Alfa Romeo brake system overhaul, Part 3

In Part 2, we covered the ongoing caliper overhaul, both front and rear. While waiting for the caliper rebuild parts to show up, I decided to remove the rear rotors and inspect the parking brake set-up.

Left rear disc, caliper, and brake line

Similar to what Volvo has used for decades, the rear rotors sit over a set of drum brake shoes which apply to the inside of the rear disc “hat”. On the Alfa, these are cable-operated. It was always gratifying that my car’s hand brake worked, but it required a significant tug of the handle to engage.

First challenge was removing the two slotted-head screws holding each rear rotor to the hub. An ordinary screwdriver wasn’t getting the job done, so I resorted to one of my favorite tools: my Snap-On hammer-driven impact driver. A long time ago, Andy Finnegan, the shop foreman at the first Volvo dealer that employed me, suggested this tool to me. While I infrequently use it, it’s one of those tools that makes you glad you have it for the occasions you really need it. This was one of those occasions.

The right tool at the right time can save hours of time and frustration – note slotted screw in rotor face

A few taps with a hammer, and the screws were loose (I also bought new replacements on the chance that I would mangle the heads during removal.). But getting the disc off also required a few heavier hammer blows. Eventually, the rotors were off, first on the driver’s side, then the passenger side.

It would not surprise me if I were the first person to expose the parking brake shoes since this car left Italy. Remember that when I bought it, the car has 54,000 original miles. I also have reason to suspect that the rear brake pads were original to the car. There has likely been little need to check or service these components.

With some effort, I removed the brake shoes on the driver’s side (access is conveniently limited by the hub). The arrangement is typical, with a star wheel for adjustment, and two springs holding the upper and lower shoes. A cable extends from the differential through an access hole in the backing plate, pulling a lever which spreads the shoes. After taking the one side apart, I decided to leave the passenger side intact for reference, and ordered all new parts from Classic Alfa.

Old shoes and springs will be replaced

It was also time to remove the master cylinder. With its so-called “standing pedals” hinged through the floor, my ’67 is one of the last Giulia coupes so configured. Within a year or so (varying by model), Alfa would switch to “hanging pedals” and mount the master cylinder in the conventional location on the firewall.

Standing pedals – accel pedal has been removed

I desperately searched for guidance on the Alfa forums for “master cylinder removal”, but nothing I came across addressed the underfloor location. So I tackled it on my own, and really struggled with it. There are two bolts which pass horizontally through the master cylinder, and these bolts mount into a plate that also holds the clutch linkage. Said plate didn’t look removable to me – that’s from the vantage point of lying on my back, with my nose about 3 inches from the car’s underside. Without removing the plate, there wasn’t enough clearance to remove the bolts. Through sheer luck, I wiggled the cylinder and the bolts and got the master cylinder cleared. But I’ll need to investigate this plate when it comes time for reinstallation.

View of master cylinder while on my back

There was also the matter of the two brake lines, both of which thread into the top of the cylinder. There was little choice but to loosen and drop the cylinder to give me access to the line fittings, but then I lost the leverage one gets from a master cylinder firmly bolted to something.

Brake fluid reservoir on firewall is where you’d expect to find m/c – note hard line which feeds it

Using my flare nut wrenches, the first fitting came out easily. The second one did not. I resorted to using a cheater bar (a length of pipe) on the wrench, and for the first time during this brake overhaul, the wrench slipped on the fitting and rounded it off. The fitting was seized. I cut the line with a pair of diagonal cutters, and the master cylinder was on my workbench. In a bit of good news, the fitting did come loose once I dropped a deep 6-point socket on it.

Master cylinder – note severed line and fitting in right-most hole

There is plenty to do next: finish the rebuilding of the two rear calipers, renew the parking brake parts, and rebuild the master cylinder. Parts were duly ordered and are on their way.

… to be continued ….

 

All photographs copyright © 2019 Richard A. Reina. Photos may not be copied or reproduced without express written permission.

 

 

Alfa Romeo brake system overhaul, Part 2

As you read in Part 1 of the Alfa Romeo brake system overhaul, the new front calipers I had purchased, through no one’s fault, didn’t get the job done. It was just as well; in an attempt to get my car ready to drive to the AROC Convention in Pittsburgh, I was hurrying through the job, which is no way to work on a braking system. If anything, the inability to make the car roadworthy gave me just the excuse I needed to do the right thing.

