Project 164 Part 8

The Factory UNauthorized guide to Head Removal

by Brad Anesi


For years, Alfa Romeo engines have been known for having problems with blown head gaskets. This legacy does not come entirely undeserved; the initial multi-piece gasket used on the 2.5 liter V6 was an inferior design, and was very prone to failure. As Alfa rolled out the 3 liter V6 in the late eighties, they changed to a more typical one-piece design which has proven to be much more reliable. Nonetheless, failures can still occur. The wet cylinder-jacket design of the Alfa V6 places a greater sealing requirement on the head gasket than is found on most other engines. A properly maintained motor should never have a failure. But in the real world, oil and coolant changes sometimes get neglected; engines can sometimes overheat (for a variety of reasons); all potential causes of a head gasket failure.

The Diagnosis

Unlike head gasket failures on most motors, the Alfa V6 does not typically lose compression when there is a failure. This is a mixed blessing. A car with a failed head gasket could be driven for thousands of miles without any loss of power to alert the driver of the problem. This is why two checks should always be performed whenever the hood is open to check for internal coolant and oil leaks. Oil leakage into the coolant is checked by looking inside the plastic coolant header tank. An oily film riding atop the coolant is cause for concern. Coolant leakage into the oil can very easily be detected by checking the back of the oil-fill cap. The presence of something that looks like dirty mayonnaise is the byproduct of overheated coolant trying to lubricate your motor.

Of the two aforementioned failures, oil leakage into the coolant is the less severe of the two failure types. In fact, I have heard of some instances where a minor oil leak has cured itself and never re-appeared. A coolant leak however, is cause for greater concern. Water and glycol (coolant) do a terrible job at lubricating the internals of a motor. If enough coolant were to leak into the oil reservoir, any number of parts could be lubricant-starved, resulting in excessive heat and wear. Just recently I heard of a 164S which was driven for several thousand miles with a coolant leak. The result was a worn bearing on the "bottom end", requiring a complete motor rebuild.

For causes I will never be entirely sure of, I found an unhealthy dose of "mayonnaise" attached to the back of my oil cap this past Spring. Although I had planned on pulling the heads at some point in the future for overhaul and upgrade, I now realized that time had come a bit sooner than planned. A quick study of the service manual was made (don't try this job without one), and a weekend was scheduled with my helper (thanks Dad), to remove the heads.

Procedures

Much like the clutch R&R project discussed in the previous article, an assessment should be made of what other major services may be due for attention. If you have the space and equipment, removal of the entire motor is not much more involved than removing the heads with the motor in the car. In my case, I had neither the space or motor hoist, so the job would be done with the motor remaining in the car. First, some general suggestions for a successful project:

Taking a similar approach as the previous articles, I'll only discuss where my experience supplements or varies from the factory approach discussed in the service manual. The important thing to understand up front is that the most challenging aspect of this project is the removal of the right (rear) head. The location of the mount for the torque-reduction rod, compounded by Alfa's use of head studs (rather than bolts), makes removal of the right head a challenge. Because of this configuration, the entire motor needs to be pivoted forward (to clear the torque-reduction rod mount), as the head is pulled up above the head studs. To accomplish this maneuver, the service manual suggests disconnecting the left half-shaft and removal of the motor mount underneath the gearbox (after a padded jack has been placed under the oil sump). If you have an air wrench, removal of the allen bolts securing the half shaft is a quick and painless process, and is highly recommended. But there is an alternative... The right head can be removed with the half-shafts left in place if the following alternate procedures are followed:

  1. Remove both front motor mounts entirely (again, make sure a jack is under the motor first).
  2. Unbolt (do not remove) the rear motor mount.
  3. Jack up the front passenger side of the car body
  4. Carefully cut the top 1/4" (NO MORE!) off the two head studs located closest to the passenger side and thoroughly file the newly burred edges BEFORE removing the head. It goes without saying (I hope) that before endeavoring to do this, you will need to fully protect the valve train and oil pump from any metal shavings with a towel. The objective of this whole exercise is to save the head surface from damage by supplying adequate clearance. I'm sure some will call this approach a "hack" and/or unnecessarily risky, but if done carefully and properly, it may actually be a safer way to avoid damage to the head surface (especially important upon re-installation). Note: If you will be replacing the clutch at the same time, removal of both half-shafts is a requirement, and will allow much greater free movement of the motor, eliminating the need for steps 3 and 4. (Incidentally, this is the approach I took, and it is certainly preferable to cutting the studs)

Having now addressed the tough part, here's some other points which may be of use to you in completing this job:

High Performance Head Overhaul

With the heads removed, my attention now turned to wringing more horsepower from the Italian cast aluminum. After quickly studying my options and choice of vendors, I opted for new S cams and mildly ported heads by Dennis Black (spdfact1@aol.com / (508) 966-3100). The S cams (as found in the 164S), provide higher valve lift and longer duration, which in turn, generates more power from the same 3 liter displacement motor. Rather than opt for a full port and polish of the heads, Dennis suggested porting out just the valve-bowl area of the heads, which is where most of the air-flow restriction is found on the factory casting. For half the cost of a full port and polish, this approach yielded most of the gain which can be realized from these heads while still retaining the stock size valves.

While "go-faster" parts are always nice, "last-longer" parts allow the practical justification we all need to feel better about our expenditures. The new exhaust valve guides Dennis was able to use fall into the latter category. Anyone who has ever worked around Italian cars knows they tend to wear out exhaust valve guides much sooner than anyone would like, resulting in noisy valves and burned oil. Well finally, Alfa (or should I say Fiat?), got the message and developed a new alloy for these guides which has proven to be much longer lasting than the bronze alloys used in the past. In fact, these new guides are now used throughout the range of new motors being produced in Italy, and have just started to become available as a spare part. Time will tell of their effectiveness, but over the first 1000 miles I've driven my "new" car, oil consumption has been near zero.

The cost for the complete performance overhaul of both heads amounted to about $850, including parts (except the S cams, which added another $500). The overhaul included a number of details designed to enhance performance (3-angle cut valve seats, blended seats, polished rocker shafts/valves), as well longevity upgrades such as the aforementioned valve guides.

The Results

From the moment this new motor was started, it was obvious I had a different beast under the hood. The exhaust note was a bit "throatier", the idle just a bit lumpier. Once on the open road, acceleration is more rapid and the motor shows no sign of topping out as it roars to red-line. While most of the power increase comes at the upper RPM range, there is little decrease in low-end grunt, as sometimes occurs with more aggressive cams. The upper speed limits of this 4-door speed-sled are still yet to be found, as I suspect they'd catch the notice of the authorities ...even in Montana.