low oil pressure

[Wally]

ONe step forward two steps back

Looks like none of my gauges are working...speedometer, RPM etc...

[Zed Head]

Any chance you could tell the people what you saw while you were in there?  Before you move on to the new wiring problem?  A story that ends unresolved is very disappointing.

[Wally]

sorry for all the posts. just very nervous. i dont want to ruin the engine. the gauge issue was a fuse. I checked the spot for instruments it was fine. However, i now know the fuse to check is the flasher spot. My fault should have checked all the fuses.

I put sensor back on and the gauges work including oil pressure. here are the #s i got. 

idle is at 700rpm. (probably too low?) =28 psi

1500 rpm =55psi

2000 rpm - 58 psi

3000 rpm= 60psi

When i hit 3000rpm smoke start coming from where the headers mount to engine block so i shut everything down. I will clean everything really good in case some oil spilled.

Couple questions

1) if some oil spilled out would it smell really strong of burning. Because i got a strong burning smell. Again i shut it right off when i saw this.

2) i have been told empty an engine will hold 5 quarts. I bought a new OEM dipstick and with 5 quarts in its still registering about 60% toward high side (h). in other words its a little 

over halfway between L and H. I am assuming better to be on high side with oil

Going to head to get some more oil.

btw. again thanks for all the feedback here.

 

Attached are two images. one with engine at idle and other at 3rpms

Once engine cools, i get more oil in, and clean it all up i will make another post. Hopefully it will be the last 🙂

 

 

 

 

 

 

Edited February 4, 2023 by Wally

[Yarb]

Order this “T” fitting from Glow Shift!!! Run both gauges at the same time. GS-FA-05. 

[Patcon]

28 minutes ago, Wally said:

sorry for all the posts. just very nervous. i dont want to ruin the engine. the gauge issue was a fuse. I checked the spot for instruments it was fine. However, i now know the fuse to check is the flasher spot. My fault should have checked all the fuses.

I put sensor back on and the gauges work including oil pressure. here are the #s i got. 

idle is at 700rpm. (probably too low?) =28 psi

1500 rpm =55psi

2000 rpm - 58 psi

3000 rpm= 60psi

When i hit 3000rpm smoke start coming from where the headers mount to engine block so i shut everything down. I will clean everything really good in case some oil spilled.

Couple questions

1) if some oil spilled out would it smell really strong of burning. Because i got a strong burning smell. Again i shut it right off when i saw this.

2) i have been told empty an engine will hold 5 quarts. I bought a new OEM dipstick and with 5 quarts in its still registering about 60% toward high side (h). in other words its a little 

over halfway between L and H. I am assuming better to be on high side with oil

The oil pressure numbers look good. I wouldn't be worried about those!

The burning you see is probably oil from running the engine with the valve cover off. It will burn off. Shouldn't be a problem.

Dipsticks are not a super precise measuring instrument. If the oil is on the dipstick it will be fine IMHO.

[Racer X]

5 hours ago, Zed Head said:

 

Here's a question for the engine builders.  Maybe it's in Monroe's book.  Are there oil galley plugs that could be loose or missing?  Of course, they would have to be internal since there are no huge oil leaks.

 

If an oil galley plug was loose or missing there wouldn’t be any oil pressure, and there would be a huge oil leak.

There are two plugs, one at the front of the block and one at the rear, to plug the holes where the main oil gallery is drilled from the front to the back of the cylinder block. The one on the front gets covered by the timing chain cover at the front. The other is on the back of the block, and is directly in front of the forward side of the flywheel (or flex plat if the engine is mounted to an automatic).

There are no other plugs in oil passages in the cylinder block.

The crankshaft has plugs where oil passages get drilled to carry oil from the main bearing journals to the rod bearing journals. In my experience not many machine shops remove them when performing machine work on crankshafts.

Oil is picked up from the crankcase by the oil pump, sent through the forward passage to the oil filter, then goes through the reward passage, some going to the passage that feeds the crankshaft main bearings (and ultimately the rod bearings and some squirts through a small opening on the upper side of the big end of each connecting rod to lubricate the cylinder walls and pistons) with some bypassed to pressurize the cam chain tensioner, and some going to the cylinder head to lubricate the cam journals and the valvetrain.

The L series lubrication diagram:

Edited February 5, 2023 by Racer X

[Racer X]

18 hours ago, Wally said:

I put sensor back on and the gauges work including oil pressure. here are the #s i got. 

idle is at 700rpm. (probably too low?)

Per the factory service manual, initial ignition timing and engine rpm is 17 degrees before top dead center at 550 rpm for non emissions engines, 5 degrees before top dead center at 750 rpm for emissions engines.

Does your engine have an air pump?

18 hours ago, Wally said:

1500 rpm =55psi

2000 rpm - 58 psi

3000 rpm= 60psi

I’ve stated previously the rule of thumb for minimum oil pressure.

Once more:

Ten pounds of oil pressure for every 1000 rpm of engine speed.

At 1000 rpm, 10 lbs.

At 2000 rpm, 20 lbs.

At 3000 rpm, 30 lbs.

See the pattern here?

Again, this is the minimum pressure required. 
 

60 lbs at 3000 rpm is plenty.

 

 

 

 

18 hours ago, Wally said:

When i hit 3000rpm smoke start coming from where the headers mount to engine block so i shut everything down. I will clean everything really good in case some oil spilled.

