For hardcore engine restorers and the regular grease monkey tinkering with engines in a garage, the engine assembly grease is a mainstay. Slightly less viscous than grease, this compound is primarily designed to prevent metal parts of the engine from being damaged at the initial startup. Newly built engines, especially those that sit for a while before being sold or installed need the assembly lube to protect the rocker arms, cam lobes, and bearings upon the first start.

The reason is that the engine oil has not run its course throughout the engine, leaving a few seconds for parts to grind against each other. The motor assembly lube protects the components in these first few seconds of the newly built engine’s first run. Assembly lubricants are not simply oils but they instead have a precise thickness that lets them stay in place and not run off to other engine parts where they are not needed.

Top Pick
Permatex Ultra-SLick Engine Assembly Lube
To ensure that you never have to make the mistake of choosing the wrong assembly lube, we have painstakingly prepared a shortlist of products that have the qualities that you absolutely need without the gimmicks. The list contains 7 of the best engine assembly lube alternatives starting off with our top choice, the Permatex Ultra-SLick Engine Assembly Lube. This product outclassed just about everything with its superior adhesion qualities to components, ensuring that the compound stays where it is supposed to be. The advanced composition ensures lubrication of metal mating components during initial start-up.

TOP 7 Best Engine Assembly Lubes Available Today

With the information above, it would be clear how we came up with our top picks for the best engine assembly lube available today. We also looked at reviews, such as the lucas assembly lube review and assembly lube vs oil pros and cons. We considered pertinent factors and the things that matter so you can be more informed when choosing.

Permatex Ultra-Slick Engine Assembly Lube

Stand out features
This engine assembly lube compound from Permatex is not called Ultra-slick for anything. This lube is favored by engine builders and can be used on all parts, including the camshaft and bearings. Being a Molybdenum composite grease, this works well with any engine build and improves oil performance. Like all Moly-based grease products, this sticks to metal and ensures lubrication at that first crucial 10 seconds of the first start of a rebuilt engine. For today’s exact and very tight engine part tolerances, the viscosity of this lube is just perfect.
Permatex 81950 Ultra Slick Engine Assembly Lube: image

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Lucas Oil Multi-Colored Assembly Lube

Stand out features
Lucas Oil has been around long sufficient to build a solid reputation and this backs up this multi-colored assembly lube with decades of experience. Its semi-synthetic compounds are perfect for building engines, staying put exactly where you put them on. This bearing assembly lube compound offers maximum protection during engine first start-ups, preventing scuffs and dry-starts from happening. Lucas oil made this lube at just the right tackiness, and never runs off in places where it should not be. This makes the assembly lube very practical while installing specialized engine parts such as the Boxster engine of some car manufacturers.

Lucas Oil LUC10153 Assembly Lube: image

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Sta-Lube’s Extreme Pressure Engine Assembly Lube

Stand out features
Sta-Lube’s old-school Moly-based lube remains a very strong contender when it comes to engine assembly lubing requirements. Used to pre-lube engine high-pressure parts during pre-firing, its a prime example of a high-performance crc assembly lube. The compound, being a mixture of Moly and high-pressure additives that is just the perfect formula for high-performance engines. This lube comes in industrial black and comes in a huge 10-ounce tube that makes it a great value for money. With just the right amount of stick and tack, this lube stays put where it is needed.

Sta-Lube SL3331 Extreme Pressure Engine Assembly Lube: image

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Red Line Liquid Assembly Lube

Stand out features
This engine assembly lube is made of almost the same formula as any other except it is in liquid form. This composition makes it ideal for use on engines with extremely tight clearances, especially modern ones. This makes this ideal for valve trains as well as timing chains. Red Line’s thinner composition allows it to reach areas that can be difficult to reach with conventional assembly lubes. The viscosity of the lube makes it easily soluble in engine oil and will not clog up the oil filters.

Red Line 80319 Liquid Assembly Lube: image

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COMP Cams Engine Assembly Lube

Stand out features
Protecting your newly rebuilt engine from metal-to-metal wear comes easy for the COMP Cams engine assembly high-performance lube. This lube is specially formulated to be applied to those parts that experience the highest pressure. Ideally made for cams and lifters as its tacky and sticky nature makes it stay put where it is applied. Made of a cocktail of Zinc, Molybdenum, it sits on a lithium base that ensures no runoffs. The COMP cam engine assembly lube is reputed to be the best break-in lube there is.

COMP Cams 104 Engine Assembly Lube: image

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Royal Purple Max-Tuff Synthetic Lubricant

Stand out features
The Max-Tuff synthetic engine assembly lubricant extends engine and equipment life by being thin enough to be applied on parts with extremely tight clearances. This lube’s viscosity is thin enough to not cause any obstructions to the normal oil flow. The great thing about this is that a little amount goes a long way. It is completely soluble in any engine oil and leaves no residue. Can also be used in other applications such as rust prevention during storage or other forms of machinery.

