Oil pressure problem when starting

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toolmanmike

toolmanmike

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My 273 build went pretty smooth and the pre-lube and initial start up went smooth also. As always with any big project there will be problems along the way. When I start my engine cold after setting overnight the engine fires immediately but it takes 10 seconds for the oil light to go out. (Long enough for a little rattle that doesn't sound like a lifter or rocker) I had the same problem before I rebuilt the engine. It's like the pump has to fill the filter up before the light goes out. I can only think of two things that are the same between the old and new engine.
1) One is I am using the same number of Car Quest premium oil filter. I am wondering if there is a filter that has a anti drainback valve in it to use with the factory right angle adapter.
2) Shame on me but I didn't replace the oil galley soft plug in the rear main bolt hole area. I remember checking it and tapping it to make sure it was tight but I didn't replace it. The block was pressure washed in a machine but not "cooked" or submersed in a hot caustic cooker. It also has a new pump and sender.
I need to do a little diagnosis like taking the filter off and see how much oil is inside before I start it. I need to hook a manual gauge up also but with the little knock just before the light goes out I'm sure there isn't much pressure. I got 65# when I pre-lubed it with a cordless drill but that was with all the asembly grease in there too. The oil clearances on the crank and rods were tight. Any suggestions? Anybody have a similar problem? Anything I'm overlooking? Mike
 
Just my 2 cents. I have always used Mopar filters from the dealer. I know other filters offer this and that feature but I have never had a filter problem in 38 years of Mopars.
 
I am trying to stay cool and not get wigged out. I would be so pumped if it were that simple. Mike
 
Did you put in a new oil sending unit or swap the old one? Maybe try another sender or a after market with a gauge to see if the oil is in fact taking that long to get good pressure. I hate relying on idiot lights only for pressures. Good luck.

just saw it has a new sender, How is the wiring to it? Do you have a good connection?
 
I run a smaller carquest 85348 (wix 51348,) with the drain back valve. larger ones wouldn't clear my headers. I would think that might just be your issue.
 
63dartman said:
Did you put in a new oil sending unit or swap the old one? Maybe try another sender or a after market with a gauge to see if the oil is in fact taking that long to get good pressure. I hate relying on idiot lights only for pressures. Good luck.
Click to expand...
I did put in a new sender and I don't like lights. I will gook up a test gauge to check for sure. I don't like the knock I hear just before the light goes out. That's what scares me.
 
camd64 said:
I run a smaller carquest 85348 (wix 51348,) with the drain back valve. larger ones wouldn't clear my headers. I would think that might just be your issue.
Click to expand...

I will definitely try those numbers. I get the same thing happening when I change oil. The filter screws in horizontally because of the adapter and I can't pre fill it with oil. I may be able to loosen the adapter and turn it so the filter is more vertical. Thanks.
 
Carquest filters are just fine, since Wix makes them. The BEST on the market. Even better than a Mopar one, just cut each open and look.

Get a mech gauge on there right away to see just how long til pressure hits the gauge area.

What oil are you running? Any additives?
 
Another thing I just thought of is if the pickup is too close or touching the bottom of the pan it might do that same thing.
 
redfastback said:
Carquest filters are just fine, since Wix makes them. The BEST on the market. Even better than a Mopar one, just cut each open and look.

Get a mech gauge on there right away to see just how long til pressure hits the gauge area.

What oil are you running? Any additives?
Click to expand...
I too like the quality of the Premium Carquest filters. I am running 10/30 Valvoline with Comp Cams break in lube. (zinc) The old motor did the same thing and even though it was worn out and the bearings were down to the copper, I thought for sure that was the cause of the problem.
 
camd64 said:
Another thing I just thought of is if the pickup is too close or touching the bottom of the pan it might do that same thing.
Click to expand...

I thought about that too but the pickup is flat metal on the bottom and the oil is picked up on the ends.
 
