Oil mods and their effect on flow/pressure

[WizardBlack]

I am interested in adding a few things to my RB to improve oil quality and life, etc. While I have read plenty on the oil pumps, the weakness of the stock and N1 gerotor design (it basically shatters; especially with some sustained high G/rpm and aggressive rev limiter action), but I don't have all the modifications to get into those, yet. Nor am I at the point to drop $1k+ on an oil pump. Nor do I think I'm at the point to modify the passenger side drain/air return from the head, etc.

Anyways, I am looking at installing an Amsoil bypass filtration system. It drastically improves the wear/breakdown rate of the oil and cuts the average and maximum oil contaminant size. It also happens to add another quart and a half or so to the capacity. (obviously not in the sump, where it'd be best, but it is more) Commercial vehicles are getting way more life out of the oil and engine with it. Anyways, it calls for a remote oil filter block, etc. Likewise, I considered adding an oil cooler and thermostat while I am plumbing lines. I considered one of the reservoir tanks for assertive priming of the system and a pressure backup. Lastly, I considered an addition to the sump for better pickup coverage (without a doubt the most important).

Now, with all of this, I know there will be a lot of oil plumbing. Capacity just with the additional bypass filter, the oil lines, the widened sump, oil cooler, etc. will go up substantially. So will the route the oil takes before it actually gets to the main galley.

I would like to hear everyone's comments on the various mods, their efficacy, effects on pressure, flow and load of the oil pump, etc.

 

Mark

[WizardBlack]

Nobody? OK, I've been around long enough to know if a tech thread gets no answers that either 1) It's a dumb question and obvious 2) It's too vague and no one wants to bother trying to get explicit details out of the poster or 3) no one has any idea or anything to comment on it. I seriously doubt it's 3.

[bjhines]

ok.. I try.

 

I am using a 327 SBC, so there may be different details...

 

The Amsoil filtration system basically puts another set of filters in parallel with the stock filter. Some of your oil flow from the pump is going through the Amsoil filters and dumping back into your pan. This means there is slightly less oil flow available to the engine. I do not like these types of filters for sports/race use on small engines.

 

Many engines suffer from oil problems in areas most distant from the main gallery. This issue is exacerbated by using the wrong viscosity, or the wrong oil temperature.

 

Overall oil pressure is set by the pressure bypass valve(in the pump). The filter bypass valves(in filter and in the engine block) will bypass oil when the filter is clogged. All the valves will bypass some oil under extreme conditions.

 

You need to run the proper viscosity oil, do not assume that sports/race use will require heavier oil. If you experience pressure drop when hot then you need to start tracking oil and water temps. If your water temp is stable and acceptable then you are likely overheating your oil. This is where the oil cooler comes into play.

 

Oil coolers can easily over-cool the oil and cause problems with oil viscosity being too high and limiting oil available to valvetrain parts. Oil coolers should always be installed with an oil thermostatic bypass valve. This will control flow through the oil cooler the same way the water thermostat controls water through the radiator. This will ensure proper oil viscosity under all conditions.

 

The various cooler parts and hoses will increase your oil capacity. You can also add a remote filter with much more capacity than the little stock filter. You can easily add 2-3 quarts capacity to the system which will also reduce the heat buildup in the oil system.

 

There are a lot of dos and dont's in hooking this system up. You need to think carefully about hose assembly and routing to ensure you don't end up with a complete system failure and a huge fire under the entire car. Remember, the factory system had all it's routing inside the engine with the exception of the spin-on filter, you are adding a lot of external components and a whole lot more failure points in the system.

[bjhines]

There are an endless number of mods various people have used to ensure proper flow under extreme conditions.

 

BMW inline 6 engines have used an aircraft style pressure bypass valve to keep oil pressure more stable under a wide range of conditions. Basically the pressure-bypass valve does not return the oil inside the pump housing. They have the return port in the engine block at the farthest end of the valvetrain feed gallery. This ensures that the farthest point in the system gets the set pressure at all times under nearly all conditions.

 

There is a penaly to pay for this unique pressure-return system. The passages from the pump, through the filter housing, and back into the main gallery can exceed 200psi under certain conditions. This means you cannot use a spin-on-filter(it would blow its can off). The gallery drill-plugs must be threaded into the block and head(press-in plugs would blow out). BMW does not use oil coolers on the M-50 and later engines because pressures can easily exceed typical oil cooler ratings. Hoses and coolers must be carefully chosen for use on these engines. A quick blip of the throttle when the engine is cold could easily blow the hoses and cooler to kingdom come.

[bjhines]

If you want to add an accusump then you must consider that this is not really adding capacity to the parts of the system that are carriying the heat. The accusump is a dead end in the system and only purges and refills when there is an extreme pressure drop. The larger accusump canisters are difficult to mount in an out-of-the-way location. Using a canister that is larger than you need is wasting space and adding useless weight.

 

How big do you need???...

You can get vastly different results from different versions of the accumulator systems. Proper installation and precharging of the system is critical to getting the most oil capacity out of the smallest canister possible.

 

1. simple system with hand operated valve.

This is the cheapest and simplest system. The valve is opened just prior to starting the engine. This precharges the system. The canister refills as the oil pressure rises after startup. Oil pressure will vary in use and the amount of oil available in the canister will vary with pressure. This system has proven to work well in race use. Typically, downshifting into a corner will blip the oil pressure to it's maximum and any sudden loss of pressure while exiting the corner will have full canister capacity to supplement the pressure drop. The actual capacity of oil in the canister will vary with pressure though, so you need to use a slightly larger canister to ensure worst case conditions are accounted for.

 

2. Canton Accusump EPC control valve. This uses an electric valve and a pressure switch to control flow out of the accusump canister. The valve will always allow flow into the accusump canister. It will only release the oil when presure drops below the switch set limit. This ensures that the maximum/peak oil pressure is contained in the accusump canister until the system pressure drops significantly. Typically the maximum oil pressure is consistent in a properly cooled oil system. You can reliably determine the oil capacity contained in the canister at any time and you can use the smallest canister possible in the system.

[WizardBlack]

Hey, thanks for taking the time to post your thoughts on the subject.

 

The particular Amsoil kit I was looking at combines a standard oil relocation with the bypass kit into one filter block, so all oil goes through the system and won't let any oil bypass the entire oiling system and just dump into the oil pan like the single kit. It comes with a spin-on oil filter adapter to screw onto the block, etc. The only concern I noted is that the main oil filter spot on the amsoil filter block has a very mild check valve in it's feed circuit to provide a little bit of backpressure so that it will actually push some oil through the bypass filter (which requires a little oomph to get through, obviously). I would suspect that this will raise the effort of the oil pump a little bit, but otherwise it would hardly push any oil whatsoever through the bypass filter.

Here is a link to the model I picked up for basically free. It's BMK-23. Page two shows the filter block.

I wasn't aware of the issues with oil coolers and the concept of overcooling the oil. Very good to know.

Likewise, the accusump's downsides (or wasted efforts) from oversizing. I take it that if you want to do the basic setup with a ball valve you have to plumb the oil line into the cockpit?

[bjhines]

IMO the Amsoil bypass filter systems are for use on large stationary engines, or large engines that rack up long duration, constant duty cycles on highway.

 

These engines operate under entirely different conditions, they suffer from soot buildup in the oil long before the oil it'self becomes unfit for use.

 

Most of the small automobile engines wear out the oil long before it becomes fouled with soot.

[WizardBlack]

Most of the small automobile engines wear out the oil long before it becomes fouled with soot.

 

OK, gotcha. So adding some capacity, keeping it cool and ensuring good pressure are the things to go after.