Royal Purple 01335 Max-Tuff Synthetic Assembly Lubricant: image

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ARP Ultra-Torque Engine Assembly Lubricant

Stand out features
When it comes to engine assembly, getting the right torque when tightening the bolts is critical and could be the difference between a successful build or a dismal failure. This lube from ARP ensures better tightening of bolts and screws by making sure they complete their turns the first time a bolt is slotted home. This compound goes hand in hand with engine assembly lubes for internal engine components. Practically brings new life and usability to older bolts.

ARP 100-9910 Ultra Torque Assembly Lubricant : image

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What you need to check before buying engine assembly lubes

While we want you to have the list, we also do not want to lead you on blindly and with that we will go through why we chose those 7 products over the others. Below are the criteria which we used to determine the best products to choose and we take a close look at each of them as you continue reading.

The composition

There are two main categories when it comes to assembly lube and they are the Molybdenum sulfide-based grease and petroleum-based lubricants. Molybdenum or ‘Moly’ as it was popularly known, has been around since the 1800s or even earlier. Petroleum-based grease arrived much later and is the most widely used today.

Molybdenum composite grease

Moly-based compound grease products are popular for a reason. Not only do they blend in with engine oil but the addition will enhance the performance. Molybdenum Disulfide does not alter its structure regardless of how hot or how high the pressure is. The only caveat with Moly based grease is that it cannot be used in the camshaft due to tiny silicone beads in its composition that can clog up bearing over a relatively short period of time.

Petroleum-based grease

While newer than Moly, petroleum-based grease products are some of the best engine assembly lube available today. Not only are they cheaper, but are readily oil-soluble and will not cause any blockage in the long run. Petrol-based grease or lubricants have no limitations as to where and what part it can be applied to. Even if it’s grease-based it will just be caught by the oil filter and deposited into the oil pan.
Method of application
There are now two main types of how assembly engine lube is applied to where they are needed. The most common is simply to spread it using your fingers or via an applicator or the more modern method of spraying it onto the surface. The compound coats and hardens on the sprayed surface and stays there. Both are fine, but more machinists and engine builders prefer the manual spreading of the compound as sprayed lube is prone to miss some areas.

The specific part it was formulated for

Some engine assembly oil is part-specific like some lubes are only meant for camshaft and bearings. Others are for more general applications so it is crucial to look at the small print to see what the grease is made for. This is done because some compounds may clog bearing parts and cause unnecessary wear.

Frequently Asked Questions (FAQs):

Where do you put the engine build lube?

Engine assembly lubrication does not mean the whole engine, but rather only on parts that will initially need surface protection while the oil has not circulated yet. The parts that need particular attention are rocker arm and valve stem tips, distributor drive gears, pushrod tips, camshaft gear drives, cams, lifters, and blower drive gears.

Is the engine assembly lube needed?

Absolutely yes, the regular engine oil will need a few seconds to reach the parts it needs to be lubricated upon the first start. These first few seconds without the engine oil are where the assembly lube will take over and simply dissolve into the oil when it arrives.

How do you lube a cylinder?

Always start by cleaning the piston, either to remove debris on a brand-new one or to clean the gunk from an existing one. Raise the seat to the maximum and apply the lube to the exposed parts, lower and raise the seat while rotating to coat everything in the lube evenly.

How do you lube a camshaft?

Depending on where the camshaft is located, you may use an end feed or via passages. This can be a bit tricky because camshafts have the oil supply naturally restricted to prevent oil from overflowing to the valve mechanism. You will have to introduce the lube through the main gallery and the main bearings.

Can I use grease instead of assembly lube?

Never use just simple grease as an alternative for assembly lube as there are two factors that can go wrong. One is that it will not be thick enough and run off to other parts where lubrication is not needed and two, it may not be completely soluble in engine oil, causing blockage and problems in the long run.

Parting words

Metal grinding against metal without any form of lubrication is a disaster waiting to happen. Knowing specifically which assembly lubricant to use, as well as the specific parts to put them into is a huge plus in the build being a success. Lube reduces friction and ensures that the engine faces no problems after being built and started for the first time. Of course, preparation and due diligence on the builder’s part is still key in a build, but the right components also play a huge part.
Whatever the engine assembly lube you choose, it should do its job of lubricating the engine on the first 10 seconds of starting up and any of the products listed above is sure to do its job. On a parting note, ensure that the engine assembly lube should readily dissolve in oil, to avoid clogging the oil pump and filters.