My 360 with a stock volume pump took longer to build pressure after sitting a few days than I liked with 15w-40 rotella in it. After break-in, I switched to 10w-30 castrol synthetic and the pressure came up faster(easier to pump?). However, on my 318, I used a HV pump and it comes up much quicker. Can't explain it, but I theorize that small block mopars have some internal leakage, like at the 16 lifter bores maybe.
 
K&N also has the drain back valve, they cost a little more, not sure worth the cost thought.
 
It should come right up, and I doubt it's the filter. Use the gage and see what is really going on. Did you get the pipe plugs behind the cam retainer in? What about the larger one just in front of the oil pump drive?
 
Mike, are you using the same oil pump or a new one? I have seen a new oil pumps where the relief valve didn't seat all the way due to a casting burr. It was a name brand (Melling) pump too.

Also, how are you liking that cam?
 
are you running a new pump or same pump for the oil?

I sure hope you didnt buy a melling......the melling factory is only a few miles from my house and I know people who worked there and know there parts are less than perfect....I personally have had 3 bad melling oil pumps and will not buy them again!.

the melling pumps the gears like to drop and eat into the bottom plate and upon doing so they kick up metal shavings which in turn chew up the gears and drop oil pressure.

I always pull the bottom plate of the pumps, inspect the gears and shaft play,make sure the making surface of the pump and plate are smooth to insure a tight seal and I locktight the bolts back on.....also, are you running a gasket between your oil pump and block? or do you have a pump with a machined smooth surface that mounts without a gasket (mostly a newer chevy thing i think)

anyhow.....as for oil filter choices.....I am not sure what all company's offer this design but I know K&N oil filters have a pressure check valve ball in them that mainstains oil pressure in the filter so on start ups the oil does not have to flow through the filter prior to pressurizing the system.

I am using a mopar brand filter on my engine and it works great.

it deffinetly sounds like your having an oil pressure issue though....not a sending unit issue.

is your pick up tube bent properly to sit in the oil inside the pan?,is the pick up tube free of any cracks?,is the pick up tubes screen clean and free of blockage?

besides pick up,pump and so on....the only other thing it could be is oil galleys and bearing clearances.

hope its not a serious problem so you don't have to yank the engine back out.

Good luck
 
Install a pressure gauge and check the pressure cold and also hot.
If you have a problem with the oil pressure, it will also show when the motor is hot.
I just replaced my sending unit because my oil light turned on and would not go off.
The problem was trying to find a good sending unit.

1)I try a new sending unit that i have in my garage \\\ no good
2)I try a old unit i have on the self \\ no good
3)I try my brothers 340 dart sending unit and it worked so i new my oil pump was still good.
4)The next day i go to advanced auto and by a new sending unit and it also ,was no good \\ I then checked all my wires.
5)Went back to the store and returned the gauge for another and it worked.

I checked my oil pressure with a gauge afterwards and it was 60psi at idle 1000rpms.
Most repair manuals say 55 pounds at 2000rpms.
MAKE SURE YOUR IDLE IS HIGH ENOUGH TO KEEP THE MOTOR RUNNING SMOOTH AT START UP.
 
Sorry, I was gone for a few hours.
moper said:
It should come right up, and I doubt it's the filter. Use the gage and see what is really going on. Did you get the pipe plugs behind the cam retainer in? What about the larger one just in front of the oil pump drive?
Click to expand...
As far as I know every plug is in and sealed with either Indianhead sealer for the cup plugs and teflon for the threaded plugs. I could have made a mistake and forgot one but I hope not. I tried to check and double check. The old engine did the same before I stripped it for rebuilding.

C130 Chief said:
Mike, are you using the same oil pump or a new one? I have seen a new oil pumps where the relief valve didn't seat all the way due to a casting burr. It was a name brand (Melling) pump too.
I am using a new Melling pump.

Also, how are you liking that cam?
Click to expand...
I am using a new Melling pump. The cam sounds good (just a little rump rump and is more powerful as the motor loosens up.

DusterDude72 said:
are you running a new pump or same pump for the oil? New Melling pump. I did reuse the pickup but cleaned and inspected it. If I decide to pull the pan and replace the pump I will replace the pick-up just to be safe.

