Purging air from remote oil filter and cooler

[Joel Heinke]

I have a kind of specialized question about best practices for engines outfitted with a remote oil filter and cooler. This relates to my Miura project car that is using a Gen 2 Coyote engine in it. Due to inaccessibility for the regular oil filter location and a very tight engine room which will be hard to keep cool, I am outfitting it with a combination remote oil filter and cooler system. This is the system I'm using: MMR oil cooler kit

I saw in an instruction manual for similar Ford Performance setup for Coyote engines, it showed using a special pressurized bottle of motor oil to "pre-fill" the hoses, filter, and oil radiator and thus purge the air from the remote system prior to engine startup. This manual explained that on older engines (Windors, FE, Clevelands, etc.) with a distributor, the best practice was to remove the distributor and rotate the oil pump directly to pressurize the engine and thus purge air from the remote filter and cooler. Since the Coyote has a crank driven oil pump, it was necessary to use an external pump to accomplish the same. The instructions were to remove the oil pressure sensor, attach a hose from the pressure bottle to that port and then pressurize the oiling system until the air was driven out through the bearings, etc.

This all seemed reasonable and makes sense to me. It does however, raise some questions in my mind about best practices for similar setups:

1. Is removing air by pressurizing the oil system just an initial setup thing, or is this the best practice to do this for every oil change?
   
   
2. If possible, should the remote oil cooler and filter be located/positioned so that the oil will drain from them and associated hoses during an oil change? If so, then the answer to prior question is likely to be air needs to be purged in both situations as quite a bit of air will likely be present.
   
   
3. If purging air from remote oil system is a re-occurring necessity, is there a best practice for the plumbing that will make this easier and result in less mess? It seems like screwing an oil sensor out and back in is neither a simple nor spill free way to do this. Maybe some sort of 1 way valve could be tee'd into the plumbing for connection of a pressure bottle. Or maybe that's overkill, how about a fill port on the uppermost hose/pipe so the air can bubble up and out of the majority of remote system? I did see on a Porsche site talking about adding a remote oil system to 914s, the recommendation to remove coil wire and crank motor till oil pressure showed on the gauge. With the newer coil on plug ignition system used in Coyote, this simple "old school" approach isn't available.

So how have you guys with remote oil systems approached this issue and what do you do?

 

[Neil]

I have a kind of specialized question about best practices for engines outfitted with a remote oil filter and cooler. This relates to my Miura project car that is using a Gen 2 Coyote engine in it. Due to inaccessibility for the regular oil filter location and a very tight engine room which will be hard to keep cool, I am outfitting it with a combination remote oil filter and cooler system. This is the system I'm using: MMR oil cooler kit

I saw in an instruction manual for similar Ford Performance setup for Coyote engines, it showed using a special pressurized bottle of motor oil to "pre-fill" the hoses, filter, and oil radiator and thus purge the air from the remote system prior to engine startup. This manual explained that on older engines (Windors, FE, Clevelands, etc.) with a distributor, the best practice was to remove the distributor and rotate the oil pump directly to pressurize the engine and thus purge air from the remote filter and cooler. Since the Coyote has a crank driven oil pump, it was necessary to use an external pump to accomplish the same. The instructions were to remove the oil pressure sensor, attach a hose from the pressure bottle to that port and then pressurize the oiling system until the air was driven out through the bearings, etc.

This all seemed reasonable and makes sense to me. It does however, raise some questions in my mind about best practices for similar setups:

1. Is removing air by pressurizing the oil system just an initial setup thing, or is this the best practice to do this for every oil change?
   
   
2. If possible, should the remote oil cooler and filter be located/positioned so that the oil will drain from them and associated hoses during an oil change? If so, then the answer to prior question is likely to be air needs to be purged in both situations as quite a bit of air will likely be present.
   
   
3. If purging air from remote oil system is a re-occurring necessity, is there a best practice for the plumbing that will make this easier and result in less mess? It seems like screwing an oil sensor out and back in is neither a simple nor spill free way to do this. Maybe some sort of 1 way valve could be tee'd into the plumbing for connection of a pressure bottle. Or maybe that's overkill, how about a fill port on the uppermost hose/pipe so the air can bubble up and out of the majority of remote system? I did see on a Porsche site talking about adding a remote oil system to 914s, the recommendation to remove coil wire and crank motor till oil pressure showed on the gauge. With the newer coil on plug ignition system used in Coyote, this simple "old school" approach isn't available.

So how have you guys with remote oil systems approached this issue and what do you do?

Those pressurized pre-lube kits were all the rage in the '70s but I have not seen one for a long time. I doubt that they are worth the trouble, given the improved bearing technology and oils.

