>I wonder why we never had a problem. 20 years is a long time to be lucky. seems you had many costomers over >the last 40 years with oil problems. Strange Read my post again. I did not say I did the work. This was on engines done by other shops which had suffered engine damage due to one of two problems. And came to me for help. One of course would be the deliberate removal of the bypass valve . The other (and MUCH more common) was the ACCIDENTAL removal of the bypass valve due to either using the wrong combination of mounting parts OR the wrong filter. Either of these will cause the filter to be exposed to excessive pressure which can cause the media to "collapse" clogging the oil system. High quality or "racing" filters are built to withstand MUCH higher pressures than the "low end" filters are and indeed MIGHT survive overpressure for a while. Cut some apart and check the thickness of the metal used for the canister and look at how the canister is mounted to the base plate. BIG DIFFERENCE!! This doesn't happen NEAR as much as it used to due to (in MY opinion) more racers using multi-weight and/or Synthetic oil. Can you imagine trying to squeeze cold straight 40 or THICKER mineral oil through an oil filter? There is an old saying that goes "If the THEORY works, USE IT,,, If what you're DOING works,, change the theory" If you're technique is working for you that's great. However it is NOT a generally prescribed modification in the industry and I would NOT recommend the average racer/engine builder try it. Contact any of the major filter makers and I doubt you'll find any that recommend it. I CERTAINLY don't. One case where it COULD be eliminated would be remote mounting dual (parallel) filters. This would effectively cut the resistance the filters see in half. An expensive setup and not one I'll bet most fellows on the list would use. >From FRAM (WIX sez the same thing) "Relief (By-Pass) Valve. In a full flow system, all of the oil passes through the filter to reach the engine. If the filter clogs, an alternative route to the engine must be provided for the oil, or the bearings and other internal parts may fail, due to oil starvation. A relief, or by-pass, valve is used to allow unfiltered oil to lubricate the engine. Unfiltered oil is far better than no oil at all. This relief (by-pass) valve is built into the engine block in some cars. Otherwise, the relief (by-pass) valve is a component of the oil filter itself. Under normal conditions, the valve remains closed. When there is sufficient contaminant in the oil filter to reach a preset level of pressure differential to oil flow (around 10-12 PSI in most passenger cars), pressure differential on the relief (by-pass) valve causes it to open. This condition can occur when the oil filter has become clogged or when the weather is cold and the oil is thick and flows slowly. " But HEY,,, that's just ME!! Bruce Hevner -------------- next part -------------- An HTML attachment was scrubbed... URL: http://splatter.wps.com/pipermail/amc-list/attachments/20080316/d5ae5f94/attachment.htm _______________________________________________ Amc-list mailing list Amc-list@xxxxxxxxxxxx http://splatter.wps.com/cgi-bin/mailman/listinfo/amc-list