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Here's what I do.....

October 12 2017 at 10:54 AM
Brent Lykins  (Login blykins)

Response to break in oil or not ? I vote no. Your experience ?

....and it has worked for me. Granted, I don't do a ton of flat tappet engines, but I've probably done 5-6 in the last couple of years without issue.

I always use Brad Penn 30W break-in oil. Non-synthetic.

I always keep the break-in spring pressures at around 100 seat and under 300 open. If this requires removing the inners or even swapping springs altogether, then that's what I do.

With the exception of just 1 or 2, I always have my cams made with the maximum amount of lobe taper. Since I do all custom cams, that's how I order them. I also have them nitrided and run Crower SBF EDM lifters.

I think the only exception to these rules was a 289 road race engine that I did, but it had titanium valves, a nitrided cam, and Trend tool steel lifters. I broke it in with the spring pressure that it was going to see on the race track, 160 seat and 350 open.

IMO, the problems that most guys face are too much spring pressure on break-in and not having the engine ready to fire immediately. You need to have the fuel bowls full and the timing set so that it will fire on the first couple revolutions. I don't doubt that there may be some metallurgy issues floating around randomly, but I think what I just listed are the biggest issues.

Back in the day, most cams would be happy with 80-90 lbs seat and 250-270 lbs open (or less) and they would break-in just fine. With today's modern lobes and necessary valve spring pressures, there's more of a chance for break-in failure when the appropriate precautions are not taken.

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