Freshly rebuild 1.6 NA (CR), what to expect? break in

[overdrivegear]

I just put in a a freshly rebuilt CR 1.6 NA in my 85 golf.  Machined head with new exhaust valves, ARP studs, pistons and rods balanced within 1 gram, rebuilt pump, new injectors, and all that good stuff.

I have 100 miles on the engine and it puts out some smoke emission...more so than normal compared to my friend's car.  The mechanical valve timing is dead on and the pump's lift is set to 1.0 mm.  There's quite a bit of vibration at low RPM also, but any RPM above idle, it's smooth as silk.  I drove it in the interstate at 75 mph and it was great; no vibrations at all.

The car starts right up every time regardless of what temp it is outside.  I have a 1000 cold cranking amp battery in there and it's absolutely divine.

My question is that is the emission and rough idle characteristic of an engine that has yet to break in? What else should I expect? Also, what procedure should I follow to break in the engine correctly?

[jtanguay]

I just put in a a freshly rebuilt CR 1.6 NA in my 85 golf.  Machined head with new exhaust valves, ARP studs, pistons and rods balanced within 1 gram, rebuilt pump, new injectors, and all that good stuff.

I have 100 miles on the engine and it puts out some smoke emission...more so than normal compared to my friend's car.  The mechanical valve timing is dead on and the pump's lift is set to 1.0 mm.  There's quite a bit of vibration at low RPM also, but any RPM above idle, it's smooth as silk.  I drove it in the interstate at 75 mph and it was great; no vibrations at all.

The car starts right up every time regardless of what temp it is outside.  I have a 1000 cold cranking amp battery in there and it's absolutely divine.

My question is that is the emission and rough idle characteristic of an engine that has yet to break in? What else should I expect? Also, what procedure should I follow to break in the engine correctly?

constant changing RPM's, and running non synthetic oil will really help.  also keeping your speed at or below 60 mph will really help too.  75 mph might be okay, but i wouldn't want to risk it after having all that engine work done... you do need to give it some though, to seat the rings (some high rpm's, but don't go too crazy  :lol:).

the idle vibrations could be a motor mount, a bad injector (yes some people have received bad injectors that were supposed to be 'rebuilt') or a pump issue.  to test the injector theory, crack each injector line one at a time, and note a change in engine noise.  if they all affect engine rpm/noise when cracked open (one at a time) then thats not the problem.