Break In After Top End Re-build

[lespaul]

I am about 2 weeks away from my top end rebuild on a 78 SC 3.0L. New rings.

When time to break in, should I follow the procedures outlined in Wayne's book for a full rebuild or are there a different set of procedures for a top end job? For example, numbers and frequency of oil changes?

[snbush67]

Break In Secrets--How To Break In New Motorcycle and Car Engines For More Power

For reference the above thread has great information.

No synthetic and drive the dog snot out of it. Lots of uphill pulls in the wrong gear, downshifting etc.

[lespaul]

Shane,

Thanks for the recommendation and link. As it says, the method in the link is "controversial" and differs from what Wayne recommends in his book. Plus, my
'78 is not a "new" engine that would support the rationale for the recommendations in the linked article.

What do others have to say about the linked article? What is the "ideal" break in procedure for a topend rebuild on a '78 SC 3.0 with 35K miles, the original Nikasil cylinders and new rings?

[RedCoupe]

Exactly what work was done on your engine should determine how the engine is broken in. For example, if you installed reground or new cams, you will want to follow your cam grinder's favorite cam break-in procedure which typically is running the engine at around 2,000 rpm with no load for about 20 minutes. If the cams aren't touched, then that step isn't necessary. I'm assuming that you will have new rings, so you will want to follow an initial driving routine to help seat your new rings. A load then unload style of driving is generally accepted as being the best way to seat new rings.

[porschetub]

Originally Posted by RedCoupe

Exactly what work was done on your engine should determine how the engine is broken in. For example, if you installed reground or new cams, you will want to follow your cam grinder's favorite cam break-in procedure which typically is running the engine at around 2,000 rpm with no load for about 20 minutes. If the cams aren't touched, then that step isn't necessary. I'm assuming that you will have new rings, so you will want to follow an initial driving routine to help seat your new rings. A load then unload style of driving is generally accepted as being the best way to seat new rings.

To me thats problematic in its self,you help the cams and don't do the rings any favours.
No load on the motor for 20mins may not harm the sealing of the rings but isn't the best situation.
RedCoupe's final comment couldn't be true enough.

[RedCoupe]

Originally Posted by porschetub

To me thats problematic in its self,you help the cams and don't do the rings any favours.
No load on the motor for 20mins may not harm the sealing of the rings but isn't the best situation.
RedCoupe's final comment couldn't be true enough.

You're so right. The proper break-in procedure for new cams is exactly the opposite of how you want to treat new rings to properly seat them. Yet, those first few minutes of engine operation are critical to the life expectancy of new camshafts. So, once the allotted time for cam break-in has passed, then you have to get that car on the road and work it. My favorite practice is to use a lonely highway and do full throttle pulls in 3rd or 4th up to about 3.5 or 4k and coast back down to 2k and repeat and repeat and repeat.

[snbush67]

Some comments from my build thread IRT the break in method :

Originally Posted by lindy 911

We have done it this way for 30+ years. I grew up with a guy that for most of his professional career set up motorcycles for American Honda that the magazines would get for testing. He basically blue-printed the bike from axle to axle. His method for break in was warm it and hammer it. A slow break in meant a slow motor.

Lindy

Originally Posted by Walt Fricke

I've always liked that advice.

Though I admit partly because it aligns with my inability to do any kind of slow break-in. I have a new motor, it is for the race car, and I can't afford to do anything other than hammer it pretty much from the get-go. Run it enough to drive into the trailer, check for leaks, and out and over to the grid.

Wishful thinking can be dangerous, but so far this hasn't bitten me in the posterior. Leakdowns are uniformly good.

Post 121:
Shanes 3.2 SS - Recommendations and Advice

[JFairman]

When I bought new JE pistons for a 3.5 liter BMW engine the instructions from JE for seating in the new moly coated cast iron hastings rings that came with them was to do around 10 full throttle accelerations in second gear up to 5000 rpm and then let off the gas completely and coast back down.
After that you just drove it however you want and changed rpms a lot for the first 100 miles. Beyond that you're just over thinking it.

2000 rpm for 20 minutes before doing that to break in new cams and frequent Oil changes for the first 2000 miles as people have already said.

[Lapkritis]

You'll hear a lot of opinions on this. Here's what I've always done:

1) Gingerly warm to temp.
2) Check for leaks and address if critical.
3) Drive with variable load and RPM up to 6500rpm. Fun time.
4) Exchange oil and filter after ~100 miles, ~500 miles, ~1500 miles and then back to normal interval.

Oil for first start up and break-in should be non-synthetic. Rotella, Delo, Pennzoil etc should get the job done. Fall in VT is tricky with temps so 10w-40 or 15w-40 should be fine. As temps drop down near freezing overnight I would avoid 15w-40 if the car has an outdoor parking spot.

SAE 30W "Break-in" specific oil is not a good idea in my opinion for anything over an idle check - it's far too runny.

[porschetub]

Always run new engines hard but don't thrash them,people forget the fuel system @ times also,that previous rich running motor will do a lot of harm to a fresh top rebuild.