Low oil pressure, intermittent low oil light

[slow6]

Re: Low oil pressure, intermittent low oil light

Don't expect the engine to last very long, or handle high HP or extended heavy duty use if you just slap in a new set bearings.

why not?

[Mogobs30th]

Re: Low oil pressure, intermittent low oil light

This engine is completely stock, and will stay that way. The ONLY thing I have modded to this whole car is headers, and I will be adding a catback, thats it.

I have a spare engine I am planning on building up, and that is the engine that will be taking all the abuse. This spare is the one that will be HEAVILY modified. Only thing I need the spare for is getting the car from point A to B, after the spare is built up, or as an emergency car when the Monte is in the shop or isn't running. I can't drive the spare on the streets (at least, not my plan to be driving it on the streets), so I need a completely stock engine to take the car wherever I need it. I have another car I drive on a normal basis, but for those days where it is really nice out, and I don't plan on driving alot, I take the Firebird.

I really don't plan on putting but maybe 30,000 on the engine that is in the car now. I don't do normal day to day driving in it, nor do I or will I put a lot of stress on it. No more than 2 people in it, NO cargo of any kind. I don't see why replacing the bearings would be a bad idea, it is significantly cheaper. I can't afford the money and space to have THREE engines lying around, but if I do tear down the bottom end, and I see that the bearings are EXTREMELY bad, or the crank is beyond repair, I would definitely look into another stock engine. That and trying to find a RWD 3800 in this city is near impossible, and when you do find one, the prices are near $900-$1200 for a low mileage.

If it comes to that point where I believe the bearings will need replaced, then what I will do is probably rebuild the Firebird engine lightly, maybe with some better than stock replacement parts, and have the crank reground. But I will not completely dismiss the idea of buying a replacement, but only as a last resort.

[CDNFB]

Re: Low oil pressure, intermittent low oil light

What I mean when I say "slapping in" is that you go out and buy new bearings (not oversized), remove the old bearings, then install the new without any dimensional checking and preparation to block, rods, crank. This is in the hopes that the new bearings will bring the fits and clearences within limits.

If you do this chances are that:
1) the bearing sizes that you bought will not match within service limits, the diameter of the crank journals. You might be lucky, you might not.

2) the crank surface conditon will not be of a proper finish which will lead to excessive wear rates of the bearings.

The crank journals must have an exact surface finish on them to ensure long life. I've seen in numerous Peterson engine rebuild guides, where they assemble the crank into the block during the rebuild, and they say that if the crank comes in contact with the block, or studs, or anything that can cause the slightest imperfection or scuff in the journal, then the crank needs to get reworked to remove the imperfection.

[CDNFB]

Re: Low oil pressure, intermittent low oil light

Mogobs:

So it sound like your expectations for your engine is not high, so slapping in a set of bearings sounds like the right action for you to take.

[AZ3.8Camaro]

Re: Low oil pressure, intermittent low oil light

Again, this is common on these engines, and is not a cause for concern.
30psi at idle is plenty of oil pressure.

Mine has been that way for 4 years.
Don't rip your motor apart for this reason.

[Mogobs30th]

Re: Low oil pressure, intermittent low oil light

What I mean when I say "slapping in" is that you go out and buy new bearings (not oversized), remove the old bearings, then install the new without any dimensional checking and preparation to block, rods, crank. This is in the hopes that the new bearings will bring the fits and clearences within limits.

If you do this chances are that:
1) the bearing sizes that you bought will not match within service limits, the diameter of the crank journals. You might be lucky, you might not.

2) the crank surface conditon will not be of a proper finish which will lead to excessive wear rates of the bearings.

The crank journals must have an exact surface finish on them to ensure long life. I've seen in numerous Peterson engine rebuild guides, where they assemble the crank into the block during the rebuild, and they say that if the crank comes in contact with the block, or studs, or anything that can cause the slightest imperfection or scuff in the journal, then the crank needs to get reworked to remove the imperfection.

By no means would I ever do that, or recommend that. "Slapping in" rod and main bearings without checking clearances isn't something I would do with an engine, either new, or with 500k on the odometer. And you are definitely right about the scuffing and scratching part. Ive had a few machine shops tell me the exact thing, which is why I am going to let them build the bottom end for me on the other engine.

