Proper way to disable the oil bypass - AGAIN

[jgkurz]

Hi All, I know this has been brought up many times but I want to be 100% correct on this procedure. The shim/rod/nut/washer needs to be put in one of these locations to put more force on the bypass valve against the screw-in plug, correct?

[ScotiaFE]

Why are you closing the valve?

[jgkurz]

Why are you closing the valve?

I will be running the bypass in my Precision Melling M-57AHV pump. I'm not sure why I'd need two bypasses. I believe some of the very expensive aftermarket 427 blocks rely on the pump bypass so it seemed reasonable to do the same.

[ScotiaFE]

Why are you closing the valve?

I will be running the bypass in my Precision Melling M-57AHV pump.

The way I understand the sideoiler to work.
A high pressure pump is used and the vent valve will regulate the pressure at the rear main to about 60 psi.
If you just use the HV pump you will never get to 60 psi at the rear main. The pressure will bleed off
and at best you will have about 50ish psi at high rpm. Just like all the rest of the non sideoilers that use the HV pump.
There is a reason why Ford went to all the extra work to do it. To keep the oil pressure up at the rear main
for endurance racing.

[jgkurz]

Why are you closing the valve?

I will be running the bypass in my Precision Melling M-57AHV pump.

The way I understand the sideoiler to work.
A high pressure pump is used and the vent valve will regulate the pressure at the rear main to about 60 psi.
If you just use the HV pump you will never get to 60 psi at the rear main. The pressure will bleed off
and at best you will have about 50ish psi at high rpm. Just like all the rest of the non sideoilers that use the HV pump.
There is a reason why Ford went to all the extra work to do it. To keep the oil pressure up at the rear main
for endurance racing.

I have never heard this but I am new to the Ford FE crowd. I certainly want to make the best decision for my street/strip setup. THANK YOU for posing the question.

[RJP]

The only problem with using the rear bypass is you'll need the high pressure bypass spring in the oil pump. The oil pump bypass is set to bypass at about 125lbs to protect the oil filter. This is for cold starts only and the rear bypass is the actual running pressure control. I've blocked the rear bypass in 2 sideoilers and just rely on the M57HV as it was set at Melling. My hot/running pressure on both is app. 65 lbs at 2500 rpm and have no problems in the 20 or so years they have run.

[Autoholic]

I know there is more than one way to skin a cat, but why not run it the way it was designed then?

[jgkurz]

I know there is more than one way to skin a cat, but why not run it the way it was designed then?

I just spoke to a friend who has forgot more about FE's then I will ever know. He said when he was racing with factory blocks he'd shim the block bypass tighter than stock then reply on the pump bypass. He never had an issue doing this. This was after many high RPM runs down the drag strip. As an interesting side note, he said the factory did the exact opposite with the pump bypass spring being much stiffer than the block bypass.

[jgkurz]

Why are you closing the valve?

I will be running the bypass in my Precision Melling M-57AHV pump.

The way I understand the sideoiler to work.
A high pressure pump is used and the vent valve will regulate the pressure at the rear main to about 60 psi.
If you just use the HV pump you will never get to 60 psi at the rear main. The pressure will bleed off
and at best you will have about 50ish psi at high rpm. Just like all the rest of the non sideoilers that use the HV pump.
There is a reason why Ford went to all the extra work to do it. To keep the oil pressure up at the rear main
for endurance racing.

ScotiaFE, Are you suggesting the use of the high pressure pump vs the high volume pump? I am rethinking my approach and may stiffen up the block spring instead of disabling it completely.

[Autoholic]

At what RPM would a high pressure oil pump be needed? And you can have both a high volume and a high pressure pump.

I found some interesting reading on Melling. Not exactly news, but it's an interesting way to really understand what is happening.

http://www.mellingengine.com/Portals/5/pdf/pdf_catalog/pressure-vs-flow.pdf

http://www.mellingengine.com/portals/5/pdf/pdf_catalog/high-volume-pumps.pdf

[Autoholic]

I've been thinking a lot about this and there has to be a reason why Ford would install a pressure relief spring in the block, rather than just relying on the oil pump relief spring. Below is the layout for top and side oiling FE's.



