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Discussion Starter #1
OK guys, looking for a bit of advice to get me started in the right direction.

I have a Wes Ingram modified "HP" Spica pump on the hot street motor in my 72 GTV. The injection was recently dialed in by Rex Chalmers, so it really purrs.

But, I am about to bring the car from approximately sea level to Denver (5,000 feet). Are there any rule of thumb adjustments to the fuel cut off selenoid to compensate for altitude?

For example, on a carbed car, you would change 1 jet size per 1,000 feet of altitude change. Does anybody have a good starting point for how much (how many turns) I should lean out the mixture?
 

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You shouldn't have to change anything. The SPICA FI pump has a "altitude compensator" (really just a barometric sensor) that will adjust the pump linkage and lean it slightly at high pressure altitudes. It's the bellows type mechanism that's attached to the temperature adjustment arm on top of the pump. If you remove the three screws, the altitude compensator just lifts out. If the car is going to live up there at 5000' PA, it might be a good idea to check the plugs for an overrich mixture after a while. If they're black, then perhaps a fine-tuning and leaning of the fuel shutoff solenoid would be called for.
 

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Discussion Starter #3
Roadtrip,

In theory, that should be correct. However, I've never found that compensator to have much practical effect on any of the Spica cars I've had. I am sure I will have to lean out the mixture somewhat, as the modified pump on this car runs rich most of the time anyway.

Also, keep in mind that the effective altitudes this car will be used at range from 5,000 feet to almost 14,000 feet. Hopefully if I get the mixture correct at the "base" 5,000 feet altitude, the altitude compensator will keep the car running well for runs over mountain passes and the like.

Joe
 

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Joe -
Last summer I drove my 74 Spider from Chicago (800' PA) to Rapid City, SD (4000' PA) and it seems the compensator did fine. Plugs are still a nice tan color. Back in the late 70s I lived in Denver and used to take my 71 1750 Spider up skiing and over the Pass (11,000' PA, I think?) and it did fine also. I never heard of an altitude compensator bellows going bad, and I'm not even sure what the symptoms would be. Maybe someone esle out there has experience with a bad bellows.

Giving it a good baseline tune at 5000' PA would always be a good idea. You can also use the temp selector to lean out the mixture slightly also. I'd probably be a good idea to set the baseline mixture on that HP pump using a CO meter this time instead of just by ear and peak rpm.

Although I have one of Wes' HP pumps sitting in a box, I've never installed it, so I don't know how much richer it runs, although I suspect quite a lot to take advantage of the hot cams.

How about contacting someone at the Alfa club in Denver. They have a web site and I'm sure someone there could give you accurate advice.

John
 

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Discussion Starter #5
Well, that's good news. I hope that I don't have to do too much with it. Maybe the compensator on my old '81 Spider was shot and that's why it didn't run well at high altitude. I'll keep my fingers crossed.

Joe
 

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If you've got one of Wes' HP pumps, it's probably in better than new condition anyway. I'm sure Wes checked everything in that pump several times over, in addition to putting in his durability and performance improvements.

John
 

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Discussion Starter #7
John,

The HP pump was installed by the previous owner and Wes matched it to the cams and head that is on the car. The build sheet for the pump says "155hp spec". It makes really nice power, but seem to have "flat spots" in the power curve.

To verify this, we swapped in a known-good running stock Spica pump without making any other changes. It ran much smoother, but had less mid range and top end kick. So, something is up with this pump, we just can't figure out what.

I've used his stock rebuilt pumps before and agree that they are "better than new".
 

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re: Spica timing

I finally got my 1750 back after 9 months!

Tonight I installed the Spica pump. When I put the pump belt on, the manual said to line the marks up on the pump and pulley and set the crank to 80 degrees ATDC indicated by the "I" mark on the pulley. It said that the first cylinder should be on the "induction stroke" and that I would see the intake valve open through the plug hole. None of this was possible. First of all, the "I" mark is on the crank pulley at what I would say is 80 degrees BEFORE TDC! I tried rotating the crank through two complete revolutions and at no time was the "I" mark lined up while the intake valve was open.

