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I have a similar thread over in the cast iron 2000 thread, mostly containing anecdotes and philosophy. I promised the mods not to foul the air over there with too much mechanical stuff, so that order can be maintained.

Anyway, I finished the fuel pump replacement today, and finished sorting the engine with it running sweetly. More on that later.

Off and on, discussion comes up about replacements for the 3-port fuel pump. I previously did this for the two pumps on my Montreal. This single pump was much easier.

First, I rejected the idea of using an L-jet pump, as this typically requires reducing the size of the return line restrictor hole. While this can help keep the pressure up around a good number, it reduces the cooling of the Spica pump via the flow-through fuel. Long term impact? I’d rather not test it.

So, I bought an off-brand version of the Bosch -044, which is a high-pressure, high-flow unit. I also bought a Holley pressure regulator, and a handful of fittings, most of which I already had in stock from my aircraft maintenance work.

Some of the pluses are that everything bolts into the existing pump and filter brackets, the fuel connection points are very close to where they were with the three-port, and all of the nipple sizes allowed the use of standard hose in matching sizes.

As the pump has an overall greater output than required, the regulator allows for a quite linear pressure control all the way from idle to full power. When I first tested the assembly, I was getting 21-22 PSI at idle, with the regulator screwed all the way to minimum. So, I drilled the restictor out to .093”, screwed in the regulator a little, and bingo, dead on 16.5 PSI from idle up. As I’m now within the adjustable range of the regulator, I can correct if future testing proves it necessary.

And, I’ve increased the flow through, improving the cooling of the Spica pump.

Total.. around $150

1603671



1603672
 

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Push hard and live
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Discussion Starter #3
We drove the MF (Millennial Falcon) last night, for the first time.

New clutch master and slave arrived (Italian-made slave cost only $12.43 with free two-day freight via Amazon). Bled up ok, but couldn’t get release. Decided disk might be stuck to flywheel, so shut off engine, put it in reverse, opened the garage door, pressed in the clutch pedal, and turned the key. As this engine starts immediately, like a well-tuned Spica should, it instantly fired up, POP!!!, and the disk unstuck.

We drove down to the nearby gas station, noting a silky smooth trans, and next to no brakes. The latter will be partly due to new seals and pads in all four calipers, but my guess is the booster is DOA. I’ll try again after some more bleeding. I really don’t enjoy changing boosters on 115s.

A little torque steer. I’ll inspect the rear track bar bushings. Also not fun, but I had bushing drivers made several years ago.

Speedo inop. Hmmm. Not important now.

Fuel pressure light came on as we were driving back from the gas station. No objections from the engine, so I’m betting on the pressure switch or wire. I explained to my son in the passenger seat that the fuel pressure light is not a warning light. It’s a “prepare to park” light. Engine runs great, but the coming deletion of the one-hole exhaust manifold and a reduced-muffler-count exhaust should improve things,

Oh, the 42 year old fan and surrounding shroud evaporated with the first acceleration. No dents in hood, thank goodness.

Waking up a long dormant Alfa is always interesting. Not always fun.
 

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This morning, the feed to fuse #6 wouldn’t light up. After a lot of fiddling, it came back. Then went away, and back. Repeat. Might be the reason the ignition switch assembly was hanging by a wire when the car arrived.

Fuel pressure light lit full time. With the instrument power coming and going, it’s challenging to diagnose. Engine still running great, though.
 

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Discussion Starter #5
Somehow, I knew it.

The cheap Chinese version of the Bosch 044 died. Operated for maybe 15 total minutes. Still enough flow to keep the engine running, but not enough pressure to move the needle on my test gauge.

Nice thing about Amazon - they’ll take it back, no questions asked, and pay he freight and packaging.

Actual Bosch 044 should arrive tomorrow.

I’ll be back on the road tomorrow, just in time for ice, snow, and sub-zero.
 

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Discussion Starter #6
Hmmm. I'm used to chasing movable electrical gremlins, but fuel pressure?

Recap. New aftermarket pump, regulator, and plumbing. Opened up restrictor to .093" to accommodate higher pressure and flow. Perfect pressure control from the beginning. Great behavior.
10 miles later, low fuel pressure. Pump? Probably, as it was Chinese. Pressure sender? Possibly. After much checking, I decided sender was OK, so had to be the pump.

Bought new Bosch "Made in Czech Republic" "044" pump. Rated at 80 psi. Installed. Ditto low pressure as "failed" Chinese pump. Did many permutations of gauge insertions, and determined pump putting out tons of pressure. Regulator in full bypass mode? No. Only answer was a too-large restrictor hole, which I originally drilled out to .093". Soldered and redrilled at .069". Pressure up to 15 psi, but not adjustable with regulator. Dropped hole to .063". Pressure at 16 psi, but still not adjustable. Hmmmmm. Maybe smaller hole tomorrow.

