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Tech QuestionsMay 2002 Tech Q & A

Answer by Technical Editor Rex Chalmers

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May Topics:

Spica to Carb Conversions | 164 Gas Mileage | GTV Dash Removal
Dellorto Carb Set-up | Carb Adjustment Primer | V6 Rod Knock | Stuck Heads

Spica to Carb Conversions : question by Otto van Ketwich | ’74 Spider

Can you please inform me how to convert my car from Spica injection to Dellorto carburators?
Answer : As elegant a solution to fuel delivery as SPICA injection is, sometimes discretion is the better part of valor and it makes sense to convert to side drafts. For several reasons, not the least of which is parts availability; I prefer using Weber DCOE carbs. There is nothing terribly wrong with Dellorto carbs, as a matter of fact, I believe that they idle better and have a smoother transition between idle speed and slow running than Webers. That said, I still prefer Webers for their ability to produce horsepower with a minimum of tuning fuss and easy availability of jetting and other replacement parts.

As to what you will need for the conversion, that depends on how you wish to accomplish this task. There is a conversion kit available that doesn’t even require that you change the intake manifold or carb linkage. This conversion is not aesthetically pleasing to my eye, but it does work. If you plan on performance mods to the engine, I wouldn’t use this conversion, simply because of airflow concerns. This kit is available from
International Auto Parts and AR Ricambi.

A more elegant solution is to retrofit the original factory parts for your conversion. You will need the following:
  • 1 Euro Weber intake manifold
  • 4 carb mounts
  • 2 Weber dcoe carbs
  • 1 carburetor brace
  • 1 fuel injection pump block off plate
  • 1 1-3 psi electric fuel pump
  • 1carbureted pedal rod assembly and linkage or a cable kit that will adapt to the FI systems pedal rod assembl
  • Either the OE air cleaner assembly or aftermarket air cleaner system

The conversion is a fairly straightforward, fairly simple bolt on project. Centerline sells the complete kit. Since you live in the Netherlands, I would imagine that you should be able to find all of the components you need for this conversion at your local automotive junkyard.

164 Gas Mileage : question by Bill Runyon | ’93 164L

How much difference in gas mileage should I expect when comparing the 5-spd 164 vs. the auto 164?

I had a '91 164L with 5-spd, that I bought new, and I kept close track of gas mileage. I drove a lot of miles, most of them fast, and I always averaged right at 25.0 mpg, and it was very consistent. That car was totaled in a crash, at 225,000 mi, when it was still performing great, so I had to buy a used 164. I bought a used '93 164L, with automatic, that had 70,000 mi. at the time. I have put on about 30,000 mi, and I average only 20.0 mpg. And, actually, I drive a little slower now.

I had a good Alfa mechanic do everything on the '93 164L auto he could to bring it up to par, but nothing helps in the gas mileage.

Should there be as much as 5 mpg difference between these 2 cars? Or do I have some problem with the '93? If a problem, where can I start looking to try to get it running better, getting better gas mileage?
Answer : One of the drawbacks to most automatic transmissions is that they are less efficient than a standard gearbox. The fuel mileage difference between the two 164s is generally between 3 to 6 miles per gallon depending on ambient conditions and driving styles. Have your Alfa tech check the emissions, compression, condition of the catalyst, air flow meter, fuel pressure, readings of the injection temp sensor, condition of the ignition system, and the air filter. I suppose the CPU could be faulty, but it is just not very likely. If all is well, chances are that the fuel mileage that you are getting is normal for your 164.

GTV Dash Removal : question by Charlie Drake | ’74 GTV

How much is involved in removing the dashboard from a ' 74 GTV?...I know that the earlier ones are difficult, but the 72-74 models appear to be more accessible. Also, what are good sources for NOS or aftermarket dashes?

I just purchased this GTV from an owner in Canada. The Canadian title says 1975; is this a mistake or did Alfa import into Canada past when they did in the US (1974)??