 

I had purchased this car in 2013 from my friend Pete. He bought it in 1968, drove it for perhaps five years, mothballed it for over 20 years, then took it out of long-term storage. After refreshing various systems, including the brakes, Pete enjoyed the car for about 10 years before handing over the keys. In my mind, this Alfa had been “recently” refurbished. However, once I added up the years and the miles, I realized my own miscalculation. At best, Pete worked on the brakes around the year 2003, meaning, the brake fluid alone was now 16 years old. Shame on me! Since I loved driving the car, I wanted 100% confidence in its brakes, so The Right Thing meant a complete overhaul: rebuilt calipers, new or rebuilt master cylinder, and new lines and hoses. I got all 4 wheels up off the ground, drained what little fluid remained, and brought both front calipers to the workbench.

Caliper with piston, dust boot and spring in place before removal

First, the dust boots and their retaining springs had to be removed. The springs were so rusty that it was difficult to see them against the boots, but with a little urging from a dental pick, they popped off. The boot for the seized piston looked like it had been on fire (it almost was), and this early discovery reinforced that this overhaul was necessary and overdue.

 

Dust boot and rusty old spring on their way off

 

This dust boot is ready for the trash can

 

I’ve rebuilt calipers before, as a Volvo tech, but it wasn’t a job we did very frequently. All 4 of my car’s calipers are of the two-piston fixed type, and research from my Alfa library led me to conclude that there was no need to split the calipers. The pistons could be removed with compressed air, and the bores cleaned up as necessary.

 

This 2-piston caliper has 1 piston behind each pad. It is “fixed”: the two halves are bolted together.

Starting with the seized right front unit, my technique was to start by pushing the pistons back into their bores with a piston compression tool. The reasoning is that any movement is good movement. Once they were fully retracted, I hit the fluid passage with compressed air, and both pistons moved outward a few millimeters. The cycle was repeated: retract pistons, apply air; retract pistons, apply air. Finally, one piston popped free.

At the start, piston retraction tool was used to push pistons all the way back

 

Compressed air is good stuff

 

But now I had a problem: the compressed air escaped from the now-empty bore, and did nothing to move the piston still in place. I reinstalled the removed piston, but the same thing happened: one piston came out, and one stayed in. I needed a way to block the fluid passages without fully reinstalling the first piston. Stuffing rags into the bore did nothing.

C-clamp is employed to hold 1st piston while compressed air dislodges 2nd one

Here’s how I did that: lubing up the piston with brake fluid, I reinserted it just a few millimeters back into its bore, enough to block air flow, but not so much that I couldn’t pull it out by hand. I held this piston in place with a C-clamp, so the force of the air would blow out the 2nd piston. It worked! The 2nd piston shot out, and once I removed the C-clamp, the 1st piston could be worked out with my fingers. With the pistons out, the inner seals were easily coaxed out with a dental pick.

Removal of the inner seal

A close examination of the pistons revealed that one had a mark along its surface. My local Ace Hardware store had 3M brand emery cloth which I bought in medium, fine, and super fine grit. While I couldn’t completely remove the nick, I smoothed it out so that it couldn’t be felt. The front lips of the pistons showed marks from pliers or Vice-Grips, so someone (not me) got aggressive with a prior piston removal attempt. Thankfully, the marks would not affect the braking performance.

The bores themselves showed some minor corrosion along the outer edges, but the insides (below the inner seals) weren’t bad, and the super-fine emery cloth made them even better. While this was going on, the rear calipers were unbolted and disassembled so that I could measure the piston diameter. According to my supplier, Classic Alfa, this generation Giulia used either 30mm or 36mm rear pistons, and of course, one needed to know before ordering parts. It turned out that my car has 30mm pistons. I placed my order with my favorite Alfa supplier, knowing that I’d have the parts within 48 hours or so.

 

 

Pistons before (left) and after (right) emery cloth treatment

 

Nick in surface could not be removed, but was minimized. Note pliers marks.

 

Rear caliper piston confirmed as 30mm

 

… to be continued …

 

All photographs copyright © 2019 Richard A. Reina. Photos may not be copied or reproduced without express written permission.

