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post #1 of 2 (permalink) Old 08-05-2017, 07:00 AM Thread Starter
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Oil leak

I have a 69 428 with the angled oil filter adapter. It's been leaking oil on to top of filter. Decided to change adapter and gasket to hopefully cure problem. Also used a plug in sending unit hole to remove that as a leak possibilty. Have used Mix and Fram filters and brand new setup leaks the same! Any ideas out there?
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post #2 of 2 (permalink) Old 08-05-2017, 01:55 PM
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Excessive oil pressures at WOT. My thinking is that the rubber compound is not the same as the "good 'ole days" and they use a harder rubber which allows the higher oil pressures at full throttle to seep past the seal. The last 400CI I ran did the same thing. Different filters did nothing. Even tried a different oil filter housing thinking it was warped or something. 60PSI pump and I used to wind it tight to 6,000 RPM's. Could also be that the tops are made thinner and some flexing is happening under higher pressures.

It is possible that these newer filters have "finer" papers to screen the oil? Today's engines have tight clearances and call for 10w-20 and sometimes lighter oils. I used the heavier 15W-40 and even 20W-50 oil which probably aggravated the problem as it went through the oil filter. So makes me wonder if today's filters actually cut down on the flow of oil needed for our older and bigger clearanced engines?

"The base gasket is the MOST important part of the "spin-on" oil filter design because if it fails, the engine loses all oil. The gasket will deteriorate with time, more than with mileage. It will either harden or soften, in either case the gasket tension that holds the filter to the engine is relieved. Engine vibration can "unscrew" the filter, and ALL the oil will be lost. The quality and material of the base gasket is what determines for how long a filter could or should be used. The low cost oil filters that cost few dollars and are used by quick oil change outfits and sold in discount stores definitely should not be used for more than the usual recommendation of 3-month/3,000-mile interval, irrespective of what oil do you use. The Base Gasket on low cost Oil Filter is perhaps worth only few pennies, and therefore not designed or intended for long term service. It is especially failure prone in both Low and High Temperature extremes. More premium or OEM oil filters that cost much more can be utilized safely for the maximum oil filter change interval that is specified by the OEM."

"Filter media can be made of cellulose or fibrous materials, or synthetic materials designed especially for this purpose. Media in an engine's primary filters pull out particles as small as 25 to 30 microns (a typical average human hair is about 45 to 70 microns in diameters). Secondary filters do better - down to 5 or 10 microns - but also add restriction to the flow."

Fram filters seem to have a very bad reputation, but I never had any bad experiences. You best bet may be to try a high dollar type filter just to compare. AC Delco, Wix racing filter, K & N, Moroso, etc. which will fit with your headers.
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