This is gonna be a long post, so please bare with me.

About 3 years ago, my daughter ended up with a 2002 F150 Lariat with the 4.6. Engine was seized. I pulled the engine and rebuilt it. Ran great for about a year, then blew a head gasket. I replaced the head gasket. While putting the head back on, I managed to let the cam slip. I didn’t know it until I went to crank it. Shattered #1 piston, bent or broke every valve on the passenger side. Decided it was faster to replace the motor rather than rebuild, again. Purchased a used motor. Once it was installed and I went to install the intake from her motor, I realized it did not have the PI heads. No big deal, I thought, I’d just use the intake that came with it. Didn’t realize until I went to put the coils in, wrong year model. Figured it might work anyway. NOPE! Never could get it running smoothly. This was engine install #2. Had no choice but to rebuild the original engine, again. Sent the block off, bored and sleeved #1, honed the rest. Sent the heads off for new valves. Rebuilt the engine and installed. After replacing the fuel pump, engine fired right up. Within about 5 minutes lost oil pressure and engine was ticking noticeably. Replaced sending unit to verify no pressure. Same result. Figured oil pump was bad, since that was the only thing I didn’t replace when I rebuilt it. Tore into the engine and replaced the oil pump. Started engine and couldn’t get pressure. Dropped the oil pan to check pickup tube. Cleaned that. Primed oil system by pumping oil through sending unit location, 4 quarts there and 2 through the oil fill. Started truck, sounded and ran great for about 5 minutes again. Engine had a tick, but was hoping it would go away. Added transmission fluid while it was running. When I went to cycle through the gears, noticed no oil pressure at idle. Oil pressure would increase with throttle. Ticking got louder.

Now the only thing I did different than the original rebuild was on the original rebuild I used ultra black sealant between oil pump and block at the passage, this time I did not.

My question is, where the heck is my oil pressure going? Could it be blowing out between the pump and block? Could it be blowing out at the tensioners? I’m about ready to set this thing on fire.

Sorry for the long post. But hopefully you can see, after 2 rebuilds and 3 engine installs, why I’m in dire straits. Any help or guidance would be, and is greatly appreciated.

 

It’s possible a little pressure is being lost due to internal sealing, but unlikely that’s what’s causing all of it. Also I don’t agree with reusing the oil pump (just from a “it’s apart now so why not?” perspective) but if you got a year of service out of it the first time, and if revving the engine raises the pressure, I doubt the pump is the problem.

In most cases, loss of oil pressure is due to excessive mechanical clearance.

When you had the block repaired, did you only send the block, or did you send it with the crankshaft and main caps? If you didn’t send it with the crank, did you plasti-gauge the main bearings and make sure the journals in the crank were clean?

What about other mechanical components? Did you re-use anything besides the oil pump?

If clearances are the problem, putting a heavier oil in it should verify it. Drain the pan only (no need to replace filter right now) and put 15-40 diesel oil in it. If the capacity is 6 quarts then 5 should bring it up to a safe level without draining the filter.

Also, use the dash gauge if you want, but I recommend getting a mechanical oil pressure gauge so you know what the actual pressures are.

 

Did you check to see if the oil pick up tube isn't cracked, missing gasket?

 

DBGrif
I did replace the oil pump, but only after the initial pressure problem. When I sent the block it, it went with main caps, but not the crank. I replaced main bearings, rod bearings, one piston and connecting rod, and all the rings. I only replaced one of the tensioner due to to Oring being torn. I did not check the journals. When I pulled the pickup tube yesterday, I replaced the Oring when I reinstalled it.

 

You have to follow procedure on oil pump specs and assembly.
At cold start there is about 75 psi until the oil heats and oil viscosity thins out.
At idle the hot pressure should be close to 25 psi.
Seeing a little pressure after the loss indicates a severe leak. The ticking likely is a hydraulic valve tick from lack of oil pressure.
The small pressure you see is the oil pump able to make volume faster than the leak loses it.
It seems the seal or the oil pump clearance is excessive or your sealing has blown out.
Reading your post indicates you to be your own worst enemy on this project from poor decisions and workmanship..
I'm sorry if it insults you at this point in your situation but you need to stop and take some time to look at how you approach these things.
Actually I say this to help you now and in the future even though it sounds harsh and your upset.
Think about his; getting upset, frustrated or angry is at yourself for not being able to succeed. It's not the motor's fault..
Good luck.

 

I understand everything you just said. And I agree about me being my own worst enemy in this matter. I learn by making mistakes. I work on my vehicles not because I want to, but, because I can’t afford to pay some else to do it for me. Usually it works n my favor. This time, not so much. What you say does not offend me, because you did provide guidance now if you would have chastised me without guidance, then that’s just being a *#%^.

Everything being said, I’ve decided to walk away from the truck until after the 1st of the year. Clear my head and get rid of the frustration. I usually don’t make the same mistakes twice. If I have to spend more money, so be it.

I honestly do appreciate ALL of the input. Unfortunately this is just about the only place I can get information that is somewhat consistent.

 

Good luck and have a Merry Christmas..

 

Sounds like you have the wrong size rod or main bearings or maybe both, buy some plastic gauge drop the pan and check the clearances.

Denny

 

Let me explain this a little further, if you have to much clearance on your bearings oil escapes out the sides of the rods or mains so the pressure drops and will starve the upper end causing lifter collapse, your ticking noise. When it's cold the oil is thicker so the pressure stays up but when it heats up the oil thins and goes out the sides of the bearings. Every motor I have ever built I used plastic gauge on every bearing journal to check clearances and rod alignment.

Denny

 

Thank you all for the input. I will be getting the plastic gauge and checking all of the clearances. Basically it sounds like I have possibly a couple issues going on. No seal between oil pump and block, blown seal between tensioner and block, and maybe wrong bearing clearance. i will be redoing the tensioners and oil pump, as well as checking my main and rod bearings after the first of the year