Full time filtering ie. no bypass???

[CJK440]

Hello, first time poster.

I've got a 4.6L motor in a Mustang Cobra that decided to eat its rod bearings. Upon disassembly I found that of course the pump rotors were chewed up from sucking up debris but I also found debris up in the heads that bound up the overhead cams.

I can only assume that the debris bypassed the filter and went thru the motor. It was a recent oil change with an FL820S.

Now years ago I remember that a common trick to small block chevy’s was to put a pipe plug in the block mounted bypass port of the oil filter adapter which forced all the oil to go thru the filter. I was assuming the filters specified for those motors relied on the block mounted bypass and did not have one internally.

Now, my mustang filter has an bypass in the filter I believe. What I am wondering is if it is possible to replace the 820S with one that does not have a bypass to get 100% filtration albeit at a more frequent change interval? This vehicle is modified and is just a nice weather car, running 5w30 synth. The reason of course would be to minimize the spread of debris in case of a future failure.

If this isn’t recommended, is there another way I can go about preventing the spread of debris?

 

[bepperb]

A filter doesn't bypass during normal operation. The reason that it would hit bypass (besides cold start) is because the element was full and restricting flow. Without a bypass, you would not get the contaminated oil (waht you want) but you would also not get any flow of oil.

Without looking at the specs, the bypass is probably around a 10~16 psi differential across the element. To reach this at operating temp, there are serious problems already.

 

[willix]

The bypass is insurance against oil starvation. Contrary to popular belief, sometimes muscle car motors just "BLOW UP" & many reasons why.

 

[The_Jeff]

What did the pickup screen look like in the pan? I concur with the theory that something blew up good, anything that gets through the screen is boulder-sized in the world of filtration.

You can play around on the wixfilters.com site, punch in your 820s and get its thread pitch and gasket size, then try other ford filters to see how they match.

 

[CJK440]

@bepperb

I guess I should have stopped and thought how the system works. From what I found the BP setting on the 820S is 16psi. This means that if the pressure differential on either side of the filter media meets or exceeds this, it goes into bypass?

So most likely in my case the debris from the torn up bearings clogged the relatively new filter and threw it into bypass? There was quite a bit of crud in the pan. Perhaps the bearings started failing before my last OC and clogged that filter. Pan was ugly for a 50k motor.

@willix

Aint that the truth. I want to blame it on the aluminum bearing shells. New build has Clevite tri metals with proper steel backs.

 

[AuthorEditor]

You might want to use a Ford racing filter (JFL820), but I wouldn't go with no bypass.

 

[CJK440]

Originally Posted By: eljefino
What did the pickup screen look like in the pan? I concur with the theory that something blew up good, anything that gets through the screen is boulder-sized in the world of filtration.

You can play around on the wixfilters.com site, punch in your 820s and get its thread pitch and gasket size, then try other ford filters to see how they match.


It definitely blew up good. 4 rods spun and 3 mains tore up. The screen had aluminum debris. The aluminum rod shells didn't "stack" but they did spin in the bores. My goal was to simply clean up the heads and bolt them on the new shortblock but that plan was shelved when I found similar alum debris in the cam journal oil feed holes.

I am guessing the bypass allowed the debris to get up there but I suppose if there wasn’t a bypass, the cams probably would have done more damage to the journals with lack of oil.

Thanks for the education guys.

 

[willix]

Have you been looking at other causes?

Detonation is a good one for scraping the oil off crank journals.

 

[CJK440]

I bought the car less than 300 miles ago. When I hooked a real pressure gauge up (factory gauge is an on/off needle) I wasn't thrilled with what I saw. From what I understand the majority of Mod motor failures are rod bearings, I don't think the 10psi of boost helped the issue. I might have been on its way out before I got it. Luckily I was already comtemplating a forged shortblock to replace the powdered metal/hypereutectic stuff. This just forced my hand.

But one other question on the bypass. Would there be any benefit to finding a filter w/o a bypass to use for initial startup and break in? Just to make sure any uglies get caught off the bat. Then change it out before road use?

 

[willix]

It appears that the mods?? what ever they are are exceeding the parameters of the knock sensor functions and a simple re program may have had saved the thing. If you bang the thrust half of the rod bearing too many times in a row you scrape all the oil off the rod journals and they go dry. Thats bad at redline.

 

[Robenstein]

Yeah the whole disabling the chevy bypass has given me some laughter over the years. Saw one guy burst a cheapo filter because he did that "trick" and put straight 50 oil in the car. We had a very cool spring and when he started it right up and did a time trial he oiled the track down pretty good.

The bypass is on there for a reason.

 

[alltrac]

You could use a CM oil filter it has no bypass.

 

[CJK440]

Originally Posted By: willix
It appears that the mods?? what ever they are are exceeding the parameters of the knock sensor functions and a simple re program may have had saved the thing. If you bang the thrust half of the rod bearing too many times in a row you scrape all the oil off the rod journals and they go dry. Thats bad at redline.


It has a centrifugal supercharger with a good intercooler. The computer was tuned on a chassis dyno by a reputable shop nearby and the timing should have been altered.

 

[willix]

Sometimes they reduce compression ratio by a couple of points when adding a blower.

But I just can't speculate.

 

[Ken2]

Quote:
Without a bypass, you would not get the contaminated oil (waht you want) but you would also not get any flow of oil.

You'd get great flow...as soon as the filter media ripped out and all the bits of filter media as well as all the crud it had trapped gets pushed through the engine along with this flood of oil.

For flushing, maybe consider a very light oil, preheated as hot as you can handle to thin the oil, a filter with no bypass, and idle for a few minutes. Change the filter, do it again and again until the cut-open filters look clean. Drain, fill with the regular oil and regular filter. Is there any way you can rig up pressure gauges on the oil to the filter and the oil leaving the filter to see the differential pressure? If the difference between the inlet and outlet gets to maybe 10 psid, immediately shut the engine off and change the filter.