Full flow oil filtration

[Wes Bender]

Harlan, I'll agree with some of what you say, up to a point. My argument for the full-flow filter is this: If nothing ever goes wrong with the engine internally, the bypass filter is just fine. Many German aircraft engines from WWII testified to this, as do a lot of Porsche 356 engines. The difference occurs when you do have something go wrong inside. Say a bearing starts to disintegrate. Then, with only a bypass filter, about 93% of the swarf is free to go through the entire engine. If you had a full-flow filter under those conditions, it would at least keep the stuff from going past the oil pump.

I would thus find it hard to advise against a full-flow filter. Of course, it's your engine and your money. How far do you want to roll those dice?

[Ron LaDow]

If nothing ever goes wrong with the engine internally, the bypass filter is just fine. Many German aircraft engines from WWII testified to this, as do a lot of Porsche 356 engines.

The original SAE paper found the major result of poor filtration on valve guide wear (something like a 40% reduction) and rings, so while the engine continues to function, it begins to lose efficiency. And those WWII aero engines were both prior to full-flow tech and lifed in the tens of hours, not the 100,000 mile - equivalent.
Simply put, there is no dynamic mechanical system which benefits from oil dirtier than you can provide; once '30s tech engines were replaced, nearly all got full-flow filtration and the life-spans increased drastically.
I repeat: Claims that full-flow filtration does not provide major benefits to 616 engines are B.S.

[Paul Lima]

To each his own. But, do you ever wonder why 100% of cars made after the 356 have full flow oil filters? Do you think all those car manufacturers did it just for fun? Is it possible that reduced wear might mean reduced warrantee costs? Just sayin'... My Roadster loves its full flow system, installed å la Craig R's book years ago.

[Martin Bruechle]

I'm going to stop by Newmark marina and ask Guy Newmark some questions about his car.

Does he have full flow ?

How often does he change his oil and what brand/weight does he run ?

Who built his motors ?

He has passed One Million Miles in his 64 C
He told me it has had 3 rebuilds so he gets 300,000 miles per rebuild.
I've seen him on the road several times and he is a cruiser.

"Over that time, it's had three engine rebuilds, and not much
else. That's an average of well over 300,000 miles per rebuild! The 356C had its first transmission rebuild at 900,000 miles,
and all that was required was to replace three bearings." https://www.roadandtrack.com/car-cultur ... ly-driver/

Back in the 80's I had a VW motor in my bus that ran forever that was Full Flow Mellings pump with stainless lines to dual oil filters for more capacity and filtering.
Used to run 2 Fram HP1's and Valvoline 40w, stock crank, 90.5 thick walled NPR (case bored to 92mm) Engle 110, Kadrons, Doghouse.

[Harlan Halsey]

Wow that was fast!

Wes, First, the full flow filter comes after the oil pump. Second, if something goes wrong, It probably continues to go bad, the filter doesn't fix it. it just hides it for a while. Third look at the VW and Porsche evidence, gradual bearing deterioration doesn't happen in these engines. They fail for other reasons first, but only after a lot of miles.

Ron, your claims that the full flow filter prevents gradual deterioration of the 356 engine is simply not born out by the facts. What you choose to call dirty oil is simply the detergent oil doing its intended job. Consider the Mercedes 300 diesels (of which I have two). Those are some of the most reliable engines ever built, going 250.000 miles to 350,000 miles before a rebuild. The engine oil in those engines turns opaque black in 200 miles after an oil change. The color of the oil indicates little about its lubrication properties.
I agree that if someone assembles a dirty engine, the FF filter will catch a lot of the harmful dirt on the first pass. Other than that it is useless.

[DonCichocki]

That's it! I'm making a an oil filter block-off plate for our Dodge Caravan.

[Wes Bender]

Re-read my post, Harlan. I said that the full flow filter would prevent the debris from going past the pump. Just "past the pump" is where the full flow filter usually resides. I'm not ignorant when it comes to these engines, although some may think the jury might still be out on that....

With regards to your second point, there's no doubt in my mind that if something goes wrong inside the engine, it will continue to get worse. That wasn't my point. Maybe I wasn't clear enough, but I was indicating that the full flow filter would most likely prevent the debris from being recirculated and causing other problems. I.e. bad rod bearing pieces being circulated and causing undue main bearing/crankshaft issues.

I really don't feel that we are in total agreement nor do we totally disagree either. We just have differing philosophies regarding the filtration system. I do have one of Ron's filters on my engine and I would probably add one to any other 356s that came through my possession.

[Wes Bender]

Now, if we want to talk about diatomaceous earth oil filters and never having to change your oil, I bet we can all retire to the local pub and enjoy the rest of the afternoon.

[Ron LaDow]

"Wes, First, the full flow filter comes after the oil pump."
Yes, it comes BEFORE the bearings, which is what we're trying to protect.

"Second, if something goes wrong, It probably continues to go bad, the filter doesn't fix it. it just hides it for a while."
I have no idea what that means and I doubt you do either.

"Third look at the VW and Porsche evidence, gradual bearing deterioration doesn't happen in these engines."
B.S.

"Ron, your claims that the full flow filter prevents gradual deterioration of the 356 engine is simply not born out by the facts."
B.S.

"What you choose to call dirty oil is simply the detergent oil doing its intended job. Consider the Mercedes 300 diesels (of which I have two). Those are some of the most reliable engines ever built, going 250.000 miles to 350,000 miles before a rebuild. The engine oil in those engines turns opaque black in 200 miles after an oil change. The color of the oil indicates little about its lubrication properties."
Strangely, with a full-flow on a 616, you can still see the dipstick after 1,000 miles even with detergent oils.

