Best way to break in a new rebuilt engine?

[Northboundtrain]

I'm just finishing up a 1.6 n/a rebuild.  Everything is stock.  It has a rebuilt head with an obviously used cam from the Partsplace.  A friend who has been into engine rebuilding for years and years was explaining to me that an engine must be broken in differently than a cam.  The engine should be idled for about 30 minutes to start, while a cam should be reved at 2000 rpm for about 20 minutes.  Since I have a used cam, he explained that I should just break in the engine (idle for 30 minutes) and don't worry about the cam.  As long as the cam followers were reinstalled in their original locations, there should be no problem.  BUT, if the the cam followers were not, then he says I'll only get about 20k out of the cam and then I will need a new one and new followers.

Anyway, I'm curious to know what you guys think about breaking in a new engine with a rebuilt head.  Any tips, suggestions?

Thanks

[janb]

...A friend who has been into engine rebuilding for years and years was explaining to me that an engine must be broken in differently than a cam. ...Anyway, I'm curious to know what you guys think about breaking in a new engine with a rebuilt head.  Any tips, suggestions?Thanks

never heard that on a VW diesel.  You don't have an alcohol fueled dragster here...

1) Hyd or Mechanical ?  If you have used hyd lifters, they must be compressed for reinstall, or you might get some bent valves, or no compression due to valve open

2) don't think I would be too happy revving a new engine to 2000RPM, just to break in a cam!

for break in, I watch temp very closely, and run short periods, (20 minutes) to increasing duration (2hrs).,  varying RPM and load, but not revving above 2500-3000 for a while.  I use dino oil for 0.5k, then 1k miles, and 2 -3k till 20k miles, then switch to synthetic  in TDI's, and 1qt synth w/ 3.5 dino in IDI's.  Filter and oil change ~3000 - 5000 thereafter.  except TDI synth, get filters every 5, and oil every 20K

[Dr. Diesel]

Every person 'in the know' i've asked this question of (I've worked in three different engine overhaul facilities) has basically said this:
Seat the rings, then take it easy for 3-4000km's on conventional engine oil.  
Seating the rings requires higher cylinder pressures. You need to 'give it'.
From what I've heard, common practice is to load and unload the engine several times. For example, around here, we have a 100km/h highway that travels up a 25 degree incline for about 3km. I always accelerate full throttle in an appropriate gear to 4500ish, back down to 2000 and repeat 5 or 6 times.  If you don't properly seat the rings, the cylinder walls will glaze and you'll have increased oil consumption and never have proper compression.  
Idling for 30 minutes is a sure way to glaze the cylinders.
As far as camshafts are concerned, that 2000 rpm trick is normally for american engines, typically V8. All the reading I've done about VW cams says the cam billet hardening process is such that a break in proceedure  outside of the abovementioned engine break-in proceedure, isn't neccessary.
Aircraft engines are similar, check for leaks, run them at high power to seat the rings, then take it easy for a bit.

[HeWhoBurns#2]

I agree with Dr. Diesel on this; I was taught to take it easy until the engine comes up to operating temperature, then pull the trigger.

[Rat407]

I also agree with Dr. Diesel. I just had my engine rebuilt last summer and did it that way and all was fine except that I had high oil consumption for 5k miles.  When I tore back into the engine I found out that the place that rebuilt it broke the oil ring on #3 cylinder and so that was my oil problem. I since then put new rings in it myself and have been going back through the same break-in run as Dr. Diesel stated and so far so good. On my first rebuild I had great compression at 5K, just no oil control on #3 due to the broken oil ring. Just keep and eye on engine operating temp.  Have fun.

[shox75]

well i rebuilt mine 15k ago now, and mines a turbo. I like Dr. Diesels method. Mine didnt work out exactly like that because while i was letting it heat up on the first start my thermostat was faulty and the engine almost overheated, was able to shut it off in time. Replaced it and tried again. Almost no smoking, warmed it up and went for a drive. Didnt push the engine for the first couple 100 kms. However, after about 400-500kms i drove the car from vancouver BC to kelowna BC, a good 600kms of highway, with car loaded and high speeds of 100-120. Then up and down Big White mountain in kelowna twice, and drove home anothe 600kms. So i didnt get to do my first oil change till about 1500kms. changed filter and oil (just regualr 15-40) and since then i've done oil change every 3,000kms. Changing filter ever time. So far havent switched to synthetic yet, but planning on it, and if i do only use Motul. Currently compression at 460psi across all cylinders. smooth running and no smoke at stock settings.
As far as i know, diesels are not like gas cars, they need a *** kicking to break in.
My teachers dodge diesel truck didnt fully start getting good milage until 100,00okms, and he also bagged on the thing hard.
Good luck.