Answer : Removal of the dash from your '74 GTV is not too difficult a project. It requires only basic tools and not a small amount of patience. First remove the A pillar trim pieces. Next remove the console and shift lever. (This step may not be necessary, but it helps with access and eliminates the possibility of damaging the console.) Remove the instrument cluster, cables, and electrical connections, as well as the radio. Disconnect the wires to the glove box light and those of any warning lights that are in your dash. Remove the two 6mm nuts and large fender washers that hold the sides of the dash in place. These are located under the dash about five inches behind the fresh air vents. The one on the left may have ground wires attached. This next step is the tricky part; you must remove the two defroster vent grills and tubes to access the two bolts that hold the back of the dash to the chassis. First pop out the grills and then, with a pick or appropriate prying tool, release the locking mechanism of the defroster tubes and gingerly remove them. Look inside and you will see one bolt in each hole. Remove the bolts and the dash should be free and ready to extract.

Now that you have the dash out, you have come upon one of those rare moments when it’s possible to make a very unpleasant chore almost effortless. See the black box on top of the transmission tunnel? That lump of plastic is your climate control system (Alfa circa 1974). Now is the time to pull the box, replace the heater valve, send out the heater core and have it flushed and leak tested, replace the heater fan and both heater hoses. If you plan on keeping this 28 year old jewel, think of these chores as preventive maintanance, and consider the cost money well spent.

As far as sources for new dashes are concerned, I would contact our friends at
RE Originals or International Auto Parts.

I don’t know if Canada had the good fortune to have 75 GTVs or not, but I did once own a GTV that had a California title that listed the GTV as a 1975 model but was built in February of 1974. I am sure that it was a '74 model year vehicle, but it was not sold until late 1975. I guess the DMV just didn’t question the dealer’s paperwork. Maybe some of our readers will have a more definitive answer for us.

Dellorto Carb Set-Up : question by Shane Murphy | 77 Spider

I have purchased (used)a pair of 40 Dellortos, an euro intake and airbox. How well will this run ,just for street, if I install this in my Alfa with the stock Spica cams? What problems could I expect?

Answer : I believe that you may be correct as to the reasons that Alfa put that pulley on Alfettas. Lord knows that the transaxle cars, as wonderful of machines as they are, did have driveline vibration issues. Personally, I don’t much care for the dampened pulley for several reasons. First of all, the dampened pulleys are prone to separation, the results of this failure can be catastrophic for the radiator, not to mention stranding you on some stretch of lonely deserted highway. Also, you are probably better off with a smaller pulley as it will slow down the alternator and water pump and is a much smaller and lighter mass. That being said, there is no good reason why you can’t use the dampened pulley if you are so inclined. I would, however check to see if it will clear the chassis of the '64 Spider.

Carb Adjustment Primer : question by Pepijn | ’69 GT1300 jr

Hello there, I'm an Alfa enthusiast from the Netherlands. Currently I'm refitting my Bertone gt 1300jr with a 2.0L Nord engine instead of the old 1.3 which blew up!

My question concerns the Dellorto DHLA 40E carbs. I've searched the I-net for hours for information concerning the adjustment of the carbs. I did find info on them but that mostly concerned settings of size and diametre of venturi's, jets, etc. However the carbs were completely dismantled, thoroughly cleaned and refitted with new seals, rings etc.

