1750 Spider Questions!

[elite38868]

Hey all,

I have a few questions about my 1750 spider.

What is the redline? What is the appropriate rpm to shift at if driving spiritedly(sp?)?

If the plugs have a milky light-brown color, does that mean the mixture is decent?

What is the correct/normal operating temperature? Mine stays around 210 if I'm going 55mph and a little hotter if I go faster. There's plenty of coolant and the radiator doesn't seem to be clogged. There isn't a thermostat in, but that shouldn't even be a problem to do with being so hot.

What is the maximum comfortable cruising speed? It seems that for mine, 65mph is a big task.

I'm really starting to love this car. Cosmetically, it looks horrible. I mean, we were moving it the other day and my dad pulled up on the rear bumper and it came off! It's broken on one side and welded on the other. The rockers have got to have tons of rust. The nose is pushed in and the front grille is cracked. The wheels are sh*te and the tires are old. The top needs to be replaced. It's been painted three different colors (I like this one the best). BUT, it starts up on the first crank after a couple of weeks sitting and is rev happy and loves being abused.

What can I say...

[elite38868]

Where are the grounds for the front and rear turn signals? Mine don't even work; front or back. The brake lights work, however, it lights up the turn signal(stays illuminated; doesn't blink) on the driver's side and the regular brake light on the passenger's side.

[Roadtrip]

Redline is indicated on the tachometer.

Shift at whatever feels right. 3000-3500 or so depending on the gear. Mixture sounds right. Is your car fuel injected or carbureted?

The engine temp should run about 180-190F with a 180F thermostat. Do not use a 160F thermostat. You should not run the engine without a thermostat in it. The lack of a thermostat can actually contribute to overheating because the coolant can circulate too fact through the radiator to effect optimum heat exchange. Also, if the car is injected, the injection system needs the engine to get up to at least 175F to lean-out to normal running.

On the electrical issues, it sounds like a couple of bulbs are reversed on the left rear. Download a wire diagram from the Electrical theads and start checking the wiring. Sounds like you have a long neglected car there that's going to take a lot of TLC to get back to her former glory.

The reason for the high revs at speed is the 4.56 rear axle. Great for zipping around town, but you pay for it with high rpms on the highway. Mine is comfortable at about 65 mph. I'm not real comfortable going over 70 or so in a light weight convertible anyway.

[elite38868]

Hi John,

On the tacho, I don't see a "red" line, but I think it goes up to 8k. If I remember correctly, these 1750 engines are supposed to rev considerably higher than the 2000's. I would normally shift the 2000 at the range you said, but the 1750 seems to want to go higher :consfused:. I would never shift at 8k though. The car is fuel injected.

I agree and I bought a thermostat from IAP and will be installing it before I run it next. I wonder why it was removed in the first place...

Any ideas on putting in an electric fan versus the stock mechanical one? I just hate the idea of thinking that it will come apart and ruin the engine and who know else. That happened in our 88 and it dented the hood and punctured the radiator. I also don't like the idea of the it being driven on the same shaft as the water pump. Maybe the pump would last longer if it didn't have this large fan on it; not to mention, you might gain some hp. I've heard of people putting in a separate thermostat that was connected to a fan. Or, since I watch my temperature gauges religiously, I could have a switch in the cabin...

[AlfaRomeo1750]

Sean,

I'm Glad to see that you are out enjoying your car... .

In my humble opinion with regard to your questions...

The Red line on the 1750 is 6500 rpm, but honestly 5500 is the usable max for a stock engine.

As for your question about shifting.. The best way is by feel. Each Alfa is different... although similar, no two 1750's will be exactly the same. So experience is your best tool.

All the books I have read say that while driving around town for best performance shift about 3500 RPM ... with regard to hard acceleration and short speed bursts 4500 -5000 rpm will be suitable.

Just be sure you go thought the car top to bottom before doing any "Real" Spirited driving. In my youth I made a lot of trouble for myself mechanically speaking by pushing my 1750 too hard. They are wonderful cars but at the end of the day they are still 35 years old.

Your engine is running a little lean... but given that most really run rich... that isnt too bad.

As for the max cruise speed, well I am afraid that is a modest 55. I have found that the car is most happy doing the speed limit... though this is not true of all my other alfas LOL LOL LOL.

If you must get to 65 mph or more, a hard pull in 4th will get the job done then settle in by upshifitng into 5th.

My car's gauge reads 180 on average hot days 75'F - 90'F . and 212 on days over 95'F. Some would say that is too hot.. but I have not yet had a problem in 10 years. You can try adding some water wetter to reduce your coolant's surface tension for better heat transfer.. but other than a recore that is your best option... I would however reinstall your thermostat. It is there for a reason.

As for your turn signal.. it may not be grounds... the relay box attached to the underside of the steering column may be bad... that happened on mine... and I damn near pulled the whole car apart until I traced that down.

Check your power supply too... sometimes it could be the fuse or the wires on the back of the fuse box.


I hope this helps, I dont mean to preach so please excuse any opinions that may have come across in that way.

Regards
Martin.

71 !750 Spider
87 Quadrifoglio
81 GTV-6
93 164S

[AlfaRomeo1750]

Sean,

About the electric fan, I never did it on my 1750 because I want to keep it stock, but when I did the water pump on my 87 quad I put on the electric fan, and it did make a huge difference with the quickness of throttle revvs.