 

 

Alfa Romeo brake system overhaul, Part 1

Now, the full story as to why I was not able to drive my Alfa to this year’s AROC (Alfa Romeo Owner’s Club) annual convention in Pittsburgh can be told. In my initial post about the convention, I wrote:

Let’s get this bit of disappointing news out of the way: while this Alfista was in attendance, his ’67 Alfa GT Junior was not. Four days before the scheduled departure, the car’s right front brake caliper locked up, and although repair parts were obtained, there wasn’t enough time to effect a safe and sufficient repair. So the green stepnose stayed home.

This is what happened: Four days before we planned to leave for Pittsburgh, I drove the Alfa to my friend George’s house. George (Geo to his really close friends) lives just five miles away, and while he was excited to join in the weekend’s festivities, he had never driven my car before. I thought it only fair that he have a crack at it before we commenced on a 6-hour journey.

As soon as I pulled out of my garage that morning, I sensed that something was amiss. The car seemed a little down on power, and it pulled to the right. Other than that, it drove OK, so I pushed onward. The moment I entered Geo’s driveway and killed the engine, smoke emanated from under the closed hood. I popped the hood but saw nothing obvious. When Geo came out, I explained what had happened, and we both decided to let him drive the car, if only for 2 or 3 miles.

Once Geo got the car back to his place, the smoke returned, only this time, the source was clear: it was pouring off the right front brake. Hindsight made the drifting and low power obvious: this brake caliper was seized. I was lucky we weren’t seeing flames.

We pulled the wheel and there was nothing visibly wrong that we could try to fix on the spot. Putting the wheel back on, I reasoned that I could “carefully” drive the 5 miles back home, and work on it there. As soon as I bade Geo ciao, I started the car, put it in first, and headed down his driveway to the street, where I would need to turn left. Hitting the brake pedal, it sank to the floor. Thankfully, my parking brake (sort of) works, and I used it to stop at the bottom of the driveway. I backed the car up the drive, and started to figure out what Plan B looked like.

Geo couldn’t understand the loss of the pedal. I reasoned that the heat had caused the fluid to boil. Sure enough, 15 minutes later, a firm pedal returned. But I wasn’t driving this car home. There’s a reason I carry an AAA card. I called, they said one hour, and the truck was there in 90 minutes. In seven seasons of ownership, and in over 11,000 miles of driving, this car has never ridden on the back of a flat bed – until this brake failure. But the risk in driving it wasn’t worth it.

 

There’s a first time for everything

While waiting for the truck, I had time to calculate how I was going to get this repaired by Friday morning, just a few hours shy of four days away. My go-to Alfa parts supplier, Classic Alfa in the UK, was still open, if barely. I had always placed my orders via their website, never by phone, and this seemed like a most valid reason to spend the money for an international call. Given their stellar shipping reputation, I could have the parts by Wednesday, which I reckoned would still allow enough time to make a repair.

I called. ‘Chris’ answered. I explained my dilemma and asked him about my options. He quickly offered the choice of either remanufactured (reman) ATE calipers, or brand new ones. I asked him for the price difference, and he replied about 20 British pounds (approximately $25 thanks to the Brexit-depressed value of the pound). I figured that the small differential between new and reman made the new ones a deal, so I ordered a set. Since a core return wasn’t required, I asked Chris to include a caliper rebuild kit, thinking that I would eventually refurbish the old ones. It was now close to noon on Monday in New Jersey, and Chris said I should see the parts by late Wednesday.

Chris was wrong. The parts were in my hands at 5:30 pm ON TUESDAY. This was a miracle, and I presumed that the boys in the UK pushed the order through, having heard that I was planning on driving this thing to the U.S. Alfa convention in 4 days. So far, so good.

Shiny new caliper, ATE-like

Opening the box, the first disappointment was to discover that while these were certainly new calipers, they were not marked ATE, and I had to conclude that they were ATE copies. I unbolted the offending caliper, and an eyeball comparison proved that the new one was identically shaped. All I had to do was swap over the pads, connect the hard brake line, and bleed the system.