Now however I need info on setting and adjusiting them correctly, when first trying to start when the new engine is in the car. I need a clear picture and description of what to do and what to look out for. This info I can't seem to find anywhere. Good Carb specialists here in Holland are rare and very expensive. I hope you can provide me with some good and clear advice.
Answer : Ok, here it goes, the short course on dual side draft carburetor adjustment. The basics are pretty much the same whether you’ve got Delorto, Weber, Solex or SK. This is the method that I recommend to most folks who are new to dual carb adjustment. There are many synchronization methods; this is the most straightforward method that I know of. Good luck.
  1. Remove the short linkage rod from the center synchronizing lever ball
  2. Back off fully the idle set screw
  3. Back off the center linkage adjusting screw, at the same time push up on the center synchronizing lever (the lever that the short linkage rod was attached to) until both front and rear throttle plate sets are closed.
  4. Now, very important, while keeping the synchronizing lever pushed up, screw in the center synchronizing screw until contact is made. At this point the throttles of both carbs should be synchronized.
  5. Next, turn the center idle adjusting screw down until it contacts the synchronizing lever. Then turn it down one half to one full turn.
  6. Screw the 4 idle mixture screws all the way down, just till they seat, if seated too tightly the seat will be damaged. For most Delorto applications the mixture screws should be turned out 3-4 whole turns from the seat.
  7. Re-connect the linkage rod that you took off in step one
  8. Start and warm up the engine, if it idles don’t try to turn up the idle
  9. Now find the smoothest lean idle for each throat using the idle mixture screw for each.
  10. Now check the synchronization of the carbs with a uni-syn or similar device. By adjusting the center linkage adjusting screw bring the highest flow carburetor down to the level of the lower flow carb.
  11. Once the carbs are synchronized, repeat step 9. If the carbs are actually synchronized, each idle mixture screw should be close to the same number of turns off of the seat, usually within 1/4 of a turn.

V6 Bottom End Knock : question by Curtis W ebb III | ’91 164L

I notice that my engine has a knocking noise in the lower end after a theft recovery and was wondering if it is neccesary to have the crankshaft turned (lathed) which means engine removable along with crankshaft removable. I was hoping that I could possibly avoid this at least $1500 expense by just removing the oilpan and checking the journal clearances with a plastigage and replacing all the bearings. Before this theft the car was meticuliously maintained with regular oil changes. I want to iterate that the car ran perfectly before the theft on that cold Valentines Day.
Answer : First, let me say that I have never heard of a V-6 that had lower end problems except for cars that have been run low on oil. I would have the noise diagnosed by a good Alfa Tech before I tore apart the lower end.

In any case, chances are that if you have a rod or main bearing worn badly enough to make noise, the crankshaft will have been damaged and will need to be turned to the first undersize. As far as plasti-gage goes, it is a good tool to use when checking for consistency of clearance, but it is not very accurate as a measurement tool.

Good Luck, we hope your 164 recovers from the theft.

Stuck Heads : question by Don Harvey | ’86 Spider

Got a problem. Head was leaking oil, so I wanted to do the right thing - pull it, rebuild it and put it back on. No problem, two weekends max. Well, the head is absolutely frozen. I've sprayed ZEP45 down the studs for almost three weeks with two pullers in the number 2 and 4 cylinders. No movement. I then tried stuffing about 2 1/2' of rope down the number 1 and 4 cylinders and cranked it. Not even a jiggle? Facing the reality of buying a complete new head with no core unless someone can come up with something else to try. And yes, I've removed the bolts in the front from the bottom.
Answer : The frozen head syndrome is not totally foreign to Alfas.

All of the ones I’ve seen can be traced back to one, or a combination of the following conditions:

  • Woefully long periods between coolant changes
  • Use of tap water instead of distilled in the coolant mix
  • Use of straight water without a corrosion inhibitor
  • Engines that sat idle for long periods of time without draining the coolant and flushing the system

As to removal of your cylinder head, it will take two head pullers, several cans of Zep 45 or similar WD-40 type chemical, time and the judicious application of heat to the block studs with a propane torch. It may be necessary to pull the engine and mount it on an engine stand that bolts on at the engine-mounting studs. I once had a head that was stuck so tight that after I got it to budge, I turned the engine upside down and used a combination of 2x4s, wood wedges and dead blow hammers to persuade the cylinder head to release it’s grip on the studs. The most important part of this equation is character, yours, so don’t give up.

I know a gentleman who got a seized head about an inch up after hours of effort and then used a hacksaw to cut all of the studs off. When he found out how much it cost to get the studs replaced, he purchased a used engine, had me rebuild it, and we turned his old block into a coffee table.

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