When building or modifying an engine, assembly lube plays a big role in protecting parts from wear at start up. What is assembly lube and do you need to use it? That’s what we’ll look at in this post.
Video transcript: What is Assembly Lube?
Featuring John Gardner, host of Motorhead Garage, and Leonard “Len” Groom, AMSOIL Director of Product Marketing (author profile).
John Gardner: Len from AMSOIL.
Would you ever dream of building an engine and not putting any motor oil
Len Groom: in it?
Not unless I wanted to build two.
John Gardner: Absolutely. Welcome to this AMSOIL tech tip. It’s all about the assembly lube. The best thing we can do is actually demo it for you.
Got this old engine over here. You wouldn’t do it on this engine, but it’s a good way to show it to you. Here’s a cam bearing right here. So Len, if you give me a little assembly lube, what we’re doing is we’re actually putting a coat of oil in between the bearing and the camshaft because we don’t want any dry starts.
That’s the bottom line and that’s going to do the job is right there. Why do we do that? Well you can look right here you actually see these oil galleries they’re going around the whole engine and the oil has to be pumped through there to lubricate the bearings and there’s all the bearings. There’s all kinds of bearings inside that engine, Len.
You got a phenomenal product to build an engine with.
Tell me a little bit about it.
Len Groom: Right. And the reason this product was designed is because everything that you were talking about there, it takes some time for that to happen. The engine could be running without oil pressure. This product is designed to come in there and provide protection until the oil gets there. There’s a couple of neat features.
It’s got a real high viscosity base oil. It is synthetic, so it does move pretty easily when we go ahead and apply it to that bearing, but there’s also some tackifier in there that’s going to help hold it in place. That’s that sticky stuff where you get those strings between your fingers.
John Gardner: Yeah, and you can see that. Now there’s a fine line. It’s not dripping off of there, which is a good thing, but you don’t want it like glue either. Exactly.
Len Groom: You want it to stay in place but only until the engine the pressurized oil gets there.
John Gardner: Now you guys have break in oil kind of helps with that. Talk a little bit about the break in oil. Why do I want to add that and what happens to the assembly lube after that?
Len Groom: Well, that assembly lube is designed to get out of the way as soon as the pressurized oil shows up. Our break-in oil is also heavily additized, designed specifically for engine break in. So they’re designed as a system to work together.
John Gardner: Absolutely. So you want to use them both so your bearings don’t end up looking like this. That’s not a good deal. Make sure you use the assembly lube and the break in oil. Go to their website. Make sure you check out those products and so many more.
What must assembly lube do?
On the surface, assembly lube has a simple task: protect new or freshly machined parts from wear after starting the engine following a build or modification.
To adequately protect against wear, however, it must remain in place after it’s applied.
After coating bearings, cam lobes or other components, time and gravity take their toll. The lubricant tends to slowly run off the parts until there’s barely any left to offer start-up protection.
Motor oil plus tackifier
To ensure the lubricant remains in place, many formulators add tackifiers to traditional motor oil. This approach works fine if the engine is assembled and run in a short period of time. However, if the engine sits for a while partially built or without running, the lubricant can slowly run off cam lobes, rocker arms/pushrods, bearings and other components, leaving them unprotected. Those few critical seconds without start-up lubrication can be enough to ruin the bearings.
The AMSOIL solution
To solve this problem, we reduced the amount of tackifier in AMSOIL Assembly Lube and instead use a higher-viscosity base oil to provide the thickness needed to ensure the lubricant clings tenaciously to parts, including inside bearings.
So, why not just use the thickest base oil possible to maximize its ability to cling to parts?
Well, some assembly lubes are essentially grease, which is much thicker than motor oil. Applying grease to parts will ensure it stays exactly where you put it.
The problem, however, lies in the third task assembly lube must fulfill: get out of the way.
One you start the engine and oil pressure builds enough to lubricate the engine with oil, the assembly lube’s job is done. It now must make way for the motor oil to protect the engine. If it’s excessively thick, however, it can clog narrow oil passages and prevent good oil flow. The lube needs to dissolve in the oil and leave little-to-no trace of its existence.
That’s another key feature we kept in mind when formulating AMSOIL Assembly Lube. Not only does it stay in place and protect components, it dissolves readily in the motor oil to promote good oil flow throughout the engine. It’s designed to excel in all three performance areas.
So, when asking “What is an assembly lube?”, it’s just as important to ask what it must do. Assembly lube is a high-viscosity oil with tackifiers (or a grease) that must remain in place no matter how long it takes to finish your engine, protect against wear at startup and get out of the motor oil’s way once the engine is running.
AMSOIL Assembly Lube excels in all three areas.
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Brad Nelson is an AMSOIL Technical Writer II who develops content about lubricant technology, product performance and vehicle maintenance. He works with engineers and product specialists to translate testing, application requirements and approved performance claims into clear customer guidance. Nelson’s work includes AMSOIL Blog articles, AMSOIL Magazine features and technical explanations concerning motor oils, gear lubricants, vehicle systems and maintenance practices.
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