mount an oil filter on engine suction side?

[martensson]

I did a search but have not found any definite answers...

the oil tank has a filter mounted on it as is on the car when it came from the factory 1971.
Now there's a 964 3.6-engine installed & we have the 964 filter mount + hard lines on the shelf.

Its not a question of must or must not, or if its been working for 30 years so why bother....you get the point

The question is.
Is it technically possible to mount an oil filter between the oil tank & suction side of the oil pump without any kind of complications like for example oil "starvation" due to poor suction thru filter or similar?

thanks

[GH85Carrera]

No doubt with enough money and time it could be done. Why bother with trying to improve a system that is race proven and simply works. Filter the oil before it get to the tank, No need to re-invent the wheel. But that is just my opinion, I could be wrong.

[Bill Verburg]

Originally Posted by martensson

I did a search but have not found any definite answers...

the oil tank has a filter mounted on it as is on the car when it came from the factory 1971.
Now there's a 964 3.6-engine installed & we have the 964 filter mount + hard lines on the shelf.

Its not a question of must or must not, or if its been working for 30 years so why bother....you get the point

The question is.
Is it technically possible to mount an oil filter between the oil tank & suction side of the oil pump without any kind of complications like for example oil "starvation" due to poor suction thru filter or similar?

thanks

993 have filters on both sides, the suction side is a full flow but there is a bypass incorporated into it, #11 & 12 are filters


older cars had a similar filter console w/ by pass here is one for '74 -89

[ganun]

Bill, the 993 diagram shows both filters on the pressure side of the pumps. Looks like it to me. .......

[Bill Verburg]

Originally Posted by ganun

Bill, the 993 diagram shows both filters on the pressure side of the pumps. Looks like it to me. .......

look at the flow arrows, there's a filter on each side

[KTL]

You absolutely can mount a filter on the suction side. If you look at the 964 oil routing, the 964 filter console is encountered pretty much immediately after the oil exits the engine.



What you can see in that parts diagram is the oil exits the engine from oil line #54. This oil line is connected to the side of the engine where the oil pump scavenge port discharges oil from the engine to be processed externally. From oil line #54 the oil goes directly to oil filter housing #47, thru the filter and then onward to the thermostat. It either goes back into the oil tank/reserve (t-stat is in cold position) or forward to the front oil cooler (t-stat is in hot position) and then returns to the oil tank.

Porsche didn't use the oil routing of the 964 for very long. With the introduction of the 993, like Bill shows, Porsche relocated the scavenge oil filter and also added a pressure side filter where the engine-mounted oil cooler previously existed on the pre-964 cars. Here's a different 993 diagram that shows the same thing Bill posted, just with different pictures.

[winders]

See this thread:

http://forums.pelicanparts.com/porsche-911-used-parts-sale-wanted/694763-965-engine-oil-filter-console-f-s.html

My race car with a 964 engine has the angled filter console installed.

[Trackrash]

Are you keeping the '71 oil tank? Porsche increased the capacity of the oil system in '72. I can't imagine that a '71 oil tank with its smaller fittings and capacity would be adequate for a 3,6 motor.

[stownsen914]

The oil filter that hangs off the engine where the oil cooler went on earlier engines is not on the suction side of the pump. It's after the pressure side of the pump and before all the bearings and other critical parts requiring lubrication. If you put a conventional oil filter on the suction side (pre-pump), you will starve your engine for oil!

There is such a thing as a coarse screen pre-filter that can be used before an oil pump tp protect the oil pump. They're usually much smaller than a typical oil filter.

[KTL]

stownsen914 is correct. I did not read the question clearly enough.

These are the sort of filters you can use just ahead of the oil feeding into the engine. Needs to be a coarse-screen filter so as to not restrict the oil demand of the pump

Peterson Fluid Systems : 400 Series Filters

[martensson]

thank you all for your inputs on the subject. Thanks for the drawings & explanations. Much appreciated

Conclusion? Now you all, including myself, know Porsche has no filter on the suction side on the "oldies" But there is room for one.

Originally Posted by GH85Carrera

No doubt with enough money and time it could be done. Why bother with trying to improve a system that is race proven and simply works. Filter the oil before it get to the tank, No need to re-invent the wheel. But that is just my opinion, I could be wrong.

Am i really reinventing the wheel? Why did Porsche themselves add one more filter on the later models?
Have you ever seen the inside of an oil tank, especially a tank that's 30 years old?
If you haven't had an oil filter on the suction side between the tank & the pump, how can you say it works as is? How can you possibly know a filter wont help to improve the lifespan of the engine between rebuilds?

These boxer engines are air- & oil-cooled only & therefor run warmer than water cooled engines. They also generate pretty much power which generates more heat & also more wear on the engine. This plus the fact that residues, carbon deposits, from the oil tank find their way straight into the pump don't make it easier on the engine.

