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Tech QuestionsJuly 2002 Tech Q & A

Answer by Technical Editor Rex Chalmers

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July Topics:

1750 Street Mods | Spider Air Bag Light | 105 Competition Springs/Shocks | V6 Oil Drinking
Plug Well Leaks | Trans Popping Out of Gear | RML Ignition/Coils

1750 Street Engine Modifications : question by Alex Twitchell | ’65 Giulia Sprint GT

I am preparing an early 1750 (street) engine to replace the existing 1570cc unit presently in the car. I have a couple of questions to ask.

Are there any cooling benefits from drilling extra holes on the inner wall of the block where the water rail runs? I have heard that this is a useful mod to aid circulation around the piston liners.

Likewise, would the engine benefit from the fitting of a windage tray, and are there any disadvantages to lower end lubrication as a result? I am looking to find one in Germany (I live in England) but no luck so far. Are there any available in the US?

I have traced an original, unused crank and con rods. Bearing in mind that I do not intend to race the car, are there any basic modifications to either that you would recommend (knife-edge crank webs, shot-peined rods etc.)?
Answer : As you are not planning on racing the car, I don’t think that you need to concern yourself with a windage tray as the standard Alfa pan does an excellent job of keeping the oil pump fed with oil. The only commercially available windage tray that I am aware of is through AutoComponenti. It also functions as a crank scraper. AutoComonenti’s unit is sandwiched between the oil pan and block and does not use any pan gasket. It is a well thought out unit, but, again, I don’t believe that it is particularly well suited to street use. I have been making a windage tray for my customers for years that is a fairly simple unit that requires drilling and taping of the oil pan at 4 points. It does not incorporate a crank scraper. The difference between the two is that a windage tray’s job is to keep the oil in the pan and available to the oil pump under cornering and braking. The crank scraper is designed to scrape oil off of the crank counter weights, thus providing less reciprocating mass and less drag. Jim Steck of AutoComponenti can be reached at 937-884-5142.

The modification to the block to improve cooling of the liners is another operation that is of little benefit for street application. As long as your water pump and radiator are functioning properly, modifying the block for increased water flow around the liners is of questionable benefit for a stock motor.

Regarding the new crank and rods; they are really not necessary as long as you have access to a competent machine shop. A good machine shop can cut the crank, magnaflux, chamfer the oil holes, check for true, polish, heat treat, drill and tap the oil galley plugs, and provide a crank that is arguably better than new. You can also have the crank knife edged, but that is not of any great value for a street engine.

It has been my experience that there is no reason to shy away from using a crank that has been cut to first or second oversize. I have a customer for whom I build race engines that prefers to have cranks cut to .020”. He is a mechanical engineer and has calculated that bearing speed is reduced a significant amount due to the fact that a cut crank has a smaller crank journal diameter. Alfa built some of the sturdiest cranks around and crank failures are extremely rare. Have your rods magnafluxed, re-sized, balanced and shot peened. Replace the rod bolts and nuts. Have the new bolts magnafluxed as well. If you do nothing else, drill out the oil galley plugs and make absolutely certain that the oil passages are surgery room clean! One bit of dirt or debris can cause scoring, restricted oil flow, resulting in bearing failure and lock up. Remember, the most common cause of most catastrophic engine failures is dirt.

Spider Air Bag Light : question by Christopher Alviar | ’92 Spider Veloce

The "Air Bag" warning light on my dash comes on almost every time my Spider bottoms out, I tap against a curve, or even when I shut the hood down. And the light stays on blinking annoyingly until I take it to an Alfa mechanic who charges me $100 to "re-set" the sensor and turns the light off. Is there a way I can re-set it my self? the mechanic says there's a special tool to do that but says I can't buy it (not from him anyway!). Any tips on how I can reset this my self or where I can find this "tool"
Answer : First of all, not all Spider’s endlessly set off the air bag light. If you brought the car to me, with that history of the “SRS” light coming on, I would have advised you that we spend your money diagnosing the problem rather than endlessly turning off the light, these systems rarely heal themselves. Obviously, there is either a bad sensor, connection, wiring concern or faulty air bag control unit. Before testing, disconnect the battery! I would first run the self-test described in Unity 45 of the factory shop manual. If all check out ok, check all sensor and processor connections for corrosion and continuity. Next, check resistance values for both front sensors for proper ground and that they are mounted securely to the chassis. Next, with an ohmmeter, check that the values for the sensor are within these parameters. (The letters refer to the labels on the sensor pins.)

R and ground:
Less than 1 ohm
R and B:
Approximately 10K ohm
R and G:
Approximately 10K ohm
B and G:
Less than 1 ohm

If any of the measurements you take are outside of these values, replace the sensor. If you need to check further into the system, get your mitts on a shop manual and refer to the test procedures in Unit 45.

Although the test procedures are very thorough, I must say that I have had occasion to replace one sensor or both after the system passed the tests in the manual with flying colors. In any case, stop throwing $100 bills at the light and fix the problem!

I am sure that if you post on the Alfa Digest some owner has figured out how to make a cheap re-set tool and will be happy to send you the information.

105 Competition Springs and Shocks : question by Robert Muir | ‘67 1750 GTV

In sprinting my 105, I am suffering from excessive weight transfer and suffering lap times. I have been advised to go to stiffer springs and adjustable Konis. The catch would be that the Konis are not externally adjustable on the car, which makes it hard to fine-tune the settings.

Is there a good alternative shock with on-car adjustability?

Answer : I don’t really know of any externally adjustable shocks for Alfa’s other than Spax, and I never been very happy with their quality. Rather than worrying about adjustable shocks, I would install a set of Bilsteins, if you like gas or Koni if you prefer hydraulic. I can’t think of an application for which I wouldn’t recommend Bilsteins, I even have them on my Sprint Speciale. The Bilsteins are self-adjusting and do a great job of keeping the tyres in contact with the black stuff.

