May just be terminology but there's a difference between high volume and high pressure pumps. High volume pumps are normally used to increase oil flow or pressure for better oiling and cooling when bearing clearances are on the high side. More oil pressure is produced at idle due to longer or larger gears.
A high pressure pump has a stiffer relief valve spring that doesn't open until a high pressure is achieved. The actual flow rate is no different than a standard pump and won't affect oil pressure at idle unless larger gears are used for high volume as well. One over the other is irrelevant since whatever is in there is pegging your oil gauge. Since we now know it's a factory-style gauge with no numbers it's hard to say what the calibration is. I'd still hook up a numbered mechanical gauge to see just what pressure is being recorded. If it's constantly over 50-60 lbs then an oil pump change may be warranted. If pressure is too high it could actually cause harm by pushing oil past the bearing surfaces before it has a chance to cool and lube the bearings properly. Dale McIntosh <http://www.chevellecd.com> 1966/67 Chevelle Reference CDs ACES #1709/TC GOLD #92 <http://www.chevellecd.com> _____ From: [EMAIL PROTECTED] [mailto:[EMAIL PROTECTED] On Behalf Of Malibu Sent: Saturday, March 31, 2007 6:27 AM To: The Chevelle Mailing List Subject: Re: [Chevelle-list] Oil pan removal It's the factory style gage. I bought the kit they sell to install the battery and oil pressure gages. The reason I really think it's the pump is when I bought the engine it was a short block and the guy was building it for circle track. I changed the cam because it was too radical for cruising. I remember the guy telling me the oil pump was a high volume. This one seems to be super high. ----- Original Message ----- From: Dale <mailto:[EMAIL PROTECTED]> To: 'The <mailto:chevelle-list@chevelles.net> Chevelle Mailing List' Sent: Friday, March 30, 2007 1:17 PM Subject: Re: [Chevelle-list] Oil pan removal If it's an electrical gauge, it's possible the sending unit in bad or not grounding properly. One reason I've always been leery of electrical temp and pressure gauges. If it's a mechanical gauge from the factory-type gauge option, connecting another mechanical gauge inline will let you know the true pressure. These mechanical dash gauges can be replaced fairly easily if the gauge is at fault. Dale McIntosh <http://www.chevellecd.com> 1966/67 Chevelle Reference CDs ACES #1709/TC GOLD #92 <http://www.chevellecd.com> _____ From: [EMAIL PROTECTED] [mailto:[EMAIL PROTECTED] On Behalf Of Malibu Sent: Friday, March 30, 2007 5:10 AM To: The Chevelle Mailing List Subject: Re: [Chevelle-list] Oil pan removal Thanks for the help. It's the gage in the dash cluster that's pegging the needle so I can't switch it. I guess I can try a different gage to see what pressure it really is. Not sure I want to pull the engine. Thanks again. Rich ----- Original Message ----- From: Brad Waller <mailto:[EMAIL PROTECTED]> To: 'The <mailto:chevelle-list@chevelles.net> Chevelle Mailing List' Sent: Thursday, March 29, 2007 6:02 PM Subject: Re: [Chevelle-list] Oil pan removal If you are sure you are going to pull the pan, you can always jack up the car and try it to see how close you come to getting it off. If you can't do it, then worst case you get a cherry picker and raise or pull the engine. I think it is possible, but I have never tried it in a Chevelle. I think I was able to do it in my '66 Corvette, but that is a much different car. You also should decide if you really need to go to the trouble of swapping out the pump (or spring) to lower the pressure. While you may not need it, and it might be costing you fractional horsepower, it will likely be a lot faster, easier, and cheaper to sawp to a high pressure gauge, as Dale mentioned. Brad Waller ([EMAIL PROTECTED]) '66 Corvette | 327/dead | 4-speed | Wilwood Brakes | 245/45/16 BFG R1 '67 Chevelle | ex-SS396 | 355/700R4 | F-Body Brakes | 275/40/17 Kumho MX _____ From: [EMAIL PROTECTED] [mailto:[EMAIL PROTECTED] On Behalf Of Malibu Sent: Thursday, March 29, 2007 11:59 AM To: The Chevelle Mailing List Subject: [Chevelle-list] Oil pan removal Can the oil pan be pulled on a '66 Malibu with just raising the front of the engine? I need to change the high volume oil pump. It's sending the needle off the gage. Thanks _____ avast! Antivirus <http://www.avast.com> : Outbound message clean. Virus Database (VPS): 000729-2, 03/31/2007 Tested on: 3/31/2007 10:26:22 AM avast! - copyright (c) 1988-2007 ALWIL Software.
