79datsun620 Posted January 23, 2009 Report Share Posted January 23, 2009 i rebuilt my L20b a few months ago its got about 2000 miles on it.is it okay to still have a little blow by.about how long is the break in period,i checked the compression and its 170-175 across the board,its eating about 1/2 qt every 2 weeks and spittin it in to the air filter box throught the valve cover breather. thanks,dave Quote Link to comment
datzenmike Posted January 23, 2009 Report Share Posted January 23, 2009 Over filled with oil? Drain and refill with the exact amount and read dip stick. Is dipstick and holder pushed down into block far enough? Break in depends on driving. Generally the faster you break it in the better 50 to 500 miles should do it now a days. Babying it prolongs the break in and does no good. ASAP give full throttle accelerations between 2K and 4.5K RPS out on the highway in 4th gear follower by long slow downs. Certainly yours is broken in by now. Compression looks good. Quote Link to comment
yello620 Posted January 23, 2009 Report Share Posted January 23, 2009 Is your PCV valve working correctly? An inefficient PCV would cause extra oil to be appearing in the air cleaner housing. Quote Link to comment
HRH Posted January 23, 2009 Report Share Posted January 23, 2009 Did you position the ring end gaps correctly? 180 degrees apart on compression rings, and about 60 degrees on the oil controls? Seems obvious, but just in case. What about valve stem seals? And when you say rebuilt, do you mean entirely, or was it just bottom end? Quote Link to comment
79datsun620 Posted January 23, 2009 Author Report Share Posted January 23, 2009 the oil could be over filled ill check that and i did space the rings.does the pcv need to be at a certain angle or anything. [/img] Quote Link to comment
datzenmike Posted January 23, 2009 Report Share Posted January 23, 2009 Just to be sure... you do have a PCV valve on the end of that hose, right. Hard to tell. Any andle is fine. Quote Link to comment
banzai510(hainz) Posted January 23, 2009 Report Share Posted January 23, 2009 I personally would mount it horizontal as its just a pc that slides back and forth to plug it one way or the other. So it wont have a tendency to throw its weight to one side. But it might not matter once running. I heard of bad oil filter haveing valve issues inside. Im winging this one. were the rings gapped. I guess if not gapped correctly they could bind at the ends when hot then break. I would ru it it just might break in longer if using chrome rings( longer to break in I heard) Quote Link to comment
79datsun620 Posted January 24, 2009 Author Report Share Posted January 24, 2009 yea the rings are gapped,and i do have chrome rings and i've heard that the break in can be longer.mike, the hose is on the pcv. Quote Link to comment
HRH Posted January 24, 2009 Report Share Posted January 24, 2009 What about the head? Did you rebuild that, new seals? I say that because if the block's rebuilt and the head isn't, all that wonderful new compression the pistons make will tend to find the weakest link. (i.e. old valve seals.) Quote Link to comment
79datsun620 Posted January 25, 2009 Author Report Share Posted January 25, 2009 the head was re-built to new seals,valve job,saved.i've seen that before to.something i just thought of is i have a oil spray bar could it be spraying oil right at the breather maybe. Quote Link to comment
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