When rebuilding the engine recently most of the main bearings had turned blue.
Not knowing the history of the engine its not possible to know why it was so worn down.
Getting to know the local Porsche owners & doing some research, rebuilding these engines seems fully normal within a span of 125k miles & not uncommon within 100k miles.

I don't know much about Porsche since its the first car i/we own. (it actually belongs to my fiancee & i´m just the muscle) but after cutting a tank in half & knowing whats inside & what does &/or will end up in the pump got me thinking.

Can i prevent dirt from ending up in the pump? Yes i can. Is there any OEM solution to this...seems as if there isn't.

So i have now begun making myself a filter-housing with a stainless steel mesh filter, full flow type. he future will tell if i´m reinventing the wheel.
Whether i´m reinventing the wheel or not i will still say its worth the time if it can prevent wear & prolong the span between rebuilds. I don´t consider engine safety being a waste of time. I was hoping there would be an OEM-alternative thou.

once again, thank you all for the info on the subject
For more on the build you can join in here: https://www.facebook.com/people/Screw-Loose-Customs/100007433597613

[winders]

martensson,

You want to put a filter on the pressure side after the oil pump, not before which is what you are calling the "suction side".

Finally, you do not want a regular filter after the tank but before the inlet to the engine (before the oil pump). This could starve the engine of oil. A filter on the pressure side and on the return to the oil tank, as done on the 993 is more than adequate. This is what is done on most race cars with 964 and 993 based race engines. Custom building what you call a "full flow" filter for the suction side seems like folly. To make it full flow enough to be safe means letting particles large enough through that the filter is not doing what you intend.

These air-cooled engines have been in use for a very long time by some very smart people that want them to live for long time. You are not being innovative here. You are making a mistake.

[juanbenae]

Originally Posted by winders

These air-cooled engines have been in use for a very long time by some very smart people that want them to live for long time. You are not being innovative here. You are making a mistake.

and there ya have it... seems like we're all done here.

[martensson]

Originally Posted by winders View Post

These air-cooled engines have been in use for a very long time by some very smart people that want them to live for long time. You are not being innovative here. You are making a mistake.

Originally Posted by car 311

and there ya have it... seems like we're all done here.

Is this what the Pelican technical forum has to offer
I´m a bit disappointed of some guys here not having any facts to back up their statements with more than, its race proven (what does that actually mean?), your a fool, your making a mistake.
I had higher hopes to a community lite this one. I was hoping to get answers on a more technical base & maybe experience based. Answers based on facts. Not pie throwing. That is not how grown up enthusiasts act.

The filter housing is almost finished & will be evaluated on the car when possible. I´ll return when I have gathered information on whether it was a mistake or not.

thanks

[billybek]

Installing a filter on the suction side of the pump can cause cavitation.
It is preferable to filter on the pressure side because of this.

[martensson]

thanks Bill. Someone else also mentioned this problem with cavitation. I know a little about this matter so it is taken under consideration
This is also one of the reasons why i asked about any problems regarding this matter. Also hoping for some experience or facts. Good points indeed Bill.

I should be able to modify the 964 filter parts somehow... Someone posted a sale on a 965 oil filter console. I should be able to make something similar & mount it om the pressure side.
Firstly the suction filter is meant to keep bigger carbon flakes & foreign objects from reaching the filter. It will not be meant to clean the oil the same way a normal filter does. This might not have been clear enough earlier....so sorry if anybody thought so.

[Trackrash]

Have you read this thread? http://forums.pelicanparts.com/911-engine-rebuilding-forum/706984-engine-bearing-failure-disassemble-heads-too.html

[onevoice]

I have been through the same thing with a 964 3.6. The original system is great as long as the tank is clean, and it should be, but things happen.

No engine I have ever seen has a filter on the suction side of the oil pump. Do not attempt that. Any filter that would stop significant debris would be too much restriction to the oil pump, it will cavitate, and will send your oil pressure to ZERO.

The 993/964 turbo second oil filter resides on a console that is mounted where the early engine mounted oil cooler normally resides. 964-3.6's had nothing there, but the holes in the crankcase are present, but plugged. There is a good pic of a 964 case with the hole plugs removed in post 18 of this thread:

Use 993 Oil Filter Console on 964 Engine? - Page 2 - Rennlist Discussion Forums

If using 964 oil inlet lines, they will fit without problems, as will 964 tin. Note that the 964turbo oil filter console is angled slightly toward the front of the car, the 993 is vertical. Also in those pictures you can see the 964turbo thermostat cover that forces oil to the filter, it is required. There is also discussion about temp sensors and hole plugs, mine wasn't like that. Mine had a plug in the crankcase hole, and I used the holes in the cover for the sensors. I don't remember which sensor goes in which hole, but I know I had to use a different temp gage sensor, it was a 944 part, I could probably look it up. I used the calibration info I got from Palo Alto that rebuilt my guages to check it against the factory 964 temp sensor and it had an identical resistance/temp profile. Sorry if this is a little confusing, but it has been awhile.

