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Discussion Starter #1
Hello all,

I am hoping to get a few reference dimensions from the SPICA owners on the forum regarding some of the rods and screws involved with this system. When I bought the car, almost everything was monkeyed with, or completely removed, which has made setup a really fun process. I would like a few dimensions so I may use them as a starting point to tune the car (note, I do not have tool A.4.0121, but I do have the Alfa maintenence manual).

Centre to centre distance for the relay crank throttle rod

Centre to centre distance for the relay crank to control unit rod

The pump gap screw - I know about the .019" dimension, but as a reference, how much thread is sticking through (this screw was completely gone when I bought the car)?

The idle limit stop screw - approximately how far should the screw be turned in?

These dimensions should give me a starting point, and then I can follow through the book, and make my adjustments from there.

Thanks,
Chrome Horsey
 

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As with most things SPICA - it's all relative, sorta. All the demensions you are asking for are set relative to the way your motor is set up. Your best bet is to go through your SPICA step by step. It is important to do all the steps and do them in order.

Preliminary:
The first question is how is the motor running now? You might want to jot down as many observations as you can so that you can get a sense of what has changed.

Major Adjustments:
1) If the pump gap screw has been messed with, about the only thing you can do is adjust it so that there is an equal number of threads extending from both sides.

2) Next check that the TA is extending to at least 28mm at 175F. Depending on the year SPICA (do a search) you may need to shim the SPICA by a couple mm.

3) Start and warm up the engine. Remove the long rod and measure the pump gap. As you know, it should be .019". Adjustment is at the bottom of the TA hole. You can be less than .019 because the long rod adjustment will dial it in.

4) Next set the idle stop so that the angle from the pivot ball to the bellcrank pivot is 10 degrees below horizontal. There is a technique where you lay a straight edge across the bellcrank spring and pivot ball and that will provide the correct position - search

5) Now disconnect the long rod and adjust the short rod so that the butterflies just close when the bellcrank hits the stop. Get this right - too tight and you'll dig into the intake tubes. Too loose and you'll never get a good idle.

6) Now adjust the long rod (with a warm engine) so that you get your .019" pump gap when on the idle stop.

You should also adjust the fuel mixture with the Fuel Cutoff Solenoid (FCS) and verify the operation of the cold start solenoid (CSS). Again, a quick search should yield much info on these.

I'll be happy to measure the rod lengths when I get to the office (left the car there today) but as I said, it's really up to your set up...

Good luck!
 

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CH - I recommend that you include the year car in your "signature" so when trying to help, we don't have to ask or guess. If I remember correctly, I think you have a '73?

Do you have the original set screw and nut for the pump gap adjustment?

If the screw has been changed there's really no way to get the pump back into exact calibration except on a test bench like Wes Ingram has.

You can try and replace the set screw visually and see if you get acceptable running. The Spica system will run acceptably even when pretty far out of adjustment.

See picture below for what a correctly position (on this pump anyway) looks like.

If you haven't done so already, download the guides at www.wesingram.com/hp.htm. I also have a Benchcheck Guide for evaluating the health of a Spica pump (as best you can at home). Let me know if you want that.

As far as the other adjustments, here's the lengths of the various items on my car. You mileage will vary. It's a starting point anyway.

Long rod: 11.783"
Short rod: 4.210"
Idle Stop Screw: .9845" measured from top of manifold to the top of the screw head.
WOT Stop Screw: .604" measure from the top of the manifold to the top of the screw head.

Pump gap adjustment set screw (allen hex): .600" long

To clarify . . . The pump gap (long rod disconnected) is set at .019" with the engine at 175F. You can do this manually or use a dummy TA once you confirm that your TA is extending to 27mm (+/-1mm) at 175F. However, as the engine continues to heat to normal ops temp, the pump gap will likely go to zero. That's normal.

Once the pump gap is set at 019" at 175F, you next connect the long rod again and warm the engine to FULL OPERATING TEMP (probably 195F). You then adjust the long rod to reset the pump gap back to .019".
 

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Discussion Starter #4
Hello Gprocket and Roadtrip,

First off, thanks to you both for the information. I have been tuning the beast today, and haven't been completely successful. At idle it seems to run fine, but then the fuel mixture gets richer as I drive. If I lean the mixture, the engine won't start on cold start-up.

I think the best thing to do is set up all the rods to the "normal" lengths and go through the procedure again. If I can't get things to work out the way I want them to, I think I will pull the pump off, and work through the bench check (and yes, I do have that - thanks again Roadtrip).

I knew this was going to be interesting when I noticed the various missing screws (such as the pump gap screw), ot the heavily messed with (the idle screw was on its last thread when we bought the car).

Once again, thanks for the information.

Enjoy the open road (and the suddenly cheap gas around here)!

Chrome Horsey,
1973 Alfa Spider (not the nicest car to tune)
1966 Mustang (one of the nicest cars to tune)
2002 Mustang (the electronic version of the Alfa)
 

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IF you have everything set up properly and the motor runs smoothly at temperature then I would guess that you should look at the mechanisms that come into play with a cold start. When cold, the TA and the CSS both engage to enrich the mixture. When cold the TA is retracted which allows the pump gap to open up. This provides a richer mixture so that the motor can idle. But to start a cold motor additional fuel is required and that is provided by the CSS. It is connected to the starter circuit. When you engage the starter, the CSS is energized - the CSS plunger extends. When you release the ignition key the CSS is de-energized but the plunger doesn't immediately retract. (I am not certain how long it lasts - Roadtrip probably does...). If the CSS is not operating you won't get that extra jolt of fuel and the motor will be hard to start.

You can check the CSS by getting the engine up to operating temp and then applying 12VDC to the CSS. If it is working properly the idle will drop from about 800 rpm to 200 rpm. If nothing happens, the CSS is not extending. Give it a little rap with a mallet and you might get lucky and loosen it.

Again, all this is moot if the ignition, fuel delivery, and/or mechanical timing is not up to spec.

BTW, I measured my long and short rods:

Long: 11.8"
Short: 4.3"

Have fun!

- Rich D.
 

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I know I shouldn't go by memory:

To set the idle stop the bellcrank ball should be above horizontal not below as I started.

Energizing the CSS the rpms should drop BY 200 rpm, drop TO 200 rpm. Sorry for the confusion.

Roadtrip is correct in saying that the normal operating temp is 195F (I sorta implied that a warm motor was 175F). The best way to check the TA at 175F is to remove it completely and drop the probe end into a pot of water heated to 175F on the stove. Use a cooking thermometer to ge the temp right. Make sure the probe isn't resting on the bottom of the pot.

Also, it's a good idea to do these things while your wife is at the spa or shopping for a new dress. When she comes home and discovers what you were up to she might be too relaxed to bean you on the head with the pot...
 
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