Right front rotor shows slight scoring, looks salvageable

With the existing pads and pad hardware installed, I knelt at the right front knuckle, held the 11 pound caliper in my right hand, and began to thread the brake line fitting into the new caliper with my left hand. The threads would not start. I tried every trick I knew; after perhaps 20 minutes, it felt like the threads had started, but I was unable to turn the fitting by hand more than half a turn. Of course, the dreaded fear is that I might cross-thread it, and ruin the caliper and/or the brake line fitting. After another 20 minutes, with blisters forming on the pads of my fingers, it felt again like it started. I picked up the flare nut wrench, and slowly, carefully, brought the fitting all the way down. It was about 8pm on Tuesday night. I was drenched, from both the 100% humidity and the nervous energy.

Flare-nut wrenches (this fitting is 11mm) indispensable for brake line work

The next evening, I removed the (good) left front caliper, and, convinced that the previous night’s issues were behind me, went through the same routine: swapped the pads, held the caliper up to the knuckle, and began to thread the pipe fitting. SAME PROBLEM. Desperate, I removed the hard line from the car, and brought it and the new caliper to the workbench, where I wouldn’t need to struggle with the caliper’s weight. I never came close to getting the threads to start.

New caliper looks great, too bad it leaks

I rationalized: I have the new caliper on the right front, to replace the known bad caliper. Certainly, I can keep the existing left front caliper in place and drive the car a few hundred miles. The left front caliper was reinstalled. Geo stopped by to assist. We were ready to bleed (the brakes, not us). I filled the master reservoir, asked Geo to climb in, and we began the “pump, hold, release” routine of manual brake bleeding.

There was a drip at the fitting at the right front caliper.

Reluctantly, I put a wrench on it and got another 10-15 degrees in clockwise motion. The bleeding resumed, and so did the dripping. I told Geo that we were done. While I did have the rebuild kit, it was now after dark on Wednesday, and I was out of time, patience, and confidence. Working on a car under such duress only encourages poor decision-making, unnecessary shortcuts, and botched repairs. My only desire was to enjoy the AROC convention, knowing that I would resume this wrenching at an unhurried pace upon my return. The new calipers would go back to Classic Alfa as defective or unusable.

… to be continued …

All photographs copyright © 2019 Richard A. Reina. Photos may not be copied or reproduced without express written permission.

AROC-NJ Hosts Luncheon Event, April 13, 2019

The New Jersey Chapter of the Alfa Romeo Owners Club (AROC), under the able leadership of Chapter President Enrico Ciabattoni, held its first event of 2019 by organizing a luncheon on Saturday April 13. Our hosts were the fine folks at Driving Impressions, a Dover N.J.-based business which sells racing accessories in the front, and has ample garage space out back.

Nice SWAG in Driving Impressions’ retail store

We had a small but enthusiastic turnout of about a dozen, consisting of a mix of AROC-NJ members with some local friends. The lunch (Italian food, whaddya expect?) was grand, but we were really there to get together to talk about our #1 passion, cars. There was lots to talk about, starting with the cars on either side of the lunch table. The service bays were occupied by Italian cars OTHER than Alfas, and there were interesting non-Italian toys too.

Love Italian food? Check. Love Italian CARS? Two checks.

One corner of the garage is rented to a tech who specializes in Porsches. A 928 with its drivetrain removed was high up in the air, and next to it, on the ground, was a 356 coupe which appeared to be in original condition. It actually gave off the vibe of one of those barn-find 356s I’ve seen at auctions that hammer for 300 large.

A 928 in for service. Not for the faint of heart or the light of wallet.

 

 

This Porsche 356 coupe appeared to have never been restored

 

Interior of the 356

 

Three Italian cars competed for my attention: a current-generation Fiat 500, with turbo and other goodies under the hood, claimed to be the fastest 500 on earth (based on a magazine article I was shown, so it must be true); a Fiat 600, with its cheeky water-cooled four-banger out back, appeared to be in the throes of major reconstruction; and a Lancia Delta Integrale, all ‘80s squared-off inside and out, lounged in the corner, looking like it was daring the turbo 500 to a duel.

Fiat 500 racecar

 

A Fiat 600 in for a refresh

 

A quick peek outside revealed the 3 classic Alfas which dared make today’s drive. It stayed warm and dry, so it was an ideal day to cruise in our classics. Alas, no modern Giulias or Stelvios made the trip.

