Fitting Pistons To Conrods

Fitting pistons to conrods would be considered to be a fairly straight forward job for most mechanics.  However, it is important that this task is completed correctly to prevent this from occuring....


These score marks were caused by a loose piston pin.

How did it happen?

By heating the small end of the conrod, the hole expands which allows the piston pin to be inserted.  Once it cools, the small end contracts to clamp onto the pin - hence the conrod is fitted to the piston.  In this case, an oxy was used to heat the conrod and too much heat was applied.

It is of paramount importance that the conrod is NOT heated too much.  When the small end is over-heated, the properties of the metal have the potential to change. The metal can develop elastic characteristics and the small end will not contract back to the same size it initially was.  The correct clamping effect does not occur in this situation and hence the pin becomes loose and has the potential to slide out.  This is exactly what has occurred in the above example.  It is very difficult to control the temperature when using an oxy to heat the conrod.  Therefore, this method of fitting pistons to conrods is not recommended.

Another method of fitting pistons to conrods is to press fit.  This however, can broach the small end of the conrod.  Once the hole has been enlarged, the piston pin becomes loose and the same problem as above can occur.

At Galloway Engines, we fit pistons to conrods using a specialised machine.  The small end of the conrod is heated by a coiled heating element which is thermostat controlled, to prevent overheating.  When the correct temperature is reached, the conrod is immediately fitted to the piston.

DON'T RISK ruining the bore of your newly rebuilt / reconditioned engine.  Have your pistons professionally fitted to your conrods by Galloways to prevent any future problems.

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Frequently Asked Questions

How do I know if my engine needs reconditioning?

Tell-tale signs that your engine requires attention are that it has lost performance or efficiency, it blows excessive smoke or it has developed an unusual noise.  However, a vehicle needn't have these symptoms to benefit from a reconditoned engine.  A complete and comprehensive recondition of your engine will increase power, fuel efficiency and extend the life of your vehicle.

Do you remove and refit engines?

Galloway Engines is a precision workshop which deals in machining and reconditioning engines.  This ensures we are specialists in our field and only a quality job of the highest standard will be delivered.  We can arrange engine removal and fitment or contact your regular vehicle servicing centre for this service.

Can I supply my own parts?

Yes. You are quite welcome to supply your own new parts should you have a preference for a particular brand name.  However, our parts prices are very competitive and our high standards ensure that only quality parts are fitted to any job.  We have liaisons with many Australian and international companies allowing us to have access to world-wide sourcing of parts.

Do you offer a warranty?

Any reputable product will come with a warranty as proof of its quality.  Galloway Engines are no exception.  We offer a full warranty on all of our work.  Contact us for more information on the terms and conditions of our warranty.

Why should I use Galloway Engines?

Galloway Engines supply a quality engine which is completely reconditioned to comply with original manufacturers specifications and are in accordance with Australian Standards AS4182 for petrol engines and AS4427 for diesel engines.  Our up-to-date equipment produces quality precision work and our team of specialised technicians are dedicated to detail.  This ensures you are getting the best job possible.

Can you recondition any engine?

Yes. Whether it be a Caterpillar engine from a giant earthmoving machine or a small three cylinder Suzuki engine, we have the equipment to be able to meet your needs.  Contact us to see how we can meet your requirements.

Do you offer engines which suit LPG?

As LPG has different properties to unleaded fuel, an engine can experience problems when converted to LPG.  We can offer options which can enhance the performance and reliability of an LPG engine.  Galloway Engine Reconditioning also stock a range of exchange heads which are modified to run on LPG.  

Do you have EFTPOS?

We have full EFTPOS facilities available and are able to accept payment via Credit or Debit Card.


  • Address:

    Galloway Engine Reconditioning,
    25 Baker St,
    Pinjarra WA 6208
  • Phone / Fax:

    08 9531 1366
    08 9531 2321
  • Email: