The true test of whether a flat tappet cam will live is usually the first few minutes after it is first cranked. This is the period when the face of the lifters and the cam's lobes are able to wear together and mate in. And because of this, extra precautions must be made to make sure the top of the lobe isn't ground off in the process.
AMSOIL's 10W-30 synthetic is a popular motor oil for racers in Saturday night classes. Its
With modern valvetrains using extremely aggressive cam profiles and super strong valvesprings to keep the valves under control, it's tougher than ever to get a flat tappet cam to live through the initial break-in. That's why the dedicated break-in additives and oils you've probably seen popping up aren't just a marketing gimmick. In addition to using a lighter weight valvespring during the break-in process, these specially formulated oils can be the difference between a happy motor that provides great power race after race and one that never makes it off the dyno.
Of course, there's more to a good break-in oil than simply dumping in more ZDDP. Groom explains, "As far as break-in oils go, you have a couple of things at work there. Number one is you want to seat the rings properly so you have good ring seal and aren't blowing oil. And number two, you want to keep the camshaft, the lifters, the valve guides, rockers and all that other stuff alive while you are doing it.
"Those two requests are pretty big--you can't sacrifice one for the other--but they are also polar opposites as far as the oil is concerned. To seat the rings, you generally have to use an oil formulation that will hurt the camshaft. So after quite a bit of research, what we have come up with is to use a conventional-based oil with a monstrous additive package. With our break-in oil, I think we are up there at 2,500 ppm on both the zinc and phosphorous. In fact, you can't put any more in there or it starts to fall out! And by using a conventional versus a synthetic-based oil stock, what we have found is it seats the rings extremely quickly, and the cam and the rest of the valvetrain is properly protected while that's happening.
"One thing we try to remind customers is that a break-in oil isn't designed for racing. On the race track you will put a lot of heat into your oil, and being able to withstand that heat isn't a priority for a break-in oil because it doesn't see that much on the dyno. So we've designed our break-in oil so that once you finish your break-in and pull the engine off the dyno, its job is done and it is ready to be drained out. You are ready to put in your regular oil and go racing."
AMSOIL has the capabilities to provide oil analysis for racers right out of their own faci
Issues with Assembly Lube
Interestingly, Groom says that the humble tube of assembly lubricant is another area where AMSOIL has veered away from the usual solutions to make an advancement. Most assembly lubes used by race engine builders are one of two basic mixtures. Some manufacturers use a grease as an assembly lube. Unlike oil, grease doesn't run, so it is likely to remain where it was applied even if the engine sits for a while before it is finally cranked. The problem with grease-based assembly lubes, however, is that some resist dissolving in motor oil once the engine is run. As a result, after the engine is run all that assembly grease winds up in the bottom of the oil pan near the oil-pump pickup or lining the oil galleries. Often, that stickiness that allows it to stay where you put it means it will stay in the bottom of the oil pan or galleries through multiple oil changes and finally only gets cleaned out at the rebuild.
The second option also has its own drawbacks. Instead of using a grease base, a manufacturer can use an oil base with a tackifier to make it stickier. But Groom says a tackifier really only makes the assembly lube want to stick to itself. "I've done tests with lots of different oil-based assembly lubes that used tackifiers," he says. "I put them on bearings and then turned the bearing on its side to see what would happen. Instead of the assembly lube staying where you put it, it just slid off in one big glob.
"When we decided to produce an assembly lube," he continues, "the best solution was to take a very different approach. We stayed with an oil base for the assembly lube, but we brought the tackifier level way down and drastically increased the viscosity of the oil we were using as the base. So our assembly lube has a viscosity that is literally off the charts. So what it does is it sticks to parts and it stays there. It won't run off of the bearings, so if your engine has to sit for a while before you are able to run it, that's OK. Plus, since it is an oil-based product it very readily dissolves into motor oil. When you drain your break-in oil, all the assembly lube goes with it. It doesn't leave any of that grease sludge in the bottom of your oil pan or your oil galleries."