Springs, sway bars, corner weights, and alignment specs are your best tuning tools. The best place for you to start, assuming that all your suspension bushings and tye rods are in good shape, would be to find out what the rates of your springs are. You can waste a significant amount of cash just throwing some “stiffer springs” on your Alfa. I would recommend that you start with a spring rate of about 1000 to 1200 front and 150-170 rear. If you call around to the numerous purveyors of Alfa Springs, you should be able to find something close. My favorite spring set up for a competition GTV is a set that I had wound at 1150 front and 160 rear. I always hesitate to tell a driver what springs to use as I can set a car up for myself and put some other driver in it and he or she may not like certain aspects of the package. If you want a good starting point, International Auto Parts, Centerline and Alfa Ricambi, as well as others, supply well thought out spring and sway bar packages.

V6 Oil Consumption : question by Penn Mckay | ’92 164QV

I've had 2 Alfas with the V6 motor, & both have been fond of oil, although there is never any visible (smoke) sign of this appetite.

The first was a GTV6 which ended up with something over 240,000K on the clock, was never opened and never needed to be but consumed oil at a steady rate.

My 164 I bought at a genuine 60,000K & it too is a steady consumer of oil. No matter whether I use synthetic or mineral oil.

In neither case was there any indication that the motor had anything wrong with it, they just drank it steadily - about a litre per 500 miles or so.

I've not worried about it but I'm curious as to whether or not they all do it.
Answer : Yes, the Alfa V-6 has been know to belly up to the bar and slug down a few Liters of Mobil 1 now and then. It is an odd thing how they don’t appear to smoke. I put it down to the heat of the cat and the angle of the tailpipe. If it is not leaking on to the ground, into the cooling system, or coming out of the exhaust, it can’t be using oil, right? It can’t just be evaporating.

Chances are that it is getting by the rings or valve guides. Brilliant conclusion don’t you think? The point I am trying to make is that we aren’t dealing with the supernatural here, the laws of physics apply even to Alfa Romeos.

It’s nice to see that you aren’t worried about it, very nice healthy attitude. I have had good results with Hastings piston rings. Normal oil consumption after a rebuild has 10-15K on it is around one quart in a thousand to fifteenhundred miles.

V6 Plug Well Leaks : question by Robert B | ’91 164 S

I have an oil leak in the engine, which covers my spark plugs and renders them useless in about 2 weeks or so. I was wondering how much it should reasonably cost me to rebuild the engine, or should I just rebuild the heads. Please get back to me as soon as possible. Thanks
Answer : Do not, I repeat, do not rebuild your engine to cure spark plug wells from filling with oil!! Remove the cam covers and replace the spark plug well seals.

Spider Trans Popping Out of Gear : question by John Whitfield | ’89 Spider Graduate

I had a mech replace my synchros on my tranny, and replace my rubber bushing mount. She now pops out of 2nd on deceleration. The gear shift lever seems to hit the plastic interior trans cover. If i hold lever down she stays in gear. I have new motor mounts on her. Could my trans mount be upside down? She seems like tranny is sagging. Or do I have internal probs with trans?
Answer : Sounds like it is possible that the Trans mount is in upside down, however I have seen many Spiders with totally collapsed rear mounts that weren’t popping out of gear. It's easy enough to find out. After verifying that the rear mount is installed correctly, Check to make sure that when 2nd is engaged the lever is not hitting the console, as this could cause the Trans to jump out of gear. If the console were hitting the lever, you would expect to see the Trans jumping out of 4th and Reverse as well. If all this checks out, you probably have an internal problem with the trans. From your account it sounds like it wasn’t jumping out of 2nd before the rebuild. The possible culprits are a weak or improperly installed detent on 2nd gear or a worn or improperly adjusted 1-2 shift fork.

RML Ignition Coil Problem : question by Clark Daily | ’77 Alfetta GT

I have an RML electronic ignition system in my car. When I start and drive it, it's fine. Once I get on the highway and maintain a speed for about ten minutes, it begins to miss and it gets progressively worse. It will continue to run however. When I get to my destination, my coil will be extremely hot. I've checked grounds and connections but can't see anything that is wrong. Voltage regulator and alternator seem to be functioning correctly. I have new Magnecore plug wires, new cap and rotor and spark plugs. I can see that it is not a fuel problem due to the fact that I can see the spark miss with a timing light hooked to any plug lead. Is the coil getting too much power? I put a high performance racing coil in and the problem seems to have gone away. But the system shipped with a regular BOSCH coil.
Answer : I have used several different flavors of RML ignition systems and have always found them to be of the highest quality and very well engineered units. The symptom you describe does point to ignition, but I do not believe it is due to any problem with the RML unit.

Just so we are all working on the same page, it is important to remember that the ignition module does not produce any spark itself. All it does is read the low voltage signal, produced by the distributor trigger, be it magnetic or optical, then amplify that signal, and tell the coil when to discharge its stored energy.

I would check, with a volt ohmmeter, the voltage at the coil and at the Ignition module. Also check that the unit is properly grounded. Because you replaced the coil and the symptom has been alleviated, I suspect that you found the problem.

I didn’t remember seeing a RML unit with a Bosch coil, so I contacted them. They informed me that RML units do not ship with Bosch coils and, in point of fact, Bosch coils will overheat and not work well with their module. I suspect that somewhere along the line a Bosch coil was swapped for the one that shipped with the RML unit, thus the miss and heat. Also, remember that the ballast resistor must not be installed in order for the coil to function correctly with a RML system.

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