If it does not change anything, does it never enrich, or perhaps it is always enriching? Odd thing number two, S&S suggests using 0.041" air jet with no indication of needing to change it much. Odd thing number three, they suggest a starting point of main jetting which is much, much larger than what yours likes. "Approximate Jetting For S&S® Super E & G Carburetors
Displacement 96 to 107 ci
Intermediate Jet .031
Main Jet .076 (air jet about 0.041")"
Your experience corresponds with these numbers on the intermediate circuit, but the high speed numbers are wildly different.
If the cold start enrichment were always on, maybe that would make sense.
Shannon, at this point the enrichment circuit is a mystery to me. All I know is that I cannot see any impact on the O2 meter when it is engaged at idle.
Bill
 
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