COMPRESSION CHECK : THE BASIC PERFORMANCE BAROMETER

In this world of increasing electronic gadjets and gizmos, some down to basic mechanical principles are to be observed. No amount of manipulation with the ECU mapping of ignition or fuel injection can compensate for weak compression, leading to power loss, high fuel consumption.

Of course, a sharp minded may ask - what is the cause for low compression ? Let me list what I can think of in a flash, in lesser degrees of severity first;

a. Incorrect valve clearance - need to re-adjust valve clearance for non-hydraulic valve actuating mechanisms. Most cars nowadays uses shims, and great skills is required, including the ability to read the micrometer.

b. Incorrect timing belt alignment - came across this problem in a Subaru XT-Turbo as it is a flat four with unconventional alignment points for both cylinder banks.

c. Particles lodged at valve seats - can be due to broken air filter allowing dust to stream thru, or excessive carbon in the cylinders causing valves not to seat properly.

d. Cylinder head distorted - due to overheating, the cyl. head may distort and throw all valve clearances haywire. Some valves may not even seat, causing blow-by. Came across this on a 73oi BMW, whose owner continued to drive with temperature at red. After coooled down, engine would not start, and I had the car towed back to my workshop, where I re-adjusted all the valve clearances.

A good indicator in-place of a compression tool may be the vacum gauge. The techniques on reading and interpreting the vacumm gauge will not be covered here, but I am sure most readers will be intrepid in searching the internet on this topic.

BRAKE SYSTEM FLUSH : BRAKE FLUID REPLACEMENT

The brake fluid is one of the most important fluid in the car, and also often the most overlooked in terms of maintenance. While some cars have a service reminder (BMW), most do not. The recommended service interval for brake fluid replacement is 2 years, or 30,000km, whichever comes first. The photo shows how the fluid looks like after 3 years of usage. The original color is clear as in subsequent photos.


Contaminants such as rust in the brake lines and caliper/drum pistons, particles from brake masterpump will darken the color over time. However, the most damaging contaminant is moisture from the environment. Brake fluid is hygroscopic, which means it will absorb moisture. It is designed that way to prevent corrosion in the brake lines, master brake pump, slave cylinders, disc caliper cylinders.


Moisture in the brake lines will cause the brake fluid to boil near the normal boiling temperature of water (100 deg. C), versus the specification for DOT 4 (about 300 deg C). Imagine going downhill from Genting Highlands, the brakes heated up the brake fluid, and the moisture in the brake fluid starts to boil. It will greatly reduce the braking performance. For this reason, heavy vehicles, such as trailers, uses "Air Brakes", which is able to withstand high temperature.

Pictured here is when the brake fluid has been fully flushed of the old contaminated fluid. Each of the four wheels brakes have to be flushed in sequence. In the photo above, I used a one-way valve to do a complete system flushing.





If the front pads are to be replaced, I would wash the entire assembly first to clear out all the accumulated dusts. This is for my own safety reasons, as well as to prevent the dusts from entering the piston via the gaps in the rubber boot.





The brake bleeding nozzle is released while the cylinder is compressed to fit in the new brake pads. If the bleeding nozzle is not released, the brake fluid in the caliper piston will be pumped back to the master brake pump, including any contaminants, when the caliper pistons is being compressed.

If the rear brakes are of drum type, the drum must be washed to remove all brake dust accumulated that will degrade the braking performance. Pictured here is the drum soaked in soap while being scrubbed clean.





The entire assembly is also washed to remove all dirt/dust/oil, to ensure 100% performance.








This is how the rear brake assembly looks like after cleaning and dried. The drum is ready to be installed.

DISTRIBUTOR REBUILT : HITACHI / MITSUBISHI

In the 1980's, majority of cars run on distributors with integrated ignition centrifugal advance and vacum advance mechanisms. This ignition timing advance mechanisms served to position the engine to repond best under speed and loading conditions. For Japanese cars, Mitsubishi and Hitachi distributors are the most popular, and they share many similarities in built and function.