So what would be the cause? Pump loss is due to surface finish, distance, elevation changes, number of bends and what type of transitions are present. What this turns into, is pressure drop the farther you get away from the pump. Resistance will build up pressure, but that pressure is not exactly uniform, due to pumping losses. So resistance to flow builds up pressure at the pump, but that does not mean said pressure will be seen at the end of the passage. So Ford must have figured that the best place to regulate the pressure for normal operation would be at the end of the flow, ensuring that the maximum-minimum pressure seen anywhere in the engine is at the end of the oil gallery, rather than before oil even reached it. That last sentence can sound a little confusing, but the point of the design is to regulate the oil pressure at the end rather than the beginning, in order to keep oil pressure where it needs to be for all parts of the engine. So you don't stop the pump at say 65 PSI which will eventually drop as the oil reaches the back of the engine. By regulating the pressure at the back, you know that the whole block receives a minimum of 65 PSI before the relief opens.

This is all based off of the theoretical functioning of the pressure relief spring at the back of the engine. How much the oil pressure drops between the pump and this spring is hard to know without putting a gauge in place of the relief spring. It could very well be a preventative measure, as engineers like to think of every possible way there could be a problem.

[ScotiaFE]

I think the sideoiler system is an excellent oiling system.
I'm sure all the guys that think they know better than Ford think they are right also. 

[IDOIT4SPEED]

thoughts on oil pumps. Melling M57HV is 390 /428 pump with high pressure by pass spring. equal to Ford heavy duty pump C9ZZ-6600-A said to flow 22 gpm at 70 to 80 psi at 4000 rpm this is a gerotor type pump with internal bypass. 427  uses C3AZ-6600-B I think this is a gear on gear pump, that was also used on the 406. does any one have an oem 427 pump that we could see pictures of.  with the right pump I see no reason to block out the rear bypass.  with an M57 type pump  when it is in bypass several thing happen. first spark scatter in the distributor. second the bypass oil is discharged back in to the intake side of the pump this can have an effect on oil pick up. this will also heat up the oil. the rear bypass eliminates all of this. and as previously mentioned oil pressure regulation at the far end of the system

[Autoholic]

So I just realized I pretty much wrote the long engineering version of what Scotia wrote.

Oh and remember, if you use a remote oil filter or an oil cooler, the oil goes from the pump to these first. You have any idea the kind of pumping losses that can be seen from this?

Here is a scan of an original advert for the 427 pump. Pretty sure this is a gerotor design as well.

[jayb]

I think the sideoiler system is an excellent oiling system.
I'm sure all the guys that think they know better than Ford think they are right also. 

Oiling systems sure are fun to argue about 

I'm not overly impressed with the sideoiler system.  It is not a true priority mains oiling system; it oils the mains and the cam bearings at the same time.  IMO it is only marginally better than the standard FE top oiler system.  The thing that makes it a little better is that the passages are larger and can flow more oil to feed larger bearing clearances.  The rear pressure relief valve would seem to be a benefit if you put a high pressure spring in the regular oil pump, so that the regulation is done at the end of the oiling system, but based on the tests I've done with oil pressure gauges at various spots in the engine, there isn't more than about a 15 psi drop off front to back, so as long as you have sufficient pressure up front I'm not sure that the rear valve is needed.  Although I have to say that when the sideoiler was designed, there weren't modern electronic ignitions, and Mike's point about spark scatter is a good one if you happen to be running points and a coil only.  With a modern electronic ignition distributor and CD ignition box like an MSD, I don't think you'd see the same problem.

The really good oiling system is the small block Ford oiling system.  That one is a true priority mains system.  That is also the oiling system that the Shelby block was designed with.