alconk

iTrader: (1)

Please help, I have 161k miles on my car and love the damn thing but my oil pres. is going south. It's running around 36-39 psi at 2500 and at idle still not changing there at 18-20. But why does it keep dropping? I swear it was 44 psi last week.. I run a mechanical Auto Meter gauge and I pick the oil up above the oil filter. I need this car to last as I don't have the cash to rebuil it right now. I used to get 50 psi until I changed the cam last summer so did I maybe nick the cam bearings?

What about installing a high volume oil pump? We that help for awhile?

CRAZZ28

iTrader: (13)

if im not mistaken 18-20 is very acceptable for idle. 44 psi at idle sounds really high.

letsrun97z

iTrader: (7)

consider yourself lucky lol on a good day i have 7psi hot idle with only 116k

infinitebird

iTrader: (11)

as said your oil pressure is normal

Formula350

iTrader: (3)

Dropping cuz the oil's getting old and thin

As you sit, as said, you're in the green right now.

spookyz28

The high flow pump is the way to go. They sell for around $85

infinitebird

iTrader: (11)

High volume pump (what he mentioned) is a bad idea on the stock oil pan. do a search.

High pressure pump is fine.

Boodyrider

iTrader: (2)

And neither one is needed on a stock motor, at ALL.

Change your oil, first, and then look at the readings. Make sure you're comparing same conditions, ie 2500 at cruise and fully warmed up idle.

At idle, 15 psi is more than enough; conventional wisdom says 10 psi per 1000 rpm, so at 2500, 25 psi (fully hot) is fine. If you had 30 psi at 6000 I'd start to think about worrying. Chiltons lists a spec for warm oil pressure.

Here's another thought... if you run 5-30, go to 10-30 or 10-40; if your clearances have grown a bit with age, the thicker oil won't hurt a thing and may give slightly better pressure.

alconk

iTrader: (1)

Well I fell alittle better now, the pressure does come up when I have a fresh oil change but it don't take long for it to start to drop. I have tried the thicker weights and the pressure comes up quite abit but upon startup my lifters clatter for several seconds???

alconk

iTrader: (1)

Another thing, under full throttle the pressure rises but then drops considerbly around 5k or so but then starts to rise again right about 6K who knows??????

Formula350

iTrader: (3)

Lifter clatter is normal, but a thicker oil should still KINDA prevent that. What causes it, is 2 things: 1 the oil has drained back down off the rockers and they aren't thickly lubed like when it's running 2 is the pump just hasn't gotten enough oil through the system to stop them from clatter. It's just fine, but don't even rev your engine just after start up. Wait at least 30seconds.

3pnt4maro

iTrader: (2)

Well if you cant afford to rebuild the motor dont drive it as hard...dont be spinning it to6000 rpm and what not...switch to a lil thicker oil..but your pressure sounds fine..I notice my roller rockers a lot more toward the end of an oil change period when the oil is thinner..just a part of the car world

and what brand oil are you running..some brands run a lil thinner as well..just a thought

alconk

iTrader: (1)

I'm using 5W30 either Castrol or Valvoine. I have used 10W40 with Lucas and those lifters clattered forever. I was told to get Lucas out of there like now! I was also told it's too think for LT1s?????

alconk

iTrader: (1)

Would it realy make a difference going to RP??

Boodyrider

iTrader: (2)

Royal Purple... is a very good quality oil made with pure synthetic base stock. It is an excellent oil, but also very expensive.

Mobile1 is a good quality synthetic oil, a bit less expensive.

You say Castrol, but not whether you use full synthetic, blend, or conventional motor oil.

The biggest differences are between conventional oil and synthetic, more than among brands of synthetic. Synthetic, in general, is better able to lubricate with a 'thinner' oil, has a better range of ability to be 'thin' when cold AND 'thick' when hot at the same time, and has a much better resistance to losing it's lubricating ability with time and use than conventional oils. There is a catch; synthetic oils also tend to do a very good job cleaning old sludge buildup out, and as a result have developed a reputation for "causing leaks" in tired, gunked up older engines which only failed to leak before due to sludge buildup. For this reason, and in my opinion this reason ONLY, they might not be the best choice for an older engine that was alway run on conventional oil.

(Note that all synthetics are NOT the same, especially since the federal government redefined what 'synthetic' means in terms of base stocks!)

Google synthetic base stocks, someone (Maxim?) just had a GREAT article on the differences among synthetic oil base stocks and on oil in general.

It is an excellent oil, but also very expensive.

Puck

iTrader: (17)

If your oil pressure rises like normal then drop while the rpms are rising only to rise again then changing the oil will not fix the problem - that means your bearings are going. The oil pressure, just like fuel pressure, should never drop while the rpms are still going up under load.

The thicker weight oil will help for now, but eventually it sounds like you will be needing a rebuild in the future, since that only gets worst.

...and yes, 20psi warm idle is plenty. It is always high at first since the oil is cold and much thicker, then as it warms up it will drop down to its hot idle psi. I believe the spec calls for at least 9psi at hot idle before "needing" service, but I would be leary of anything under 15.

My oil pressure reads 45+ on a cold start, then as it warms up to its highest standing temp it settles to 22psi using 5w30...with 160k on the shortblock!

These engines last ages when well takin care of.

3pnt4maro

iTrader: (2)

get the lucas out of theur..pick a good conventional oil and run it..I tend to agree that you have to many miles to be running a synthetic..maybe a blend..not sure how your motor would react to a blend

spookyz28

who told you that?

letsrun97z

iTrader: (7)

dammn that pisses me off i bout my car off of a old *** guy only owner and had 99k now it has 116k i drive alot in a year and hot idle is 3-7 depending on what oil and how old it is already changed sending unit no clicks pops and all service records were given to me upon purchase lol i know that 80yr old man didnt beat on this car i guess i just have Bad luck

Puck

iTrader: (17)

I would NOT drive an LT1 with 3-7psi hot idle. Your bearings are in some serious danger there.

Does it rise rationally to rpms, around 10psi per 1k? Either your pump is shot or your clearances are totally unacceptable.