While their mechanisms are almost as reliable as the Swiss watch, some maintenance is required to ensure that they perform as per specifications. The major threats to distributors are oil, dust / sand particulates. Notice how badly this one is fouled with oil leakage.





The insides of a distributor that is still in pristine condition, except for a slight wetting by engine oil penetration from outside of it's body. I called this "pristine" as the bottom looked dry, indicating that the distributor rotor shaft seal is in good condition. The shaft connects directly into the camshaft drive gear.

Another look at an aged distributor in pristine condition. This one is coming from a 1980 Mitsubishi Galant (4G32 engine).







The magnetic rotor, top actuating plate is removed to reveal a clean bottom, consisting of the centrifugal advance mechanism. When I tried to twist centrifugal advance rotor, it would not move.






It turns out that the shaft is slightly corroded, and the grease have dried and hardened, causing the centrifugal advance to be "locked" in position of zero advance.






This is how the bottom looks like after the cent. adv. rotor is removed. I had to pull it out using a bearing puller (sorry, not pictured).

After cleaning the shaft, Molybdenum grease is applied to ensure full advance is achieved when the rotational speed is increased.

A closer look at the cen. adv. rotor, which is curved with a very-very conservative ignition advance curve. Considering the weight of the car, it would be appropriate.

Finally, not the least, the distributor cap is cleaned of oil and dirt contamination before the engine is fired up. As the centre carbon has reasonable extension length, I decided to re-use the cap.

SUNROOF MAINTENANCE

Coming soon ...... one of my favorite subject.

While it is less used in Malaysia, having one "seals the deal" when used at the right time, and right conditions. A must have item to entertain the kids.

Sunroof tends to enhance the interior by creating a "bigger" space.

NAZA RIA : SPARK PLUGS REPLACEMENT

The Naza Ria first came out in the 2004 (?), initially as Kia Carnival CBU. Decent ride & equipment specs. for a reasonable price compared to other MPV's.






See, my daughter totally agrees with my opinion. She liked the BIGGG space inside the MPV. The setback is the maintenance cost for a V6 powertrain. Changing sparkplugs is not a job for an amateur.





Pictured here is the intake manifold removed to gain access to the Bank 2 cylinders spark plugs (Cylinders 2,4,6). The Ria's V6 is not exactly positioned upright, but slants at an angle of approx. 30 deg. The reason is to facilitate a compact hood, enabling the designers to cram in the intake runners, and ancillaries such as the alternator, A/C compressor, Pwr Steering, etc.



The photo shows the intake manifold removed, cleaned and ready for re-assembly back to the runners. I always blocked off the throttle body entry to prevent accidental dust / sand entry as it is a very sensitive part.





See how much I have to stretch to reach Bank 2 Cylinder spark plugs.







New O-ring seals are used to prevent any possible leakage that may lead to misfire or delay in throttle response. The other 3 cylinders uses a spring metal gasket that is re-useable (sorry, not pictured).

This is a good look at the spark plugs (NGK PN6 -11) that has been used for 4 years ! They are with Platinum core. This particular set has been running for 38,000km.

Another look at the sorry set, which are 4 years in service. Notice the oil deposits on the threads. The owner has been using synthetic oil, which explains the penetration.






As the Ria has 3 induction coils, I increased the spark plug gap by 50%. Standard platinum gap is 1.0mm. The advantage of doing so are high spark intensity, longer flame travel, resulting in more completed combustion and increased power. The spark fire must be checked prior to doing this (refer other resources on checking spark intensity).



This is a comparison between standard spark gap (right spark plug) and with increase of 50% (leftmost spark plug).







As a favor, I checked the timing belt, under service for 4 years with 38,000km. Authorized service centers recommends replacement at 36 months, but they looked OK to me. I gave the green light to the owner to go another 10,000km before replacement.