Now enjoying a "Chateau de cardboard" Cab Sav. I can live with 16psi, but just what happened here?
 

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Hmmm. I'm used to chasing movable electrical gremlins, but fuel pressure?

Recap. New aftermarket pump, regulator, and plumbing. Opened up restrictor to .093" to accommodate higher pressure and flow. Perfect pressure control from the beginning. Great behavior.
10 miles later, low fuel pressure. Pump? Probably, as it was Chinese. Pressure sender? Possibly. After much checking, I decided sender was OK, so had to be the pump.

Bought new Bosch "Made in Czech Republic" "044" pump. Rated at 80 psi. Installed. Ditto low pressure as "failed" Chinese pump. Did many permutations of gauge insertions, and determined pump putting out tons of pressure. Regulator in full bypass mode? No. Only answer was a too-large restrictor hole, which I originally drilled out to .093". Soldered and redrilled at .069". Pressure up to 15 psi, but not adjustable with regulator. Dropped hole to .063". Pressure at 16 psi, but still not adjustable. Hmmmmm. Maybe smaller hole tomorrow.

Now enjoying a "Chateau de cardboard" Cab Sav. I can live with 16psi, but just what happened here?
Don, where are you taking the pressure readings, at the front of the car or at the regulator discharge? You may want to take a look inside that regulator, could have a sliver inside that is affecting the diaphragm balance. Or, maybe an obstruction in the hard line to the front. The regulator ought to respond, regardless. Educate me here... where is the restrictor orifice you mention?
 

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Some of the years have a bypass valve in the front fuel filter that can stick open.
 

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Discussion Starter #9
Short version..... CRAP!

Got the Bosch fuel pump making ok pressure, took the car out for a drive and BOING, on comes the low pressure light.

I can take a hint. Tomorrow I’m taking out everything between the tank and the Spica. This behavior is exactly like an obstruction or faulty regulator. I know it’s been 10 years since the car was operated, and some things on the car date back nearly 20 years.

No more fussing around piece by piece.

The orifice is part of the nipple fitting at the front of the Spica pump for the fuel return line. It is intended to allow a constant flow through the Spica for cooling, among other things.

I’ve already replaced all of the rear hoses, and will finish what I started by doing the forward hoses. Shoulda done already. Also inspect the main filter mount internals. Old, gummy fuel can do bad things. Ditto new regulator, in case something made it through the new rear filter.

Meanwhile, gotta get back onto 1488. It leaves for Scottsdale in early-mid January, and a mystery vibration needs solving.
 

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OK-- thanks for the explanation on the orifice location. It maintains a backpressure and flow through the pump circuit. I'm just not familiar with the SPICA cars.
But-- I do agree you should blow out the hard lines with 35-45 psi clean compressed air. Then replace any other fuel hose you see, pressure or return side. I serviced an MGB long time ago, it had literal slime strands of gelled gas inside the fuel lines, from sitting.
You mention the new rear filter, that plated can filter off the tank, with the red hose into it? Is that an OEM item on the SPICA cars, Don? If not, then I would hesitate to add anything on the suction side of that pump that could create a pressure drop. Now, strainers inside the tank won't create any measurable pressure drop unless they are clogged with debris. But I don't think those pumps are designed to run with a delta P on the suction side--- only atmospheric or even a slight head of positive pressure on them.
If the SPICA systems came equipped with such an external suction filter, then fine- disregard my comment.
 

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Discussion Starter #11 (Edited)
Yep, the rear filter is original config. Car has a built-in bracket for it. Modern turbine pumps don’t like being fed chunks of stuff from the tank.

I’ll be checking and redoing the whole fuel feed system tomorrow. We got the vibration in the 102 sorted today.

The MF 115 is now queued up for...

Fuel feed redo
New fan and shroud
Replace exhaust manifold and exhaust
Powder coat replacement valve cover without hot air tube guides.
New rear axle support straps
Hidden Bluetooth radio system. (Need to find a suitable blanking plate)
New carpet
Repair tear in driver’s seat.
Rear track bar bushings.
New trans and dif fluids.
New Turbina emblems.

All in a day’s work.
 

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Discussion Starter #12
OK. So I’ve yanked it all out. Tested 044 on the bench, with restrictor orifice. Tons of pressure and flow, plus that sewing-machine purr typical of a happy Bosch pump.

That’s the current hint.

In the car, the pump is noisy.

Tomorrow, I’m going to recheck the feed and plumbing from the tank to the pump. It’s an obstructed feed that makes them noisy.
 

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Discussion Starter #14
It generally seems embarrassingly obvious once you find the solution.

