troubleshooting oil pressure

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TomSchichtel

TomSchichtel

73 Duster
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Newcastle, CA
I have read many oil pressure threads and tried a few things with no luck, but at least I ruled some things out already.

The motor: 74 360 .40 10.5:1 J heads about 400 miles on fresh rebuild with 2 thousands bearing clearances (told by machinist, and I checked with plastigauge).

Symptoms with Mopar Performance HV oil pump and old mechanical/hydraulic gauge:

50psi cold oil pressure with old mechanical/hydraulic gauge mounted by the distributor. When motor is between 180-200 degrees city/HWY the oil pressure was at 20 psi. And at idle it would peg 0 psi on the gauge. I could use the throttle to keep it up around 20 psi. I didn't continue to run the motor like this.

Symptoms with Melling standard volume oil pump and brand new mechanical/hydraulic gauge:

75psi cold oil pressure, motor between 180-200 degrees pressure grows and drops as rpm goes up and down. Stays between 20psi and 40psi depending on rpm. 5-10 psi low using the scale of 10psi per 1000 rpm. Hot idle psi drops to 10- 15psi.

What I have checked so far is that there is an (rear main) oil galley plug and it is roughly 1/8th" deeper set than my 340 builder block which still has that plug in place. So I believe I can rule that out. The intermediate shaft is in good working condition with no rounded edges where it should meet the pump. The other things I have done were change the oil pump to stock melling from HV mopar pump as well as a brand new gauge, which increased cold psi by 25psi but low psi at operating temp still remains an issue.

Any tips on what I should check next? I am used to Pre-rebuild having consistent 50psi at operating temp, which leaves me concerned about my present oil pressure. Thank You in advance!
 
On a 340 I once had only 25 psi cold start and down to 10 warm.

Turned out that the machine shop forgot to put the two oil galley plugs in that go behind the camshaft thrust plate.
 
There is also another oil galley plug in the back of the driver's side lifter galley. there is another "access" plug on the rear of the block to get to it. It is just in front of where the distributor drive bushing goes.


Check for that one also.
 
take the intake off to check for/ intstall those? By the way I'm running 10w-30 as my machinist recommended for my bearing clearances. I chose to go with royal purpal.
 
TomSchichtel said:
I have read many oil pressure threads and tried a few things with no luck, but at least I ruled some things out already.

The motor: 74 360 .40 10.5:1 J heads about 400 miles on fresh rebuild with 2 thousands bearing clearances (told by machinist, and I checked with plastigauge).

Symptoms with Mopar Performance HV oil pump and old mechanical/hydraulic gauge:

50psi cold oil pressure with old mechanical/hydraulic gauge mounted by the distributor. When motor is between 180-200 degrees city/HWY the oil pressure was at 20 psi. And at idle it would peg 0 psi on the gauge. I could use the throttle to keep it up around 20 psi. I didn't continue to run the motor like this.

Symptoms with Melling standard volume oil pump and brand new mechanical/hydraulic gauge:

75psi cold oil pressure, motor between 180-200 degrees pressure grows and drops as rpm goes up and down. Stays between 20psi and 40psi depending on rpm. 5-10 psi low using the scale of 10psi per 1000 rpm. Hot idle psi drops to 10- 15psi.

What I have checked so far is that there is an (rear main) oil galley plug and it is roughly 1/8th" deeper set than my 340 builder block which still has that plug in place. So I believe I can rule that out. The intermediate shaft is in good working condition with no rounded edges where it should meet the pump. The other things I have done were change the oil pump to stock melling from HV mopar pump as well as a brand new gauge, which increased cold psi by 25psi but low psi at operating temp still remains an issue.

Any tips on what I should check next? I am used to Pre-rebuild having consistent 50psi at operating temp, which leaves me concerned about my present oil pressure. Thank You in advance!
Click to expand...
i`m not familiar w/ mopar small blocks, but went thru the same thing on a 406 sbc. I put a washer under the spring(the correct size of course) to bump up the oil pressure just a tad, went to about 18-20 idleing hot, idled w/ that cam about 1200 rpm. never had a problem w/ it------bob
 
TomSchichtel said:
take the intake off to check for/ intstall those? By the way I'm running 10w-30 as my machinist recommended for my bearing clearances. I chose to go with royal purpal.
Click to expand...

for the one in my second post that goes in front of the distributor drive shaft on the back of the oil galley. You may not need to pull the intake if you can may be able to see it with the distributor out.


The two behind the camshaft thrust plate, you have to disassemble the front of the engine and pull off the timing chain to check it, but you don't have to pull the engine if it is not already out.
 
kuda might have to give the your washer trick a try once I confirm the plugs that krazykuda is talking about are in place.
 
thankyou for the input so far! I'm headed out to check for the plugs krazykuda has suggested right now I'll check back soon with the results!
 
TomSchichtel said:
kuda might have to give the your washer trick a try once I confirm the plugs that krazykuda is talking about are in place.
Click to expand...

Don't do that!

