Hello, I am new on the forum with posting and stuff.
I've read I think everything on this forum and internet in general about my problem.
Basically: built d16z6, vitara pistons, skunk2 rods, ACL extra oil clearance bearings. The block and crank is a d16z2 but it's the same as z6 (z2 didn't have vtec).
My bearing clearances measured with plastic-gauge were 0.0020'' on mains and about 0.0017' on rods which I considered ok.
I ported the pump and the oil passage to the block, shimmed the pump also.
I put 10w40 first 50miles for break in oil. I had an electronic oil pressure gauge and as it warmed up I started to see that I had about 3bars (45psi) at 3k rpm, 4 bars at 4k as so on but on idle it was dropping hard to 0.
Ok, I changed the oil with 10w60, the oil pressure didn't change its trend, 3 bars at 3k rpms. I drove about 500km like that on a big road trip. Closer to home I think I hit vtec.
Next road trip I started to almost 4 bars at 3.5 rpm (which before would have been 3.5 bars).
The idle pressure is still 0. I installed a universal mechanical gauge. It reads the same as the electronic one. I have that type of T of the stock oil pressure switch of the block.
The dash light for low oil pressure seems to work normal, on when engine is off and ***** off as soon as engine starts and when I stalled it once intentionally, I saw 500 rpm before the engine stalled and the light wasn't on as long as the engine rotated.
The oil pan is not dented, I know it had some scratches but not extreme.
My questions:
1. The dash light shouldn't come on at 0 psi of oil pressure?
2. Does anyone at what pressure determines the switch to come on? I've heard that on some GM's they come on at below 0.5 bars and someone told me that honda's come on at below 0.4 bars (5-6 psi) (not trusted source).
3. What could have I messed that bad to have no oil pressure at idle? the engines sounds happy af, pulls strong, vtec hits, it maxes out at 5 bars of pressure on the gauge (70psi). The point where the pressure relief valve opens can be spotted so it's not sticked open.
Next things I'll do:
1. Put the oil pick-up gasket on (I didn't had one but put little honda-bond and torqued hard the nuts on it, I don't think I'll have any luck with the gasket put because the surfaces are flat enough already) (the o-ring where the pump meets the block is on, yes).
2. I'll try to take the gauge off the line that connects it to the T on the block to see if oil comes off it.
3. I'll try to look in the valve cover after letting it idle for some minutes to see how much oil is there (it idled for coupled minutes before without extra noises)
I will have to wait for the gasket about a week, that's why I made the thread now, maybe someone will look over it meanwhile.

 

I'd suspect those main clearances,if I'm not mistaken thats the service limit on them. Are you using the OEM Yamada oil pump ? You could also be losing some pressure by not having the pickup to pump gasket installed even though the surfaces looked good and you used some rtv.Try putting one on and report back.