Ken, I think Jeep in the 80's sometime changed to having the bypass in the filter instead of the engine. The one in the engine could get gummed up and clogged and stick open or not open at the wrong time. With it being part of the filter it is being changed to a new one at every oil change so that isue goes away. I would NEVER use a fram filter on any car. Do a web search on fram filter problems. My opinion on the oil is.... the older engines were designed with the oil of their times with the higher zink propertys. I would continue to use oil that is still like the old oil This means race oils or using today's oil and adding the EOS. Newer engines of today do not need the same oil because they are designed with more roller bearings and new bearing technologies that require less lubrication. Most engines today are roller cam engines. so they would not have the same lubrication needs as a flat tappet type cam. Hope this helps explain it a little better. Davis ksiroonian@xxxxxxx wrote: So, there has been a long thread on this oil issue and the zinc, etc.? and the filters. ?so 2 questions.... do all the amc engines have the oil filter by pass valve in the engine and thus do not have to worry about it-? should it be changed, does it wear out? I guess i mean from the latest generation 6 and v8's from 66 and up. the only difference I can tell is that they went from a long filter to a shorter one in 75 due to the pacers space issue, and you can use the shorter one on all of them, up to the change in early 80's to the fram? PH3675 smaller one , and then the metric. one in 86 or so. Also , on the oils and the zinc- I went to wall mart- saw the pre 1988 10w 40 oil for 1.39 a quart, and also the chevron, shell and mobil 10w 40 diesel oils, about 9.19 a gallon, all very reasonably priced. I have been using the valvoline high mileage stuff in my cars, none are for racing or other than light driving, going to a car show, under 500 miles a year. ?so for the reader's digest condensed version... is it still better to use these above oils with the extra zinc in them, or is it not needed, and are you guys recommending that stuff only for engine rebuilds and racing and such? Or is the GM EOS ok or even needed? I know in the AMC repair manual it does say to coat new engine parts in a rebuild with the AMC EOS, and I know for years dealers would add it to each oil change, though I always thought it was just a profit builder, like the 3 most profitable words in America.... lather. rinse.. repeat. I know many of you are into the racing and the performance and things so just wanted to get the readers digest condensed version. Regards, Ken. ? _______________________________________________ Amc-list mailing list Amc-list@xxxxxxxxxxxx http://splatter.wps.com/cgi-bin/mailman/listinfo/amc-list Supercharge your AIM. Get the AIM toolbar for your browser. -------------- next part -------------- An HTML attachment was scrubbed... URL: http://splatter.wps.com/pipermail/amc-list/attachments/20080316/3a434da5/attachment.htm _______________________________________________ Amc-list mailing list Amc-list@xxxxxxxxxxxx http://splatter.wps.com/cgi-bin/mailman/listinfo/amc-list -------------- next part -------------- An HTML attachment was scrubbed... URL: http://splatter.wps.com/pipermail/amc-list/attachments/20080316/79a7ab09/attachment.htm _______________________________________________ Amc-list mailing list Amc-list@xxxxxxxxxxxx http://splatter.wps.com/cgi-bin/mailman/listinfo/amc-list