LT1TA

iTrader: (17)

I have a 99 trans am with heads, cam, intake, lt's/td, tb. The car has had royal purple 5-30 and k&n filter since i've had it (about a year) so far, the only issue i'm having is when it warms up and the first few miles driven, the op stays at 40-45 idle and goes to about 50 driving. Once it gets to that certain drop point the oil pressure dropping to 25-30 at idle only after the car ha been driven a few miles. when that happens, i notice a slight difference in throttle response and acceleration. Other than that the car is strong and drives fine. like i said, it works fine the first few miles and then it acts up. any suggestions?

samb0ness

My pressure doesn't hang that low @ idle (i'm also cammed), but i've read on here several others with similiar situations that seemed normal...

nysbadmk8

verify with a mechanical gauge. 25-30 on hot oil is on the lower end.. but its fine. as long as your getting 35-50 at cruise and 55 in the upper rpm range, No biggie.

BIG_MIKE2005

iTrader: (116)

Get rid of that trash *** K&N filter & you'll see better pressure as well. I made the mistake once of buying one of those overpriced turds.

What alot of these filter manuf. seem to forget is yea its great to have a very fine or low micron rating on a filter but once you get to a certain point it can become a restriction. It will also become clogged alot easier.

A filter I have always had great luck with is a Purolator & its cheap. FWIW I also dont buy the synthetic oils everyone raves about, including Royal Purple. I have always from day one buying my car ran Castrol GTX 10w30 year round. When we tore my top end off for my H/C swap the car had 103k miles on it, I bought it with 64k on the clock. Very minimal tarnish in the heads, no sludge to clean up & the cylinders still had the factory cross hatchings in them. Thats enough to show me I dont need to spend $75 on a oil change with high dollar oil & filter for my engine to live. Hell its got 152k miles on it now after 3yrs of beating on it with the H/C combo every day of the week, still runs strong with great oil pressure too.

incbed

If your engine is not new and has more than 50,xxx miles I would not use 5w30. Any engine no matter how well you take care of it the tolerences change alittle.

A perfect example is my daily driver which is a 2005 Malibu with the ecotec 2.2 with 97,xxx miles on it (by the way it still gets 31mpg) anyways when my wife was using it as her daily driver one day she had the bright idea wile at Walmart to let them change the oil in it. Well the next morning I walked her and our kids out to the car and all that good stuff and she started the engine up with awful upper engine noise coming from the engine for about a second then went away. I asked her what weight oil did you tell them to put in it she said I didn't and handed me the Walmart shop recipt. Sure enough they put 5w30 in it and the car had around 75,xxx on it at the time if I can remember right

With 10w30 the engine purrs like a kitten every morning on start up even with almost 100,000 miles on the factory engine.

DID you replace the oil pump when you did your H/C/I install??

I just did a H/C/I on my 2000 Z28 with 115,xxx miles on it and before I refreshend it my oil pressure at idle in 45min of stop and go traffic in 90degree weather my oil pressure would be around 20psi with K/N oil filter. When I removed the factory oil pump the gear inside the oil pump was so loose that the gear was just flopping around inside the oil pump housing.

I went with the Melling# 10296 and I have driven the car about 100 miles with the oil pressure at idle never dropping bellow 41psi in upper 90degree weather,,but I use 10w30 with a K/N oil filter.

Change to 10w30 and see what the oil pressure is then.

LT1TA

iTrader: (17)

wow, i have not changed the oil pump. what's strange is even at operating temperature, the oil pressure will sit normal. but afterwhile it will go to about 35 hot at idle, and kinda jump up a little and back to 35. at that time my car acts really crazy and drop really low in rpm's and accelerate sluggishly. i will definitely try the 10w-30

sscamaro1384

iTrader: (163)

get rid of the royal purple. go 10w 30.

RsSean

iTrader: (27)

We had a engine that showed similar results that you are having. When the car was cold, the oil pressure was dead idling just to the right side of 40psi, after the car was warm the oil pressure at idle would drop to 20-25 near that left hash mark on your cluster. Come to find out after th motor was pull there was damage to the lifters and cam, which cause the oil pump to pick up causing bearing tolerance that were to much for the weight of oil and the pump to maintain. Hope that is not your case but factory lifters suck!

BIG_MIKE2005

iTrader: (116)

I'd say factory lifters suck when thrown into a improper combo. I have 50k hard miles on my factory LS7 lifters which are a direct replacement for the stock LS1 lifter now. Not a single issue from mine.

RsSean

iTrader: (27)

Ok like I said the factory lifters that come in our cars sucks! Now since you have upgraded to a different design then yes they are fine, I have the same ones in my car

LT1TA

iTrader: (17)

Well, I have the same issues, haven't had time to change my oil and filter, the issues i'm having doesnt seem like it's oil related. Maybe I'm wrong? So now i have the same idle dropping issue when it runs for a while, and the sluggish throttle response. It's only done it once, but It was a rainy day. So, I don't know what to say I drove it today and it drove fine for about 20ish miles. I could tell it was getting to the sluggish response again, but it drove fine. I had another code come on p0442 (Evap small leak) Around the time it drove it's worse, the SES light flashed and went away, then the car drove fine. I'm rambling because i'm very tired and getting yelled at by the wife for ignoring her. I was about to change the fuel filter only to realize that i was thinking of the fuel rail pressure regulator, not the fuel pressure regulator in the pump assembly.