low resistance one way valve

[Kevin Johnson]

Looks like a great piece. Unfortunatly Master Mccar doesn't deliver overseas.

The other thing that comes up in forum discussions about this topic is that they keep track of firms or individuals who buy these parts with the intent to circumvent their shipping restrictions by supplying third parties. These firms or customers are then blacklisted from further purchases, even for domestic use.

[Belgian1979]

In any system air release starts first and if the pressure decreases further, cavitation
may occur. This means that, sometimes, people talk about cavitation when the real
phenomenon is air release.

I am glad that the removal of the check valve has resulted in acceptable pressures at the gauge. Please keep in mind that this behavior is also indicative of air entrainment, dissolution and release at a pressure drop in the circuit (the check valve). This being particularly so if the behavior only results after the engine has been operated for some time (allowing air to be entrained and dissolved) and is different from the viscosity drop due to temperature rise.

Whatever you decide to do, good luck.

I ran the car without the Canton check valve. Pressure drop is gone.

Pressure in general is lower than connected directly to and from the filter, but this is to be expected. Seems I loose about 10 psi in the lines. This as well on rpm as at idle.

As for the drainback filter : the filter is on the side of the block mounted on the frame. The accusump is under the front bumper bracket. There is no other place to put the accusump. If would want to connect the accusump to the line from the filter to the engine, it would mean another line from the engine towards the front. Rather difficult solution.

I'm thinking about 2 check valves in parallel

Maybe a stupid question but how does one discern between a pressure drop due to air entrainment and viscosity change ?

[Belgian1979]

Looks like a great piece. Unfortunatly Master Mccar doesn't deliver overseas.

The other thing that comes up in forum discussions about this topic is that they keep track of firms or individuals who buy these parts with the intent to circumvent their shipping restrictions by supplying third parties. These firms or customers are then blacklisted from further purchases, even for domestic use.

To be honest I don't understand the people from Mcmaster Carr. What is it that is so prohibitive that their products are sold overseas ? They come across like people with their noses high up in the air.

[Kevin Johnson]

Looks like a great piece. Unfortunatly Master Mccar doesn't deliver overseas.

The other thing that comes up in forum discussions about this topic is that they keep track of firms or individuals who buy these parts with the intent to circumvent their shipping restrictions by supplying third parties. These firms or customers are then blacklisted from further purchases, even for domestic use.

To be honest I don't understand the people from Mcmaster Carr. What is it that is so prohibitive that their products are sold overseas ? They come across like people with their noses high up in the air.

In July 2003, McMaster-Carr was fined $8,000 by the US Commerce Department for multiple violations of the antiboycott provisions of the US Export Administration Regulations (EAR).The Commerce Department’s Bureau of Industry and Security charged that McMaster-Carr failed to report its receipt of boycott-related requests within the time period required by the EAR. The alleged violations occurred in eight transactions involving sales of goods from the United States to Oman, the United Arab Emirates, Kuwait, Qatar, and Saudi Arabia. McMaster-Carr voluntarily disclosed the alleged violations to the Department.

It could be this or possibly that they have been put on notice they are under scrutiny. When I researched the fines for EPA violations for diesel engines in California, the fines were based on the maximal ability of the firm to pay. Newspaper articles then went on to tell about the wonderful things that were being done with the fine money.

As an aside, I get asked fairly often to deliberately undervalue goods that are being exported. There are very severe civil and criminal penalties that go well beyond the forfeiture of the goods. People do not seem to understand that it is not just the importer that could have problems. If it is determined that the violations are deliberate then the penalties are more severe. Note above that McMaster-Carr self-reported the violations (albeit of a different nature) and they were probably not deliberate but rather from ignorance of individual employees. I understand that this has been done for a long time and you do not hear many stories of people being caught.

[Kevin Johnson]

In any system air release starts first and if the pressure decreases further, cavitation
may occur. This means that, sometimes, people talk about cavitation when the real
phenomenon is air release.