993's supposedly used the extra filter because of the hydraulic lifters, but I think it is just good insurance for any engine that has suffered a failure that could potentially contaminate the oil tank/cooler/lines.

The plugs in the crankcase are pressed in and must be drilled out. Can't be done on an assembled engine because removing the plugs would put shavings in the main oil galleries.

I also contemplated tapping the crankcase for fittings and remote mounting the filter, but the factory console was a cleaner way to go and I had the space.

Again, the only way to really filter the oil is on the pressure side. Doing it on the suction side will be a disaster.

Edit: you can buy the 993 crankcase mounted oil filter console new, and the thermostat housing cover also.

[winders]

Originally Posted by martensson

Is this what the Pelican technical forum has to offer
I´m a bit disappointed of some guys here not having any facts to back up their statements with more than, its race proven (what does that actually mean?), your a fool, your making a mistake.
I had higher hopes to a community lite this one. I was hoping to get answers on a more technical base & maybe experience based. Answers based on facts. Not pie throwing. That is not how grown up enthusiasts act.

The filter housing is almost finished & will be evaluated on the car when possible. I´ll return when I have gathered information on whether it was a mistake or not.

thanks

What an insulting and ungrateful post. I stated that if you put a filter on the "suction" side that flowed enough to be safe for the engine that it would allow particles large enough through to the engine that would cause the damage you are trying to prevent.

This is the very reason no Porsche air-cooled engine, production or race, has a filter on what you call the suction side (between the tank outlet and the engine inlet).

You seem to think you know more than Porsche engineers so you go right ahead and insult people here when they are trying to help you....and destroy your engine.

[mytoy]

Originally Posted by martensson

thanks Bill. Someone else also mentioned this problem with cavitation. I know a little about this matter so it is taken under consideration
This is also one of the reasons why i asked about any problems regarding this matter. Also hoping for some experience or facts. Good points indeed Bill.

I should be able to modify the 964 filter parts somehow... Someone posted a sale on a 965 oil filter console. I should be able to make something similar & mount it om the pressure side.
Firstly the suction filter is meant to keep bigger carbon flakes & foreign objects from reaching the filter. It will not be meant to clean the oil the same way a normal filter does. This might not have been clear enough earlier....so sorry if anybody thought so.

Martensson;

I know of no dry sump system that is safe with a filter system on the suction side that would prevent starvation. If you want facts here are a few for you to ponder:

1) All pressure side filtration systems have a by pass system built in. This is a safety measure in the case that the filter is so efficient and proper maintenance is not maintained and the filter can not pass the required flow to the end usage. The bypass systems are based on pressure differential which means that when the pressure reaches a higher level than the relief valve then the relief valve opens to allow full flow around the filter.

2) I know of no relief system that works off a suction pressure differential to allow for full flow if the filter were to become clogged.

3) There is no fuel system which I know of which has a pre filter to the fuel pump. All filters are on the outlet side and the good systems have a relief valve system also. Why? If your pre filter were to clog up enough to starve the pump from full flow then you would certainly have a problem with a lean condition which would play havoc on your engine under full throttle. (Ever seen what the bottom of the fuel tank looks like?)

4) I have designed pumping systems for industrial usage and also for high performance automobile usage and have never contemplated a suction filter.

That being said I have incorporated a pre screening system for industrial use in a specialized process. This was a rotary screen on the return system which was meant to screen large particulate out of the system before re entering the system to prevent filter clogging. But remember that a rotary screen is a pass through system and the if the screen is clogged it still allows full flow to the pump system and if the filtration system were to clog then the pressure relief valve would open and allow full flow (contaminated or not) to flow to the process.

5) Every form of racing which utilizes a dry sump system (which is what the Porsche system is) from drag racing to formula 1 do not incorporate a suction filer for the mere fact of the potential failure and damage involved.

6) There is no commercial manufacturer of any automobile manufacture (that I know of) that incorporates a suction filter in their oiling or fueling systems. Why? Because of the potential damage to the systems from clogged or partially clogged pre filters.

There is no safety relief valve commercially available to allow a clogged pre suction filter to maintain full flow to the suction side of the pump.

Now you being an engineer must be smarter than most and can see the potential for disaster. But maybe not and you are smarter than the average Bear. If so please report on your development and show us how you over came the potential for pump starvation on a clogged or partially clogged suction filter system.