Engine Rebuild Break-in after 200 miles

[scoll911]

All,

As usual, the more people you ask the more answers you recieve. I'm trying to figure out what to do in the first 200 to 1,000 miles after a complete rebuiild. My mechanic in Phoenix (who helped me rebuild) said oil change and valve adjustment at 500 miles. I moved to Albuquerque, talked to two mechanics one said wait until 1,000 miles the other said 600 to 700 miles for both. Any thoughts? I have about 400 miles on the engine now.

P.S., Does anyone know of a good mechanic in Albuquerque.

[RoninLB]

I don't see a signature or what 911 you have under a signature..and what kind of pistons/cylinder, etc. rebuild happened...anyway I'd change the oil filter/at least..and are you using 30w non-detergent? ...and how much oil are you burning now? ..did you re-torque head stud nuts yet? ..and how are you breaking in the engine?? .................Ron

[scoll911]

I guess the specifics would be helpful -- I have a 78 3.0. I have not touched the engine since the rebuild. It is running pretty well, although it seems to have an oil leak on the right upper valve cover. It also sounds like it definitly needs a valve adjustment. Non detergent 30 wt

[john walker's workshop]

if the valves are really noisy, just do them now. no sense letting them pound for another 600 miles. normally i would recommend a valve adjust/oil/filter at 1000 miles as long as they were not ticking much.

[Jim Sims]

Russ Kelso of Precision Motorcar Investments
He in Corrales on the north side of Albuquerque; tele: 898-6487
Jim Sims

[Wayne 962]

From the new book:

The Next Day & Beyond – After your initial drive, I recommend that you let the car sit and cool down completely overnight. This will give the seals and internal engine parts a good chance to go from cold to hot to cold again. You don’t really want them going from cold to hot to warm to hot again, because it may not give them a good chance to completely seal within the engine.
Fill up the car again with oil, if you didn’t already do that the previous evening. Start the car, and let it warm up by driving it around the neighborhood a bit. When the car is warm, you can then recheck the ignition timing, and also adjust the carburetors. Detailed procedures for adjusting the timing and adjusting your carburetors or fuel injection can be found in the book, “101 Projects for Your Porsche 911.”

Drive the car for about 500 miles, and then change the oil again. At this time, you will want to adjust your valves (see 101 Projects), and retighten your head stud nuts. You can reach the head studs with your head stud tool when the valve covers are off during your valve adjustment. The engines with aluminum crankcases typically don’t require any additional tightening, but you will probably find that the magnesium case head stud nuts will turn at least a quarter turn before tightening up to their final torque. At about 1000 miles, change the oil again, readjust the valves, and tighten the head studs one more time. At this time, your engine should be completely broken in, and oil consumption should be down to about 1 quart per 1000 miles. This is about the average amount for a newly rebuilt 911 engine.

A lot of people aren’t really sure what motor oil to use in their car. Traditionally, the characteristics of motor oil were linked closely to their weight. Heavier weight oils protect well against heat. Lighter weight oils flow better in engines in cold environments. In general, if you live in a cold climate, you should use a 10W-40 or similar oil. This oil is a 10 weight oil that behaves and protects against heat like a 40 weight oil. In warmer climates, you should use a 20W-50 oil. This oil doesn’t flow as well at the colder climates, but gives an extra ‘edge’ on the hotter end.

The question of whether to use synthetic or ‘dinosaur’ oil often comes up amongst car buffs. Consumer Reports (July 1996) did an extensive test a few years ago on both types of oil, and after tearing apart engines, and measuring wear, they couldn’t find any discernable differences between the two. Still some people swear by synthetic oil. In general, you should not use the synthetic oil if you have an older car with old seals in the engine. There have been many documented cases where the addition of synthetic oil has caused an otherwise dry car to start leaking. If you own an older 911 that doesn’t have fresh seals in the engine, I would stick to the non-synthetics. However, since your engine seals should be brand new at this stage, the use of synthetics should be fine. I would recommend against using them for the first 1000 miles of engine break-in.


-Wayne

[mtelliott]

Is it typical to have a valve get noisy all of a sudden? I've got 300 miles on a rebuild. This included a 200 mile roundtrip ride with a 6 hour break in the middle. No problems. Started it up that night after the long road trip to take the wife out, drove no more than two miles, then started hearing a loud noise that changed with the RPM's. I'm guessing it's in need of a valve adjustment but do they go from no noticable noise to very loud quickly?

I'll be draining the oil and pulling the covers to check. It just seemed weird that it happened so quickly. And it's definitely loud. I have a targa with the top off and we could hear it in while driving. I turned it around and put it back in the garage.

911 SC 3.0 Stock

Michael