72 318 Scamp. Low oil pressure 1 minute after startup.

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Scampi

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Hi everyone. I recently bought a 1972 Plymouth Scamp with a 318 and 904 automatic. The engine/Transmission has to come out because of a broken flex plate.

I have a question. The engine starts up fine with no noises besides the flex plate scraping... ok I didn't run it for long. When the engine first started it has 50 to 60 psi oil pressure. Then about a minute later the oil pressure drops to about 5 psi! Any suggestions on what to look for when I take the engine apart? I did put new oil and filter in it after towing it home and the oil pressure was still the same. Going to try and pull it out this weekend for inspection. Any help would be appreciated.

P.S. Sorry for the dumb question. I have worked on a lot of Chevys but not a lot of Mopars so I am learning.

Thanks

Eric
 
Before everybody else chimes in... popular topic... use the search function. There's been many threads about that symptom.
 
One question. Is the oil pressure gauge electric or mechanical?
 
weak bypass spring in the pump? Or so much valve seal crap in the pickup that it cant scavenge the oil properly.
 
Before everybody else chimes in... popular topic... use the search function. There's been many threads about that symptom.
Thanks for the search suggestions. I will try looking some more. I just haven't had a engine act like this before. Usually oil pressure is good when cold and low when the engin gets warmed up. This low oil il pressure problem happens so quick.
 
Before everybody else chimes in... popular topic... use the search function. There's been many threads about that symptom.

^^^^this gets posted a lot.

actually, probably a lot of threads on just about every topic there is on small block mopars here on FABO over the years. I say we just eliminate the Forums and just have the search bar, because usually all subjects have been discussed. Let's see how fast this site dies …… LOL

Oh, P.S. - when somebody does use the search bar and post in a thread from 2012, we post right away... "why are we digging up a post from 2012... :D LOL
 
I'm off today so I'm going out to the shop now to work on the car for while. I am wondering about the clogged oil pickup suggestion. I heard that the mopar oil screens had pretty small holes on them?
 
I'm off today so I'm going out to the shop now to work on the car for while. I am wondering about the clogged oil pickup suggestion. I heard that the mopar oil screens had pretty small holes on them?
Starting a cold motor, as you are aware, will always have more pressure. As soon as it begins to warm, it will fall. Why on yours so low? Could be cam bearings are shot, or could be somebody else was in there before you and left a plug out. You said you've replaced the oil pump, so I doubt the oil pump is issue here.

By the way, welcome to the site !!!! :D
 
Starting a cold motor, as you are aware, will always have more pressure. As soon as it begins to warm, it will fall. Why on yours so low? Could be cam bearings are shot, or could be somebody else was in there before you and left a plug out. You said you've replaced the oil pump, so I doubt the oil pump is issue here.

By the way, welcome to the site !!!! :D
I just changed the oil and filter. Not the oil pump.
Thanks by the way. I really like the helpful and knowledgeable Mopar people on this site.
 
This what the engine looks like. Edlebrock performer manifold and edlebrock carb.

20190404_101057.jpg
 
I just changed the oil and filter. Not the oil pump.
Thanks by the way. I really like the helpful and knowledgeable Mopar people on this site.
ok, as mentioned above, could be the pump...
 
by the way.... glad you made it here. I think you posted this question on my Utube channel..... ???
 
Hmmm Hmmm
Yes, you have a very nice channel. I have learned a lot already from you. Thanks
My brother in law has three 69 Dodge Darts. I did a search here and one guy mentioned to prime the engine with the valve covers off and if it's "leaking". Them the timing cover and maybe find the problem that way. Of course if the oil pickup is clogged or falling off that would do it also.

Might install headers and possibly a mild cam while the engine is out.
Any cam suggestions while your here?
Thanks for your help.
Eric
 
Yes, you have a very nice channel. I have learned a lot already from you. Thanks
My brother in law has three 69 Dodge Darts. I did a search here and one guy mentioned to prime the engine with the valve covers off and if it's "leaking". Them the timing cover and maybe find the problem that way. Of course if the oil pickup is clogged or falling off that would do it also.

Might install headers and possibly a mild cam while the engine is out.
Any cam suggestions while your here?
Thanks for your help.
Eric
cam depends a lot on the components around it. Gears and converter being a couple of key pieces. But just for the say.... I'd say stay between .430 - .460 lift and 206-216 duration @ 050. But all is a mute point if the engine isn't "up to snuff". LOL. Besides correcting the oil pressure, give it a compression test.
 
Yup you got me on one of my 1st posts!!! Won't do that again !!! LOL
Because were a bunch of old grumpy men... :D :D :D
Sometimes I read where somebody is asking a question, and I go to answer and I realize the thread is so old I they are not even a member here anymore.... LOL
 
I'm not grumpy; I just look grumpy, and since my wife has a headache all the time, I just don't gibachit,lol.

It's not that Mopars have small holes in the pick-up screens; rather the valve seals bake hard, crumble, fall into the pan, and end up getting sucked into the pick-up housing. After the pieces from all 16 get in there, then there ain't much room for anything else!
But that sudden drop with fresh oil has me stumped. It's more like a shop rag is in the pan and getting sucked up.
 
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Because were a bunch of old grumpy men... :D :D :D
Sometimes I read where somebody is asking a question, and I go to answer and I realize the thread is so old I they are not even a member here anymore.... LOL
Some are even dead. (RIP)
 
My vote is for crap sucked up in the oil pickup screen.
 
I'm thinking junk on the pickup screen as well, what does the oil pressure do if you rev it up a bit after the pressure at idle goes way down? Does it pick up quickly or take a while to build pressure? Also what's the max pressure it hits when warmed up? Could also be the oil pump is just worn out.

BTW what weight of oil did you put in?
 
Seen sludge doe this in a short time. Same engine tended to get sludge blockage on the pickup going downhill to a certain stop sign too.

Also wonder if the intermediate shaft hex is slipping and it takes a minute when cold to start doing it.
 
I changed the oil in my Valiant before I got it running. I put an entire quart of Marvels Mystery Oil in the oil when I did it. After about a week of driving it, I changed it over to 10/30 synthetic. When I drained it, I got all kinda globbiness out of it. I know beyond a shadow of a doubt some of it came off the pickup screen. It was taking several seconds for the oil light to go out when started. Now it goes out almost immediately.
 
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