---------------------------------------------------------- Engines-List Digest Archive --- Total Messages Posted Fri 09/02/05: 3 ---------------------------------------------------------- Today's Message Index: ---------------------- 1. 05:10 AM - Re: Engines-List Digest: 3 Msgs - 09/01/05 (Gary Casey) 2. 06:15 AM - Oil pressure relief valve? (Grant Corriveau) 3. 02:58 PM - Re: Oil pressure relief valve? (Gilles St-Pierre) ________________________________ Message 1 _____________________________________ Time: 05:10:14 AM PST US From: Gary Casey Subject: Engines-List: Re: Engines-List Digest: 3 Msgs - 09/01/05 --> Engines-List message posted by: Gary Casey > Another question that maybe some of you have experience with: What > can > most likely be the causes for an increase in oil pressure(also > Lycoming > O-540)from normally about 80 psi to suddenly near 100 with the same > oil > temperature and other conditions like same weight/brand of oil, power > settings and RPM, etc? It has been suggested that a main bearing could > have rotated and blocked flow, but I would think the oil pressure > relief > valve would still hold the pressure stable by relieving the excess > pressure caused by reduced total oil flow? Yes, in theory the pressure regulator will hold a fixed pressure, but in practice the pressure of the system is dependent on oil flow - restrict the oil flow and the regulator will allow a higher pressure. It just isn't a sophisticated enough design to be very accurate. If all the conditions you described really stayed the same, but the oil pressure suddenly changed, either up or down, I would be very worried about something in the system that has changed. It could be something in the regulator itself, or it could be a doomsday scenario as you suggested. I would start with the externally-accessible devices first - regulator, filter, cooler, vernatherm. If none of these have any obvious plugging or other defect - and an oil analysis shows metal, it is probably time to go in. But I'm not any kind of expert - that's just what I would do. I've found that things important, like airplane engines, don't change characteristics without a cause. As my old boss in the transmission development shop in GM said as he stood over the smoldering ruins of my experimental transmission, "I think it's trying to tell us something..." Gary Casey ________________________________ Message 2 _____________________________________ Time: 06:15:12 AM PST US Subject: Engines-List: Oil pressure relief valve? From: Grant Corriveau --> Engines-List message posted by: Grant Corriveau > check the relieve valve spring for binding..Could be wise to put a new one > in > gilles st pierre I have a CAM100 (Honda 1.5L conversion) and my oil pressure this year has crept slightly above the max limit during warmup... (up from 60 to 63 psi...) If this is a trend, where/how would I find and correct an oil pressure relief valve? Is there one installed in every engine? OR is it a feature incorporated into the oil filter?? Thanks in advance -- Grant Corriveau C-GHTF / HDS / CAM100 ________________________________ Message 3 _____________________________________ Time: 02:58:48 PM PST US From: "Gilles St-Pierre" Subject: RE: Engines-List: Oil pressure relief valve? --> Engines-List message posted by: "Gilles St-Pierre" Normaly located at the base where the oil filter screws gilles >From: Grant Corriveau >Reply-To: engines-list@matronics.com >To: >Subject: Engines-List: Oil pressure relief valve? >Date: Fri, 02 Sep 2005 09:14:11 -0400 > >--> Engines-List message posted by: Grant Corriveau > > > > check the relieve valve spring for binding..Could be wise to put a new >one > > in > > gilles st pierre > >I have a CAM100 (Honda 1.5L conversion) and my oil pressure this year has >crept slightly above the max limit during warmup... (up from 60 to 63 >psi...) > >If this is a trend, where/how would I find and correct an oil pressure >relief valve? Is there one installed in every engine? OR is it a feature >incorporated into the oil filter?? > >Thanks in advance >-- >Grant Corriveau >C-GHTF / HDS / CAM100 > >