I recently changed my head gasket on my poorly build b20vtec. I did a lot of research before doing it because it was my first time. I had the help of a friend who is a mechanic and everything went smoothly. Car started up fine after we completed the installation, but now I got a huge problem. We let it ran on idle for a couple of minutes to make sure everything was okay but as soon as I hit the gaz pedal, a big white smoke trail would come out of the exhaust. I removed the spark plug and they were full of oil and I could see on the piston there was also some oil. Did a compression test and I got 210 on cylinder 4 and 175 on the other 3. I did a leakdown test on cyl 4 and 1 (they were at TDC) and it was coming out from the oil cap and the dipstick hole. What could be the problem? Piston ring or the valves?

 

Air coming out from the oil cap and dipstick hole sounds like piston rings not sealing. Did you get the block bored/honed? Do you know your piston to wall clearance? What are your ring end gaps?

 

I don't know any of those. I bought the car a year ago, never really had problem with it. Until last week, when I had to change the head gasket. We noticed some things when dismounting the head, like the piston had valves print on the them. No intake gasket, no dowel pins on the head, really shitty electric circuit and a couple of other problems. We just washed the head before putting back the new gasket, because I didn't have the time. Should I change the head (my friend is giving me one for free, just need rocker arms) and check the piston while the head is out?

 

As far as I'm aware, you can't check piston to wall clearance or piston ring end gap with the pistons in the motor. The marks from the valves present a different, but no less problematic issue. Have you tried doing a wet compression test? the low compression numbers you got could be related to valve issues, although your leakdown results would seem to disagree.

 

I know. I just need a car running to go to work and I don't have money to buy a new one. Also, today we discovered that there was nothing connecting to the PCV valve.

 

It sounds like it was assembled with high amounts of slap-dashery. Basically poorly, as you said. There's no telling how well or if the assemblers spec'd everything before putting it together. You may need to do a rebuild to fix the issues, or at least check the tolerances. It sounds like the first engine I ever assembled, my buddies b18. We had to rebuild the engine in his backyard with $200 and a socket set and without a clue between us. I didn't measure ring end gap and lo and behold, lots of smoke, burning oil, etc.

 

The engine was fine (except for HG) before I changed it. It was puffing a bit of oil, just like any other used motor. Pistons were fine and all. Maybe I put too much air during leakdown? I read it was normal to have a small % of air coming down the dipstick tube. But from the oil hole on the valve cover? We changed the cams also and thought they were the same so we didn't ajust the valves.

 

Okay anytime the cams are remove valve lash needs to be at the very least checked. Yes a very small amount of air can come out of the crank case( the oil drain back holes inside the cylinder head lead to the crank case). A proper leak down test is with a dual gauge leak down tester that pushes 100psi of air through both the first will show the amount of air being supplied and the second will show the amount of pressure loss( I.E. if the first shows 100 and the second shows 70 then you have a 30% loss, acceptable loss is around 5-15% depending on the condition of the rings and cylinder wall). Why did you change the head gasket? You may have a valve stem seal issue as well. Did you Buy new head dowel pins? Do the valves have marks on them from the valves hitting the pistons? I never recommend that anyone that does not have knowledge on how to do jobs this extensive to do it on their daily drive simply because Murphy's law (Anything that can go wrong will go wrong).

 

Yeah, best to have the piston rings checked once more.