'88 ranger 2.3 no oil pressure

[Shran]

I got the engine back from the machine shop yesterday. They did all the typical rebuild stuff to it and bored it 30 over.

They said that it was just very worn out and it could have just been a coincidence that it lost oil pressure when it did. It also had a broken head bolt and the head was packed full of radiator stop-leak crap (as was the radiator, I bought a new one too.)

While I had the engine out, I pressure washed the engine bay, front axle, trans, etc and found three bad u-joints in the front axle as well.

Reassembly starts tonight. I have never sunk this much money into an engine before!

Any specific tips on engine break-in? I have a bottle of Lucas ZDDP additive that I will run with the first oil change.

 

[RonD]

I would disable the spark and fuel pump, then crank engine over a few times to get some oil circulated before first startup.

 

[Shran]

Cool, did that. Got it all put back together and running yesterday.

Quick question about setting the timing - I pulled the SPOUT and set the timing to 10* BTDC, shut it off, reinstalled the SPOUT. I read something about it being advanced to 20* after the SPOUT is reconnected, is 20* the max it should advance, or should it be at 20* and advance from there with RPM? It was sitting at about 15* at idle.

 

[IRKillroy]

Oil pressure sending unit is not leaking, it is on the main oil passage.

Could new oil filter be clogged/bad?

Oil pump runs off a timing belt gear so engine would have shut off on it's own if belt broke.

If possible remove oil pressure sender, disable spark(no start) and crank engine, with bowl under sending unit hole, see what kind of flow you get.
Then remove oil filter and repeat, if you get flow out of filter housing and not sender hole then filter was the problem.
If no flow from filter housing then oil pump or gear is bad.

My bet is bad oil filter.

All oil filters have a bypass so there will always be oil even if the filter is clogged.

 

[IRKillroy]

The Ford oil pressure switch that was on it was set for 6psi, as long as pressure was above 6psi oil gauge stay at 1/2 or just below it.

General rule of thumb for oil pressure is 10psi per 1,000rpms, but it is a curve so there is less pressure at higher RPMs, i.e. not 50psi at 5,000rpms, maybe 30-35psi, 700rpm idle would be 7-9psi.

Oil pressure means there is TOO MUCH OIL
The oil pump pushes oil to the filter and then out to the main oil passage and then to the bearings, oil pressure sender is on the main passage, oil flows to smaller passages and to the bearings.
If there is more oil coming in than the bearings can pass, then the oil backs up, pressure builds up in the main passage, that's the oil pressure you see, there is too much oil.
Because of gravity you need above 5psi for the valve train to get oil, depends on the setup but usually above 5psi is OK, you start to get ticking valve train noise below 5psi.

The 40psi at 2,500-3,000 RPMs sounded high for what I assume is a medium to high mile engine.
20psi would be more like it.
High oil pressure causes issues as well, 8-30psi is an acceptable range for most engines

"oil pressure means there is too much oil"???? seriously?

Oil pressure means there is oil being forced through small spaces. The 40 PSI means his pump is working... It's a High Volume melling pump.

Ticking valve train happens from clogged oil passages and lifters not getting enough oil...

If the oil pressure came back it was probably silicone stuck in the pick up or the pump.

 

[IRKillroy]

Cool, did that. Got it all put back together and running yesterday.

Quick question about setting the timing - I pulled the SPOUT and set the timing to 10* BTDC, shut it off, reinstalled the SPOUT. I read something about it being advanced to 20* after the SPOUT is reconnected, is 20* the max it should advance, or should it be at 20* and advance from there with RPM? It was sitting at about 15* at idle.

Make sure you do the timing with the spout disconnected so it won't auto time. After you plug it back in it doesn't matter what it reads. I'm guessing it's running great now?

 

[Shran]

Make sure you do the timing with the spout disconnected so it won't auto time. After you plug it back in it doesn't matter what it reads. I'm guessing it's running great now?

Yes, other than some weird idle issues, it is running fine.

I re-read my book and checked the timing again yesterday. I must have misread something. Its set on 10* with the SPOUT unplugged now

On another note, I had a chance to bench bleed the clutch while the engine was out. I had some clutch release issues before and it is certainly nice to not have to force it into gear.

 

[Shran]

FML... I am really not very happy right now.

New engine has started pissing oil from the front main and developed a very loud knock under load today.

On the bright side, it is holding oil pressure...