One common problem with most engines is carbon build up. Don't be mistaken IT SAPS POWER.

First, what is carbon and where does it come from?

Carbon is produced as a by-product of combustion. Fuel impurities and oil all get burnt during combustion, producing carbon. Carbon in itself is not the problem. It is very fine and powdered. The problem is when it mixes with oil vapor it becomes what is quite often referred to as "COKE". In this form it is exceptionally hard and unfortunately, over time builds on itself.

Where does it "gather"?

Hardened carbon deposits build up in the combustion chamber, the back of valve heads, in vacuum lines and ports and behind rings. I have re-built engines with less than 100,000 K's and found carbon deposits on the back of valves over 2mm thick. When you consider a valve only opens millimeters, this has a huge effect on flow. It also reduces compression as it can prevent the valve from fully closing. It can seize the rings in their piston lands and block the oil holes to the oil rings.

This can all be prevented/cured by performing a simple de-carb, using a can of carby cleaner. I find the CRC and Nulon carby cleaners to work very well. This should be carried out just prior to a oil filter and oil change.

HOW TO ON EFI CARS:

IMPORTANT NOTE. INTRODUCING CARBY CLEANER IN LARGE QUANTITIES INTO AN ENGINE WHILST IT IS OFF MAY RESULY IN HYDRAULIC LOCK OF THE CYLINDERS. THEY CAN FILL WITH FLUID AND THEN LOCK WHEN YOU TRY TO START THE CAR.

The process is quite simple. Get an aerosol can of carby cleaner with one of the small tube extensions. This will set you back from $10.00 to $20.00.

Start the car and bring it up to temperature. You may need a friend to "play the throttle" to prevent the engine from stalling. Alternately pick a suitable spacer (cardboard/plastic) and place it between the throttle stop and actuator on the throttle body to up the revs. With the car running (VERY IMPORTANT AS PER NOTE ABOVE) start with the PCV Valve on the cam cover. Unplug the hose at the PCV Valve, leaving the valve in place on the cam cover. Hold your finger over the end of the hose to prevent the "un-metered" air from stalling the engine. Squirt the carby cleaner into the hose in short bursts, say 2 to 3 seconds at a time with a second or two in-between squirts. Use about 1 third of the can. Now do the same for all other vacuum hoses going to the Inlet Manifold. In particular the hoses that provide vacuum advance to the distributor. Let the car run for a few minutes. Turn the engine off and leave the car for a few hours. Repeat the process, using any remaining carby cleaner. Take the car for a drive. Don't give it a hard time. Just a nice open run. Leave the car over night. Next day, bring the engine up to temperature and then change the oil and oil filter.

You will be surprised at what a difference this will make.

There is no need to do a de-carb every oil change, however it will clean out the inlet manifold.

The process is much the same for carby engines, however it is best to also remove the air filter and squirt carby cleaner directly into the carby. Don't forget to clean the vacuum lines. They do block up over time.

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