low oil pressure

[Zed Head]

9 minutes ago, Racer X said:

If the oil pickup was loose enough to allow air into the oil passages, then the oil would get foamy. The oil in the videos doesn’t look like it has air in it (although the video quality is poor)

So, what path forward are you suggesting?

[Racer X]

5 minutes ago, Zed Head said:

So, what path forward are you suggesting?

I’ve already made recommendations going forward.

So far Wally hasn’t followed them.

He even ignored my recommendation to not run the engine with the cam cover removed.

Simply turning the engine by hand, or with the starter while the ignition is disabled, will move enough oil to determine if the system is pushing oil to the valvetrain.

Edited January 30, 2023 by Racer X

[Racer X]

13 minutes ago, Racer X said:

If the oil pickup was loose enough to allow air into the oil passages, then the oil would get foamy. The oil in the videos doesn’t look like it has air in it (although the video quality is poor)

I would also add that if the pickup was loose, and air was getting into the lubrication system, the oil pump, rod and main bearings, camshaft journals, cam followers and cam lobes would be damaged fairly quickly, and horrible noises would be coming from the engine.

[Zed Head]

8 minutes ago, Racer X said:

I’ve already made recommendations going forward.

What are they?  He is convinced that he only has 10 - 13 psi at any RPM.  Are you suggesting that he needs a new gauge?  Or that 10-13 psi at the gauge port is just fine?

No offense, but your posts are of the "nope, not right" variety, but no concrete actions suggested.  What should he do now?  He has a new gauge, he made a fuzzy video.  What are you suggesting today?

[Wally]

53 minutes ago, jonbill said:

the relief valve is only active if the oil filter is clogged. I'd leave it. 

don't you need to take the oil pan off to confirm there's not an air leak in the oil pickup to block? 

yes sir. forgot about that. Got the pan all loose.

it wont slide out. theres only about an inch between the pan and the crossmember and if i try to slide it backward toward rear of car it hit the tranny. 

What am i missing here? Do i need to put a little jack pressure on something?

 

btw, for those reading. once drained put the plug back in before trying to remove the oil pan. There is still a bit of oil in there that will come down as my head can now atest to

Edited January 30, 2023 by Wally

[Wally]

1 hour ago, Racer X said:

I’ve already made recommendations going forward.

So far Wally hasn’t followed them.

I have tried to. you said check the relief spring. i just did. you said check the threads on the pickup. I am trying to do that.  I am also going to empty all oil and start with clean filter like you said. 

You did comment on "bearing clearance" and such but sadly that is over my head. But you did say you didnt think this was the issue

As for starting the car, others said to do so(i think Mark, before you posted to) and see what i could see. the only harm was spilled oil which i cleaned up. 

I do appreciate your all advice though.

 

I got the pan off. Turns out the i need to manually turn the crankshaft a hair so the front part of pan would clear some bolt coming from the front cylinder area

Here are images i took. Everything looks clean but bolts on pickup dont have thread lock. they came out really easy. 

The thread locker would i assume blue?

 

The pickup has zero obstruction btw. I am sure hard to tell by images.

 

 

 

 

Edited January 30, 2023 by Wally

[Zed Head]

I think that you might have to get Piston #1 to the bottom of its stroke so that the counterweight is up in order to get the pan off.

Too late but I would have spent more time at the oil pressure gauge port and maybe even at the oil filter when everything was together.  Watched some oil come out, see what it's doing.  Oh well.  You'll know a lot more about your engine when you're done.

[Racer X]

On 1/23/2023 at 6:58 AM, Racer X said:

First, why are you guys recommending a pressure gauge for a water system?

Buy a good quality oil pressure gauge like Stewart Warner or Autometer. These can be had at local auto parts stores.

Next, the recommendation to check inside the cam cover through the oil cap is a good one, as indeed the oil can be seen, but it still does give any idea what the pressure is. Running the engine with the cam cover is not a good idea, even when taking precautions to catch the oil that will get thrown about, and, you still won’t have a clue about how much oil pressure the pump is producing.

And even with measures in place to catch the mess, you will have engine oil on the ceiling of your shop.

Don’t ask me how I know.

