spica help?

[78-AR-SPIDER]

Well today I thought I would check the t/a to see if is the reasno my 78 spider backfires on decell. When I removed the air horn this is what I saw. dose not seem right compared to The Owners Bible and Car Disk. Wanted the boards thoughts. It appears that the throttle cable is attached to the t/a. Thanks for the help

[DriverJon]

Aha.. that must be the famed Shankle Sure start (might be a different name)

I have never seen one, but have had them described to me. the cable is replacing the bottom end of a bad thermostatic actuator. You can see the top bulb part that goes in the block (the brass thing just above the cable in a line up from the pump) with it's broken off stub of the capillary tube that used to go to the Spica pump..

I guess there should be a knob somwhere under the dash that operates it, and it should act like a choke, you pull/push it when the engine is cold, and push/pull it when it gets hot.

These things are not highly thought of, and were a cheap and not that great replacement for the expensive TA. Most have been removed since your Spica really wont work right without one.

They are basically a little thermometer, they push out a little pin proportional to the engine temp, this adjusts the fuel mixture in the Spica.

Unfortunately, setting the pump gap to the right distance with the engine hot, is critical to all the rest of the pump internal calibration.. so you really want to get one back in there.

Sounds like you need to get the Spica book from Wes Ingram, it is a must have for understanding and adjusting your fuel injection. He is THE guru of Spica pumps.

www.wesingram.com

You also need to get a TA, which will cost you a bit, Wes probably has the best price at $165 plus $95 core charge.
Since someone threw away the bottom half, I doubt you could get anything for the top bulb.. but ask.

If it sounds pricey.. it is, but it is more at other places. $200 and $100 are more typical. These things are long extinct, and rebuilt old units are all that are left.

Finally, you might be able to improve things by getting the book, gaining understanding of the system, and resetting the Sure Start so that the pump gap is correct when it is pushed/pulled in whichever way normal running is.

Then go thru the rest of the tuning up of the Spica and you might be ok, till the sure start wears some more.. But I'd strongly suggest that you bite the bullet and get a new TA, even if you are in mild So CA..

Hope this helps..

Jon

[Roadtrip]

What you have there is a "Shankle Sure-Start" aftermarket retrofit in place of the Thermostatic Actuator. Instead of a hydraulic action of the T/A, heated by the engine coolant, pushing down the piston to lean out the mixture for normal running, the PO has installed a cable assembly to do the same thing. Somewhere n the passenger compartment, you will find a knob that pulls and pushes less than an inch throw. Pull out and the mixture is enrichened, push back in and the mixture is leaned to normal running. To check and see if it's calibrated correctly, warm the engine to 170F and check the gap between the throttle arm on the back of the injection pump and the reference screw is .019" with the long rod disconnected.

If the pump gap is more than that, that might be the cause of the backfiring. Is the backfiring bad or just occasional. Holding slight pressure on the gas pedal will cause backfiring also, as will an inoperative Fuel Cutoff microswitch or solenoid, or throttle butterflies that aren't closing all the way at idle.

CORRECTION: With a "sure-start" mod, you don't need to warm the engine. That's irrelevant because the "sure-start" is not temperature dependent. Just disconnect the long throttle rod, push the knob in, and check the gap NGT .019". With the long rod attached, gap should be .019", sure-start IN (disengaged).

[78-AR-SPIDER]

Thanks I have ordered Wes's book but would like yours also Roadtrip. I knew somthing was up when it didnt look like the pictures or diagrams. I will wait untill i get a book and read it before I do any other work.

[emr5503]

By '72 Alfa had removed the panel on the left lower side of the dash where the accl. & choke controls were mounted for carburated cars. Most likely your Shure Start is connected to the fast idle knob by the steering column as suggested in the installation instructions.
If you are going to throw it away, send it my way. I can always use a spare to the one I installed 15 + years ago.

[Roadtrip]

Starting in 1971 there was the change to the new interior style and Kamm Tail. 1978's had the "Hand Throttle" (what emr5503 calls a fast idle knob) located at the left rear of the center console. When a few owners retrofitted Shankle Sure-Starts, they removed the hand throttle and installed the sure-start. Others installed it on the other side of the console. Other installed it who knows where. If it's working fine and makes the correct pump gap when the engine is warm, i'd just keep it. If it's broken, I'd replace it with a proper T/A.

As far as manuals, what I have finished presently is the fuel supply system troubleshooting guide. If you'd like a copy PM me your email address. Been working on a SPICA system guide, but just got a digital camera to make the pictures with.

[78-AR-SPIDER]

John Thanks I would like your fuel supply system troubleshooting guide. My e-mail adderss is bcasteve@aol.com tried to pm you but your box was full.
I always wondered why the throttle worked more like a choke
now I know Its is (sort of). I am in the prosess of getting a new t/a.
emr5503 I think I will hang on to the Shur-Start for now But will keep you in mind if I ever clean out my garage.

[montelatici]

AR Ricambi sells the same thing for 65 USD. It really just replaces the manual choke on a European carbureted car. If one gets it calibrated correctly, it is probably more reliable than a thermostatic actuator. Frankly, I suspect that immissions US standards required that this abortion (the thermostatic actuator) be installed in the SPICA. A manual enrichment system seems much more practical for the SPICA. Using the "throttle" cable spot on the console, which is of no use, seems a good idea.

