Oil Pressure gauges....what and why?

[chickentendah]

I've seen people strongly urging the use of oil pressure gauges....

this might sound like a really stupid question, but we gotta learn some time right?...................

so what does an oil pressure gauge tell you?why do we need it?where are oil pressure senders usually installed under the hood?

[USDMSTALKER]

1. How much oil pressure is in your motor.2. If you have a turbo motor or any motor if the oil press. goes low you don't have a motor any more because you will spin rod bearing and turbos will seise up.3. The oil pressure sending unit i think is located right beside the oil filter at least it is on a sr.

[msaskin]

USDM is mostly correct. To add a bit:

Oil pressure senders on most stock cars are located right on (or near) the oil filter housing. The downside is that a number of cars (the 240sx included) don't have oil pressure gauges stock. They simply have a "low oil pressure" warning light, which is what the pressure switch near the filter is for. The 2nd downside is that when that light comes on, odds are you've already done some fairly serious damage to your motor...it may not be knocking yet, but that low pressure has probably done at least some damage to your bearings.

Also, low oil pressure will not damage turbos. In general, a turbo needs only a small trickle of oil. In cars the usual cause of low oil pressure is a lack of oil in the system...that is what will damage turbos.

Oil pressure gauges are good and will protect you from missing the fact that you're burning oil over time. What it won't save you from is spinning a bearing due to the oil pump starving of oil...I speak from experience on this point. I killed off my motor at streets of Willow Springs a few weeks back and never noticed a problem on my oil pressure gauge...the oil in my pan just ran away from the pickup for a few seconds during a hard banked turn (my guess) and by the time I was out of the turn, the motor was knocking already. Oil pressure appeared healthy the entire time.

~matt

[SRdave240]

So, if your on a budget (aren't we all), AND you don't seem to have any oil pressure problems, AND you track your car. Do you think an oil pressure gauge or a Greddy pan is a better investment?

[s13EastTN]

Well, I would imagine that the safest thing would be the gauge, considering that you can have any kind of oil pan, but if you don't have pressure or oil at all you will know it with the gauge, but the pan wouldn't tell you anything. I would imagine having both would be safer than just having the gauge, but from what I have learned, most aftermarket oil pans are designed to keep oil cooler, keep it from sloshing around, and to keep it from being pushed to teh back of the oil pan and away from the oil pump under hard acceleration.

btw SRdave240 are you superdave from HMC2?

[msaskin]

I would have to disagree.

If you track your car, I would consider the GReddy pan a 100% necessity. Granted, I did spin a bearing on the road course a few weeks back, so that kind of puts a slant on my view

~matt

[SRdave240]

btw SRdave240 are you superdave from HMC2?

Why yes I am! You must be reddragon?? I don't get on this board too often. Usually just FA.

Quote »Granted, I did spin a bearing on the road course a few weeks back, so that kind of puts a slant on my view [/quote] With the Greddy pan??? Did you have enough of oil?

[msaskin]

No, with the stock pan. I did have enough oil, it was a case of the stock pan not being baffled and leading to oil pump starvation for a few seconds on a banked turn (lap after lap...)

Oil pressure gauges are good (in my opinion) for knowing the general health of your oiling system. If you notice pressure is down a given amount one day, you know you may be low on oil, your pump may be dying, etc...

By the time you see an oil pressure gauge at a dangerously low level and react to it, the damage has already been done. I had an oil pressure gauge installed on my car @ willow springs...it sure as hell didn't save me. I was busy concentrating on my driving and on the track. Besides, I doubt even if I was paying attention that I would have noticed the quick little dips in pressure during one corner of the track.

~matt

[sirwarrior]

Greedy pan has a fitting for a gauge.So i say get the pan, than get the gauge.BTW you want to have about 10PSI for every 1K of RPMs

[msaskin]

The fitting on the greddy pan is for an oil temp gauge. Measuring oil pressure at the pan doesn't tell you anything...the oil in the pan shouldn't be pressurized anyhow. If it is, you've got some serious problems with your motor.

~matt

[SRdave240]

LOL - that is what I was thinking!

[Phax]

I would have to disagree.

If you track your car, I would consider the GReddy pan a 100% necessity.

:withstup

The stock oil pan only holds about 3 quarts, or some ridiculously small amount of oil. The Greddy pan should be considered a requirement if you're going to be doing any sort of performance driving.