For mopar SB oil pumps, there is a spring kit available through Mancini racing for high pressure. It comes with the cup plug and new spring, you have to remove the cup plug from the oil pump relief valve (without getting any chips in it) and change the spring and then put the valve back in and the cup plug. The cup plug goes backwards compared to what you are used to. Pay attention to how the original one comes out.

I can give you directions to do that if you need it. The spring is a Mopar Performance part and is under $10.
 
There are two trick plugs in Mopar SB

One is the one mentioned above. This is a screw in plug behind a second screw in plug in the rear of the block. You can see it looking down the dist. hole. One guy on here actually installed it through the dist. hole

The SECOND is a drive in plug which is installed before the rear main cap is installed. This goes up in the vertical gallery going up to the oil sender. There is a way that you can remove the oil sender and stick a rod down in and measure to determine if it is there EDIT READ BELOW

THIS WOULD NOT prove there is not a hole in the plug from say, rust or hot tanking.

This is a photo of the one in the dist. hole. The wrench is coming through a plug in the rear wall of the engine

http://image.moparmusclemagazine.com/f/projectbuild/mopp_1007_project_plymouth_valiant_effort_engine_upgrade/27598010/mopp_1007_03_o%2Bplymouth_valiant%2Binstalling_oil_galley_plugs.jpg


You take a rod or wire, and insert down from the top through the oil sender hole. If the rod goes down much more than 7" the plug IS NOT in there

Here it is READ THIS:

http://www.forabodiesonly.com/mopar/showthread.php?t=40544

Post no 10:

http://www.forabodiesonly.com/mopar/showpost.php?p=316787&postcount=10

fishy68 said:
You can check to see if the one Rumblefish mentioned is there easily by inserting a 1/4" piece of round rod down the oil pressure sender hole. It should only go down about 7-3/4". If it goes much more than that the plug isn't there.

The one Deadly Dart mentioned can be seen with just the dist. removed. Like he said put the drill in and spin it and look down through the dist. hole and if you see oil gushing out there's your problem. This plug were talking about is screwed into the drivers side rear of the lifter galley.
Click to expand...
 
TomSchichtel said:
thankyou for the input so far! I'm headed out to check for the plugs krazykuda has suggested right now I'll check back soon with the results!
Click to expand...

I just took some pictures of some myself. I am down loading them to my computer, then have to name and resize them.
 
67Dart273 said:
There are two trick plugs in Mopar SB

One is the one mentioned above. This is a screw in plug behind a second screw in plug in the rear of the block. You can see it looking down the dist. hole. One guy on here actually installed it through the dist. hole

The SECOND is a drive in plug which is installed before the rear main cap is installed. This goes up in the vertical gallery going up to the oil sender. There is a way that you can remove the oil sender and stick a rod down in and measure to determine if it is there

THIS WOULD NOT prove there is not a hole in the plug from say, rust or hot tanking.

This is a photo of the one in the dist. hole. The wrench is coming through a plug in the rear wall of the engine

http://image.moparmusclemagazine.co...mouth_valiant+installing_oil_galley_plugs.jpg

For some reason I can't find the dope on the one in the vertical galley, maybe someone will find it
Click to expand...



I just went and took some pictures of the plugs, I'm now downloading them from the camera and have to name and resize for posting. Stay tuned...
 
Ok, here are some of the oil galley plugs in the back of the block:


This is of the oil galley plug in the back of the driver's side lifter galley wide angle:

View attachment 360 rear cam oil galley A01 B2.jpg


This is of the oil galley plug in the back of the driver's side lifter galley a little closer:

View attachment 360 rear cam oil galley A02 B2.jpg


This is of the oil galley plug in the back of the driver's side lifter galley showing it's location with the distributor drive gear bushing:

View attachment 360 rear cam oil galley A03 B2.jpg


Here's the rear of the block. The one on the left is the clearance plug to access the one shown above for the driver's side rear lifter galley. The one on the right is the passenger side lifter oil galley plug:

View attachment 360 rear face A01 B2.jpg


Here's the rear of the block that shows all three plug locations at once. The one on the left is the clearance plug to access the one shown above for the driver's side rear lifter galley. The one in the middle is the passenger side lifter oil galley plug. The one on the lower right is the oil galley plug leading to the oil filter:

View attachment 360 rear face A02 B2.jpg


Here is a closer view of the two plugs for the lifter galley. The one on the left is the clearance plug to access the one shown above for the driver's side rear lifter galley. The one on the right is the passenger side lifter oil galley plug:

View attachment 360 rear face A03 B2.jpg

Here's a closer view of the one on the bottom right for the oil galley to the oil filter base:

View attachment 360 rear face A04 B2.jpg





 
Thanks, Krazy There seems to be a fair amount of controversy about the front plugs, which are covered up by the cam thrust plate. Some guys say that some engines never HAD these plugs and rely on the thrust plate to plug the galleries. I'm not sure I'd worry about them.
 
67Dart273 said:
Thanks, Krazy There seems to be a fair amount of controversy about the front plugs, which are covered up by the cam thrust plate. Some guys say that some engines never HAD these plugs and rely on the thrust plate to plug the galleries. I'm not sure I'd worry about them.
Click to expand...

Yes, there are some who don't think that you need it.


