No oil pressure while cranking

[Tobias Bylund]

Hi, been working on this engine forever, but getting nearer to completion now.

It is a 2110cc, efi with dry sump oiling (Autocraft 2 stage pump). I have had the laptop hooked up to verify my wiring and that i am getting everything setup/configured correctly before adding fuel for the first startup, and while cranking i can see in the tuning software that i am not getting any oil pressure.

As i said it is dry sumped, and i have disabled the internal pressure relief (flywheel side) and i am running the Jaycee oil control system with built in pressure relief that is returning to the oil tank. I have plugged the internal pump pickup in the case. I am still using the original doghouse cooler and i also have an external cooler with fan mounted above the driver side torsion tube.

-I have checked the remote filter and it is full of oil, i am getting what seems like a decent amount of oil out of there while cranking without the filter in place

-I have removed the pressure sender that is located right before the oil returns to the case in the usual full flow location, and i am getting oil out of there while cranking, not as much as i was expecting though, but oil is getting to that port at least.

-I have checked the oil level in the tank, and the level is above the pumps inlet location, so it should have oil available there at all times.

-I went and bought a cheap oil pressure gauge and sender tonight, to eliminate a faulty sender/sensor or possibly having the sensor setup incorrectly in the EFI software. Still no pressure.

-I verified that i am getting oil in and oil out in the scavenge side of the pump by disconnecting the lines.

-I verified that i am getting oil out of the pressure side of the pump, and that i am getting oil (some) in the line post external cooler.

-I also disconnected the pressure relief line that is dumping back into the tank, but that line is dry, logical since i am not building any pressure, and that opens at i think 90 psi.

I am kind of out of ideas here, the only remaining thing i can think of is that the plunger at the pulley side is stuck open somehow and dumping all the oil straight back into the case, and therefore not building any pressure?

Also, i dont know how long i would need to crank to get pressure, i dont think i have cranked for more than consecutive 10 seconds. I am not that worried about it though, i used good quality assembly lube and have tool steel lifters and i have not yet mounted rockers or pushrods.

Any ideas that come to mind?

[chrisflstf]

I would hit it for another 10 seconds. Sounds like you have everything covered.

You can pump/pressure lube into the stock oil pressure sensor port with a hand pump sprayer also

[vince1]

When you say you disabled the oil pressure relief, is the plunger still in place blocked on the top ?

Did you plug the discharge holes of the two relief pistons in the case ?
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[Tobias Bylund]

Yes the plunger is still in place, stuck in the top position by a solid rod in place of the spring.

I did not plug any additional holes other than all that are necessary to drill/remove when cleaning the case. I thought that positioning the piston at the top of the bore would be enough, i still want to retain the functionality of having oil routed through the cooler (or not) by the rear plunger (pulley end) so i did nothing there, still stock plunger and spring.

And i have cranked the engine several times, just not for extended periods of time, maybe 3-5 seconds each time, but i dont think it would drain back quick enough between tries that it would keep it from building pressure. I dont know what is going on, feels like i have done something wrong with the plungers... but even if i did, the holes that are bleeding off pressure are surely small enough that some pressure would show on the gauge? Its not like its a massive 10mm hole, more like 2-3mm right?

[RickS]

Deleted

[borninabus]

i don't know jack about your fancy oil system, but i do know from your description that there is a lot of oil that needs to travel a long way to actually build pressure. when i crank a regular engine for pressure, it usually takes 2 or 3 consecutive cranks of about 10 seconds each to get the idiot light to go out.

good luck
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[jim martin]

I run autocraft dry sumped motors .
Not sure how you primed both sections of pump but pretty easy .
I have an oil pressure pump system installed and the complete system is pressurized to 20psi hot oil before every start.
For you this is what I would do 5 litres in tank , sorry don’t know your tank size .
So 3/4 full . 1 litre into motor so sump can prime suction side ,
Pre-filled oil filter . Fill line from tank to pump pressure section .
Plugs out. . Battery charger on and crank it .
FYI just to make sure scavenge section closest to case and pressure section farthest out
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[Tobias Bylund]

I have the section with the wider gears (38mm) plumbed as scavenging, in my case that is farther from the case. From what i could see on autocrafts information the narrower gears (26mm?) are for the pressure section, is that not correct?

As for priming; my tanks oil level when full is above the pump inlet so it should self prime, i have about 9qts total volume including the lines, filter and cooler.

As for pickup from case; when dry sumped there is a special sump plate from where the pump scavenge, so no internal pickup is needed

I wont have time to mess with this again until easter weekend is over, but thanks for all your suggestions and advice! Happy easter to everyone!

[Tobias Bylund]

Ok, been messing with this some more;

Re-plumbed the lines so that the section of the pump with the wider gears (furthest from case) is the pressure section like you mentioned Jim. That made no change, still no oil pressure according to the sensor.

I then turned to the sensor again, it is a generic chinese 150psi sensor, i verified the wiring, and checked calibration again, but still nothing. Will try another sensor that i have available next and see if maybe the sensor itself is bad.

I disconnected the line going to the filter from the pressure section of the pump and cranked with the line off, and oil is coming out of there, so the pump should definitely have prime.

I seem to have scavenge back to tank working as well, so both sections of the pump are primed. I had about 2qts in the case and 7-8qts in the oil tank and after cranking a while i have close to nothing left in the case.

What oil pressure is normal to see during normal cranking rpm?

