im on my second oil pressure gauge, my last one while driving would flicker like it was on crack than drop to zero, relized everything was fine when my car didnt blow up

 

I believe you are supposed to be idleing around 36psi when warm. And 85 psi at 3000RPM.

If you are only seeing 50psi, I would NOT push the vehicle until the pressure normalizes (i.e. - you find and correct the problem).

Directly from the Honda S2000 Repair Manual:
Bring it back to Mase.

Sellout - Please know the engine's oil pressure "normal" readings before you post that its just the oil warming up. That is how people blow their motors... They take advice that is not correct. There is NO WAY that pressure drop is due to the oil warming up alone. Not meaning to jump on you, just trying to stop misinformation.

My OPS is REALLY close to my coolant return line, and the rub every once in a while. Light flickered once, I tightened the screw on it, and the light went away for good. IMO, better safe-than-sorry when it comes to oil pressure.

John

 

OK I went ahead and deleted the post. Sorry about that, I had just got done dealing with someone who couldn't handle the normal temperature fluctuation he was seeing on his aftermarket water temp gauge when I got to this thread, and you're right, I should have double checked what the oil pressure is supposed to be.

The OP has a built engine, would you still go by the factory repair manual guidelines for oil pressure in that case?

 

^Not sure. I would maybe expect them to be a BIT lower, but not almost 30% lower at idle (25psi/35psi)... And even more than that at 3000 (cruising) RPM (50psi/85psi = 42% lower). This is also assuming the OP is seeing 50psi at 3000 RPM, and not in the "upper RPM" as he stated. I believe the higher RPM's are in the mid-90's psi-wise.

I am not really sure what impact a built motor has on oil pressure, but I THINK its usually a BIT lower due to different clearances.

I am wondering if his ground-down crank / oversized bearings are chewing oil... If that machining was not PERFECT, they will wear faster / chew oil. That is the first thing I look at with low oil pressure (other than the oil being compromised by coolant, which can be checked on the dipstick). I have never heard of anyone using oversized bearings on the f20c before.

John

 

Do you guys really see 85psi at 3k? Thats a hell of a lot higher than ANY honda motor I've ever had. I don't have an oil pressure gauge on my S yet, but that just seems really really high. What is the relief pressure inside the oil pump then?

 

if the clearances aren't as tight, the oil won't get chewed, it will just go past the bearings and the crank easier, as there is a larger gap. Which in turn will lower the oil pressure.

 

^ Interesting. I know that worn bearings, that are eating oil, result in lower oil pressure as well... I think it has to do with the oil not returning to the pan as it should... Less fluid = less pressure. My oil pressure dropped like a ROCK when my bearings started to wear.

The larger bearing/rod/crank clearances due to the machining of the crank probably lowered the pressure a bit, and if the machining was not perfect, that could lead to another possible source of the pressure drop (oil being consumed by the bearings...).

I was seeing 17-20psi at idle, and 35-40psi at 3000RPM, when my bearings were toast.

Not sure of the physics behind it, though.

To the OP... I recommend you do an oil change asap, and strain the oil through a cheese-cloth, or something similar. Look for copper-looking shavings. If you see ANYHING, drop the pan and inspect more. Relay what you find to us.

John

 

Looks like the OP has discovered what is most likely the problem...

https://www.s2ki.com/forums/index.php?showtopic=706231