98RedBird

iTrader: (77)

I've got a 98' Trans Am. It's got about 65k miles on it and I'm starting to freak out after reading alot about spun bearings and how the LS1 oil pump just loves to fail. The questions that I have are how do you know if you've got an oil pump going out or not? Mine right now when the car is cold will sit at 40psi. Then once it gets hot it will sit at 20psi or a little lower. But what really scares me is that it will bounce around ever so slightly right around 20psi when it's hot. It'll say 20 then drop to 19 then jump back up to 21 and just do that over and over again. I thought it should stay rock solid. So, I'm thinking that I really need to switch out the oil pump. What do you guys think?

Also, what oil pump should I put in there? And do you think it's possible that I've hurt a bearing yet? or anything in the motor from a lack of lubrication? How do I know? I really want to catch it before anything happens and completely tears my motor up. I really don't have money for a new one right now being in college and all. Please help! I'm scared to death to even turn the thing on and drive it at all right now.

ArcticZ28

iTrader: (14)

Well, you won't know if anything's wrong until it happens. If your oil pressure is that low at hot idle, it would be a good idea to upgrade. There are many choices, the most popular being a Melling ported oil pump or a ported LS6 oil pump. They are all good and better than stock.

Blk97WS6

iTrader: (19)

Yeah man, id swap it as well. Are you planning on a cam swap, or just want to replace the oil pump? FYI with my ported ls6 pump, im at about 60psi at idle when cold, and the lowest it EVER gets is just after the 40psi mark when its really warm.

1baddls1

iTrader: (31)

def swap the ls6 pump in there - weather it be stock or ported/shimmed

rule of thumb is 10 psi per 1000 rpm... dipping below 30 @ hot idle scares me as it is... let alone 20psi and less

while your in there may as well do LS2 timing chain - & why not a cam while your in there

vader99

iTrader: (4)

I have a 98 trans am vert a4 that has a lower oil pressure than my 99 ws6 ttop car. My 99 idles at about 42 psi hot most of the time while the 98 is usually at 38 cold and then drops down if it gets really warm to high 20's.

Not sure how common those pressures are for those years??

ArcticZ28

iTrader: (14)

That would most likely be attributed to the fact that 98 gauges are accurate and 99's are not.

tilly

iTrader: (5)

GET A NEW PUMP NOW.

This what my oil pump did right before I spun a earing or something. It would idle around 20 psi, but quiver ever so slightly. Get the ported and shimmed LS6 from TSP worth the money.

outkast6991

iTrader: (34)

fwiw my 98 had the same oil pressure before my cam swap.i put in a ported pump from thunder racing and it made no difference at all.cold starts are around 50 and hot idle is around 22-25 with a little movement.when i ran mobil 1 i couldn't get 20 at hot idle.now running gc 0/30 and it made a noticable difference

98RedBird

iTrader: (77)

do you guys think that i hurt anything yet? I am going to swap it out but how hard is that to do? I'm just really scared that I may have hurt something....

ArcticZ28

iTrader: (14)

Unless there is any screeching or a severe drop in pressure out of nowhere, you shouldn't have hurt anything. Just nip it in the bud before anything does happen though. To swap it out is a bit of a pain, but it's worth it. Check out www.ls1howto.com to see how it all goes.

98RedBird

iTrader: (77)

alright, well it's still under warranty so I think I'll take it into the dealership and see if they will do anything for me

dub.ya.es.SICK

iTrader: (3)

my oil pressure in my 98 ws6 is sweet no less than 40 anytime...47k miles..

-=Modified=-

iTrader: (3)

Just FYI my TSP ported LS6 oil pump pumps at around 57 psi at idle if that helps any.

Studytime

iTrader: (15)

Here we go again! Porting a oil pump will do ZERO for oil pressure. If you old pump was failing, normal oil pressure will be higher after installation of a new pump, but otherwise simply porting a pump will not increase the oil pressure.

You increase the oil pressure by shimming the pressure relief spring on a pump. More shim requires more pressure to bypass the pump and thus you get more pressure in the motor.

... and my '98 sees around 30psi at a hot idle. That's off of an autometer gauge not the cheesy factory one. Also, as your oil gets older pressure will decrease.

Ben T.

98RedBird

iTrader: (77)

Here's something else that I forgot to mention.... That 20psi is using synthetic oil, which I believe is thinner. And it's 0W40 which is also thinner. Just thinking out loud I guess. I'm trying to think of reason's that it would be so low. I took it into the dealership and if they say it's bad then i might just ask to have an LS6 pump put into it. Do you guys think that that would be acceptable?

-=Modified=-

iTrader: (3)

Also, what he said. A ported pump merely allows more flow of oil not neccessarily more pressure.

Studytime

iTrader: (15)

No, a ported pump DOES NOT allow more flow. Our pumps are positive displacement pumps and FLOW cannot be increase by porting it. The only thing that "porting" it does is decrease the amount of hp it requires to drive it and also gives ppl something cute to add to their car's signature. It can't hurt, but will not help much either.

Ben T.

-=Modified=-

iTrader: (3)

So how does it decrease the needed hp needed to drive it. Isn't that the point of porting something, to allow more area to flow? I am not trying to sound defensive, I am merely trying to understand something I may be confused about, especially because I put a TSP ported LS6 in mine.
I was under the impression better flow will allow oil to operate at lower temperatures.

Studytime

iTrader: (15)

This is a different kind of "porting". The pump requires xx amount of hp to drive it based on the major and minor losses of pumping oil through the motor. If you can make the inlet/outlet of the pump have less "losses" then the pump will be able to pump oil with less restriction and thus require less power to pump the oil. The amount of oil pumped is a fuction of the design on the pump. There's nothing you can do about that (except redesign it). Each revolution once primed will pump a set volume of oil. That's the reason you can't increase the amount, you simply increase the ease at which it can move that amount of oil and the theory is you get a hp gain.

Basically if you keep in mind you can't change these things it makes it easier to digest; the pump's speed is a linear function of engine rpm- we can't change that, the pump's volume is a function of design per revolution- we can't change that either, pressure will not change as it is controlled by a different means- shimming or milling around the pressure control spring.

Ben

ArcticZ28

iTrader: (14)

Something else to add is that pressure does not mean everything. A lot of people gauge how good a pump is by it's pressure. That does not tell the whole story at all. Adding on to Studytime's explanation(s), you could have the opposite of a ported pump (say, you restricted the opening) and you'd have really high pressure... but poor flow. It's a combination of the two that you are looking for. More flow is better. Higher pressure is better. It's finding a happy medium of the two.