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Tech QuestionsJune 2001 Tech Q & A

Answer by Technical Editor Rex Chalmers


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June Topics:

Electronic Ignition Upgrade | Steering Box Rebuild | 2 Liter Piston Rings |
Front End Shimmy | 17" Milano Wheels | Modifying Distributor Advance

Electronic Ignition Upgrade : question by Ben Clauss | ’74 Spider

I would like to changeover the ignition system to a modern electronic unit. I Plan on replacing everything form the distributor to the coil. What are my options and what do you recommend?

Answer : There are several options available to Alfa owners who want to convert to electronic ignition. Because you plan on replacing the complete ignition system, I would take a close look at the systems available from Alfa Ricambi and RML's Performance Ignition. Both units are complete with coil and distributor. Alfa Ricambi’s system uses a converted for Alfa use Bosch / VW distributor and a high performance Bosch coil. All the electronics of the Ricambi unit are part of the pick-up inside the distributor. Performance Ignition’s system is a bit more high-tech as it uses an external ignition module, a high output coil, and an optical trigger. Either of these systems would be a good choice for a street Alfa. Alfa Ricambi’s system has the benefit of no external spark box and a lower price. RML’s Performance Ignition system delivers a more accurate and higher energy spark. I have used both units in high performance Alfa engines that with red lines around 7500 – 8000 RPM with no problems. RML’s unit can be bought direct from RML or through International Auto Parts. If you have a good distributor that you want to use, Alfa Ricambi sells their system separately, International sells a unit from Crane. My personal favorite is a little known system called Luminition. Luminition makes several units from mild to high voltage, variable dwell units with programmable rev limitier. A Luminition retailer can be found by contacting Import Products at 1-800-366-5955. Whatever system you choose, it will lengthen the time between tune-ups, improve performance and fuel mileage.

Steering Box Rebuild : question by Greg Mack | ’74 GTV

I'd read somewhere that it's possible to reshim the steering box (Burman, I think) on my gtv. It's got a fair amount of slop and I wonder whether reshimming is a job for a guy with modest mechanical skills.

Answer : I would not suggest that the owner with modest mechanical skills attempt to repair a Burman steering box. Before you do anything else, pull out the cotter pin from the big nut on the bottom of the box and check the torque of the nut! I have seen literally hundreds of loose Burman steering arm nuts. Next check all the tye rod ends, idler arm bushing play, the torque of the nuts that hold the idler arm box and the steering box to the chassis. Also check the chassis for fatigue cracks. These cracks most commonly appear in the chassis just behind the steering box. If the only problem is excess on center play in the box, it is possible to remove shims from the tension adjuster plate to try to take out some of the play. Check the shop manual for the procedure. If this procedure doesn’t cure the play, or if you have other concerns about the box, take it to a professional for repair. The Burman steering box is one of the best steering boxes that I have ever seen in a mass produced vehicle. The only problem that occurs with any regularity with a Burman box is that the shaft bushing and seal tend to fail after 10-20 years of faithful service. I have seen many a Burman box last for hundreds of thousands of miles and many others ruined by lack of lubricant and improper adjustment. They are no longer available as new units, and the ZF replacement just doesn’t give the same response and road feel. So look after your Burman boxes, keep them adjusted and full of lubricant.

2 Liter Piston Rings : question by Bill Richards | ’74 GTV

I am rebuilding my engine and have discussed with others (with varying opinions) the advantages of using after market rings (Deves or Hastings, $$$) in place of the OE rings supplied with ATE piston and liner sets. What is your opinion/experience with these upgrades for both oil and compression rings?

Answer : There are many brands of rings available for most Alfa bores and ring widths. The OE Borgo/AE rings work quite well. I don’t believe that there is any reason to not use the top two ring sets that come with the pistons. They are of very high quality and provide a very long useful life. They will far outlast the life of the OE oil control ring. The Borgo/AE ring is a very low-tension design and provides very low drag, is free revving and makes good horsepower. That said, I prefer using Hastings, Total Seal or Sealed Power for the oil ring or as a whole set. That’s because these rings, although they have a slightly higher tension, seal better, don’t loose their tension as fast as the OE oil ring and therefor have a longer useable life.