 

[Jac Mac]

I have a kind of specialized question about best practices for engines outfitted with a remote oil filter and cooler. This relates to my Miura project car that is using a Gen 2 Coyote engine in it. Due to inaccessibility for the regular oil filter location and a very tight engine room which will be hard to keep cool, I am outfitting it with a combination remote oil filter and cooler system. This is the system I'm using: MMR oil cooler kit

I saw in an instruction manual for similar Ford Performance setup for Coyote engines, it showed using a special pressurized bottle of motor oil to "pre-fill" the hoses, filter, and oil radiator and thus purge the air from the remote system prior to engine startup. This manual explained that on older engines (Windors, FE, Clevelands, etc.) with a distributor, the best practice was to remove the distributor and rotate the oil pump directly to pressurize the engine and thus purge air from the remote filter and cooler. Since the Coyote has a crank driven oil pump, it was necessary to use an external pump to accomplish the same. The instructions were to remove the oil pressure sensor, attach a hose from the pressure bottle to that port and then pressurize the oiling system until the air was driven out through the bearings, etc.

This all seemed reasonable and makes sense to me. It does however, raise some questions in my mind about best practices for similar setups:

1. Is removing air by pressurizing the oil system just an initial setup thing, or is this the best practice to do this for every oil change?
2. Ford in recent decades seem to have built this problem into engines, 5 cyl Ranger Diesel has it, if you drain pan & remove filter then take a break for smoko they often wont register oil pressure on restart with new oil &filter. Pre filling filter & immediate restart seems to work most of the time. ( thats on factory stock engines.
3. If possible, should the remote oil cooler and filter be located/positioned so that the oil will drain from them and associated hoses during an oil change? If so, then the answer to prior question is likely to be air needs to be purged in both situations as quite a bit of air will likely be present.
   Fill new filter with new oil and then try answer Ive suggested below to Q4.
4. If purging air from remote oil system is a re-occurring necessity, is there a best practice for the plumbing that will make this easier and result in less mess? It seems like screwing an oil sensor out and back in is neither a simple nor spill free way to do this. Maybe some sort of 1 way valve could be tee'd into the plumbing for connection of a pressure bottle. Or maybe that's overkill, how about a fill port on the uppermost hose/pipe so the air can bubble up and out of the majority of remote system? I did see on a Porsche site talking about adding a remote oil system to 914s, the recommendation to remove coil wire and crank motor till oil pressure showed on the gauge. With the newer coil on plug ignition system used in Coyote, this simple "old school" approach isn't available. 5
5. This is plan Ive adopted to work on virtually any setup, Get a barbed fitting to match the thread of your oil pressure gauge fitting, screw it in and connect to a piece of clear plastic tube about 5 ft long. Grab a quart oil container and drill a hole in the cap that the plastic tube is a tight push fit into and do the same on bottom of container. The hose on bottom of container is just an air bleed to allow oil to drain freely into engine. Use duct tape or whatver is available to hang the oil container from ceiling and oil should flow into engine, give it an hour or so, then remove fitting & replace gauge pressure unit. Start engine & check pressure. ( I leave it all hooked up overnite) on new builds. Oil Light/ Pressure should come up virtually straight away. IIRC the ford filter will have an anti drain back valve inside ( usually a rubber flapper ring against the outer row of holes in filter face., dont get caught out with a filter that doesnt have that feature)

So how have you guys with remote oil systems approached this issue and what do you do?

 

[Terry Oxandale]

My understanding is that this is a practice for a newly built motor that has had no oil run through the engine. I do this after any rebuild. Once the run-through is complete, the bearings and system have enough oil to not worry about anything for the next startup. An oil change does not affect that. I have two remote filters on mine with a dry-sump system. I can crank the motor after an oil change (yes, I fill the filters with oil prior to screwing them up onto the remote) with the ignition off, and it will quickly fill the lines and slightly pressurize the system. I'm good to go then.

My setup was a discarded freon tank. I welded a very short 1-1/2" gas-filler tube, with a threaded cap, onto the top of the tank, and then attached a hose to the freon outlet valve, with the other end of the hose having a threaded fitting that screws into the block where the original filter would have gone. I also welded a bung onto the top what has a screw-on tire air valve. Once I fill the tank up with a couple of gallons of oil, and screw the cap on, I put about 10 psi of air into the tank, turn it upside down onto the handles, open the freon valve, and let it push oil through the system.

 

[Brian]

I would suggest an easy alternative is remove the spark plugs and just run the starter motor until you see oil pressure. With no spark plugs, there's no compression and very little bearing loading and not too much electrical load on the starter. Don't go more than 20 seconds and then rest 1 minute.

Pulling the distributor and putting a drill to the oil pump drive is not an option on a Coyote.

 

[Fred W Ballinger]

I understand that is good practice to position the oil cooler with the connections upwards so that oil cannot drain from it back to the sump when the engine stops.