Alfa Romeo Spider

 

Alfa Romeo Nuova Super 1600

 

Alfa Romeo GT 1300 Jr

With the AROC National in Pittsburgh fast approaching in July, there was some discussion among the Alfisti about who was attending, who was driving there, and who might want to caravan. Your author has volunteered to lead the caravan; now I just need someone to agree to join it.

In spite of the relatively small turnout, it was a great day. First, we all needed to shake off the winter cobwebs (from ourselves as well as our cars). We also want to continue with local events as we gear up for summer (and July at the AROC Convention, which will be held in conjunction with the Pittsburgh Vintage Grand Prix). Stay tuned for more exciting Alfa events as the year progresses.

 

Italian and non-Italian friends play well together

 

All photographs copyright © 2019 Richard A. Reina. Photos may not be copied or reproduced without express written permission.

The Alfa Gets Its 2019 Tune-up

When I bought my Alfa Romeo GT 1300 Junior in March of 2013, it was for the express purpose of using it to participate in automotive events. There’s no denying that I have piled on the miles. The four New England 1000 rallies of 2013, 2014, 2015, and 2018, the Alfa National (International) excursion to Montreal in 2017, and two trips to the Greenwich CT Concours have accounted for the bulk of the mileage. Add to that the innumerable local breakfast drives and car shows, and you can understand how in 6 years of ownership I’ve managed to spend 11,000 miles behind the wheel of this fine Italian automobile.

 

Bosch rotor, unlike ones I serviced on Volvos, uses a set screw to hold it in place.

 

Old rotor showed tip wear, but appeared normal to me

 

Alfas, and Italian cars in general get a bad rap as “unreliable”. That’s not been my experience. Except for a dead battery right after purchase, and a failed alternator on the ’18 NE1000, those 11,000 miles have been trouble-free. I’ve mentioned to those who ask that the more I drive the car, the better it seems to run. The other side of that coin is that, as a ‘60s European thoroughbred, the car’s mechanical state of tune must be strictly looked after; indeed, the Alfa maintenance schedule, which requires more frequent service than an American car of similar vintage, should be followed as closely as possible. This is where ability to work on your own vehicle becomes a significant advantage compared to needing to pay someone to do what is in essence straightforward service work.

C-clip holds points in place; tricky to remove and hold onto

 

Points showed rather severe pitting

After I finished the valve adjustment a few weeks ago, I noted that the idle was terrible, and in fact, it was difficult to get the engine to consistently respond to accelerator inputs. My first suspicion was the car’s ignition system, so an order was placed with Classic Alfa for the suite of tune-up parts. (And they spoiled me again, with the package on my front porch is less than 48 hours.)

Bosch rotor is different part number for 1300 compared to US-spec cars- note German “OEL” (oil)

The service books recommend removal of the distributor for service work, and it’s held in place by a single 10mm-headed bolt, so it’s easy to pop it out. Checking the usual suspects for wear, I didn’t see anything severely out of the ordinary, although the points were badly pitted, and the gap was too small.

Freshly-serviced distributor, with new points, condensor, and rotor

I ended up replacing the spark plugs, plug wires, cap, rotor, points, condenser, and, for the first time under my ownership, the coil, which looked original. The car fired right up, and as I’ve noticed immediately after prior tunes, the tip-in is magnificent. I took the car for an all-too-brief run around the neighborhood, and felt infinitely better about all the driving I’ve got planned for the Alfa for this year, especially the Alfa Club Convention in Pittsburgh in July.

In addition to replacing coil (old one here), I fabricated a new coil-to-distributor wire

The one remaining item on the tune-up to-do list is the ignition timing. If I’m reading the books correctly, the best way to set the distributor timing for utmost performance is by checking it at 5,000 rpm. At that engine speed the “M” (for “massimo” or maximum) should line up with the timing pointer. The books also recommend NOT adjusting the distributor while at 5,000 rpm, and that’s good advice.

Note to self: every year, the ignition system needs to be checked, adjusted, and renewed as necessary at the start of every driving season.

 

All photographs copyright © 2019 Richard A. Reina. Photos may not be copied or reproduced without express written permission.

