An engine stand such as this...
An engine stand such as this one from Performance Racing Warehouse (PRW) is relatively inexpensive. It allows a break-in and post-break-in service to be done on an engine before it is installed in the car or put on the dyno. With the current hourly cost of dyno time, this stand will have paid for itself by the fourth dyno test session.
To get rings to seal and deliver low friction levels, the bores must be correctly honed with a finish to suit the ring material and subsequently cleaned. Even the more modern honing techniques and equipment can still leave a certain amount of honing stone debris in the finish. The first part of breaking in a bore is to see that it is absolutely spotlessly clean. I use a Scotchbrite pad intended for pot scouring and Gunk engine cleaner to both clean and prep the bore surfaces. When inspected under a microscope, even the best bore finish has jagged spikes of material that will tear into anything that rubs against it. When I clean the bore with an up and down action, the Scotchbrite pad lops off the peaks of these microscopic spikes. The amount of material removed with the Scotchbrite pad is a fraction of one ten-thousandth of an inch, so it's not really a measurable amount. The same treatment should also be applied to the ring faces.
So, how does this help the break-in procedure? After all, everything will smooth out as the engine runs. The key is the break-in procedure. When the newly machined parts rub over each other, there is microscopic welding and tearing. Each time a weld is torn, it creates another microscopic rough patch or surface wound that also needs to be broken in. In essence, the mating parts need to either very finely machine their mating counterpart or knock down the microscopic spikes to smooth the surface. If too much microwelding occurs too quickly, the surface finish is worn out rather than improved. We need to avoid too much speed and load to prevent excess microwelding and surface tearing. So far, the bore prep is off to a good start.
This is what can happen to...
This is what can happen to the lifters of a flat-tappet race engine unless adequate precautions are taken. We are outlining the solutions here, but they will only work if you apply them.
I use a lot of Total Seal rings, so when the Quickseat powder bore lube was introduced, I gave it a try. I used it on about a half-dozen engines, and it appeared to work just fine, but nonetheless I stopped using it. The very fine black composition of Quickseat not only stuck to bores like it is supposed to, but also my hands, cameras and white walls. This stuff is cheap. If you have any doubt about the rings in your engine seating in-use it.
Your carefully built engine is now ready for its first run. There are three places this can happen: in the car, on a break-in stand, or on the dyno. Running the engine in the car is the least costly option of the three, but going that route has only cost as an advantage. If the engine has even a minor problem, such as a leaky seal (hey, it happens), it has to come back out. It is really a great asset to break-in an engine prior to installing it either in the car or on the dyno, unless you happen to own your own dyno. Dyno time typically costs $80 to $100 per hour, and a proper break-in session with a post-break-in service can use two to three hours. After about your third engine, you will have paid for a professionally built engine break-in stand.
Here's the cam that was paired...
Here's the cam that was paired with the concave-worn lifters shown nearby. You can be sure that this cam's glory days are long gone.
Regardless of where the engine is first fired, the perennial question is, should it be broken in on mineral or synthetic oils? Allowing that a successful break-in is an accumulation of build procedures as well as lubes and techniques applied during the break-in, I have found little difference between top-quality mineral or synthetic oils over the past 15 years. My policy has been to break-in for the first 20 minutes with a quality mineral oil, such as Castrol GTX. Its low cost figures into the equation pretty heavily considering it will only be used for 20 minutes before being dumped along with the filter.
I recommend using a quality oil filter because the amount of debris the engine creates in the first few minutes of running is at its highest. At this point, I cut open the filter and inspect what is inside. There will always be a certain amount of fine metallic particles, and these are hard to see. If you see particles that might have originated from bearing material, and they are not in the realm of fine particles, there is probably a problem with the bearings. If the engine is on a break-in stand, it does not take long to dump the oil and drop the pan to make a check on the bearings.