I ended up putting the belt on with the "I" mark lined up during the compression stroke. I hope this is correct.

Any feedback would be helpful, especially if I did it wrong!
 

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Yeah, I've seen 80 deg ATDC in many manuals, even the '69 1750 Alfa FI manual, and have yet to see a pulley marked that way (the 71 FI manual says 70 BTDC). On all the pulleys I've seen, the "I" mark is at 70 deg BTDC. That's what I set the pump timing to.
 

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Yes, it's before TDC. Another method is to set the crankshaft timing mark on "P" (TDC) and the FI pump on the marks, then count 13 teeth back (CCW as you face the front of the engine) and set the belt.

The system can actually run surprising well with the FI pump timing fairly far off, so make sure that you doublecheck you work.
 

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Thanks to everyone for the Spica timing help. I think I have got it right, we will see when I finally get to start it!

OK, next question. I did not take the Berlina apart myself, but I am putting it together. I have almost everything in, but it looks like I may have some left over parts! Here are some photos of the extra parts.
 

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One more question - There is a cable that goes from under the steering column through the firewall near the brake booster. Is this some form of cruise control?

My Berlina is a '71 and my parts catalog only goes through September 1970.
 

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Discussion Starter #15
That cable is the "Hand Throttle". It is more like a choke than a cruise control.
 

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Jeff,

I pulled a Spica pump off an engine I bought a few years ago. I believe the extra pieces are brackets that hold the Spica pump to the engine block. Not sure about the 2nd piece pictured, but I am sure about the 1st & 3rd pieces. They go together as follows:
 

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Jeff –
Without a picture it’s a little difficult to describe, but I’ll try.

The almost square plate is the rear support for the pump. The three holes in a triangular shape attach behind the right motor mount. The “lip” portion is on top. The two vertical holes attach onto the rear of the FI pump. Which holes they bolt to on the FI pump will be obvious.

You are correct in the orientation of the other two brackets with relation to each other. However, where you have the two bolts connecting the two brackets now are really where the bolts attach to the midpoint backside flange (side towards the engine) of the FI pump. The bolts will go in opposite to the orientation in the picture. The unused end hole (in your picture) of the triangular shaped bracket attaches to a point on the engine behind the distributor cap. The other hole on the small piece is the clamp mounting for the metal fuel injection lines. The hole in the middle of the triangular bracket has no function.

It’s very important that these brackets be installed. There is a lot of vibration and you don’t want the four pump-to-engine block bolts to be carrying all the load.

Also, it’s VERY important that the metal fuel pipes be secured to the bracket to prevent excessive vibration and premature failure. Those fuel pipes are virtually irreplaceable. Keep ‘em clean, rust-free, and secured.

What appears to be a hand throttle is NOT meant to be used as a "cruise control" It's sole function is to be used during engine warm-up and NOT while the car is in motion. It merely holds the foot throttle in a given position and WILL NOT disengage upon braking like a purpose-built cruise control.

John
 

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Discussion Starter #18
Well, the car is up here in Denver now, and it ran pretty well without any tuning at all.

But, the throttle response was much slower than before, so I leaned out he mixture 1 and 1/16th turns and things seem to be pretty happy there.
 

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There is an altitude bellows that should compensate for higher pressure altitude. If the car is going to stay up there, it's probably prudent to do a tuneup at the predominate altitude, like you've done. 1 and 1/16 turns sounds like a lot but it may have been overrich to start with. Did you use a CO meter or just set the mixture to max RPM at 2500 rpm throttle opening?

Make sure you listen for detonation, and also check your plugs after a week or so to be sure you're not running too lean. At 5000' PA, you can expect a noticable power loss since the engine is not turbo or supercharged/normalized to bring the ATM in the intakes down to sea level.
 

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Discussion Starter #20
What I did to lean out the mixture was the following (as per Wes Ingram's manual):

1) With the car hot, set idle.

2) Loosen mixture locknut and turn selenoid in (clockwise) until RPMs drop. Then back off 1/2 turn.

3) Adjust idle again.

This corresponds with the tuning procedure given to me by Centerline as well. I had one of the guys there take the car for a spin and they concurred that it was running pretty rich.
 
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