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Replacing CD 150 in '69 Alpine

Bill Blue

Platinum Level Sponsor
Enrichment circuit? No. Removed the pintle valve and cleaned the black goo off it and the seat in the carb. Dropped a 5mm ball into the well, replaced the spring, made excellent contact. Then replaced the cover nut, which put tension on the ball. Made absolutely no difference. I'm not so sure the circuit is complete. Going to check it with carb cleaner as Shannon suggested.

Next, locate the accelerator pump inlet and block it. Yes, I'm close to the end of the list of possible culprits, which does not mean I'm close to getting it to carburete correctly.

Bill
 

Shannon Boal

Platinum Level Sponsor
And, somehow, we think of fuel injection as "complicated"....
Enrichment circuit? No. Removed the pintle valve and cleaned the black goo off it and the seat in the carb. Dropped a 5mm ball into the well, replaced the spring, made excellent contact. Then replaced the cover nut, which put tension on the ball. Made absolutely no difference. I'm not so sure the circuit is complete. Going to check it with carb cleaner as Shannon suggested.

Next, locate the accelerator pump inlet and block it. Yes, I'm close to the end of the list of possible culprits, which does not mean I'm close to getting it to carburete correctly.

Bill
 

Bill Blue

Platinum Level Sponsor
Things are getting weird. It wanted to idle (900 rpm) in the stoic (300-400mv.) range, something I have never seen, Usually runs in the sub 100's when warm. That is with the idle rich screw set for best idle on the high side of lean falloff.

Aside from the soft acceleration, it was lean (50mv) on the top end with moderate throttle and in 3rd. Still cruised at 900+ mv. I think I will try closing the entrance of the Enrichment Circuit, rather than the "On-Off" valve.

Bill
 

Bill Blue

Platinum Level Sponsor
The lean condition while in 3rd got me to exploring. Seems that in my desire to lean out the engine, I have gone way to small main jet. Will try a .055" main with .032" air. Also decided to close another progression jet. Need to let the nail polish setup over night, so no answers today.

Bill
 

Bill Blue

Platinum Level Sponsor
No impact. Runs in the 900's except barely opened throttle, say flat road, 3rd gear, 1200 rpm. When the throttle is opened a bit more, it jumps to 900. Cruises at 3,000 rpm and mvs at 900. Open the throttle, mvs instantly drop to double digits. Going to go a couple sizes larger for the main, trying to get into the triple digits. Then will close the 3rd progression jet for tomorrow's test.
Bill
 

Bill Blue

Platinum Level Sponsor
Well, partial success. Enlarged the main jet until I had 900mv while accelerating. The lean out that had plagued me was due to small main jets. The readings were now a bit too high. Removed the .031" air jet and installed a .076" jet. No impact on readings. Installed a .110" jet and drilled a few more .050" holes in the emulsifier tube. Readings dropped to low 30's! Nice to see something work like its supposed to. Instead of backing off the air, I increased the fuel jet from .061" to .066". Will continue the air/fuel dance until I get mv's in the 500-600 range. Also permanently (JB Weld) plugged the Enricher Circuit fuel intake. Never used it and in fact, could never see that it ever enriched the mixture. If that is not successful, will close another (3rd of 4) progression hole.

Bill
 

Bill Blue

Platinum Level Sponsor
So, the air correction jet was maybe ineffective because there were no holes in the emulsifier tube....?
The air correction tube has had holes in it both towards the end of the stock tube's life in the carb and the homemade tube I'm now using. I just put a few (6) more in it.

The latest changes, larger main jet and three progression jets plugged had an impact. I had to readjust the idle speed and richness. I now see cruising mv's in the 800's and single digit 3,000 rpm pull in the single digits. So I think the hole I plugged was providing enough gas to move the hard pull mv's into the low 30's. Going to do the Full Monty and plug the 4th hole. Will install the largest main jet, .078. If that does not move the hard pull numbers up at least into the triple digits, I will then start decreasing the air jet.

Bill
 

Bill Blue

Platinum Level Sponsor
Things are actually starting to look good. 3,000 rpm pulls were in the low triple digits and I can drive slowly in 3rd gear at well below 900 mv. Cruise mv's are in the 700-800 range. Pulled the carb, installed a .100" air main, removed the nail polish and closed the progression holes with JB Weld. Need to wait for the JB Weld to set up, so the next test will be tomorrow. Hopefully getting close to "good enough".