Couple questions

1) if some oil spilled out would it smell really strong of burning. Because i got a strong burning smell. Again i shut it right off when i saw this.

You made a huge mess when running the engine with the cam cover removed. Oil can, and will, go everywhere. 

You will likely have oil burning off of the exhaust system for a while.
 

18 hours ago, Wally said:

2) i have been told empty an engine will hold 5 quarts. I bought a new OEM dipstick and with 5 quarts in its still registering about 60% toward high side (h). in other words its a little 

 

We’ve covered this already.

Crankcase capacity is 5 quarts including the oil filter.

Put 5 quarts of oil in an empty crankcase, start the engine and run for a minute or two, sun it do2n and while waiting for the oil to return to the crankcase, inspect for leaks, especially at the oil filter and drain plug, as you just had them off.

After the engine has sat without running for a few minutes, check the level.

If it isn’t at the “full” mark, it doesn’t matter. You know you just put enough oil in it. 

Make a note of the position of 5he oil level, relative to the high and low marks on the dipstick (by the way, this will work with your old dipstick, you didn’t need to buy a new one).

Since you know the distance between the high and low marks on the dipstick, and you now know the actual full position, it should be easy to interpolate where “add” should be.
 

 

 

Edited February 5, 2023 by Racer X

[Zed Head]

Thanks RacerX but I already posted that drawing of the oil passages.  And loose and missing are not the same thing.  And, you can't know the quantity of oil that will pass through a loose or missing oil galley plug or the pressure drop that will result if a plug is loose or missing.  You can only assume.

Anyway, this looked like an interesting problem but it's not clear at the end here that the problem was anything more than just a goofy gauge or a piece of crud stuck in the gauge port.  Lots of parts moved around and removed and replaced but no reason shown or even guessed at for the low gauge reading.  For some unknown reason the gauge now reads oil pressure that is perfectly suitable for the engine.

The dipstick is meant to show the distance of the oil from the bottom of the block.  That distance could have been confirmed while the oil pan was off.  The dipstick has to match the dipstick tube.

Carry on.

 

[Racer X]

12 hours ago, Zed Head said:

Thanks RacerX but I already posted that drawing of the oil passages. 
 

 

Sorry, I missed that.

12 hours ago, Zed Head said:

 

And loose and missing are not the same thing. 
 

The plugs are tapered pipe thread. They would either be tight, or they would work their way out. The resulting leak would not have been characteristic of OK oil pressure at idle that falls off as the engine speed increases. More likely that there would have been little to no oil pressure, and the bearings would have been wiped out very quickly.

 

12 hours ago, Zed Head said:

 

And, you can't know the quantity of oil that will pass through a loose or missing oil galley plug or the pressure drop that will result if a plug is loose or missing. 
 

I suppose it could be calculated. 
 

We would know the size of the hole.

The output volume of the oil pump can be calculated, indeed the engineering team that designed it had to do so to ensure it would adequately lubricate the engine.

 

12 hours ago, Zed Head said:

You can only assume.

Never assume.

 

12 hours ago, Zed Head said:

 

The dipstick is meant to show the distance of the oil from the bottom of the block. 

No.

The dipstick is meant to show how much oil is in the oil pan.

Yes, the level relative to the bottom of the crankshaft is important, as you wouldn’t want the crankshaft turning in the oil. Every effort is made to keep oil from the sump from coming in contact with the rotating assembly after it comes out of the bearing journals. 

It is called windage.

It is important to know that there is adequate oil capacity to keeping the oil pickup submerged in oil.

 

The basic design for road going engines is a compromise between cost and complexity. For racing engines elaborate compartments with trap doors, and a close fitting tray to “scrape” the oil (it doesn’t actually touch the crank, but fits very closely) from the rotating assembly for wet sumps, or, for dry sump systems, a tray, with a shallow oil pan and several fittings connected to a multi stage scavenging pump that removes every last drop of oil as soon as it falls into the pan.
 

A trap door setup:

 

A windage setup for L series engines:

 

 

 

A dry sump pan:

 

 

 

 

 

 

Edited February 5, 2023 by Racer X

[Zed Head]

Let's call this a "bench building" thread, like bench racing.  No verification, lots of pontification.

On the dipstick, if you put a larger oil pan on your engine do you change the dipstick?  No.  The dipstick is there to verify the proper "level" of the oil, not the quantity.  For some of the very reasons that you described, windage and the pickup tube entrance.  Both of those are determined by level, not quantity.  Your logic went awry, you made the points against your own "no".

Anyway, I was hoping to learn something interesting regarding the odd pressure readings.  Didn't learn anything.  Lots of contributions, not much returned.

[Mark Maras]

45 minutes ago, Zed Head said:

 

On the dipstick, if you put a larger oil pan on your engine do you change the dipstick?  No. 

 When you say larger oil pan, do you mean wider or deeper?

[Zed Head]

Of greater capacity.  The crankshaft position and the oil pickup position do not change if you change the capacity of the pan.

 

If the pickup position is changed then an argument can be made for a dipstick that has different marks on it.  The marks indicate level.  When people say add the quantity that the factory said to use then mark the dipstick, there is an assumption that the oil pan capacity is what the factory had in mind when they put the marks on the dipstick.

If you're not sure what dipstick or dipstick tube that you have then remarking your unknown dipstick is valid IF you have the factory oil pan.

Most of the statements in this discussion need to be qualified.