Low Oil pressure

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vghoon

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Gooday from down under
Long time reader first time poster

I am having a problem with my recently rebuilt 318 la oil pressure staying low
After running in the cam in, i noticed the oil light flickering on at idle, Fitted a gauge to reveal
about 18psi cold & 10psi hot at idle & a maximum of 35psi at revs ( will not go higher).
After reading many posts i changed to 50 grade oil & very slight improvement but not fixed,
checked with another gauge , same, Changed oil filter & inspected inside no metal same oil pressure, checked rear plug , & its in , checked rear cap plug down the oil pressure hole & its there as well.

Bored .030 new mains & big ends fitted ,
small summit cam kit, with can tensioner fitted
original cam bearings & oil pump were used after inspections
plastigauged mains & bigends & all were within specs.

I am thinking the valve relief is set way too low or partialy unsealed or perhaps
the cam tensioner plate not sealing the oil shafts,

Any thoughts welcomed

cheers pete
 
Did you check to see if all of the oil galley plugs were installed when assembling the block?

I had a similar problem on the first engine that I rebuilt. I finally found the problem to be the machine shop didn't install the oil galley plugs that go behind the camshaft thrust plate.

Look in this post below to see where they are:

http://www.forabodiesonly.com/mopar/showthread.php?t=287231
 
Hi & thanks for your reply

No i did not fit plugs here & i cant remember if they were fitted or not
I see your pictures & the description is very similar to my problem.
I thought the new thrust plate would seal the holes?
 
vghoon said:
Hi & thanks for your reply

No i did not fit plugs here & i cant remember if they were fitted or not
I see your pictures & the description is very similar to my problem.
I thought the new thrust plate would seal the holes?
Click to expand...

It didn't in my case, so I make sure to check them all the time whenever I work on them. The oil can hydraulically lift the plate enough to loose pressure.

Some people say that you don't need them and thrust plate will seal the holes, but not in my case - it surely made the difference. And those are easily forgotten/missed when rebuilding.
 
is there anyway to check this without pulling the front of engine apart ?
like through the fuel pump hole?
 
That sucks ! Likely you're screwed to take something apart. Might as well be something that doesn't require pulling the motor. Sorry to hear it ....
 
I thought the chain tensioner would blank the oil ports, but i removed the fuel pump too see inside & atatched a drill to prime the pump.
At 5 psi i got a huge gush of oil splashing down on the chain, i would think this is way way too much oil
as i have still installed the bolt with the small hole to lube the chain. the video shows at 5 psi it actualy misses the chain & gets the front cover. I think theres afew psi's there to be had for sure.
I took a little video of it
 
vghoon said:
is there anyway to check this without pulling the front of engine apart ?
like through the fuel pump hole?
Click to expand...

No, it is behind the camshaft thrust plate. You have to take the timing chain cover off, and the timing chain to get the camshaft thrust plate bolts off and then remove the thrust plate to see if they are there...

No tricks to get around it, that's why Before assembling a block I always check for all of the oil galley plugs at least once....

I had to pull and engine out 5 times before finding out that was the problem.... :banghead: :banghead: :banghead:


Once you have done that, you don't make that mistake again...

*********************************************************************

If you are loosing that much pressure, you should use the method that was suggested to me by a good mechanic that I knew: Get a priming tool and spin the oil pump with a drill. Then tear the engine down a little at a time and run the drill. If you see a bunch of oil gushing out, then you have found your leak.

That is how I found out that my camshaft thrust plate oil galley plugs were missing. When I spun the oil pump. the oil shot 6 - 10 feet out of the engine while it was on the engine stand.


Any leak that will loose that much pressure, will be a gusher...
 
j par said:
That sucks ! Likely you're screwed to take something apart. Might as well be something that doesn't require pulling the motor. Sorry to hear it ....
Click to expand...

He can start with what he can do without pulling the motor, but if he can't find it, he will be best off pulling it and tearing into it on a stand.
 
Also too, anything at ALL that keeps the oil pump from seating all the way down on the main cap can cause a leak. If those surfaces are not perfectly flat and free of sharp edges and the like, you can have a problem. And if you happen to be using the ARP oil pump stud kit, that can sometimes cause issues with the same problem. The oil pump not seating properly. There has been more than one member here have that problem.
 
Thanks guys
I pulled the front cover off & found a oil hole on the tensioner plate just below the oil hole in the bolt & some leakage from the other side of the plate , so i will use freezer plugs in the 2 front oil ports & fit a smaller diameter hole bolt in the top left as it was from factory & see what results i get
cheers
 
vghoon said:
Thanks guys
I pulled the front cover off & found a oil hole on the tensioner plate just below the oil hole in the bolt & some leakage from the other side of the plate , so i will use freezer plugs in the 2 front oil ports & fit a smaller diameter hole bolt in the top left as it was from factory & see what results i get
cheers
Click to expand...

Awesome! I bet that was it.
 
Ok fitted the plugs & there is no more oil coming from there
I primed the pump with the drill to check for further leaks & found the rear gallery plug
feeding the oil pump drive to be feeding alot of oil there, is this normal?
does that gallery plug have a hole in it?
 
Are you talking about oil squirting out on the intermediate gear itself? If so, that's probably a mod someone did. It's a popular mod if it's the one I am thinking of and it won't hurt a thing. Pics would be great.
 
the rear gallery plug facing the oil pump shaft & dizzy drive gear,
how is this lubricated?
will get a pic
 
vghoon said:
the rear gallery plug facing the oil pump shaft & dizzy drive gear,
how is this lubricated?
will get a pic
Click to expand...

It is not lubricated on purpose in a stock engine. It is simply splashed lubed. If someone drilled a small hole through that galley plug, that could be what you are talking about and it is an acceptable mod. We can verify it with a pic.

As long as they didn't drill a 1/4" hole in it, LOL it should be fine. I think the accepted size is 1/16".
 
that is a picture with me on the drill & that is the flow to that drive gear in the dizzy hole
is this normal?
 
Yup. It appears someone drilled that plug. That's a good mod as long as the hole isn't too big and it appears it is not.
 
Have you got the gauge hooked up to it now? How much pressure is there? If you don't, hook it up and see.
 
vghoon said:
i am getting 40psi with the drill
Click to expand...

Depending on drill speed, that is probably about what it will be at idle. Do you get the feeling it would increase with RPM? If so, you may have fixed it.
 
only time will tell if it increases with speed i guess
i have not installed the cam thrust plate yet but yet i am not getting oil to the front
bolt hole
can you tell me why?
 
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