Break In Question, Top end rebuild Options

[jim_hoyland]

What the recommended steps for a break- in after a top end rebuild ? Oil, valves, etc
Replaced heads with new valves, springs, valve guides; new 96 mm pistons, and cylinders.
500 miles ?

[jim_hoyland]

Interesting: i can do a series of short drives of 60 miles mostly flat but a couple of hills ( 405 then down the 73 and return

And / or a drive up Hwy 1 to San Simeon, about 190 miles, overnight stay then return to Huntington Beach

I better load up on motor oil; looks like I can expect 2 changes ?

[earossi]

Interesting: i can do a series of short drives of 60 miles mostly flat but a couple of hills ( 405 then down the 73 and return

And / or a drive up Hwy 1 to San Simeon, about 190 miles, overnight stay then return to Huntington Beach

I better load up on motor oil; looks like I can expect 2 changes ?

Most of the comments so far are directionally correct; however, I suggest you consider some points during the break-in.

First, driving the car with a light throttle (i.e. "babying" the engine), is not a recommendation that will be made by any engine builder I've known. Drive the car with light throttle will promote cylinder glazing which prevents the rings from every seating in.

The correct way to break in a Porsche engine is to drive the car "like you stole it", which means driving it hard. The caveat is that during break in, do not rev the engine past 5000 rpm. Also, you should initiate 6 to 12 instances at the beginning of the break-n cycle where you "bog" down the engine. To do this, take the car up to about 30 mph, put the tranny into 3rd or 4th gears, and then take your foot off the throttle allowing the car's speed to bleed down. As the speed gets low enough to stall the car, give the engine full throttle just before stalling and take the engine up to about 3000 rpm. Then repeat the same cycle. Applying full throttle to an engine that is beginning to bog down produces high cylinder pressures which serves to exert high outward forces on the piston rings promoting rapid seating of the rings.

Driving the car like you stole it means doing rapid acceleration of the car as much as possible during the break-in period while observing an engine speed limit of 5000 rpm.

During the break-in period, run a proper break-in oil such as Brad Penn 30wt Break-in oil. High zinc levels in break-in oils assure that the contact surfaces between tappets and cam lobes are properly protected during the break in period. Once the break-in period is completed, change to a 20W50 oil that has high levels of zinc (greater than 1300 ppm zinc).