hey whats up. i've got an oil pressure question. on a turbo teg, i've not been able to get the right oil pressure. when drive n around at 3K rpm the oil pressure is at 35-40psi where it should be around 70-80 psi

to fix the problem:
the oil pump was changed----> still got low oil pressure
Changed all the bearings. got clearance of .0015" on the rods using honda brown bearings, and .0018-.002" on the mains using honda blue bearings. we started up the car wit 10W40 oil and oil pressure was struggling to stay at 70psi at cold start up. changed the oil to 20w50 and got 80psi oil pressure at cold idle. i let the car warm up till the oil pressure dropped to 20 psi at idle. reving the car up the oil pressure went to 80 psi. Now i took the car out to test it. Driving the car, the oil pressure was still the same low 35-40 psi at 3K rpms. WTF?

Im stumped now. any of u guys care to put a word in about this issue and how to help solve it. The engine is a built turbo car. it has golden eagle block sleeved to 84mm, and a B16 head. let me know if u guys have any solutions

 

what motor is this?

.0020" on the main bearings is slightly larger than factory spec for any of the mains on a B18c. The middle main bearing (#3) has the largest gap with .0017 - 19" the rest are .0009 - .0017".

Im not sure if this would cause a significant drop in oil pressure but it should have some affect. And again I assumed this was a B18 motor since you said it was in a teg.

 

try a different gauge?

 

ya know, you can wire a gauge backwards

 

Your sure your bearing clearances are correct? Is this a newly built motor? If so you may want to take it back to the builder to have the clearances checked? If you clearances are too much the OIL pressure will be LOW. ALso where are you taking the oil pressure readings from?

 

Where are you getting your pressure from?

My engine had 29 K when I when over to the dark side. I ran a line from the block to the firewall, a T was used for the pressure sensor, and then to the turbo it went. Apparently the problem was the fact that it was flowing through the T and turbo. That was causing it to read lower.

I put the sensor straight to the block and got numbers that were a lot better. The turbo oil feed now came off of a fitting that T's right off of the blocks pressure sensor openning. The pressure is now off by a negligible amount.

GL

 

also make sure you dont have dent in oil pan. The pickup will be getting full sucking power and not have the pan to close to it. its a dumb idea but it may have been overlooked.

 

You should get just @ 15 psi per 1000 rpms.

15x3=45psi in my book. i want to make sure i understand you correctly tho, if you are driving or revving @ 3000rpms, you get 30-45psi?? if so thats normal.


when on cold start up it should go up to about 70 and then slowly fall back down. thats fine, it shouldnt stay at 80psi.

the pump will only move so much oil volume, and pressure comes from bearings, so if your bearing tolerances are correct, and you have the correct psi.

you are good

 

in my personal car, a 97 LS, i hit 70-75 psi cruising at 3K on the highway. i have my mechanical oil pressure sensor run n from the block (where the stock oil pressure sensor was)
im gonna check to see where this oil feed signals coming from. (its a mechanical gauge so i cant hook it up backwards)

clearance of .002" shouldnt throw off the oil pressure that much. .002" is the service limit for B series motors.

 

Do this unhook your ecu fuse, remove your mechnical oil pressure gauge so you can purge the line. get rid of all the air in it. Basically with the gauge removed crank the car over several times till oil comes out of the line, once it dose hook it back up to the gauge. this will give you a more accurate pictures of the oil pressure.


Modified by fipracing_com at 11:00 PM 2/15/2005

 

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by mrbsponge &raquo;</TD></TR><TR><TD CLASS="quote">You should get just @ 15 psi per 1000 rpms.

15x3=45psi in my book. </TD></TR></TABLE>

As far as I remember, thats wrong.

The oil pressure maxes pretty early and extra pressure is released out through a release valve in your pump.

EDIT:

Just got my helms:
Engine Lubrication -- Section 8
Relief valve:
@ idle : 70 kPa 10 psi min.
@ 3,000 rpm: 340 kPa 50 psi min.

 

what about the O ring under the middle cam cap

 

when you add the extra lines for a turbo, you are filling much more volume than the stock oil pump was intended for. You will notice a drop in pressure. One solution is to use an oil pressure reducer for the turbo. it keeps the turbo from seeing too much pressure while restricting the flow from the block helping to keep the oil closer to it's proper pressure.

 

u guys really think a clearance of .0015" on the rods and .002" on the mains = excessive bearing clearance. the rods r dead on---&gt;, but the main might be a little loose, but it shouldnt be that loose to drop the fuel pressure so much.... or will it????

the gauge was changed as well as the oil lines for the gauge. so the problems not the gauge. the oil feed was taken straight from the stock oil pressure sensor and not the golden eagle fitting on the oil filter. on the GE fitting, oil for VTEC and oil for the TURBO are taken from it.

Im think n that it might be a problem with the head cuz the clearance seem to be good.

 

I'm tellin you check for the o ring under the center cam cap just a hunch

 

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by eLusive ek4 &raquo;</TD></TR><TR><TD CLASS="quote">I'm tellin you check for the o ring under the center cam cap just a hunch</TD></TR></TABLE>

alright i'll check that out. thanks for the input

 

Did you install a gasket between the pump and pick-up? Also, as someone else said, a bent pan and bent opening in the pick-up can cost you 30 lbs of pressure. Also check the screen in the pick-up

 

Earl could his bearing gaps result in that amout of pressure drop? How big would they have to be to drop 20-30psi of oil pressure?