The crankcase is full of oil. Ive changed it 3 times and it measures to the full mark on the dipstick. Ive even added an extra qt, then drained it back out since it didnt fix it. I thought the pick up was coming uncovered too at first but i dont even have to be accelerating much, just put the engine under a load and it starts dropping. Can run steady at 3500rpm without any issue, even kick it in neautral and rev to 5000. Nodrop. Im gonna start with the filter, then pull pan and wok my way up until i find it for sure since its got me puzzled
360 oiling problem under load
- Thread starter Dartish
- Start date
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MOPAROFFICIAL
Oogliboogli
"contestant no.1, come on down" lol
Because it a rebuilt short block 318 on a stand sitting in the yard under a tree, it was a toss in on a deal I made in 1999 on a basketcase/project. When I needed the car to be mobile, I blew it out with air , pan'd and top'd it with some shelf heads/intake etc and threw it in the car-temporary thing- Leaves, dust, were the things flying out, it could have been a beetle or cob web...debris all the same and it was a stuck relief deal, happening not long after initial break in. I cringed putting the effort into installing it in the condition...but under the circumstances needed to move it a good distance. I wasn't trying to insult you aor anyone, so relax. Keep in mind when people encounter odd ball stuff, like your cracked pickup tube, they can sometimes assume things will always be as unique a culprit, but never overlook the basics....people don't always get the block completely cleaned.
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MOPAROFFICIAL
Oogliboogli
Man I really hope you aren't just speaking of the oil psi drop coinciding with a normal rpm drop when put into gear??
Not at all. Barely drops when u put it in gear from park. Im talking driving at pretty much any speed in any gear,warm engine and go from 65psi to a quick steady drop when u go 1/3 or more throttle. I can put it in neutral and rev it as hi or as long as i want in any gear with no loss, butput in in gear and load the engine it drops. Not sure if it drops to zero but it drops steady and fast. I let off when i see it drop, but ive noticed it drop 20psi and come right back up when i let off throttle
MOPAROFFICIAL
Oogliboogli
The 318 would show good at idle as well, under throttle and cruise would have 18-20 psi, let off ...right back to normal pressures. An oil pump doesn't care if the motor is under load, the pump is either turning and pumping or not. At what psi it pumps or doesn't, is up to the relief and spring.
if this was a pick up tube, like a cracked straw...under little suction works pretty much as normal...but aerates , pulling from the crack " shortest distance" instead of the screen,which further down the line once the demand/suction increases.
Have you checked for the crank moving forward with some throttle ?
if this was a pick up tube, like a cracked straw...under little suction works pretty much as normal...but aerates , pulling from the crack " shortest distance" instead of the screen,which further down the line once the demand/suction increases.
Have you checked for the crank moving forward with some throttle ?
I'm chill don't worry. This isn't a contest... I was just adding first hand experience that I have that matched the symptoms that the OP posted in an attempt to help him solve his oil pressure issues. The pickup may or may not be his problem but it was for me when I had an engine with the same symptoms.
My engine was a "rebuilt" 340 I bought that was burning oil. All he did was re-ring it and the cylinders were too far out of round. I had the it bored and square decked along with a very intensive cleaning of all of the passages following some of the oiling mods that I did. The engine had a new oil pan on it when I bought it and the pickup was perfectly clean so I reused it. A few months after I fixed the cracked oil pickup I talked to the guy who sold me the engine. He told me the original pan was dented so he replaced it. He also said he had to bend the original oil pickup some because it was too far from the bottom of the oil pan. He did this when it was installed in the pump. Since the threaded portion is the weakest this most likely caused a high stress area that failed after I reused the pickup. I use a new pickups now and if they need adjustment I do it properly like I always have(when it's not in the pump obviously).
Hopefully it helps the OP or possibly some future member who runs across this post who has the same issue. I would hate to see him miss a cracked pickup or possibly help some avoid having it happen to them.
nm9stheham
Well-Known Member
OK on the adding and then removing extra oil; pretty much eliminates of that question.
What type oil pressure gauge do you have? If mechanical and with a plastic line, make sure the line is not being pinched. If an electrical gurage, like the original Mopar, an erratic connection or ground would raise the circuit resistance and lower the pressure reading. Flexing of the harness and the connection through the bulkhead connection through the firewall and perhaps the ground from head to firewall could do this. Odd and unusual, I know, but you have odd and unusual symptoms....
Have you perchance put on a different gauge and checked? Just throwing out ideas.....I see you tired a different gauge but was it all changed out from the block up or just the indicator?
What type oil pressure gauge do you have? If mechanical and with a plastic line, make sure the line is not being pinched. If an electrical gurage, like the original Mopar, an erratic connection or ground would raise the circuit resistance and lower the pressure reading. Flexing of the harness and the connection through the bulkhead connection through the firewall and perhaps the ground from head to firewall could do this. Odd and unusual, I know, but you have odd and unusual symptoms....
