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Different Oil Pressure Problem

Discussion in '"Stock" Alpine' started by HPMotors, Dec 10, 2020.

  1. RootesRooter

    RootesRooter Platinum Level Sponsor

    I would get rid of that PRV just to avoid the 80+ psi on startup. Sounds like a good way to blow a filter base gasket.
     
    Shannon Boal likes this.
  2. RootesRacer

    RootesRacer Platinum Level Sponsor

    My adj OPV mod changes the springs preload. Just limiting the piston displacement would be a horrible idea and would likely result in a broken drive gear or a sheared pump pin.
     
  3. todd reid

    todd reid Gold Level Sponsor

    Since we are grasping at straws, if everything is good in the bottom end how about leak in the supply line to the valve train?
     
    Shannon Boal likes this.
  4. Shannon Boal

    Shannon Boal Bronze Level Sponsor

    Further thoughts Re. straw-grasping.....I have never seen a pressure relief valve malfunction when hot; most things are free-moving when hot. But, what if the valve were aluminum, in an iron bore? The valve would expand faster than the bore, as it heated up. Brass, no idea...
     
  5. Tom H

    Tom H Platinum Level Sponsor

    Well Henry, the original poster, has not been on this forum since Dec 10, so we don't know how it turned out. But I want to restate that I am convinced that the PRV problems I experienced, which occurred within the first 8000 miles after I rebuilt my engine in 2008 were the result of TINY bits of grit in the oil. During the rebuild I was very careful to clean the block and all the parts. I ended up pulling the PRV about 10 times during the 8000 mile trip I took in 2011 after completing the rebuild. Each time I found the PRV a bit sticky, but also each time I was able to operate it easily and simply by actuating it with a screwdriver and then finding absolutely no further stickyness while holding it in my hand. Each time I could see absolutely zero dirt or grit anywhere on or around the PRV. One time, on that 8000 mile trip, I DID manage to pull the PRV while still hot and DID find it stuck in the open position. Again, I was able to actuate it pretty easily with a screwdriver and found no further stickyness while holding it in my hand. After a several oil (and filter ) changes on and after that trip in 2011, I have not had many (none??) occasions of that PRV sticking in over 10,000 more miles. I am convinced that the PRV problems I had were due to tiny amount of grit flowing through my oil. I think I like Kevin's idea to epoxy paint the inside of the block when rebuilding an engine. Obviously it is also possible, as others have noted, that a burr or ridge might get worn into the tube of the PRV.

    Here are links to the previous discussions about my PRV problems:
    http://forum.sunbeamalpine.org/index.php?threads/oil-pressure-relief-valve.16416/

    http://forum.sunbeamalpine.org/index.php?threads/oil-pressure-relief-valve-sticking.20801/

    Tom
     
    puff4 and Shannon Boal like this.
  6. Shannon Boal

    Shannon Boal Bronze Level Sponsor

    "During the rebuild I was very careful to clean the block and all the parts....... I am convinced that the PRV problems I had were due to tiny amount of grit flowing through my oil."
    That is one heck of a saga; with all the driving, it was an Alpine Odyssey! (Maybe we should have a blog category for Alpine Odyssey?)
    Once upon a time, I built a nice Buick V6. I had the block ready for assembly on my engine stand, all machining finished, white glove clean, with a big trash bag wrapping it to keep it clean. The engine was assembled and put into service for a period of time, during which it developed a bearing knock.....when I tore it down, I found.....a mud dauber had deposited dirt in my oil gallery while the nice clean block with the trash bag on it was on the stand. The oil pressure flushed it out of the gallery into a main bearing, causing knocking and damage....You can't make this stuff up!
    Tom[/QUOTE]
     
  7. puff4

    puff4 Gold Level Sponsor

    Yeah, I’ve been called everything from ‘anal’ to ‘crazy’ for epoxying my motors, but as I say, I’ve known British sand castings to keep releasing little bits of grit for *years* after they were made, and particularly so after a strip-down, clean and rebuild. I’ve never had a stuck PRV, spun bearing or any internal issues in any motor I’ve built, so I’ll keep doing it.
     

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