Once it is determined the oil pressure is inadequate, the cause needs to be determined.  The only way to do that is to remove the pump, disassemble it and inspect it for wear or damage.

The shop manual details the inspection process, inspection of the gerotor for defects and damage, and clearances.

It is possible the spring in the bypass valve has broken or become weak.

It is also possible that the oil passages weren’t fully cleaned, and something has clogged a passage. Something as small as a human hair can block enough oil flow to cause lubrication failure.

 

 

 

 

On 1/23/2023 at 1:53 PM, Racer X said:

The cylinder block deck has a bushing (if memory serves it is brass) pressed into a counterbore at the oil passage from the block to the head. Some people like to open it up a bit when hot rodding the L series engine.

They think it will aid in getting more oil into the cylinder head (cam, followers, etc).

I dunno. 

My kid brother was “helping” with an engine build once and he oversized it a bit, against my wishes.

I had to shim the pressure relief springs in the pump to get the oil pressure back where I wanted it. Besides, I wasn’t, and never did have, lubrication troubles with any L series engine I’ve built.

Could you explain to me what you hope to find?

If the engine was properly cleaned prior to assembly, and if it was assembled correctly*, and you haven’t introduced anything to the crankcase that shouldn’t be there, what will that achieve?

 

*During assembly, some people use silicone sealer in places it isn’t needed**, in amounts that far exceed the amount needed. I have seen where excessive squeeze out of the sealer has later come loose. These chunks of sealant then can get ingested into the oil system and cause problems. This is easy to verify, without removing the pan. Simply observe the parting line between the pan and the lower crankcase rail. It there evidence of sealant use? If so, how much? The amount seen outside should be about the amount that would also be squeezed inside.

 

**The correct oil pan and cam cover gaskets do not require any sealant to be use to ensure no leaks. I use them on all my L series engines, with no sealer, and no oil leaks.

 

 

On 1/23/2023 at 2:17 PM, Racer X said:

Your L series engine has an oil pump. The pan doesn’t have to be removed to take the oil pump off, it bolts to the lower right front corner of the timing chain cover. Four bolts, drops right out.

You may have to take the front stabilizer bar loose to get room.

 

On 1/24/2023 at 9:04 AM, Racer X said:

 

Again, unless the engine builder did poor work, or you have introduced something to the crankcase that doesn’t belong, there won’t be much to see, or do.

 

On 1/25/2023 at 10:06 AM, Racer X said:

So Wally, this engine was running fine, and oil pressure was good, correct?

If so, then there is really only a few things it could be.

1. The oil pressure relief spring may have broken, or lost its springiness. This would result in low, or inconsistent oil pressure. The spring can be removed without removing the pump. 
 

An easy check.

2. The builder didn’t use thread locker on the oil pickup where it attaches to the bottom of the cylinder block, and the bolts have come loose. This would result in air getting sucked in and the oil would get bubbles in it. You would see this on the dipstick and in the oil you splashed everywhere when running the engine with the cam cover removed.

I doubt this is the problem.

3. the bearing clearances have somehow become too large. Excessive bearing clearances will definitely result in low oil pressure, but there will also be an accompanying knock as the rods and main bearings rattle about. 
 

Again, I don’t think this is the issue, as an engine doesn’t last long when this occurs.

4. If you reused the old oil pump, and it wasn’t disassembled, cleaned, and inspected to verify adequate clearances, it could be the cause of low oil pressure.

5. The correct amount of oil in the crankcase, and the correct dipstick.

The oil sump capacity is 5 quarts if I remember correctly.

Starting with an empty crankcase, and a new filter (should hold about one quart), refill the engine with the correct amount of oil, start it up, run for a minute, then shut it off.

After waiting five or ten minutes, check the oil level.

It should be within the high and low marks on the dipstick.

(as for the question of the correct dipstick, have you replaced it with the one that was with the engine originally?)

 

 

On 1/25/2023 at 11:05 PM, Racer X said:

That is the relief I mentioned. I have worked through many different combinations of spring setups to tune the oil pump for the race engines I build. I’ve used two springs, one inside the other, single springs of varying rates, and made shims to fine tune the pressure in the system.

