Engine Overhaul Notes

 Engine over haul is basically rebuilding the engine to make it work like new all over again. This job is more like a 'Project' and might take several weekends.

The reasons for an engine going bad are many including :-

1.) Normal usage (>200K Miles ) where compression values of the cylinders fall to significantly low values such that the engine

does not develop enough power.

2.) Previously badly maintained car.


Other un-common reasons include :-

1.) Engine Seizure due to running with out coolant or having a coolant leak

2.) Engine Seizure due to low oil or oil leak.

3.) Failure of a Head Gasket

4.) Bad Valves

5.) Excessive use of additives or chemicals in the Fuel /Lubrication system


In most cases engine overhaul consists of replacing the piston and rings and bearings. You can buy entire engine re-build kits online and at stores , these come with most of the items needed for a overhaul.  If you are going a bigger size piston , you might have to re-bore the cylinder. It will also involve replacing most gaskets , like the head gasket. Some time a head rebuild will also be required to make the engine to like new performance and feel. An extended rebuild might involve re-surfacing the Cylinder block and head and also taking out any bents of the crankshaft.

Engine rebuild makes sense to hardcore DIYers if a used engine is hard to find for that model. Car performance enthusiasts also do rebuilds at car performance shops , to enhance the engine output and take it beyond the original specifications.

In most cases overhauls are considered a last measure. This is since the cost of Used engines (60K to 80K) in the US are far cheaper or around the sum of the parts and additional tools needed to do a rebuild. So it is cheaper to replace a damaged engine , than do a rebuild.