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Blow-By Tech Tip

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  • Blow-By Tech Tip

    The Volvo keeps losing oil out of the front crank seal (vibration dampner-to-front cover). I was worried that there was too much crankcase pressure and that was pushing the seal out. I worked with BluePrint (you may remember that they built the engine) and they suggested a couple of neat tech tips.

    1) Leave the system alone (PVC, filler cap, etc.) but pull the dipstick and attach a length of rubber hose to read the pressure. When they told me this I thought, "Duh, why didn't I think of that?" With a SBF, a piece of 3/8 ID hose slides on tightly (I added a hose clamp just to be sure) and a 1/8" NPT tubing adaptor fit snugly in the 3/8" tube and adapted to my gage inlet tube.

    2) I had a spare boost gage which is a bit course in terms of pressure graduations but, like I said, I had it already. Turned out to be OK.

    3) The BluePrint folks said that 3-5 PSI is pretty normal for a not yet broken in engine like ours. That's a bit of info I'd never heard, just that you could have "too much".

    4) I drove the Volvo with the gage attached and even at WOT the crankcase pressure was unreadable so that's NOT the issue.

    In our case I noted that the front leak was there with the old engine as well as the crate engine and I had transferred the front cover from the 5.0 to the new one. A bit of reading turned out that it's possible to crack the Ford front cover when installing a new front seal as they're made of pretty thin cast aluminum. The solution is to pull the cover to install the new seal and support the back of the cover as you tap the seal in. In our case we'll need a new cover just to eliminate the possibility of a crack - on order. Your solution may vary.

    malc and Monk like this.

  • #2
    Dang Dan you're a walking miracle. How can you live so long and still have so much going on? I'm familiar with blow-by, but it's about a brake caliper. You are The Man Dan.
    Charter member of the Turd Nuggets


    • #3
      Wow, hopefully I'll remember that trick in the future!
      Patrick & Tammy
      - Long Haulin' 2008, 2009, 2010, 2011, 2012, 2014...Addicting isn't it...??


      • #4
        Originally posted by silver_bullet View Post
        Wow, hopefully I'll remember that trick in the future!
        Yeah, I thought that was pretty slick! And having a number for "normal" (at least for a new engine) is really helpful.