Have you perchance put on a different gauge and checked? Just throwing out ideas.....I see you tired a different gauge but was it all changed out from the block up or just the indicator?
nm9stheham
Well-Known Member
BTW, what lifter setup do you have? Just wondering if the lifters are doing something odd at the higher, loaded RPM's and exposing the oils galleries somehow; that would allow a lot of oil to escape.
Its a mechanical gauge. An auto meter, then tried my old sunpro. Same on both gauges and first thinv i did was replace plastic tubing with copper. No change
Its a 450" lift hyd cam with 214 duration at 050". Pretty mild with stock rockers. All was good the first 4000 miles. Just started losing pressure on way home from work the other day
TrailBeast
AKA Mopars4us on Youtube
The filter should tell more than the last page of posts. 
Cut filter open and ckecked it over every fold, then checked it again. VERY CLEANThe filter should tell more than the last page of posts.
How sure are you that the two oil galley plugs behind the camshaft thrust plate were installed???
I had oil pressure problems on our first engine build, pulled it 4 times before finding out that the machine shop left out the two oil galley plugs for the lifter bores that go behind the camshaft thrust plate...
I found it by making an oil priming shaft and spinning the pump. When I spun it, it was fine, then my brother came in and saw the drill and hit the trigger and oil shot 6 feet out at me from behind the thrust plate. It may be intermittant as sometimes the thrust plate may hold some of the pressure...
Positive all the plugs are in. Checked for them before it left machine shop after tanking and cam bearings. The guy that did the work went over everything he didand hes built many mopars. Mild to all out race roller motors. He even ponted out the one by distrubuter gear thats sometimes overlooked. I drove it about 50 miles after installing new Wix filter.Run it at 2200 rpm all day at 60 to65 psi. Roll in the trottle in hi gear and it keeps dropping until u let off, even at low rpm. Still idles hot around 30 to 35psi.
nm9stheham
Well-Known Member
Not too suprised; the filter would not change loaded or not.
All of the easy stuff is falling by the wayside.....Just to be clear:
- Full pressure at all RPM's sitting still.
- Pressure drops at mid to upper RPM's when just in high gear? How about 2nd?
- Does the oil pressure come back if you close the throttle an hold the higher RPM's in 3rd, or stay low?
Any chance the symptoms change if you are uphill vs downhill?
No change up hill or down.climbing a hill at part throttle it drops at even low rpm. Let of it shoots right back up. Holds steady pressure at any rpm until u try to accelerate in any gear,any rpm. I can cruise in low or second hold 4000 rpm and steady oil pressure. This is really gettin to me. Leaning toward main bearing issue but id think the oil pressure would have droppwd across the board, especially at idle, when hot but its same as when i first started it 4000 miles ago. Always good oil and filter, no coolant or other contamints in oil, so not understanding how i would have wiped the mains overnight. Appreciate all the input and ideas. Always been proud to be a mopar man and enjoy the mopar culture commeraderie
TrailBeast
AKA Mopars4us on Youtube
Well one thing we know is you don't wipe bearings without some being in the filter, so that's probably out.
diymirage
HP@idle > hondaHP@redline
he did mention he had the crank polished and mic'ed out to 2 thou tolerance on the mains
I wonder if that number may have been off?
(of course, that doesn't explain why this wouldn't have been an issue from the get go)
unless he egged a rod...but you would hear that like a bad knock-knock joke
I beginning to think the pick up tube cracked or is it possible the Oil pump bolts were not torqued down? When on the throttle and off the throttle the oil pump drive is moved forward and backward possibly breaking the seal of the oil pump at the block? Just thinking out loud here.
MOPAROFFICIAL
Oogliboogli
Thought about that too, that's hard to mess up and the gasket if even used is so thin, but its down to those few things.
The oil pans gettin pulled tomorrow and im gonna pull the pump and pick to check them over. I rememember torqueing, and retorquing the oil pump. Iv been tossing around the idea of the cam gear or intermediate shaft too. Even though both were new and the shaft was the hardened M.p unit, but that doesnt mean its still good. Most of the M.P parts seem to be coming from offshore suppliers now and im totally convinced, from experiance, most of the off shore auto parts were being supplied now are TOTAL CRAP! Wondering if one of the gears, or both went south. Gonna pull distributor just for giggles and see if the gears are noticeably worn. I measured the crank, had it polished, then had machine shop mic it too. We both came up with same numbers. I checked every journal with plasti gauge, several places on each journal, and 002" was what the plasti gauge showed too. Never heard a single tick, knock or rattle out of the engine
Subscribed..got my curiosity
Snake
Mopar Nut
My bet is a bad pump.
nm9stheham
Well-Known Member
I've raced lotsa miles with .0020-.0025" bearing clearance on a lot of engines with nary a problem in pressure or wear.
Loose rear main cap or broken cap bolt? Moves back with torque and open up the oil delivery passage? Ditto with oil pump bolts. Just more ideas...
Loose rear main cap or broken cap bolt? Moves back with torque and open up the oil delivery passage? Ditto with oil pump bolts. Just more ideas...
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