 

[Howard Jones]

Here:

https://documents.holley.com/199r10623.pdf

 

[Joel Heinke]

Firstly, thanks for all the information shared already!! The members of this forum are knowledgeable and generous.

Ok, let me be more specific on the concern that prompted me to start this thread. It's specifically a decent volume of air that will be present in the remote portion of the engine oil system (i.e. from block adapter plate, about 2 feet of -10 hose, oil radiator, oil filter, and hose back to adaptor plate) if steps aren't taken to purge the air prior to engine startup. A rough guesstimate is about 2 quarts volume of air. The oil radiator itself is 8.5 X 12 X 2 inches that I'd guess will hold about 1.5 quarts of oil. Yes, I can prefill the oil filter but that still leaves a large volume of air. I'm concerned that if this volume of air is pushed into the engine block oil galleries with the engine running that there could be oil starvation causing premature wear on critical components. For example, the Coyote has 4 cams that run without bearings directly in the aluminum heads. I'd hate to have any unnecessary wear happening there.

I'm not really concerned about the oil pump loosing prime during oil change, at least not within the context of this thread/discussion.

The pressurized oil bottle I mentioned in initial post looks to be called a " Engine Preluber/Fluid Transfer Kit" with the Summit brand here: Engine Preluber/Fluid Transfer Kit There appears to be different brands of this tool at different price points and I've also seen DIY options (like the Freon bottle mentioned) for under $50.

It sounds like the majority of initial feedback is that the air should be purged. What I'd like to draw out from here is the best way to do that and whether this should also be done during every oil change or just upon initial setup.

 

[JP Verweij]

As mentioned before, the old skool way works great.
If you can't prime the engine by taking the dizzy out, just remove the sparkplugs and use the startermotor to prime the engine.
It won't take long, less tha a minute. Just a few seconds.

 

[Joel Heinke]

Here:

https://documents.holley.com/199r10623.pdf

Howard: thanks for the link to those instructions, they are the most complete I've seen so far as to the remote oil system installation. Specifically the sequence of oil filter and cooler in the remote system. These instructions don't however speak to the air purge issue. Funny how something potentially very important is just skipped over. The instructions provided with the remote system I purchased were just a simple warning that if the hoses weren't hooked up right, the engine would be ruined. So even less helpful than those you linked to.

 

[Joel Heinke]

As mentioned before, the old skool way works great.
If you can't prime the engine by taking the dizzy out, just remove the sparkplugs and use the startermotor to prime the engine.
It won't take long, less tha a minute. Just a few seconds.

I do think disabling the engine from starting and then cranking it over is a viable way to build oil pressure and thus purge the air. I'm doubtful pulling the plugs on this engine is as simple as you've made it sound. For one thing, there's 8 coils that need to be removed just to get to the plugs. In addition, I plan to fabricate some aluminum covers that will go over the plastic valve covers to make the engine look more period correct for the car. Maybe they will be easily removable, maybe not, won't know until that bridge is crossed.

Given it's an EFI engine, maybe a good way to disable it from starting is to disconnect power from fuel pump. Is there a negative side effect for doing that?

I'd still like to hear thoughts on other good ways to purge the air from remote oil system beyond just cranking a disabled engine over. My past experience tells me this engine will be pulled out and put back in a few times before the car gets fully sorted. It's just the way it is on a custom built car as much as I'd like it to be a simple assemble and go thing. The remote oil system will need to be disconnected to remove engine, so my preference is to find a reasonably simple, foolproof way to ensure the oil system is good to go prior to engine start after an engine re-install.

 

[Neil]

If you wire individual circuits to a switch/circuit breaker such as this, it is a simple matter to crank the engine without starting it. Steps:

1. Main battery switch ON.
2. Ignition switch/breaker OFF
3. Ignition switch OFF.
4. Fuel pump switch/breaker OFF
4. Power switch ON.
5. Press starter button.

 

[Joel Heinke]

If you wire individual circuits to a switch/circuit breaker such as this, it is a simple matter to crank the engine without starting it. Steps:

1. Main battery switch ON.
2. Ignition switch/breaker OFF
3. Ignition switch OFF.
4. Fuel pump switch/breaker OFF
4. Power switch ON.
5. Press starter button.
View attachment 128076View attachment 128075

Neil: that's a great looking setup for a track car

My application is a street car that has an integrated EFI/ignition system (Holley Terminator X). I plan to operate it either from a traditional key on the column (for steering lock) or a fob/start button or a combination of both. I'm trying to keep the normal engine start process simple as I'd really like to have my wife wanting to drive the car on occasion. Experience has taught me that she's dramatically more supportive when she can be "involved" with a car versus when she's not. She accepts and likes "our" Cobra because she's driven it but despises "my" 250 GTO because she's not had any "involvement" with it. I'm guessing you married guys might know what I'm talking about here.

