SSPerformance

iTrader: (76)

my 98 ta make 19psi at a hot idel....the motor has 75k on it. Do you think its the oil pump? or is it geting tired?

black00TA

iTrader: (3)

i have to ask.

do you have any oil in the car?

BriancWS6

iTrader: (18)

I agree, check your oil level first and report back.

SSPerformance

iTrader: (76)

Yes.............im runign 5w30 mobile 1

BriancWS6

iTrader: (18)

Well the 5w30 isn't the preferred viscosity for the LS1 with Mobil, 0w40 or 5w40 is the best. With that said it won't make your car idle at 20 psi

I am guessing it's the pump, I wouldn't see an LS1 that was even half *** maintained getting that tired at your mileage.

SSPerformance

iTrader: (76)

we run 5w30 in all 4 f-bodys in the family including my 408 in my camaro and there all making 40+ at a hot idel. Now i no the 98 have problems with the oil pumps. If im changeing the pump im gona thro in a mild cam.

BriancWS6

iTrader: (18)

Like I said, the 5w30 isn't gonna make it idle like that, but it's still not the viscosity that you should be using in an LSx engine. For the best protection you should use one of the ones I mentioned.

About the cam install, that's a GREAT excuse for a time to do it Good luck!

SSPerformance

iTrader: (76)

did a new mellings pump today and dident make any diff

BriancWS6

iTrader: (18)

Maybe it's time for an A pillar and some good gauges

kossuth

iTrader: (12)

20 psi isn't that bad really. You only need about 10 psi per 1000 rpm to adequately lubricate the engine. Also remember that the factory gauges are close at best. If it worries you that much I'd put a mechanical gauge on it.

SSPerformance

iTrader: (76)

nope already swaped gauges and no difff

BriancWS6

iTrader: (18)

Well what else could it be besides worn internal parts?

Sprayed1998

iTrader: (10)

what does it look like at WOT and normal driving

Mr.Nitrous

iTrader: (51)

Well, here's my input. I just did a cam,spring, oil pump swap and have low oil press. When you fire up the motor cold, it makes 40-45 psi, then as it warms up it drops to 18-20 psi. Then at the lower oil press. the lifters start to collapse and clatter.I changed the pump back out and still the same problem. And no the o-ring is fine. The only thing I have left in mind is that a cam bearing moved and uncovered an oil gallery. Keep you updated.

Billy177

before you do anything change the oil with 40wt using a decent filter.

BriancWS6

iTrader: (18)

His oil pressure shouldn't be what it is, and putting in a thick viscosity to try and "bandaid" it, is not going to solve the problem.

SSPerformance

iTrader: (76)

my car runs very very strong....there aint a ls1 in my town with the same mods that can stay with it. im just gona keep driving it and start spraying it....another excuse for 1 more 408

NHRAMAN

iTrader: (1)

???? What about the 10psi per 1000 rpm benchmark.???? what have i missed in the last 40 years.... .............kossuth is right.

hammertime

iTrader: (1)

I remember this too. I guess the problem is, going from 40+ psi at hot idle to 1/2 that is alarming (I would be concerned too).
Are you still getting an increase in psi as rpms rise? Does it meet the 10 psi/1000 rpm minimum? Any noise as described by Mr.Nitrous?

Bo White

iTrader: (59)

I have also seen were the cams have smaller basecircles and move the lifters further away from were the need to be and its an internal oil leak but thats super rare. 10 psi per 1k is all thats needed and his engine(- some NOS damage) will probably last another 75k. I run 10w40 Castrol GTX in everything Ive ever owned dino based wise and will always will. It does give some more pressure but its a "bandaid" as said earlier for something amiss in the engine. I built an engine for my self back in the 90s that had 18-20 warm idle pressure and it was one of the best running engines I ever built. It did however have 60 or so psi going down the interstate at 3500 rpms.