So I would do it... however all the aftermarket thermo switches I have bought have been garbage... mainly the ones IAP sells which are made by Hayden. Well pretty much the only ones you can get are made by hayden.

I went through 3 of them before I got fed up and wired the fan to the ignition and added a circuit breaker. I even added a second hi flow fan for better A/C cooling on the quad which acts like a secondary when the A/C is on.

There is plenty of room, so if you are inclined... go for it... but I will warn you it is an all day job.

Regards
Martin.

[Farace]

The grounds for the rear signals are inside the trunk. You'll see wires in a couple of spots ending in terminals under screws. Unscrew, clean both sides of the terminals, clean the spot on the trunk wall where they attach, clean the screw. Everything should be bright and shiny before putting them back. The fronts are screwed on somewhere; I forget exactly but it won't be hard to locate. Again, get them really really clean. Also do what you can to clean the power connectors. That might only mean disconnecting and reconnecting them several times, or you might have some contact cleaner to spray on them.

I'm curious what everyone is referring to when they say a "comfortable" cruising speed. Comfortable for the car, or comfortable for the driver? Braden, IIRC, made a point in his Bible that Americans used to US cars aren't used to sustained driving at high revs, and I think he's right. Until I got my Alfa, once I got up to speed the engine was a low-pitched hum rather than a high-pitched whine. I'm getting used to it now, though, and I love keeping it up in the 5k range. 5k in fifth gear will be in the neighborhood of 100 mph, no? Honestly, though, I don't do a lot of highway driving with my Spider, and around town I almost never get above third gear, which is a great gear, good for a rather wide range of speeds, some of them still too high for the roads I'm on.

I wonder if your tach is like mine. It's not really easy to see the red line, but it's there. It's not an actual line, but a point where the concentric circles change color to red. As stated earlier, it's around 6500 (although I was going to say 6750, but I haven't been in the seat since November). Don't do 8k unless you have a race-prepped motor.

[Roadtrip]

The 1750 doesn't have the torque of the 2L, so rev'ing it a little more to get into the power curve is necessary for spirited driving . . . about 3000-3500, not 2000 like you said.

Ditto on checking the engine out first before you make big demands on it. The bottom end of Alfa engines are very strong, but if you screw them up, 1750 crankshafts are very hard to find in good condition. Also, I absolutely would not drive other than VERY moderately and minimally until the safety aspects of the entire car are checked and inspected . . i.e. steering box & joints, suspension bushings, alignment, wheel bearings, brakes, etc, etc, etc. To do otherwise is irresponsible and a danger to others.

I noted that you used the term "abused" in your first post. Alfa's will bite if abused. If maintained and driven competently, they are very high performance automobiles. Overconfident drivers and a poorly maintained machines often make a fatal combination.

[Gausie]

Your brake lights illuminating the rear indicators is a sure sign of a poor earth. They earth through the mounting post bolted to the u shaped bracket.

Undo it, give it a scrub with a wire brush, refit and you'll be fine. and get those sills sorted - it'll be a different car!

[wilkie]

Quote:

Originally Posted by Farace I'm curious what everyone is referring to when they say a "comfortable" cruising speed. Comfortable for the car, or comfortable for the driver? Braden, IIRC, made a point in his Bible that Americans used to US cars aren't used to sustained driving at high revs, and I think he's right. Until I got my Alfa, once I got up to speed the engine was a low-pitched hum rather than a high-pitched whine. I'm getting used to it now, though, and I love keeping it up in the 5k range. 5k in fifth gear will be in the neighborhood of 100 mph, no? Honestly, though, I don't do a lot of highway driving with my Spider, and around town I almost never get above third gear, which is a great gear, good for a rather wide range of speeds, some of them still too high for the roads I'm on.

[Ianc]

When I was young and foolish(er) I used to drive to San Francisco in my 1750 Berlina to race 5O5's, leaving Vancouver after class on Friday at 3:00 PM, getting to St Francis YC at 5:00 AM, sleeping in the car (there's something that I wouldn't want to do in a Spider), racing at noon and on Sunday, to leave at 3:00 PM on Sunday and get home at 5 or 6 AM to teach at 8:30. That's an average speed down I5 of about 85 MPH. I wouldn't try it now (I'm older and there are more cops these days) but the car had no problem doing it.

[rogerspeed]

Sean, Sounds like you have a ground problem, in addition the 4 prong original flashers can go bad after 30+ years. Having the radiator flushed and rodded isn't very expensive and often will cure the temperture problem, your car shouldn't be running that hot, assuming the guage and sender are in spec i've seen cars that had neglected antifreeze and when the waterpump is removed the impellor is found to be corroded down to hub. I would also add that too lean is as bad, if not worse than too rich, too lean leads to burned valves and pistons.

[sndesign]

My first 1750 would do 135 indicated on the speedo,(not bone stock)
the tach saw a lot of time over 7k and no problems.
I also had the thing over 100 in the snow with A008's,
not for the faint of heart.

I would drive from San Francisco to Humboldt over 100
most of the way, one gas stop.
I was only stopped once by a chp who gave me a lecture,
and them some...
I guess 110 in a high speed sweeper and passing a vette and a ferrari
was a dead give away.

Alfa's :"drive em like you stole it"