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Published on January 30, 2008

Changing a car's engine is highly popular in Thailand because there are many imported used engines from Japan on the market, making for a cheaper option than repairing the old one.

It takes less time to change an engine than to fix the old one, and there is less work for the mechanic to do. If there are any problems, the source is also easier to trace because only the engine shop and the mechanic are involved, whereas with overhauling the old engine there is the quality of work of the mechanic who disassembled it, the quality of the parts used and sometimes the quality of the machining, if the engine needs to be modified. So if a problem arises, the cause can be difficult to trace.

Despite all of this, I favour repairing the old engine because you never know the condition of the used engine you are buying. The shops will not allow you to open the engine to check it for wear, while repairing an old engine involves disassembling it, and the replacement parts are definitely new. The final job depends on the quality of the parts you buy for the repairs.

Most used engines from Japan come from car wrecks, so you don't know whether they have been affected by the crash or whether the previous owners took good care of them.

After the engines are removed from the vehicles in Japan they are stored for a long time before being shipped to Thailand, and they endure all sorts of weather conditions. Then they are placed in front of the used-engine shops or warehouses in Thailand. It takes about one year for used engines to reach the hands of buyers in Thailand, and this can't do them much good.

However, in cases where parts needed to repair an old engine are too expensive, or if the parts cannot be found, or if damage to the engine is too widespread to repair, then replacing the engine is an obvious option. In these cases, always bear in mind that the same type of engine should be used and the power output should not be higher than that of the old one.

Using a different engine, or one from another brand, requires many modifications in the engine mounting area, and there is a good chance that the balance will be affected, resulting in vibration when the engine is running.

A more powerful engine is also more expensive and requires more modifications. For instance, the suspension and brakes may need to be upgraded to cope with the higher power.

Even the body may need to be strengthened, leading to more cost. And when you want to sell the vehicle, the resale value will have fallen because the original engine is not there.

I also advise against the installation of fuel systems using both diesel and natural gas in diesel pickups.

However, when pickup-owners insist they want to use natural gas, my only suggestion is that they replace the diesel engine with a petrol engine first, then convert the petrol engine to run on natural gas. I also tell them to be very careful and to avoid hasty decisions, because if they make a mistake it will be difficult to return to square one.

n E-mail your motoring questions to Pattanadesh@nationgroup.com.

By Pattanadesh

Asasappakij

Ultimate in Luxury

The Luxury LS 460 is a wonderfully comfaortable car fitted with all mod cons, althoough not necessarily the most fun vehicle to drive.