dDuB

Here's the jist. Freshly rebuilt motor, just over 2k on it and break-in recently ended. I installed an Autometer Electric Oil Pressure gauge mounted via the racing beat pedestal adapter to verify the numbers in case the stock one was junk. Here are my results:



Cold -

Idle stock gauge = 30psi

Idle Autometer gauge = 35-40psi

3k stock = 60psi

3k Autometer = 75+psi



Warmed up to operating temp -

Idle stock = 0 or barely above

Idle Autometer = 0 or barely above

3k stock = 30psi

3k Autometer = 35-40psi

7k stock = somewhere just above 60psi

7k Autometer = Over 75psi



I was running cheap Sears brand 10w30 during the break-in for my motor because I didn't want to waste expensive oil due to the 500 and 2000 mile oil changes so I was hoping it was just that crap oil. However, I changed my oil to Redline synthetic 20w50 and a new Atkins Rotary OEM spec oil filter. Something to note, though, is that the cold oil pressure after the oil change was much much higher than before, but after it started to warm up it began to drop again to where it was before. Could this possibly be because it was then mixing with the other 10w30 sears oil that was in the oil cooler and engine already? I know it's a long shot and I doubt this to be the answer to my low oil pressure problems, but I thought I'd ask.



History of engine. I did the rebuild not because it needed it but because I wanted to port. Engine had ~150k and ran great. Idled perfectly, fair compression, no smoke, and oil pressure (as much as I can remember) was normal. No seals or anything were blown prior to the rebuild. Engine now runs perfectly. Fires up on every try hot or cold, never floods (hardly did during the rebuild even), idles perfectly solid when warm (a little brap to it when cold though, but that is most likely due to mods), and is very smooth driving.



Oil related things I can think of that were done during the rebuild. New o-rings, used atkins viton oil rings, put in corksport SS oil cooler lines, inspected other oil related things during rebuild everything looked fine, used an Atkins thermal bypass pellet, when I did the oil change today there were no sparkles or metal shavings at all in it after being drained, and that's all I can think of right now but feel free to ask me questions.



Also another thing to note that I think might be contributing but am not sure. During the rebuild I put in a rebuilt rear oil pressure regulator good for 80-85psi however I DID NOT SHIM the front regulator. Could this cause these problems? I forgot to shim it and haven't gotten around to it since I put the engine back in. I will be doing this soon hopefully to see if it helps.



My symptoms seem weird because idle seems way low, 3k or so seems a tad low, and up to redline it seems fine (reaching over 75psi with the unshimmed front regulator). An idea I had came from reading a how-to on here about e-shaft oil mods where you replace the ball and spring under the large screws with carb jets. Doing this gave much better pressure and flow at higher rpms however at idle they said oil pressure could and would drop to near 0 or at 0. They said to remedy this you'd want to get an 80-85psi rear OPR and shim the front one. I was wondering if the ball/spring might have had something go wrong and are now stuck "open" all the time in a way like these jets would cause? Is that possible? And if it is would it be causing these symptoms? Because it seems to follow the oil mods they describe for the e-shaft. Just curious...



That's all I can think of for now for information and questions, please if you have any ideas or suggestions don't hesitate to help me out. And if there is any more info you need to know I'll be glad to do my best to answer your questions.



Thanks.

dDuB

One other thing. The readings I got for idle and warmed up for psi were taken in neutral in my driveway. One thing that might be worth noting is that when I was driving while monitoring the Autometer gauge it seemed to only be at about ~30psi with load at 3k rpms when fully warmed up, yet in neutral it was higher? I dunno just throwing it out there. And while driving with the engine cold at 3k it was over 75psi easily, in neutral it was a little above 75psi.

C. Ludwig

http://www.mazdatrix.com/faq/oring.htm



First place I'd look. Also, while the front cover is off check the spring in the front regulator. While not common, they can break.

Lynn E. Hanover

The first thing that comes to mind is the "O" ring between the front cover and front iron. Should have a plastic washer around the outside of it. If you rev up on a cold engine you can blow this ring out, or cut part of it.



shimming the front relief will do nothing for idle oil pressure. It is there to protect the oil cooler. Unless the spring broke. Same for the rear relief, does nothing for idle oil pressure, only maximum oil pressure.



The pickup tube gasket may be damaged or the bolts loose. Beyond that I have no help.



Lynn E. Hanover

dDuB

The teflon washer around the o-ring is for s5's, I have an s4 so I don't use the teflon o-ring holder.



I'm going to be replacing a lot of things and hopefully this gets fixed, if it doesn't I'll post what I replaced and whether or not it helped and by how much.

C. Ludwig

Some of the S4 irons can have the larger land that requires the teflon ring. Also, ditch the gasket if you used one and just use silicone.

chase78

The webber jet upgrade will not lower oil pressure to the point that you have it.



I think its your oil pump.



You should spend the $90 to get a new one. many times people rush through the inspection of these this part. The specs of the oil pump is just on the board of it limits. But i bet you if you get a new oil pump and and your old one and do a really carefully exam of then you will notice not a huge difference but a differnce non the less.

Judge Ito

helpful tip here. turn the engine on. go and squeeze the oil cooler hose coming out of the engine. It should be brick hard from good oil pressure. If it's not, then check everything else Lynn H. said.

guitarjunkie28

i stopped using the o-ring on the s4's. now i use a furniture finishing washer. problem solved...no more blowouts, NEVER had one fail. and you get to keep the front cover gasket--may or may not reduce leaks...