Alfa Romeo Valve Adjustment, Part 2

As you read in “Alfa Romeo Valve Adjustment, Part 1” (or if you skipped your reading assignment, you can find it here), the valve gaps on my 1300 engine were out of whack, especially on the intake side. With cams temporarily removed, I measured all the existing shims, did the algebra to calculate the sizes of the needed shims, and placed my order with Classic Alfa in the UK. I was not the least bit surprised when the order I placed at 10 p.m. on a Saturday night landed on my front stoop before I got home from work on Tuesday. (I need to email them and enquire what happens after Brexit, presuming that Brexit happens.)

This magnet was very helpful in encouraging the slippery follower to come out

The following weekend, all the old shims came out, and the new shims went in, again following the “one cylinder at a time” rule I established so as not to cross-install the followers which must remain with their original cylinders. When reinstalling the cams, I could not get the timing marks between the cams and front bearing caps to line up. It made me nervous enough that I removed and reinstalled the cams a second time (remember that the timing chain remained attached to the sprockets). I finally convinced myself that once I released the bolt holding back the spring tension in the timing chain tensioner, all would return to sync, and that is exactly what happened. With the tensioner pressing against the chain, I rotated the crank and cams through two complete revolutions, and then tightened the bolt in the spring tensioner. The marks were still aligned, thankfully.

I double-checked and wrote down all the new valve clearances, and all seemed good (but read on). Since I had the spark plugs out, a new set of NGK B7ES plugs, which are in stock at my local Advance Auto Parts store, went in. With plug wires, intake plenum, and air filter hose back in place, it was time to attempt to start this baby, remembering that the engine had not been run since the car went to sleep the previous autumn. The engine started on the second try, however, there was an unhealthy miss at idle. I shut it down, and made plans for a complete tune-up, which was next on the Alfa’s to-do list anyway.

 

Never-seize coating on plug threads
Postscript: I jotted down all the “new” valve clearances, and really didn’t give them a second glance, undoubtedly presuming that everything was done correctly. Today, while composing this blog post, I noticed that my spec for intake valve #3, .450mm, was unchanged from its original measurement, yet I have no doubt that the 2.15mm shim which had been in there was replaced with a 2.10mm shim, which means that the new measurement should have been .500mm. For now, I’m leaving this alone for several reasons: valve #3 was the closest to spec of all the intake valves during the original check; testing the thicknesses of the new shims revealed that how tightly I cranked on my micrometer made a difference in the measurement (including the effect of residual oil on the shim); and I’m not yanking that cam again for 0.05mm!

 

All photographs and video recordings copyright © 2019 Richard A. Reina. Photos may not be copied or reproduced without express written permission.

 

Alfa Romeo Valve Adjustment, Part 1

The owner’s manual for my 1967 Alfa Romeo GT 1300 Junior calls for the engine valve clearances to be checked every 18,000 kilometers. According to Google Calculator (before Google Calculator I would have used my slide rule), that’s every 11,185 miles. Coincidentally, I’ve put almost exactly 11,000 miles on the Alfa since purchasing it in March 2013. So in part to prepare for what is anticipated to be a very busy 2019 driving season, and in part because I really don’t know when this was last done, I decided to check all 8 valve clearances (4-cylinder engine, 2 valves per cylinder equals 8 valves).

The Alfa engine, before any disassembly

Accessing the valves and followers is the simple part. This overhead-cam engine has its two camshafts at the very top. The valve cover can be removed once the spark plug leads, air hose, and the top of the intake plenum are out of the way, which is a 10-minute affair. The valve cover is held in place by 6 large Allen screws along the top, and two bolts at the front. I had never had the valve cover off this engine before, and my first reaction was one of pleasant surprise at how clean the engine looked.

Valve cover removed

My first task was to find the camshaft part numbers, to verify that these were Alfa Romeo cams and not some hot aftermarket replacements (in which case the clearance specs would be different). A prior conversation with Pete, the family friend who sold me the car, revealed that he wasn’t sure what cams were in it. The part numbers of both cams were readily visible, and verifying them against my technical literature confirmed that these are indeed the factory cams.

This is the correct part number for a 105-platform 1300 Junior engine (105020320001)

Now it was onto the actual clearances. To rotate the engine, I first tried getting a socket on the crank pulley bolt, but the fan shroud blocked that. The next-easiest way to spin the engine was via the nut on the front of the alternator. Popping out the plugs provided less compression resistance, and some moderate thumb pressure on the alternator belt was all that was needed to get the crank and cams to spin.

