Any body had trouble using the 60 year old oil filter bypass valve . Spring seam pretty weak .
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Re: Oil filter bypass valve
nos ones were available from AC about 15 years ago. may still be or try ebay. i used up my last NOS piece several years ago and should get one or two more. mike -
Re: Oil filter bypass valve
Dan------
If you're talking about one that's been in a box for 60 years, it should be fine. If you're talking about one that's been in service for 60 years, it might not be a bad idea to replace it. Repeated heat cycles could weaken the spring over time. Replacements are available and they look pretty good to me.
GM #5573979, discontinued but there should be some around if you want to go NOS.In Appreciation of John HinckleyComment
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Re: Oil filter bypass valve
Has anyone studied how often the bypass is open during normal operating cycles?
On another forum, a post said the bypass is typically open for more than a few seconds during cold starts because of oil thickness. Not sure if I believe that.Mark Edmondson
Dallas, Texas
Texas Chapter
1970 Coupe, Donnybrooke Green, Light Saddle LS5 M20 A31 C60 G81 N37 N40 UA6 U79
1993 Coupe, 40th Anniversary, 6-speed, PEG 1, FX3, CD, Bronze TopComment
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Re: Oil filter bypass valve
Joe
My oil filter bypass valve ('66 327) is Gm #3959104, not 5573979.I am changing back to the cartridge from spin on adapter. The gasket supplied with the bolt kit I bought does not have the 'bulge' in it required to go around the actual check valve 'hole'. I can find no info on part # 3959104.
PeteComment
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Re: Oil filter bypass valve
Peter------
I cannot find that GM #3959104 was ever a released part number for a finished part. So, I expect it's just a casting or component number for some other assembly. I highly doubt that it was ever used on any GM #5573979. With no doubt, at all, GM #5573979 was the original part number for the 1957-67 oil filter valve assembly. It is long-since GM discontinued and it had no supersessive part number.In Appreciation of John HinckleyComment
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Re: Oil filter bypass valve
Gary:
I remember reading about the magnesium years ago, and also thought it strange. Maybe GM changed the material of construction later.......I do not know. Anyway, here is a link with the advantages etc. More of an ad, really, but a good summary. If you go into the link a bit deeper it compares magnesium directly to other various metals as well.
LarryComment
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Re: Oil filter bypass valve
FWIW the bypass was disabled by racers in the know back in the 60's as it allowed non filtered oil to by pass the filter. Simply remove the spring, pry out the retainer & replace with a large bolt & nut. Your bearings will last a lot longer. As long as oil does not leak around the can, all is well.Comment
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Re: Oil filter bypass valve
Joe,
I'm sending a couple pics of mine. It had no gasket under it and was used in conjunction with a spin on adapter. My AM shows no gasket? However my manual is a reprint. Maybe you have the first edition (autographed!).
PeteComment
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Re: Oil filter bypass valve
Peter------
The gasket, GM #3903322, between the valve assembly and the block was added during the 1967 model year. So, no earlier engine was equipped with this gasket. Of course, it could be retrofitted to any earlier engine. I've never understood the purpose of this gasket as, functionally, it seems quite superfluous to me. Curiously, while the 3903322 gasket was once available in SERVICE, it was never cataloged by GM for any Corvette application. It was discontinued without supersession in July, 1981. Of course, reproductions are easily available if one wishes to use the gasket. Would I use one on a 1957-67 engine? Probably. I don't think it's necessary but it can't do any harm.
As far as the valve assembly you have is concerned, it was part of a Chevrolet-supplied SERVICE-only oil filter conversion kit released in late 1968. It was never available as a separate part from GM and that's why I could not find it. It is configured somewhat differently than the GM #5573979 (SERVICE) or GM #5573837 (PRODUCTION) valve assemblies. (note: these are AC Division part numbers and AC Division part numbers are often different for PRODUCTION and SERVICE for the exact same part). The KIT which contained the 3959104 valve assembly also included several other components which you should also have as part of your conversion.
So, the question is could your 3959104 valve assembly be used in place of a 5573979/5573837 when converting back to a canister style oil filter? I do not know the answer to that but, if it were me, I would not use it thusly. I'd obtain an original 5573979 or a known reproduction thereof.In Appreciation of John HinckleyComment
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Re: Oil filter bypass valve
You have the original type oil filter bypass for early Chevrolet engines. It will work well for you when converting back to the can filter. I believe this is the magnesium version, and the 55xxxxx part number may be the same or possibly if/when GM began using aluminum for the material. That I do not know.
No gasket is required with this oil filter bypass, and none was installed by GM. But gaskets are available from the vendors. I used a gasket on my 1967 car. You need to accept that a small amount of oil leakage without the gasket is not bad, when the bypass itself allows unfiltered oil to bypass the oil filter directly to the engine.
Install it with or without the gasket using the correct length bolts........and tighten up snug. Use a new rubber square gasket with a NAPA Gold #1143 or WIX equivalent in the oil can. NAPA Gold and Wix are the same filter, but each has a different part number depending on the Brand.
Pre-fill the oil can and new filter with oil, install, and then torque the bottom can bolt to 20 ft-lbs. Start the engine and immediately check for any leaks. If done correctly, the oil can seals very very well...........but it is unforgiving if you take a shortcut or hurry the install.
LarryComment
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