Bill
 

Bill Blue

Platinum Level Sponsor
Well, it is way too lean. I think that I did not completely block off all the progression jets with the nail polish. Now runs at 2400 in 4th gear with mvs in the 40's -50's instead of the mid 900's. Will drop the air jet to .080 to see if I can get the main circuit working to cover the gap.
Will use the blocked off progression jets to get a good main fuel/air jet relation worked out. Then work on the intermediate circuit. In the meantime, I will also go to a larger intermediate jet to be sure I'm not starving the intermediate circuit of fuel like I had done with main circuit.

Bill
 

Shannon Boal

Platinum Level Sponsor
I think this sort of work used to be done on a testbench that measured fuel flow, have never seen one.
Well, it is way too lean. I think that I did not completely block off all the progression jets with the nail polish. Now runs at 2400 in 4th gear with mvs in the 40's -50's instead of the mid 900's. Will drop the air jet to .080 to see if I can get the main circuit working to cover the gap.
Will use the blocked off progression jets to get a good main fuel/air jet relation worked out. Then work on the intermediate circuit. In the meantime, I will also go to a larger intermediate jet to be sure I'm not starving the intermediate circuit of fuel like I had done with main circuit.

Bill
 

Bill Blue

Platinum Level Sponsor
Mystery time. Intermediate jet was the largest I have, so no change. Decreased the air jet from .099" to .081". Reinstalled the carb, then came the big surprise! I could barely get the car to move, there is a huge off idle hole. There was a weak off idle in the previous test that I could easily compensate for. I could barely get the car out to the highway - no way that I would risk an attempt to drive further. This hole is massive in comparison to the previous one and I can think of no earthly reason why the change.

So, I'm going to remove all the JB Weld that I can, hoping to open up one or two cracks that will bleed a bit of gasoline.

Bill
 

Shannon Boal

Platinum Level Sponsor
Mystery time. Intermediate jet was the largest I have, so no change. Decreased the air jet from .099" to .081". Reinstalled the carb, then came the big surprise! I could barely get the car to move, there is a huge off idle hole. There was a weak off idle in the previous test that I could easily compensate for. I could barely get the car out to the highway - no way that I would risk an attempt to drive further. This hole is massive in comparison to the previous one and I can think of no earthly reason why the change.

So, I'm going to remove all the JB Weld that I can, hoping to open up one or two cracks that will bleed a bit of gasoline.

Bill
Ooff.. wire wheel in a dremel? Heat gun....?
 

Bill Blue

Platinum Level Sponsor
Swiss Army Knife. Was planning on using a dremel tool with a carbide bur. Knife worked just fine, left the outline of a progression hole. Think it is #2. I used a dental pick (Harbor Freight) and magnifying glass to poke out the tiny bit of JB. To took it out for a test, was running good, but rich. Ran out of gas. No phone. By the time I was back on the road it was pretty dark, so ended the test before the critical part of the test. Will cover the newly exposed holes with resin to hold every thing in place. Might diddle a bit with jets, go to the leanest intermediate jet that will work and maybe the main fuel or air jets. Would like to lean out the cruise while leaving the hard pull as is. Looks to be in the low triple digits, but runs good and pulls nicely.
Bill
 

Bill Blue

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
Here is the reason I won't be using a Volvo transmission/O.D. Please note: The bell housing is a functional extension of the gearbox, setting bearing clearance and providing oil control. The idea was to mate the Alpine bell to the Volvo transmission. That's way beyond my meager talents.
IMG_8198.JPG
 

husky drvr

Platinum Level Sponsor
Bill,

Wow, I like the engineering design, but I understand some of the issues for your project. :(

Any thoughts about another option to try?
 

Bill Blue

Platinum Level Sponsor
Bill,

Wow, I like the engineering design, but I understand some of the issues for your project. :(

Any thoughts about another option to try?
Some wild thoughts have passed through my mind, but were quickly discarded. For openers, the input shaft is about 3/4" SHORTER than the Alpine bell. That pretty much eliminates mating the Volvo bell to the Alpine engine. Also makes making a special plate to go between the trans and Alpine bell. The only viable method would be to graft the small end of the Volo bell to the Alpine bell, which could be shortened enough to compensate for the shorter input shaft. I can shorten then, no problem. Whack them off on the bandsaw and clean them up on the mill. How to properly align them for welding, well I don't have a clue where to start on that problem. Maybe make a plate to bolt onto the engine end of the Alpine bell. The plate would engage the pilot bearing. Set the Alpine bell on the Volvo trans, positioning it to align the Volvo pilot with the Alpine pilot bearing, then weld. Much easier said than done. The Volvo trans weighs nearly a hundred pounds. Oh yes, I can't weld worth a crap, not to mention welding Aluminum. May have to make a plate to set between the two halves in order to mate widely differing shapes. I'm pretty sure that all of that could be done, not at all sure I could. Especially the welding part. Maybe if an itinerant welder happened to appear.

Bill
 
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