Do I Need Assembly Lube?

Yengine assembly, assembly lubees!  Does it matter what you’re assembling?  No! Assembly lube is a must for anything you are putting together in your car or bike.  If your thinking “assembly lube is just for professionals”, or “assembly lube is just for brand new motors” chances are you’re in for some premature failures for components you’re putting together.

All the mechanical devices on your car or motorcycle are designed to be lubricated to keep things running smoothly and reduce friction.  Friction is the enemy of all machines because it creates heat and heat breaks things. In any rotating assembly in your vehicle, the shaft is supported either by journal bearings or roller bearings.  Journal bearings use a smooth surface on the shaft surrounded by an oil film that is surrounded by another smooth surface on the case to support the shaft. Roller bearings have two similar smooth surfaces but instead of just an oil film in between, they also have small rollers to support the weight of the shaft.

Journal bearings are especially dependant on oil pressure to create the oil film and reduce friction.  Without oil, you have metal on metal contact which can create enough heat to melt either the shaft or the case surface in a matter of seconds.  Roller bearings are a little more tolerant of a lack of lubrication but even one rotation without lubrication can score the surface of the bearing rollers. Even though this scoring won’t lead to immediate failure, the score will lead to pitting which will cause vibrations and noise from that bearing much sooner than if it was properly lubricated.

Now that we’re on the same page about bearing wear, you can see how important it is to have good lubrication on your bearings even from the first turn of your motor, transmission or differential.  It’s also important to understand how important cleanliness is when you’re assembling or rebuild a mechanical system. Removing dust, dirt, and impurities is essential to a good rebuild or first-time assembly.  Using a good cleaner is the best way to get things ready to assembly but after a good cleaning, some lubrication is needed.  

Why do I need Assembly Lube, Can’t I Just Use Clean Oil?

PJ1 Engine Assembly lube is a much better option for the pre-lubrication of engines, transmission, and differentials.  While engine oil works will while it’s under pressure and warm, assembly lube does a much better job liberating cold and under high pressures like the initial startup of an engine or transmission.  PJ1 Engine Assembly Lube comes in an aerosol spray unlike make lubricants so it can be easily applied in just the right quantity in even the hardest to reach places!

Pictures Provided By:

engine_assembly.jpg – By SergeyKloptov – Licensed By Getty Images – Original Link

2 responses to “Do I Need Assembly Lube?

  1. what about 2-strokes? I’m putting a new crank into a old Kaw H1 cases. Seems like I should oil up the new bearings before starting it. However the manual states Locktite 609 should be used on the main bearing races. Not sure its possible to use both the lube and licktite on the same bearing.


    1. Randall-

      It would be best to use the Loctite 609, as recommended in the manual, to ensure the bonding of the metal surfaces. Using oil would interfere with the bonding and the crank wouldn’t be fitted properly.

      Thank you!


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