[msaskin]

The big difference is not the extra oil capacity. The difference (and benefit) of the GReddy or ARC pans are the trap-doors and baffling

~matt

[sirwarrior]

The fitting on the greddy pan is for an oil temp gauge. Measuring oil pressure at the pan doesn't tell you anything...the oil in the pan shouldn't be pressurized anyhow. If it is, you've got some serious problems with your motor.

~matt

Im sorry, you are correct. I am thinking about getting both, oil temp and press, so I mixed them up. :dunce

[sil80drifter]

Is it common for the KA oil pumps to give out on high mileage engines? The reason I ask is that I've recently aquired an oil pressure gauges (sensor and all) and noticed that my new warning light (goes off if pressure sinks under 11.4psi, unlike stock which only goes off under 5psi) goes on while I idle. So my oil pump is not doign too good, as idle oil pressure shoudl be around 15-20 psi. And mine never goes above 50 even after 3k rpm, although it's supposed to be around 60psi after 3k rpm.

Also I've developed a rattling, appearing only under load, between 2.5-3k rpm, which I think is the timing chain tensioner not having enough oil pressure making the chain rattle. I've replaced all timing chain components 40k miles ago (I'm at 142k now).

At first I thought it was rod knock, but then I remembered that rod knock is constantly present, and the higher the rpm, the more severe. My noise disappears after 3k rpm, to be explained by the oil pressure getting high enough for the tensioner to tension the chain.I've ordered a 280ZX oil pump (I have an SOHC), and hopefully this will solve my problem, and if I have to I'll replace the timing components agai, if they have sustained enough damage at this point.

Any one else have their oil pump give out on them? I've put in 20-W50 oil for now, to keep the pressure up, and try to drive the car smoothly without stomping the gas (so the rattling is not present) until I've replaced the oil pump.

sil80

[sirwarrior]

Is it common for the KA oil pumps to give out on high mileage engines? The reason I ask is that I've recently aquired an oil pressure gauges (sensor and all) and noticed that my new warning light (goes off if pressure sinks under 11.4psi, unlike stock which only goes off under 5psi) goes on while I idle. So my oil pump is not doign too good, as idle oil pressure shoudl be around 15-20 psi. And mine never goes above 50 even after 3k rpm, although it's supposed to be around 60psi after 3k rpm.

Also I've developed a rattling, appearing only under load, between 2.5-3k rpm, which I think is the timing chain tensioner not having enough oil pressure making the chain rattle. I've replaced all timing chain components 40k miles ago (I'm at 142k now).

At first I thought it was rod knock, but then I remembered that rod knock is constantly present, and the higher the rpm, the more severe. My noise disappears after 3k rpm, to be explained by the oil pressure getting high enough for the tensioner to tension the chain.I've ordered a 280ZX oil pump (I have an SOHC), and hopefully this will solve my problem, and if I have to I'll replace the timing components agai, if they have sustained enough damage at this point.

Any one else have their oil pump give out on them? I've put in 20-W50 oil for now, to keep the pressure up, and try to drive the car smoothly without stomping the gas (so the rattling is not present) until I've replaced the oil pump.

sil80

I've seen a Saturn motor that had low oil pressure and lost the tensioner.Not a pretty sigth.Fix it ASAP.

[askpcguy909]

I had a ka24e with 180,000 miles or so and my mechanic suspects the oil pump failed. Despite regular oil changes, it still tore up the engine. and I was forced to get a low mile ka swap.

[sil80drifter]

I wonder if I should take off the chain cover to see if there is any damage, I did order a new tensioner/guides/gasket already, just in case, so maybe I will just replace them all this weekend.Got the pump already, looks nasty, can't wait for that high flow beast to start pumpin oil through the engine

sil80

[MarkEmark]

USDM is mostly correct. To add a bit:

Oil pressure senders on most stock cars are located right on (or near) the oil filter housing. The downside is that a number of cars (the 240sx included) don't have oil pressure gauges stock. They simply have a "low oil pressure" warning light, which is what the pressure switch near the filter is for. The 2nd downside is that when that light comes on, odds are you've already done some fairly serious damage to your motor...it may not be knocking yet, but that low pressure has probably done at least some damage to your bearings.

Also, low oil pressure will not damage turbos. In general, a turbo needs only a small trickle of oil. In cars the usual cause of low oil pressure is a lack of oil in the system...that is what will damage turbos.