Front End Shimmy (2 questions on this topic):

question by Bruce Testa | ’87 Milano

I've owned this car for over 2 years and use it April - December. The car suffers from a shimmy felt in the steering wheel and on the dashboard at the 50-mph mark. I t dissipates above 55mph. I have balanced the wheels twice and I have replaced one of the front wheels which was bent. One rear wheel has a small blip on the inner rim but it has been balanced. Lower tire pressure reduces the shimmy as does hot weather. I have had the front end checked and re-checked by a good Alfa mech. The tires came with the car. They are Cooper mid- range with plenty of tread. I am using them at a low tire pressure 22lbs and 24lbs. I have heard that tires can compromise their shape and cause a shimmy. Any ideas?

question by Steve Gumerman| ’94 164Q

I am having a very frustrating mild shimmy of steering wheel at 35 to 40 mph - some times it’s higher, and it comes and goes. I have had tires and wheels balanced, the suspension checked, and even had a slightly bent wheel replaced with another stock wheel. The car now rides better, but mild shake is still there.

Answer : Neither the 164 or Milano have chassis that are hyper sensitive to wheel balance. If you had your wheels balanced, rotate the tyres front to back. If there is no change in the vibration, there must be a mechanical problem with the suspension bushings, tye rods, steering rack, rack bushings or mounts or with some other mechanical component between the tyres and the steering wheel. There is also the possibility of chassis fatigue or cracks. The fact that both of these vehicles have a relatively short period of vibration points to wheel balance, a slightly bent wheel or flat spotted tyre as the root cause of your concerns. An out of round tyre, tread separation or belt de-lamination are also possibilities, but would usually give a more pronounced vibration. An experienced technician can spot tyre and wheel problems fairly quickly just by watching the wheel rotate on the balancer. I would talk to some folks in your area who participate in Motorsports and ask them who balances their tyres.

17" Milano Wheels : question by Martin de Campo | ’88 Milano Verde

I'd like to put BBS RS wheels on my Verde, preferably 17 inch ones, however BBS only makes wheels that'll fit 5 lug VWs. Anyway these could be altered to fit the 5x98 lug pattern of my Verde? Would it be dangerous?

Answer : Putting 17-inch wheels on a Milano would severely limit turning circle and wheel well clearance; it would also compromise the ride and significantly shorten bushing and ball joint life. Yes, it would probably look real cool, or, on the other hand, it could look like hell depending on the style of wheel and aspect ratio of the tyres installed. Beauty is in the eye of the beholder. Of course that ‘s just my opinion, I could be wrong. To answer your question, depending on how far off the bolt pattern is, a competent custom wheel store could modify the bolt circle to fit the Alfa lug pattern. As long as the work was done correctly, I wouldn’t worry about the safety. Custom wheel shops are aware that civil liability lawyers are always trolling for a good case.

Modifying Distributor Advance : question by Ron Thiel | ’ 69 Berlina

What is the optimum ignition advance for the 1750 engine modified as follows: compression ratio 10.4 to one, over sized intake valves and seats, ported and polished, cams -Alfa Ricambi AL 5418a, 40 DCOE carbs, headers, Crane cam electronic ignition, Bosch distributor?

How do you modify the distributor to achieve the desired timing curve?
Answer : It is damn near impossible to give you the exact advance that will be the optimal correct setting for your engine. 1750 engines generally like max. Advance setting somewhere between 36 and 40 degrees. The type of driving you do, as well as your mixture, jetting, venturi size, coolant temperature, actual compression ratio, spark plug heat range, advance curve, and time spent at full chat in top cog can all have a bearing on where your optimal max. advance setting will be.

If this vehicle is used primarily for time trial and competition purposes, the max advance can be set where you determine is best for your motor. Disregard the advance curve, because if a competition motor is tuned correctly, with the correct transmission and differential ratios, the distributor will always be at max advance except when it is exiting or entering the pit lane.

Re-curving of a distributor is accomplished by changing advance springs and in cases where more max advance than the distributor has built in is required, the advance weights need to be modified. I would suggest that you seek out the services of an engine dyno, if the engine is still out, or a chassis dyno if the engine is installed and set up the carbs and ignition on the dyno. Trial and error can work, however it should only be performed by an experienced tuner. A degree or two too much advance can be extremely costly.

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