I sure hope you didnt buy a melling......the melling factory is only a few miles from my house and I know people who worked there and know there parts are less than perfect....I personally have had 3 bad melling oil pumps and will not buy them again!.

the melling pumps the gears like to drop and eat into the bottom plate and upon doing so they kick up metal shavings which in turn chew up the gears and drop oil pressure.

I always pull the bottom plate of the pumps, inspect the gears and shaft play,make sure the making surface of the pump and plate are smooth to insure a tight seal and I locktight the bolts back on.....also, are you running a gasket between your oil pump and block? or do you have a pump with a machined smooth surface that mounts without a gasket (mostly a newer chevy thing i think)

anyhow.....as for oil filter choices.....I am not sure what all company's offer this design but I know K&N oil filters have a pressure check valve ball in them that mainstains oil pressure in the filter so on start ups the oil does not have to flow through the filter prior to pressurizing the system.

I am using a mopar brand filter on my engine and it works great.

it deffinetly sounds like your having an oil pressure issue though....not a sending unit issue.

is your pick up tube bent properly to sit in the oil inside the pan?,is the pick up tube free of any cracks?,is the pick up tubes screen clean and free of blockage?

besides pick up,pump and so on....the only other thing it could be is oil galleys and bearing clearances.

hope its not a serious problem so you don't have to yank the engine back out.

Good luck
Click to expand...
Thanks for the support. The bearing clearances were all good (except for the cam bearings which I couldn't check) but the bearings were new and installed by the machine shop.

T67POWER said:
Install a pressure gauge and check the pressure cold and also hot.
If you have a problem with the oil pressure, it will also show when the motor is hot.
I just replaced my sending unit because my oil light turned on and would not go off.
The problem was trying to find a good sending unit.

1)I try a new sending unit that i have in my garage \\\ no good
2)I try a old unit i have on the self \\ no good
3)I try my brothers 340 dart sending unit and it worked so i new my oil pump was still good.
4)The next day i go to advanced auto and by a new sending unit and it also ,was no good \\ I then checked all my wires.
5)Went back to the store and returned the gauge for another and it worked.

I checked my oil pressure with a gauge afterwards and it was 60psi at idle 1000rpms.
Most repair manuals say 55 pounds at 2000rpms.
MAKE SURE YOUR IDLE IS HIGH ENOUGH TO KEEP THE MOTOR RUNNING SMOOTH AT START UP.
Click to expand...
In the next few days when I find time I will do some diagnosis. I think I'll pull the filter off first to see how much oil it has in it then replace it with a good filter with a check valve. I can screw my test gauge in for a cold and hot test. Then I can go from there. Mike
 
toolmanmike said:
My 273 build went pretty smooth and the pre-lube and initial start up went smooth also. As always with any big project there will be problems along the way. When I start my engine cold after setting overnight the engine fires immediately but it takes 10 seconds for the oil light to go out. (Long enough for a little rattle that doesn't sound like a lifter or rocker) I had the same problem before I rebuilt the engine. It's like the pump has to fill the filter up before the light goes out. I can only think of two things that are the same between the old and new engine.
1) One is I am using the same number of Car Quest premium oil filter. I am wondering if there is a filter that has a anti drainback valve in it to use with the factory right angle adapter.
2) Shame on me but I didn't replace the oil galley soft plug in the rear main bolt hole area. I remember checking it and tapping it to make sure it was tight but I didn't replace it. The block was pressure washed in a machine but not "cooked" or submersed in a hot caustic cooker. It also has a new pump and sender.
I need to do a little diagnosis like taking the filter off and see how much oil is inside before I start it. I need to hook a manual gauge up also but with the little knock just before the light goes out I'm sure there isn't much pressure. I got 65# when I pre-lubed it with a cordless drill but that was with all the asembly grease in there too. The oil clearances on the crank and rods were tight. Any suggestions? Anybody have a similar problem? Anything I'm overlooking? Mike
Click to expand...

I also reused the pickup from the old motor. I did clean and inspect it and install it with a new gasket sprayed with a bit of red Permatex to keep it in place.
 
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