Oil pressure gauges are good and will protect you from missing the fact that you're burning oil over time. What it won't save you from is spinning a bearing due to the oil pump starving of oil...I speak from experience on this point. I killed off my motor at streets of Willow Springs a few weeks back and never noticed a problem on my oil pressure gauge...the oil in my pan just ran away from the pickup for a few seconds during a hard banked turn (my guess) and by the time I was out of the turn, the motor was knocking already. Oil pressure appeared healthy the entire time.

~matt

I'd rather have an oil temp gauge...The idiot light works, and works like a charm...nissan engineers didn't design it so that once it went on catastrophic engine damage has already ocurred; otherwise there would have been no reason to design this safety warning in at all (why even bother putting a warning light in if the engine's destroyed by the time it comes on)?

How do I know it works? Because it went off on my car after some oil-cooler hoses blew off the nipples when i had first t/c'd the car. I haven't observed an iota of MANIFEST damage since that happened--car has ran just as perfectly as it did before this happened.

This same low pressure oil light came on my Dad's 1986 Volvo 740 turbo and similarly, nothing bad happened to the engine that was detectable.

As long as you immediately shut the engine off after seeing the light, you should be good.

Just my .02, although if I had the time/money, I wouldnt mind having an oil pressure gauge

[sil80drifter]

Here's the scoop/update:Did the chain swap, guides were still fine, but I replaced the passenger's side one anyway, tensioner was fine too, replaced anyway, and left the chain, because it never really needs replacement, especially not after 40k miles. Replaced the oil pump with a 280ZX oil pump. Result: Oil pressure is now normal, no "start-up rattle" or audible rocker/valve tick. So the oil pump helped.

The "rattling" that was present between 2k and 3k rpms under LOW THROTTLE ONLY, turned out to be.... PING! Can you believe this?! I've been pinging for a good week! I did an injector replacement recently, put in 460cc instead of the old 270cc, because I'm going turbo soon, and tuned them with the SAFC. Well technically, 40% of 460cc is ~270cc, so I initially just put -40% all across the board, BUT! As I've been trying to figure out the nature fo the rattle, and it's disappearing under WOT (at any rpms when it would usually be present otherwise), and thought about how even 460cc injectors can't flow too much at idle and low rpms, since other cars have them and they don't seem to have idle problems (i.e.: the RX-7 they are from originally), I figured that I should try to rich-en the low throttle map. I did, and went with around -12% between 1000 and 3000 rpms... and the pign is gone.

I cannot believe how long the engine took this abuse, considering I've driven it to work for a couple of hundred miles with this condition present. I think my scenario is prety specific, and the rattle I had is not timing chain/rocker arm/valve related, but I just thought I'd share, so others can maybe learn from my experience. I did fix the start-up rattle though, for which the new oil pump was great help.

sil80

[askpcguy909]

I had the same rattle/clicking noise at 2k 3k rpm under low throttle. Wide open I either did not hear it, or it was gone.

One day, I was driving at night and started to get a need for speed, so I speed up only to hear the rattle become worse. I figured it was just getting too hot, so I'd check in the morning. Yup still present, loud rattle/click at 2k rpm and above.

Took it in, engine was pulled and stripped.. Bearings are shot, crank has some scorning, and a piston head froze.

So, I'm having the crank machined, will buy TOGA HP bearing combo set and a high volume oil pump. I also need a performance gasket for the KA24E single cam 1990 240sx. Any help is appreciated.

[stfuad]

Not to bring this thread back from the dead or anything but I have both the rattle on startup, and the pinging problem...

After reading up on it a little I found this article, http://www.msgroup.org/Contrary/NEG037.html , it's pretty informative.

Also can anyone recommend a Oil pump? About the 280zx oil pump, it matches up perfect?

[thundachiken]

To add to this for turbo owners, Detonation can be detected through a oil pressure gauge. The needle will actually become erratic & twitchy during detonation. Learned this through the turbo escort fourms.

[nab911]

Ok, i have an oil pressure gauge but its the autometer one that has a very tiny plastic line (its mechanical). How do i hook this up? Do i need to run a small stainless line and get fittings because i know the line will melt with hot oil running through it.

[sil80drifter]

I bought the 280ZX pump for my SOHC. It's identical to my old one. I hope it really pumps more. The gauge shows a 10psi improvement.

sil80