well I guess we all get to learn lessons from time to time, its always good when their reasonably cheap. I just had the pleasure of yanking the A15 out for the 3rd time & installing a new cam & lifters - went flat & dished the lifter face pretty good.

not sure how well you can see but its wiped....



then got it back together & running, had the dist off a tooth so it read 25* instead of 12* or 14*, resolved that & noticed an ugly blue / white smoke literally pluming out of the exhaust at times, usually after sitting at a light. Checked compression, its running 2 160# in 1,2 & 3 & 170# in #4 so that wasn't it. Started worrying about stem seals & checked them as best I could, I have double springs & wondered if one had snagged on the inner spring - nothing obvious, they all looked seated.

Then I started playing with the fueling in the weber & changed to a smaller main jet & larger air corrector -that actually helped but the smoke still would billow out at times, usually into some poor bastards face behind me as I left in a cloud. Finally I pulled the PCV & let it hang loose & installed a mini K & N filter I had off an oil catch can setup & went for a test drive - Wah La, problem solved !

At the time I replaced the catch can setup with a PCV I stupidly went to Schucks auto & picked one out that had a 90* top fitting to it so it could easily go to the vent pipe on the crankcase - BAD IDEA! It apparently had WAAAAAY too much vacuum at idle and was obviously for a different motor setup, I've no idea what as I didn't look when I bought it but spending another $1.99 on a nissan A series specific PCV solved the problem. It was drawing so much vacuum at idle it'd literally pull oil out of the crankcase & load the cylinders so on takeoff it was like a smoke bomb going off.

Maybe one of you guys can learn form my screw up & realize you dont replace a PCV with something other than what the mfg spec is.

BTW - this was another issue when i pulled down the motor - the timing tensioner piston had actually stuck in the body of the tensioner & was a 1/4" from the chain. This were all new parts not too long ago, I went and pulled an old tensioner off anothe A12 I have & used the housing along with the new piston as it moved freely in the original Nissan housing but woud stick in the aftermarket one. go figure - shi**y parts....




new piston in old OE Nissan housing...



Moral of the story - don't stray completely off the reservation when modifying systems ,some are designed for very specific reasons.

your cam made so much vacuum at idle? what cam is that?

I dont think it was the cam necessarily but the wrong PCV valve. There isn't a spec for one in "inches of mercury" & PCV's aren't sold that way so no way to find the right spec in a different version.