Saying that though, I'm not opposed to wiring in a toggle on the fuel pump circuit to disable it assuming there are no negative side effects to doing that. The ECM/computer controls the fuel pump circuit to control fuel pressure during the engine crank phase. I'm guessing there's no real harm to the ECM in having that circuit "open" via a toggle switch as I believe it goes through a relay anyway. Hiding away such a toggle switch is actually a good addition to a vehicle anti-theft system and wouldn't complicate the normal engine start process for the wife.

But given all that, I'm still interested in finding a "mechanical" process that pressurizes the oil system to purge air from it. I guess cranking a disabled engine just feels a bit fuzzy to me as to what signals when the air purge is complete. I don't plan to have a mechanical oil pressure gauge in the car (digital gauges with oil pressure reading provided by ECM) and even with a mechanical gauge the air bubble may of just been pushed far enough into the internal oil gallery to build pressure behind it. I'm guessing that seeing a change on the sump dipstick of a couple of quarts of oil would be a more sure indication that air purge is complete. Maybe I'm being over cautious here but I thinking better safe than sorry.

 

[Howard Jones]

Unrefined thought. How about using an accusump-type system to prime oil galleys? It might be fairly easy to attach to the filter housing in place of the filter. How about we group think this.

You can always lift the fuel pump fuse.

Dry sump? Take off the belt and drive the pump with a drill motor.

 

[Howard Jones]

How about this? You could simply attach it to one of the remote oil cooler lines (back to the engine) and cap the other. Then allow oil to drain from the oil drain on the pan into a clean oil tank. When you have run the oil through the engine and are satisfied you have good oil pressure you can either discard it or reuse it.

Or........you could fill the engine with oil this way or at least add the first couple of quarts, check oil pressure, and pre-lube at the same time. Then top off to full oil quantity. Thinking on the go here, Will this work?

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[Joel Heinke]

To provide more context, here is what I've come up with for preliminary remote filter and cooler locations. The brown paper behind and under the cooler is there to designate future aluminum sheet panels that will close off the passenger compartment. The cooler is positioned where it is because I think air can be ducted to it from an opening in the lower rocker panel just behind the passenger door.

If oil filter mounted in this position, it will obviously need a "debris shield" to protect from rocks, etc. that might come from tire rotation. The oil cooler should be protected by the wheel house that will go over the rear tire.

Conceptually, it seems that a viable way to purge air from remote oil system is to "mimic" the normal engine oiling operation but with the engine off/not rotating. In other words, provide pressurized oil to the remote system at the point it would normally exit the engine block/enter remote system and let this oil push the air out through the system, into the engine and out through normal oil exit points.

Here's the oil adapter plate I'm using that mounts in place of the normal oil filter mount on the Coyote.

The oil pressure sensor port is located where the oil returns to the engine so that can't be used for what I'm describing. I'm concerned that pushing oil backwards through the remote system won't work as the oil filter probably has an anti-drain back feature that acts as a one way valve. So I'm thinking a port could be added, right about the middle of the first "M" and a small hose be attached to this port (say a 6 - 8 inch long -4 SS braid hose) which can be attached to an "oil pre-lube/transfer bottle" (like the one Howard posted after I started composing this response). I'm thinking the hose could/should be left in place and capped off during regular car operation as access to the oil adapter plate is very limited by headers and coolant pipes.

So when air needs to be purged from remote oil system, uncap the hose, attach oil pre-lube bottle, purge air, and then recap the hose. If oil loss from the hose after purging is an issue, a simple ball value could be used to stop it and cap placed on ball value to ensure no leakage. Sounds simple enough for me (at least conceptually). Am I missing something???

 

[Neil]

Neil: that's a great looking setup for a track car

"I'm trying to keep the normal engine start process simple as I'd really like to have my wife wanting to drive the car on occasion. Experience has taught me that she's dramatically more supportive when she can be "involved" with a car versus when she's not. She accepts and likes "our" Cobra because she's driven it but despises "my" 250 GTO because she's not had any "involvement" with it. I'm guessing you married guys might know what I'm talking about here. "

You are a wise man!

 

[Howard Jones]

And because I tend to drift off on tangents when I am looking up stuff on the internet:

Primer on oil systems:

Lubrication Systems for High Performance Piston Engines

 

[Neil]

And because I tend to drift off on tangents when I am looking up stuff on the internet:

Primer on oil systems:

Lubrication Systems for High Performance Piston Engines

Good information, Howard.

 

[Joel Heinke]

And because I tend to drift off on tangents when I am looking up stuff on the internet:

Primer on oil systems:

Lubrication Systems for High Performance Piston Engines

As one of my metal shaping mentors frequently says, "Every day is a school day!" This article even provides a clear reason why the oil filter should be sequenced before the oil cooler. I've heard this antidotally before but never have heard a clear reason why.