"I agree that if someone assembles a dirty engine, the FF filter will catch a lot of the harmful dirt on the first pass. Other than that it is useless."
More B.S. Quite simply, you do not know what you are talking about.

[Martin Benade]

I'll just throw in one more "example". The VWs from the sixties typically needed a rebuild after about 60 or 70K miles unless they got exceptional care. I worked in a small shop that usually rebuilt a couple per week. We forget how short the lifespan of most engines used to be. And I like and have owned lots of VWs. A couple of examples of 356s lasting a very long time does not prove that cleaner oil is not helpful. Also nobody mentioned a goal of keeping the oil attractive, it has all been about removing metal particles from it so it will not be abrasive.

[Alan Hall]

Didn't VW's from the sixties have no oil filters at all? No question that oil filters are a good thing, just about the relative worth of bypass vs full flow. Personally I feel full flow is better, but not that much better, and btw all that 7% business is really BS! A full flow filter filters all the oil all the time, a bypass filter filters all the oil every 20 minutes or so, so the difference in the degree of contamination is the amount of contamination that occurs in around 20 minutes of running.

[Neil Schlabaugh]

I mean no disrespect to anyone here and my thoughts and opinions are only my own. OK now that I got the disclaimer over I would like to point out a few things that we have seen firsthand.

Back at Registry in the Heartland there was a gentleman that got crossed up in a parking lot ( outlet to street not clearly marked ) and drove off a curb and hit the filter housing on the curb. Of course it pulled it almost completely off.

We have seen full flow filters blown out INSIDE. We have a filter cutter so we cut it open and there was a good sized hole in the filter media. Doesn't this result in partial filtering??

We have heard of other failures, rock piercing a remote filter in the wheel well.

I went thru this mental debate on a motor we are building for Walt our '53. I decided to do a full flow and it wasn't till Frank Hood posted a pic of his car on Instagram and a big puddle of oil underneath. The filter had blown completely off. The only left on the adapter was the base of the filter with the threads on it, everything else was gone. As i recall he had just changed oil and fired it up. It was at that moment when i decided to stick with the stock setup.

The motor Lee had in his '59 was a stock type 1 motor rebuilt by Lee and I for my high school car. it had roughly 20k on it when we put it in his car and he put on another 70k before rebuilding his original motor. That motor is now in our '57 oval beetle. We change oil religiously every 2k. As pointed out there has been millions of miles put on unfiltered/partial flow motors.

Reasons for me not going with a full flow are as follows. Worrying about ripping the filter and or adapter off if i have and "incident". Not having to buy a elect Pre-A tach. Not worrying if I start my car in the morning when its cold and blowing the filter off. If the filter blows internally ( like we've seen ) its now a partial flow anyway.

At the end of the day everyone does what they feel is right, no skin off my back. I just thought I'd bring up a few issues that no one has mentioned yet. I hope if I am broke down on the road with a motor that died because of a partial flow system you guys will still stop and help me. I will do the same if your oil filter and adapter is ripped off or filter blown completely off, or if you motor is dead because of dirty oil because your filter has blown internally in which case we might be dead together..

Now onto the discussion of what oil is the best! ; )

[John Jenkins]

Last year my engine was taken apart to have the cam changed in search of more power. This engine had Ron's full flow filter set up all of its 60,000 miles. The main and rod bearings looked brand new as you would hope. I've had more than six engine rebuilds for my car and the bearings never looked that good. I used to change the oil and filter every 2000 but the bearings still looked like some one poured sand on them. That was after only 80,000 miles, my normal tear down time. I didn't change the oil but every 7,500 with Ron's full flow filter. I got 246,000 miles out my '88 911 and it still passed California smog test and got 4000 miles to a quart. All it needed was valve guides at 125,000. Pistons and cylinders were still great. Full flow filter. I have a '70 Triumph motorcycle. I had the shop put a full flow oil filter on it. The mechanic didn't want to do it. He said he could only put it on the return line. I told him OK but junk only goes through once. The first oil change (and second and the third) time I changed the oil I took the filter apart and showed the nice shiny metal particles embedded in the paper filter. I am a believer and every engine manufacturer in the world is too. The trouble with common sense is it's not so common.

[Mike Wilson]

I have the full-flow oil filter on the third piece with a Pure Power cleanable oil filter. I have to be careful about steep curbs or driveways as it has hit a couple of times but hasn't broken.

For me, having the oil filtered all the time is an improvement as pointed out: all cars now have the same system. It gives me peace of mind after spending a lot in rebuilding my engine. Unless I missed it, one thing not mentioned is the amount if miles we now put on our cars and the type of driving you do. If driven infrequently and you change oil regularly, I don't see a problem staying with the original system.

Martin mentioned the Million Mile Porsche. I personally know the owner and have done minor work on his car. The engine does not have a full-flow oil filter. The engine and trans were probably rebuilt by Fred B. in Marina del Rey.

Mike

[Norm Miller]

Somewhere around '59 -'60 several of us (Speedster owners) were discussing oil change intervals.
Some said; 1500, some 3000, etc.
It came around to Larry and he said uh uh if I get a good batch I leave it in, not to upset the works.
Young men tearing around somewhat abusing the cars as young men will.
I've no recollection of failures with high mileage usage. Mine went 123000 miles before tear down.
Methinks the engines work both ways so get out and drive them.