Paper and pencil at the ready, the valve clearances were checked in firing-order order (1-3-4-2) and recorded. While my owner’s manual provides specs in both millimeters and inches, I decided to stick with the metric measurements – I have metric feeler gauges, and the needed shims are sold in metric sizes.

The spec for the intake valves is 0.475-0.500 mm, and the exhaust spec is 0.525-0.550 mm. Six of the eight valves were out of spec: all 4 intakes and 2 exhausts, and, all 6 showed too little clearance, meaning the valves were not seating completely, subjecting them to less cooling since they were not making full contact with the valve seats.

The worst measurement was #4 intake: 0.350 mm, meaning it was 0.150 mm too tight compared to a correct outer range of 0.500 mm. Yes, we’re talking fractions of a millimeter, but specs are specs, and I felt that the clearances should be corrected.

Here is where it got interesting. My Alfa engine was originally designed in the early 1950s. It’s a very sophisticated layout, with not only overhead cams, but all-aluminum block, wet cylinder liners, hemispherical combustion chambers, etc. However, like most other OHC engines of its time, adjusting the valves requires removing the cams to allow access to the followers (buckets) and shims which are under the buckets. Most friends to whom I mentioned this procedure looked at me with a combination of horror and pity. “It’s really easier than it sounds” I would retort, which did nothing to alleviate their sympathy for me.

(As a complete aside, the first OHC engine to incorporate a valve design which allowed for adjustments with cams in place was the Fiat twin-cam engine, introduced in 1966. My 1970 Fiat 124 Coupe used this design, although I never did adjust those valves!)

The timing chain’s master link is to the left of center

The official Alfa procedure calls for locating the timing chain’s master link, disconnecting it, and swinging the two chain ends out of the way. This method opens the possibility that the cam timing would need to be adjusted at reassembly. Of course, some very clever people have devised a work-around. One of the service books I own is the Alfa Romeo Owner’s Bible, written by the late Alfa expert Pat Braden. He describes a method that does not involve unhooking the chain. Instead, he suggests loosening the chain tensioner, pushing the tensioner all the way IN (making for a loose chain), locking the tensioner in this position, and then lifting the cams toward the center of the engine without disturbing the cam sprocket/chain connection. In this way, on reassembly, the cam timing does not change at all. Ideally, this is done with both cam timing marks lined up with the bearing cap marks.

This is exactly what I did. With the tension off the timing chain, I started on the intake side and removed the 3 cam bearing caps (Alfa thoughtfully numbers the caps 1 through 6, and I documented everything with photos before turning the first nut). The intake cam was lifted and placed over the spark plug holes (which were protected with clean rags). The chain remained on the cam sprocket.

Cam bearing cap #3 – cap nuts were loosened gradually

 

Intake cam lying over spark plug holes- note timing chain still on cam sprocket

The next trick was getting the buckets out, as they were oil-covered and lacking a way to grab them. I realized that a magnet might do the trick, and it did. The bucket came out, and under it was the shim, which was also removed.

These slippery guys were tricky to remove!

Working on just one cylinder at a time so as not to mix up any of the locations, I measured each shim with a digital metric micrometer. The value was recorded on the same sheet of paper as the clearances. I started on the #1 intake valve, went down the line to the #4 intake valve, then did the same thing on the exhaust side. Once all these measurements were taken, the shims and buckets were back in place on the engine. I gently placed the valve cover on top of the engine, lowered the hood, and took my measurements inside so that the ‘new’ shim sizes could be calculated.

Bucket/follower (top) and shim (left) pose with micrometer

 

Starrett No. 216 records a shim value of 2.15 mm

I knew that all the out-of-adjustment valves were tight, so I needed greater clearance, so all the new shims needed to be thinner than the current shims. I found an online “Alfa shim calculator” someone built in Excel, and I used it, but I also checked all my numbers two more times. I aimed for the higher end of the spec, figuring that if the valves are tightening up over time, I had best start by providing the maximum clearance while remaining in spec.

 

Documentation of initial clearances and shim thicknesses

My go-to Alfa supplier, Classic Alfa in the UK, sells shims in increments of 0.125 mm, so it was a fairly easy task to calculate my needed shim sizes. The order was placed, and now I just needed to wait for the shims to show up. But it certainly felt like the hard work was behind me!

 

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