I am glad that the removal of the check valve has resulted in acceptable pressures at the gauge. Please keep in mind that this behavior is also indicative of air entrainment, dissolution and release at a pressure drop in the circuit (the check valve). This being particularly so if the behavior only results after the engine has been operated for some time (allowing air to be entrained and dissolved) and is different from the viscosity drop due to temperature rise.

Whatever you decide to do, good luck.

I ran the car without the Canton check valve. Pressure drop is gone.

Pressure in general is lower than connected directly to and from the filter, but this is to be expected. Seems I loose about 10 psi in the lines. This as well on rpm as at idle.

As for the drainback filter : the filter is on the side of the block mounted on the frame. The accusump is under the front bumper bracket. There is no other place to put the accusump. If would want to connect the accusump to the line from the filter to the engine, it would mean another line from the engine towards the front. Rather difficult solution.

I'm thinking about 2 check valves in parallel

Maybe a stupid question but how does one discern between a pressure drop due to air entrainment and viscosity change ?

You could somehow draw a sample of the pressurized oil while the system is conjectured to be aerated and look for air bubbles.

[Belgian1979]

I think that is difficult.

I did notice that after doing some 6 full throttle 7000 rpm pulls that the engine seemed to idle a a lower 20-25 psi of oil pressure. Some driving thereafter and the oil pressure was around 30-35. I thought this was caused by the oil being very hot at that moment, since it went back up after some more relaxed driving.

Really need to get myself an oil temp gauge.

[Kevin Johnson]

I think that is difficult.

I did notice that after doing some 6 full throttle 7000 rpm pulls that the engine seemed to idle a a lower 20-25 psi of oil pressure. Some driving thereafter and the oil pressure was around 30-35.

That is a classic symptom of air entrainment.

[Belgian1979]

Ok, while going to the tech inspection center I used the drive to check some things. This time I lowered the level of the oil to just below the add mark (1 qrt less). Was better, but the oil seems to rise about 1/4 between the add and full mark when hot. Need to take that into account.

I'm also going to connect the accusump in the line between the filter and the block.

Anyway, the pan is going to come off, since it developped a slight leak at the rear of the pan.

[Belgian1979]

An update for those who might interest this.

In the meantime I took off my oil pan to fix the seal issue. I intend to close the gap on the side of the baffle like Kevin suggested.

I also tried several amounts of quarts in the pan. with 7 qrts the oil is still under the baffle but since the baffle is not long enough it's exposed to windage at the front of the pan. At 6 liters it's all covered. At 5 liters it sets about 1 cm below the baffle.

[John@RED]

After some testing my oil pressure drop problem seems to point to the accusump one way valve being the issue.

However it is mandatory when you run an accusump in your lines and I would like to keep the accusump if possible as I also noticed it does help maintain oil pressure when going over bumps and such.

I've read comments about the Canton 1/2" one way valve being too restrictive. What would be a good alternative. I run -10 lines.

Thanks

Who says a check valve is mandatory when using an Accusump? It is not necessary. The oil pump will prevent backflow into the pan.

-jim

Hello, back on this subject.
Always thought the same, oil pump will prevent backflow, so one way valve not really needed.
Moreover this will let us install it between oil pump and oil filter, correct?

[amc fan]

DFT valves http://www.dpt-valve.com check valve threaded. Just search DFT valves.

[Kevin Johnson]

Hello, back on this subject.
Always thought the same, oil pump will prevent backflow, so one way valve not really needed.
...

One possible argument against using the pump to stop backflow is that the volume of high pressure oil from the accumulator is limited. As the piston moves through the stroke, the oil supplied into the circuit drops in pressure because the pressurized air volume is expanding. It would be most desirable to have this high pressure oil directed to bearing clearances alone rather than battling the oil pump gears or lobes. Fractions of a second at high rpms and low oil pressure count.

One method to increase the volume of high pressure oil supplied by an accumulator is to use a separate container to pressurize the area behind the piston. In doing so you could enable an accumulator to deliver near its entire volume near the maximum pressure. The downside is the increased weight and complexity of using a remote pressure reservoir. You would also have to contrive a way to let the accumulator recharge its full volume when the pump is once again supplying high pressure oil.