Oil pressure problem?

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dartkory

dartkory

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I finished my 318 with 360 head build a couple months ago, and the only thing I've been some what worried about is how much my oil pressure drops when it warms up.
When I first start it in the morning the pressure is around 60 psi, but after sitting in traffic a little while it drops to about 10 psi sometimes even 8 psi, but as soon as I give her gas to go it jumps back up to 20-30 psi, or higher if I floor it.
I'm running 10w30 in her right now with a quart of the lucas oil that is reasonably thicker.
am I running the right weight oil or should I go thicker? or am I just worrying myself over nothing?
I replaced the oil pump with a hd unit when I did the rebuild.
The only other thing I thought of was maybe I tightened the hose to my pressure gauge to much and its messing up my numbers, is that possible?
Thanks for any help -Kory
 
thats the way mines been since I first put the 360 in my Dart 4 years ago... pressure around 60 when fired cold... once hot, especially idleing in traffic, its around 10 or so, until the light turns green and im back on the gas... then it comes back up.. my friends told me that was normal so I have never worried about it.. whether they're right or not I dont know, but I havent had any motor trouble in 4 years..
 
the rule of thumb, From what I have been told by many here, is 10 per 1000 rpm so that would make it fine. At idle your 800rpm +/- so 8 to 10 fits right in.
 
ok awesome thanks for the help, I was just worried cause with my other 318 I rebuilt that was pretty much stock, it would be around 20 psi at idle, so I was worried I messed up on something.
 
Run a straight 40 weight or 20/50 and it will have more pressure at idle. Usually 10-20 lbs. Your clearances are prob a little loose is all.
 
is having loose clearances really bad? or something im gonna have to think of fixing soon down the road?
 
dartkory said:
is having loose clearances really bad? or something im gonna have to think of fixing soon down the road?
Click to expand...

I had a small block that was doing the same thing, went to 20/50 and it always had 25 at idle and about 65 on the pedal warm. About 80 lbs cold.

No big drive it like you stole it!!
 
So I finally figured out my problem! when I put together this motor, I purchased the Mopar valve covers which came with the oil fill caps only. I installed a rubber grommet on one side with the pcv valve, but only used the fill cap on the other side. Well after changing my oil and driving around a little bit I wanted to make sure there were no leaks so I popped my hood and with my car off I heard a weird hissing, upon taking my oil fill cap off it made a woosh sound as though there was to much suction inside my motor. So I went to an autoparts store and replace the oil fill cap with a breather cap, and my car runs like a dream now! the oil pressure is up to 20 psi at idle, and now when I put it in park, it doesnt jump to 1400 RPM! Now I only hope that it only messed with my carb and not anything internally! -Kory
 
I have the same issue on my 318. I also have sealed caps. I will replace these and see what happens. That would be great to fix this. I thought I had a bad oil pump.

I had a Eddie manifold and 600 on and it started the day I brought it home. Never before. I am hoping this is a quick fix. If not, I will move onto step two.

Thanks for the info.
 
no prob. Let me know if it works! I couldn't believe i've been driving around for a couple months now with that idle problem and all it took was $6 to fix it!
 
I was worrying about the oil pressure last weekend when I took my very stout 340 previously track only car down the country road to the local pool bar. Was seeing 40 PSI at 2000-3000 cruising down the road. 20W-50 with the break-in oil (with cam lube) after a hotter cam was just installed. I was wondering if the oil filter was clogging up.

I have 6 qts of green 20W-50 oil. May change out the oil and filter but now I gotta worry about the darn zinc. Additive?

So worried about blowing this 340 that maybe I should just build a stroker from one of the 360's I got with the car and leave the little 340 alone for now till I can see exactly what's in it.
 
from my understanding 40 psi while cruising is pretty good. Does it stay at 40 even when you floor it? cause they say 10 psi for every 1000 rpm is what it should be at
 
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