Alfredo

[dwc]

You guys shouldn't be so hard on the Shankle Sure-Start. I've got one on my '74 Spider, and I don't think it's ever going to be replaced by a TA. If you think about it, the TA is out of the loop once the engine reaches operating temp. If the water temp remains constant, so does the length of the TA. Certainly the TA is needed for a cold start, but in that case, rich or too rich won't make much of a difference, although the Sire-Start is continuously variable for starting the engine.

What I like best about the Sure-Start is that when tuning the Spica pump, you can simulate a hot or cold engine without ever running the engine. If one wants to check the pump gap on a hot engine, simply push the Sure-Start knob fully in. It works just like a dummy actuator, except it's adjustable on the fly.

AR Ricambi doesn't have any Sure-Starts, and hasn't for quite some years. I've got a spare that's not for sale, and I do know someone who has machined a few repro's, though.

Speaking of Shankle, anyone remember the Heel and Toe kit? Another worthwhile but simple addition to any Spica car. They're also NLA, but wouldn't be hard to reproduce.

Regards,

Dean
Lutz, FL
'74 & '87 Spider Veloce's

[dwc]

Also, here's a pic of the working end of a Sure-Start. These are both repro units.

Regards,

Dean
Lutz, FL
'74 & '87 Spider Veloce's

[DriverJon]

My question about these is how accurate and repeatable are they?

You're simulating the stroke of the TA, which is something like 3-4mm of travel, with a long cable and levers, etc...

Does it set you right on the correct pump gap every time, does it wear and need to be recalibrated often? How hard is it to slowly push it in as the car warms up, so you aren't running to rich or lean? I guess the car would stand running a bit off mixture during the warmup time.

The gap of course is critical for the whole Spica system to work properly.

I have no direct experience, am just imagining the level of task this has to perform as a mechanical linkage. I'd guess you have to adjust it from time to time, wheras a TA will have the pump set to it's warm length, and until it leaks or the pump wears, there should be NO reason to have to adjust it. And they can go 5-10 yrs without leaking. (or less) So, I wouldn't call them an abortion.. just another input to the mechanical computer so it stays on the right mixture, regardless of engine temp.

[montelatici]

I believe that the US immissions standards and tests required that an automobiles immissions be tested over a cycle of start up, warm up and then regular running. I further believe that this test had to be passed without the driver's intervention, i.e. the reasoning was the human could forget to release the enrichment mechanism and the automobile would run rich, polluting more. If it wasn't for this, I cannot understand why any engine designer, would add unneeded complexity of an automatic enrichment system when the manual choke was standard and all were accustomed to using the choke when starting the automobile when the automobile was cold.

Like you I am curious to hear what downsides there may be to the mechanical actuator, if any beyond originality.

[emr5503]

The only downside I have been told is that sometimes the spring gets tired. It hasn't happened to my Shankle Sure Start in 15 + years, but other makers' springs may differ.

[Roadtrip]

The "sure-start" works fine, although it's basically an ON-OFF switch that lacks fine temperature modulation of a T/A . . . . but's that's not really a problem either. As far as adjustment goes, as long as the sure-start plunger pushes the pump's internal mechanism down at least 27-29mm (depending on pump "T" number/model year) from the top of the pump, the pump's going to go to running mixture. Depending on the climate, you may need little if any starting enriching mixture at all. If I was using a sure-start, I'd push it in as soon as the engine would run well without enriching, regardless of coolant temperature.

[dwc]

John is correct in that I use the Sure-Start basically as an on/off switch, and that's all that's required. The small mixture adjustments made by the TA during the short warm-up period just aren't neeeded. To start a cold engine, I pull the knob all the way out (several mm), and when I see the temp gauge indicate 140 - 160F, I push it all the way in. Since I'm in S. Florida, warm-up time is maybe 2 - 3 minutes, although 25 years ago I used a Sure-Start in CT with no trouble.

The pump gap is always correct when the knob is pushed all the way in, and really won't change because of the spring and stop built into the Sure-Start mechanism. And, as I said, it makes adjustment of the pump a breeze, since you can "set" the engine's temp to hot or cold, at will. To set the pump gap initially, the appropriate screw inside the Spica pump is adjusted, just as with an initial TA install. The Sure-Start cable is attached to the 'Throttle" knob on the rear, vertical face of the center console of my '74 Spider, although on an earlier Spider or GTV, the dash mounted throttle lever could be used.

While I appreciate the elegance on the TA, and Italian engineering in general, sometimes it's not necessary. My friend who machined those repro Sure-Starts found an Alfa shop in S. California that makes an electro-mechanical TA replacement. An electric temp sensor replaces the TA bulb in the manifold, while a stepper motor replaces the TA pushrod in the Spica pump. I think it has 10 or so very tiny steps between cold and hot. But again, who needs it, especially for ~$350? If one could find a solenoid with the appropriate throw, it could be used with a simple on/off switch, and work just as well.

So, to each his own, as both the TA and the Sure-Start work admirably well. For me, the Sure-Start is just one less thing to worry about.

Regards,

Dean
Lutz, FL
'74 & '87 Spider Veloce's