AZ, my only worry is if it does dip down below 30 psi. But there is another worry that I might have a bad oil level sending sensor too. The low oil light is always on until the pressure drops to about 35-40 range, and after it has been running for about an hour or so, then the light goes off. I think what I need to do first is have the pressure tested at a shop, and get the level sending sensor replaced. Go from there.

[slow6]

Re: Low oil pressure, intermittent low oil light

Again, this is common on these engines, and is not a cause for concern.
30psi at idle is plenty of oil pressure.

mine was ALWAYS at least 60psi at idle before my $hitty rebuild

get Clevite 77 Trimetal bearings

[Mogobs30th]

Re: Low oil pressure, intermittent low oil light

Update: I drove the car for its longest trip since the rebuild, and I seen the pressure dip BELOW 30 psi, barely below, but below. What makes me skeptical about all of that is that the needle seems to be moving around to the inertia of the rest of the car. My guess is that I think either 1). the gauge is broke, and not reading correctly, or 2). the sending unit is broke and not sending the proper info. Im HIGHLY doubting that the pressure is off, but I still am a little wary of it, so I will observe it for a few weeks and see what hapens.

[CDNFB]

Re: Low oil pressure, intermittent low oil light

Good plan.

[slow6]

Re: Low oil pressure, intermittent low oil light

I just bought a new sensor cause I broke mine with a sledge
$21 at autozone

[Turbo V6 Camaro]

Re: Low oil pressure, intermittent low oil light

Again, this is common on these engines, and is not a cause for concern.
30psi at idle is plenty of oil pressure.

Mine has been that way for 4 years.
Don't rip your motor apart for this reason.

word perfecly normal

you can get 5w30 in the north winter helps a bit ;)

[CDNFB]

Re: Low oil pressure, intermittent low oil light

perfecly normal

I disagree with that.

Even though this oil pressure drop has occurred on many cars, and the overall impact to engine durabiliy so far as been minimal, I still would not classify it as normal. Acceptable maybe but not normal.

I've been watching my oil pressure very closely in the last couple of days, just to see how it reacts to various engine temps and driving conditions. This turned out to be very boring because at cold startup the oil pressure is around 70 psi. At operating temperature the pressure is not much different at about 65 psi. The pressure does not change with engine RPM or with forces that slosh the oil around in the pan (cornering, braking, acceration). The needle just sits there.

If my oil pressure was to suddenly drop to 30 psi, I would not consider this normal. Something would be up in the engine/lubrication system. Now it's nice to know that at this pressure the engine is not going to sieze up on me. But I would seriously do all that I could to find that problem and fix it.

[Turbo V6 Camaro]

Re: Low oil pressure, intermittent low oil light

I disagree with that.

Even though this oil pressure drop has occurred on many cars, and the overall impact to engine durabiliy so far as been minimal, I still would not classify it as normal. Acceptable maybe but not normal.

I've been watching my oil pressure very closely in the last couple of days, just to see how it reacts to various engine temps and driving conditions. This turned out to be very boring because at cold startup the oil pressure is around 70 psi. At operating temperature the pressure is not much different at about 65 psi. The pressure does not change with engine RPM or with forces that slosh the oil around in the pan (cornering, braking, acceration). The needle just sits there.

If my oil pressure was to suddenly drop to 30 psi, I would not consider this normal. Something would be up in the engine/lubrication system. Now it's nice to know that at this pressure the engine is not going to sieze up on me. But I would seriously do all that I could to find that problem and fix it.

read your cars instruction manule IT IS NORMAL

unless your running a OIL PSI KIT 20 psi is fine at idle and should gor to 50-65 at WOT on stock car

[4thgenowner]

Re: Low oil pressure, intermittent low oil light

I dont have a 3.8 but on my 3.4 when its cold the psi is a constant 40 but when its warm its 15. Its normal. Same thing on my LT1.

[nascar24jd]

Re: Low oil pressure, intermittent low oil light

I had this problem with my Olds Cutlass. I installed a temporary mechanical oil pressure gauge to find the truth. The truth was that the factory gauges in most GM cars STINK. They are not accurate and flop all over the place. Just install a mechanical guage for a few days and you will have piece of mind.

My guess is the pressure is fine, gauge is off.