I bought a 95 z28 in pieces with a fresh motor. When i first got it running it had problems running good because of MAF problems, but at idle it had 60 lbs and with a lil throttle it jumped to 80. Fixed the MAF so it runs good, and after driving it,(when it warms up) it goes down around 0 at idle and 20-30 with throttle. After it cools off it jumps back up around 40 idle 60 throttle, Any suggestions how to get the oil pressure back up for when the car is warm? Thicker oil? Thinner oil? I just need to try something before i assume its cam bearings or something, but i dont want to put to much in it because i bought it to make money.

 

should be 60-70ish cold no matter how much throttle , 5-15 at idle warm, 40 at wot while warm.

 

when it warms up and gets down around 5 at idle the check gauges light comes on. I was thinking warm it should idle around 30 and 60 wot. When it warms up and drops down it starts smoking out the valve covers, that means its not oiling properly, right?

 

It should never be that low, if you do not know the engines history I would start off by going to a thicker oil (10W-40 or 20W-50) just to see if that helps keep pressure at idle, but chances are the bearings are shot. If its only low at idle, and good when you give it rpm its most likely cam bearings, if its bad everywhere its rods and and main bearings.

Are they puffs of smoke comming out of the valve covers, or is it like burning metal smoke?

 

It seems to be more like burning metal smoke, cant really tell. But that what it smells like. But what i dont really get is when its cold its ok at idle. around 50.

 

are you just going by the gauge on the dash or do you have a dedicated oil pressure gauge or a scanner/reader for actual psi?

what i meant was it should hover around 15-20 at warm idle (thats adequate oil pressure, should be around the first tick)

if its lower than that like he said try a thicker oil first

i was thinking of some other gauge or somethin stupid don't mind me when i said 5-15, i meant the first tick heh

 

The guy i bought it from said he and his dad rebuilt it and put all new seals and bearings in. New pistons, rings, rear main, cam bearings, rod bearings, etc.

 

gauge on the dash. It is around 5 warm idle, but like he said, thats low. lol. The first mark is 20.

 

Get an autometer mech gauge and some thicker oil, my car did the same thing (gauge goes down to nothing and the check gauges light comes on) Put better oil and a mech gauge in at the same time and i enough pressure all the time...

 

I thought all an lt1 needed for oil pressure at idle is around 8 psi?

but mine is around 19-20 warm at idle and 40 with throttle warm.

 

I just picked up some 20w50 and a new filter. If it dont work im might sell it. I bought it to make money on, but if i got to pull the motor back out to change cam bearings ill lose money. I should be able to break around even just selling it like it is. Maybe the oil will work

 

Check if the pickup came loose/fell off. That is very common when it is not tack welded after a rebuild.

 

The Owner's Manual for my 96 LT1 says that under certain conditions, hot oil pressure at idle could be as low as 6 psi, which, the manual says, is normal.

Jake

West Point ROCKS!

 

The owners manual might say it, but it dont make sense when the check gauges light is on. But anyways, did the oil change and its back up around 40 idle 65 wot warm. I put the 20w50 in but im not so sure it was the thickness of the oil apposed to how much metal shaving came out with it. lol. When it was apart i gasket matched the heads with em on the block, and i guess i let more metal in than i could get out.( me being stupid). I think im going to run this a week or so and then try to go back to 10w30 or 40 syntec. Thanx everybody! Im relieved.. 2 more t-body bolts to find and ill be done with this pup!

 

I thought I read somewhere going too thick on oil with the LT1 causes other problems... I ran 5w30 after reading that and I have never seen my oil pressure drop below 15 PSI unless the idle goes to like 200rpm's...

I have another Autometer Electrical Gauge but no where to put it. I will see what I can do and where I can mount it tomorrow.

Either way just food for thought, maybe what I read was wrong.

 

My last lt1 car had a similar issue i put a Autometer gauge on it and confirmed the dash gauge was lieing to me. rule of thumb is 10 pounds for every 1000 rpm.

 

Like i said, i dont think putting the thick oil in helped as much as just flushing the old oil that was filled with metal shavings. Between the metal that came out of the oil and what was stuck to the magnet on the plug, the oil filter 'filtered" as much as it could stand. lol. I knew something was wrong, ive never had a motor that idles less than 30 lbs.

 

[QUOTE=Cross;11571928]I thought I read somewhere going too thick on oil with the LT1 causes other problems... I ran 5w30 after reading that and I have never seen my oil pressure drop below 15 PSI unless the idle goes to like 200rpm's...

I dont believe in thick oil either on a fresh lt1, thats why im going back with 10w30.

 

If you clogged the filter with metal shavings you really should tear it down and check everything out.

There is an oil bypass valve to prevent oil starvation that sounds like it had a good chance of opening and throwing all those metal shavings around your engine.

 

Thats what me and a friend of mine was discussing today, but i dont think im going to go through the trouble when i got my oil pressure back. Besides, we figured the bypass wasnt opening up to well anyways since it had 0 to 5 lbs at warm idle.