I see now that I automatically assumed the cheap, Chinese pump was at fault. That led me to start working at the outlet end of the chain. A second, and more expensive, pump and regulator later, I had no choice but to investigate to inlet end.

A nearly completely plugged tank outlet filter.

I had blown through it before installation, as it was an apparently new NAPA unit that I had laying around the shop. It blew without restriction. I had also flushed the tank several times, using various cleaners and de-gunking agents. My only guess at this point is that a) something ugly washed out of the tank and was caught by the filter, or b) the aged-if-new filter had some sort of collapse inside. I'll cut it open later, perhaps wearing a hazmat suit.

Meanwhile, while I was draining the MF's tank, I got the new fan, shroud, bypass hose, and return fuel line replaced. Plus, fixed a couple of pinholes on 1488's fuel tank.

I've got an hour to install a new filter, pour in some gas, and see if my observations have identified the real culprit.
 

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"Meanwhile, while I was draining the MF's tank, I got the new fan, shroud, bypass hose, and return fuel line replaced. Plus, fixed a couple of pinholes on 1488's fuel tank. "

So that cloud had a silver lining, after all! Wunderbar...

Don't feel too bad, I have had to change out suction filters numerous times on hydraulic units, starting them up from major system work or resurrecting old systems that have sat around for years. It takes time, and fluid flow. And, the correct filter. Too fine a filter on the suction side, and some pumps will protest with cavitation, especially those pumps which cannot pull much suction anyway. They always need a flooded suction condition, even with filtration.

Keep on keepin' on... you'll slay those dragons one by one. ;)
 

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Discussion Starter #16
4 1/2 hrs nonstop in the shop this morning. Did a last leak-check on the 102 gas tank, and reinstalled it in the car. It is now officially ready for Bonhams in January.

Turned my attentions back to the MF 115. Did a flow and pressure test. Flow correct, pressure too low.

Changed main fuel filter (I wonder how many Spica cars still have the snap-around blue plastic protector on this fuel filter?), soldered up restrictor, and redrilled it one number smaller. Recheck, got 18 psi. Good enough. Removed inline fuel gauge.

Reinstalled plenum, with new straps, and now with different front plate without hot air snorkel. We’ll get to the exhaust manifold another day.

Reversed fan blade. Although reinstalled the same way as the one that it replaced, it seemed to be making small contact, although no marks on the shroud. Test all good.

Apart from picking up a set of tags, sorting out a workable sound system, and some interior sorting, I think it’s operational. I don’t like the sound when cranking the starter. PITA to even investigate, let alone fix.


Compare to my 102 start, plus an uphill acceleration test in the 102



The last pic below shows why no test driving. I drove my last 115 in the snow one time. Never again.

1605619




1575237622844.jpeg
 

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The replacement fan blades you get today. Sit further back then the originals. Its suppose to go on one way so it pulls air into the engine compartment. When you look in the center you will see a step mplded into one side. That side goes towards the engine.

Since the new one sit further back the blades will sometimes hit the crank pulley. Especially the double belt pulleys.
 

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Discussion Starter #18
I wondered, but confirmed it cleared my now-single pulley. I can see where it wouldn’t clear a double groove.
 

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4 1/2 hrs nonstop in the shop this morning. Did a last leak-check on the 102 gas tank, and reinstalled it in the car. It is now officially ready for Bonhams in January.

Turned my attentions back to the MF 115. Did a flow and pressure test. Flow correct, pressure too low.

Changed main fuel filter (I wonder how many Spica cars still have the snap-around blue plastic protector on this fuel filter?), soldered up restrictor, and redrilled it one number smaller. Recheck, got 18 psi. Good enough. Removed inline fuel gauge.

Reinstalled plenum, with new straps, and now with different front plate without hot air snorkel. We’ll get to the exhaust manifold another day.

Reversed fan blade. Although reinstalled the same way as the one that it replaced, it seemed to be making small contact, although no marks on the shroud. Test all good.

Apart from picking up a set of tags, sorting out a workable sound system, and some interior sorting, I think it’s operational. I don’t like the sound when cranking the starter. PITA to even investigate, let alone fix.


Compare to my 102 start, plus an uphill acceleration test in the 102



The last pic below shows why no test driving. I drove my last 115 in the snow one time. Never again.

View attachment 1605619



View attachment 1605617
Thanks for sharing with us. You have a couple of really nice cars. I bet the toughest decision you have in the morning is what car to drive. HaHa. The workshop is very nice too.
 

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I wondered, but confirmed it cleared my now-single pulley. I can see where it wouldn’t clear a double groove.
Also being a 76 and later you should have the aluminum spacer that goes between the fan and the w/p pulley.
 
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