The rule of thumb for oil pressure, in any engine, is 10 pounds for every 1,000 rpm. So at 5,000 rpm you want to see at least 50 psi, 8,000 rpm (yes, I turn these engines that fast) you need 80 psi.

A couple pounds more is OK, a couple pounds less, not so much.

 

The spring and valve are under the fitting circled in red.

 

2 hours ago, Racer X said:

If the oil pickup was loose enough to allow air into the oil passages, then the oil would get foamy. The oil in the videos doesn’t look like it has air in it (although the video quality is poor)

2 hours ago, Racer X said:

If the ball can be depressed with a finger, and is clearly free to open when needed, there isn’t any reason to mess with it.

2 hours ago, Zed Head said:

What are they?  He is convinced that he only has 10 - 13 psi at any RPM.  Are you suggesting that he needs a new gauge?  Or that 10-13 psi at the gauge port is just fine?

No offense, but your posts are of the "nope, not right" variety, but no concrete actions suggested.  What should he do now?  He has a new gauge, he made a fuzzy video.  What are you suggesting today?

No offense taken Zed.

 

Notice the post where I mention the rule of thumb for oil pressures, never did I indicate that 10-13 is ok at anything but idle.

Also notice comments about all the possible reasons for low oil pressure. Again, I don’t see any purpose in repeating what I have already posted.

 

[Racer X]

2 hours ago, Wally said:

I have tried to. you said check the relief spring. i just did. you said check the threads on the pickup. I am trying to do that.  I am also going to empty all oil and start with clean filter like you said. 

You did comment on "bearing clearance" and such but sadly that is over my head. But you did say you didnt think this was the issue

As for starting the car, others said to do so(i think Mark, before you posted to) and see what i could see. the only harm was spilled oil which i cleaned up. 

I do appreciate your all advice though.

 

I got the pan off. Turns out the i need to manually turn the crankshaft a hair so the front part of pan would clear some bolt coming from the front cylinder area

Here are images i took. Everything looks clean but bolts on pickup dont have thread lock. they came out really easy. 

The thread locker would i assume blue?

 

The pickup has zero obstruction btw. I am sure hard to tell by images.

 

 

 

 

So clean the threads, both in the block and on the bolts.

Blue thread locker is supposed to be removable, red is intended for a more permanent lock. I use red for things like this, as it isn’t impossible to remove, and the bolts are less likely to come loose.

 

[Racer X]

2 hours ago, Wally said:

I have tried to. you said check the relief spring. i just did. you said check the threads on the pickup. I am trying to do that.  I am also going to empty all oil and start with clean filter like you said. 

You did comment on "bearing clearance" and such but sadly that is over my head. But you did say you didnt think this was the issue

As for starting the car, others said to do so(i think Mark, before you posted to) and see what i could see. the only harm was spilled oil which i cleaned up. 

I do appreciate your all advice though.

 

I got the pan off. Turns out the i need to manually turn the crankshaft a hair so the front part of pan would clear some bolt coming from the front cylinder area

Here are images i took. Everything looks clean but bolts on pickup dont have thread lock. they came out really easy. 

The thread locker would i assume blue?

 

The pickup has zero obstruction btw. I am sure hard to tell by images.

 

 

 

 

I know your experience causes you to be reticent to do so, but now is the perfect time to check bearing clearances to rule them out as a cause, or determine if there is a problem. You’ll also be able to asses the condition of the bearing shells.

Did you mention how many miles on this engine since the rebuild?
 

How many oil changes?

 

[Wally]

so as far as i know the method to check bearing clearance is to measure diameter of rod and subtract inside bearing diameter.. Thus the difference being the clearance. If so, yes, that does scare me to attempt. If there is a way to remove one conrod cap and measure the clearance gap i feel safe to do that...but i dont think that possible. I may drive up to the engine rebuild shop and ask the man to pull up his notes from my rebuild and see what he has written down. Of course this wont let me see shell condition

 

Since rebuild, I have put maybe 100 miles on engine. Only oil change since then is one i am doing now. 

[Patcon]

You would use plastigage and remove one bearing cap. Install plastigage. Retorque cap and then remove the cap and analyze the crushed plastigage.