[jim martin]

just some fyi ON AUTOCRAFT 2 AND 3 STAGE PUMPS ,and yes the stage and a half is not a drysump pump just a wetsump pump with a small suction stage for heads or turbo back to engine oil sump

- AUTOCRAFT 2 STAGE PUMPS - first section closest to block is 2x 25mm gear sets and 2nd section farthest from block is 1x32mm gear set
SO first stage is 50mm scavenge block and return to tank top , second section is engine pressure section feed in from bottom of tank and out to oil filter and motor oil passages

-AUTOCRAFT 3 STAGE PUMP IS ALL 3 STAGES 32MM GEAR SETS -so you have a combined total between the first and second sections of 64mm to scavenge motor and return to tank and the 3rd /last stage is still a 32mm pressure section.
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[Tobias Bylund]

Update: i hooked the analog oil pressure gauge back up, and i actually had some pressure while cranking now, about 10-12 psi. Does that sound about right?

[jim martin]

Yes Depending on rpm while engine is cranking, weight and temp of oil you ok.
I use a gear reduction starter so engine crank rpm is less , you may have the same.
you need to adjust oil level in tank while engine is running .
Post up a pic or 2 of your setup and tank .
also what brand tank and are you able to open it up.

here is a pic of my Peterson tank .your manufacture will tell you where the oil level should be.
inside the tank there is a series of baffles and vent and pickup tubes . my tank is modified with a temperature sensor , additional inlet from my vacuum pump a oil level site glass .
with my engine oil up to temp and running about 2000 rpm my oil level is about 1/4" above the separation seam . easy to see and adjust will engine is running . You need to have correct level so the returning oil can swirl and defoam as well as allow space for correct venting .
fyi :my total oil capacity is 7.5 liters

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[Tobias Bylund]

I made my tank myself to fit between the axle tube and the torsion tube. I had purchased a round standard type tank, but i had a hard time placing it somewhere inconspicuous, i did not want it in the rear parcel area where it would be visible.

I made my tank with internal baffles and an de-aeration plate, i have a curved plate on the inside and the return from the pump is routed so that it flows along that plate before coming down to the oil level.

The tank holds 9 liters (full), i need to check level with engine running, but i estimate that the two coolers and all the lines, and some in the case hold about 3 liters, so the tank would be about 2/3 full during running.

Wiring will be cleaned up when i have the body back on, i realized now when looking at pictures of it that it looks quite messy

Tank drain on the bottom, outlet to pump and temp sender is barely visible on the side towards the rear. I have an additional temp sender right after the oil cooler, i use that as coolant temp for the moment. I have a thermocouple on one cyl #3 headstud, but havent been able to configure that as coolant sensor in my ECU software yet.

Lines will be trimmed to length now that i know that the routing is correct

You can barely tell that there is a dry sump system on there from the outside

Top is return, middle is pressure relief and then a breather, cap is vented as well.

[jim martin]

Looks great .
Nice to see some fab work being done .
Get a buddy and fire it up watch your pressure gauge and your tank level.
Those dot’s will put it to the pavement
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[mikedjames]

Looks good, probably will run with good pressure.

I would be worried about the support of your tank- those support brackets look thin and the welds into the side of the tank wall are possible stress points. Might be better with thicker metal on the brackets and straps round the tank instead.

A bit of bouncing around and you may have a very dry sump and an oil trail..
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[jim martin]

Good eye . Not seeing how it is mounted and the other side . But yes in would agree , if it’s the same setup on the back side installing to straps running from the mounting points under and around bottom of tank would be a smart decision
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[Tobias Bylund]

There is an additional support on the rear where it ties into the frame horn, i also use that mounting point as a body ground. I plan to add a strap to the body mount bolt once i have the body back on, the tank would then be supported in all 4 corners basically.

The tank is steel so should handle bouncing/bending better than aluminium, but i will keep an eye on it!

I see from that photo that i need to add additional wearprotection on the parking brake cable sheath as well, might chafe a bit on suspension travel.

[halfassleatherworks]

Would it not be better to put a 90 on the vent and raise it above the tank?

[Tobias Bylund]

Yeah definitely, the body is right above there though so i didn’t think i’d be able to fit the filter in that orientation. We’ll just have to see what happens once it is up and running.

I have to plumb the fuel system with the ethanol sensor before i can start the engine, and that sensor i plan to mount to the underside of the parcel shelf, ptfe line is expensive so i’d rather only do it once. But might rig up something just to be able to test start the engine before mounting the body once that has been painted.

Thanks for all your comments, it is nice to get some fresh eyes on things once in a while!

[yamaducci]

I have two different dry sump systems and each have their quirks. I also have the JayCee Direct Shot oil tube which it does not look like you are using and the oil filter relief mount. If you are using the JayCee concept you are supposed to drill and tap the relief hole that dump into the cam well and back by the number 3 exhaust lifter and through the rear of the case into the relief bore is another dump hole.
So first thing is your oil level needs to be higher than the fitting where it goes back into the case. If the pick up on your tank bottom is lower than your pressure input fitting on the case, you may always have supply issues with priming and possibly while it's running. It helps to prefill the oil hose between the tank and pump input so the pump does not have to pump air for such a long time while priming the line. You can easily wipe a cam out or burn up a starter on a new engine while priming the lines and case the first time.
2), What is the piston doing on the pulley end? I didn't see a comment on that. Is it present with a spring?
3) The solid rod on the Flywheel end is not a great idea. If that rod becomes a loose fit as the engine heats up or even right now at room temperature. it will break the piston's seal and constantly bleed off pressure It will dump out the relief hole that dumps back into the last lifter bore area and the hole that dumps into the sump. You mixed and matched components and concepts on the direct shot oil system and dry sump oil system. For the direct shot oil system you did not drill and tap all of the places that are required and with the dry sump you are trying to rely on the filter relief as a total oil system relief. Neither are going to work without executing the install perfectly. If you don't want to fully tear down the engine and tap the required relief holes and you do want to run a stock oil cooler you will have to go back to both pistons and both springs. You can keep the dry sump and keep the filter relief mount too.
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