I know that on my first 340 the machine shop left those plugs out. I had to pull the engine out of my car 4 times before catching the problem on the fifth. I built an oil pump priming rod in my high school welding class as mopar didn't offer them back then. When I spun the oil pump, oil came shooting out from behind the thrust plate. There was where it was loosing pressure. After installing the plugs, the oil pressure was fine after that...


So they can say what they want. It did matter on one of my engines and I am sure to always check for them now. If someone doesn't want to use them, then that is their decision. It's their engine.


From my past experience, I choose to run them in all of my engines.


If you choose not to use them, then that is your call. As long as you are aware of the risks and accept the consequences...
 
wowee! krazykuda you went above and beyond your mopar call of duty! Thank You very much.

Here is what I have got so far: I do have the oil galley plug in the back of the driver's side lifter galley, and the thread in plugs on the back of the block. I can confirm that. I took my intake off to visualize the cam bearings are not leaking under pressure, while drilling the oil pump. One thing in forgot to do was rotate the engine to see if the cam oiling holes were lined up in order to lube those bearings though so I will double check that tomorrow (no lighted garage to continue playing) I didn't take the timing cover off (in order to see if there are plugs behind the thrust plate) today because I'm missing 1 pesky bolt to pull the balancer with, but that will be my task tomorrow. I will update progress found tomorrow!
I will look into getting that high pressure spring kit for sb pumps once I confirm that my crank and rod bearings are looking good and I have the one or two? plugs behind the oil filter plate. I thing I have learned is that I will take many pictures of all of the plugs on my next build so that I can rule them out if this ever happens again! 20/20

Thanks guys for the advise and don't forget your valentines tomorrow! Because we all know tits and wheels will always give you trouble unless you maintain them! :)
 
you have a little extra bearing clearance some place. I don't think your pressure would reach 75psi with a missing plug.
 
With 10W30 and the main brg clearance at .002" I would not be all that surprised at the hot pressures listed with the 2nd pump. How about seeing what it does with some 10W40....

75 psi pressure cold is plenty; be careful if you put in the stiffer spring; up near 100 psi or more, you run some small risk of blowing out the oil filter seal when cold. (Ask me how I know...). Or you can pump excess oil into the heads at sustained high RPM's....

If you find nothing, then run it a while, 'til the rings seal up good (probably done so already if you have loaded it up a bit) with 10W40, and then use 10W30 or 15W40 Mobil 1 and it will last forever.
 
great pix of the plugs. That is great help! The rocker shafts are not upside down are they? It is not a roller cam??? check the oil leakage with the intake off and rotating the engine, looking @ the lifter bores [bottom side when possible] Please post your findings/fix!
 
well you can forget all the plugs on the outside of the block or you would have a big puddle
 
fishmens67 said:
you have a little extra bearing clearance some place. I don't think your pressure would reach 75psi with a missing plug.
Click to expand...

It possibly could if it were the ones behind the camshaft thrust plate.
 
How about a cracked / broken oil pump? I myself have had trouble with pump / pan interference, and others have had troubles with ARP main cap bolts

I'm not referring, here, to pickup striking the pan, but rather the pump body hitting the rear of the pan
 
Here are pictures of the high pressure relief spring and where it goes on the oil pump.


Here is the package showing the part number:

View attachment MP HP spring kit A01 B.jpg

Here is the package showing the spring and cup plug:

View attachment MP HP spring kit A03 B.jpg

Here's a picture of the oil pump showing where the pressure relief spring is:

View attachment Oil Pump A01 B2.jpg

Here's a picture of the oil pump showing where the pressure relief spring is closer:

View attachment Oil Pump A02 B2.jpg

Here is a close up of the cotter pin and cup plug. Note that the cup plug has the lip facing inward where you can't see it from outside. You may need to get a spare cotter pin if you can't reuse the one after taking it out.

View attachment Oil Pump A03 B2.jpg

To replace the high pressure relief spring, remove the cotter pin shown in the pictures above. Then punch a hole in the cup plug with a punch that is ground to a sharp point. I use a medium weight ball peen hammer and use a sharp blow so as to punch a hole in the cup plug and not push it deeper into the bore. I recommend using a punch to reduce the chance of getting chips in the oil pump relief valve bore. One chip can cause the valve to stick and the oil pump to fail. I don't recommend drilling because of the chips.

Then get a #8, #10, and #12 screw from the hardware store about 1" long with matching washers. Screw the screw into the hole in the cup plug at least 3 turns with the washer under the head of the screw. Then hold the oil pump in a vise and pry the cup plug out. After removing the cup plug, then tip the pump and let the pressure relief valve and spring drop into your hand. ***Note which way the valve goes in***.

Then place the new spring in the oil pressure relief valve bore and then install the relief valve after that.

Then install the cup plug with the lip facing inward making sure that the spring is properly seated in the relief valve and the cup plug. Be careful when installing the new cup plug not to push it in too far past the cotter pin holes.

Then install a cotter pin (reuse the old one or get a new one).

I like to mark an "H" on the outside of the pump with a paint marker afterwards so I know that I put the high pressure spring in it.
 
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