Lots of blowby

Discussion in 'Stage II Tech' started by Alky V6, Jun 1, 2010.

Lots of blowby

Discussion in 'Stage II Tech' started by Alky V6, Jun 1, 2010.

  1. laz

    laz Tso Racing 2010

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    That gear drive give me chills lol . I hope you have better luck than some ppl i know . The deal with the total seal rings i think there ok to use my machinst uses em and the won the outlaw 10.5 championship running 4.20s@185 they had an injector stick and it bent the piston pin and the rings where reused on another application the freshened the motor after 1 season and put them back in the car runs 4.70s so i dont think there so bad .
  2. Alky V6

    Alky V6 Let's go racing, boyz!

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    I've been using this same geardrive set in two motors since 2003.
  3. Alky V6

    Alky V6 Let's go racing, boyz!

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    I should add, my installation of the geardrive set is not completely per manufacturer's instructions. I perform a special mod to the geardrive set to give it a longer life and run quieter.
  4. GARY HARVEY

    GARY HARVEY Member

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    Donnie, how many passes with this set-up?
  5. Alky V6

    Alky V6 Let's go racing, boyz!

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    If you're referring to the geardrive, hundreds. Plus, countless hours of simple testing in the shop.
  6. GARY HARVEY

    GARY HARVEY Member

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    Short block?
    Awhile back (pullin') w/Allison Twin Turbo, the same problem after aprox. 60/75 passes. Everything looked good but the pistons (ring lands) were showing some stress. Thinking this may be related to your situation? Went with new pistons and the problem went away for another series of passes.
    Cryo'ed the pistons and they lasted aprox. half again longer before the same situation. Then went to w24 and other things started falling apart.
    You think may be you have reached the service life of the pistons or have you had this situation since you first put this unit into service?
  7. Alky V6

    Alky V6 Let's go racing, boyz!

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    You could very well be onto something. I had the same feeling myself. The pistons are pretty old. They've been used through a few builds. Blowby has been a problem with this latest build from the get go. Not bad enough to cause oiling of the plugs. Just excessive blowby on a hard pull.
  8. GARY HARVEY

    GARY HARVEY Member

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    Yep,
    physics of combustion pressure tend to upset things. Problem is, it only takes things to get a little out of spec and... oh well, the rest is only money.
    Look at it this way, you didn't hole the motor and darned if I wouldn't use the same brand pistons again. Hopefully you got your money's worth.
  9. Alky V6

    Alky V6 Let's go racing, boyz!

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    I think I did.
    I should also add that I'm pushing this build quite a bit harder than the previous builds.

    By the way, how much blowby would you expect from close to 1200 hp out of a 224 cid engine? I think expecting a 1/2" hole in the front of the block to be able to pass that amount of blowby isn't reasonable no matter if the amount of blowby I'm generating is normal or not. What do you think?
  10. GARY HARVEY

    GARY HARVEY Member

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    Doesn't sound like much of a vent does it?

    Any chance on venting the pan some place under your windage tray toward the snout. Maybe a canister, like the set-up older Chevy's used that bolted onto the valley and then vented out the back of the block via a stand pipe that was pressed into the block (which could go to the Vacuum pump instead)?

    Then again, if you go with a fresh pistons, this whole situation could end up being a wasted excersise.

    Wouldn't you rather leave the block untouched?

    As for blow by: any blow-by is clearance somewhere.
    My Diesel had a good amount of blow-by that was fixed after 300K by replacing the valves and guides. Hey... I didn't know Cummins wasn't using guides!
    Anyway, now I don't have any blow-by & the oil leaks disappeared mysteriously!
  11. Alky V6

    Alky V6 Let's go racing, boyz!

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    On the next PMing of the motor, the plan is to add more holes to the front of the block to vent more to the valley area and out the valve covers. Maybe add another vent hose to the valley cover instead of trying to push it out the valve covers.
    I added a vent hose to the timing cover. It seems to be getting me by, at the moment.
  12. Alky V6

    Alky V6 Let's go racing, boyz!

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    I've finished with a blowby catch tank. I'll get some pics posted when I get a chance. Probably the most expensive and over engineered blowby tank in history, but it looks cool anyway. I'll be testing it out this weekend.
  13. GARY HARVEY

    GARY HARVEY Member

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    What happened to the fresh set of slugs??? :(
  14. Alky V6

    Alky V6 Let's go racing, boyz!

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    Slugs?
  15. Nasty Wendy

    Nasty Wendy Perverted Lurker

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    Allow me to answer yet another tech question for you Donnie. Slug is a slang term used for piston. The question was what happened to the plan to get a new set of pistons.:cool:
    :D
  16. Alky V6

    Alky V6 Let's go racing, boyz!

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    The plan is to PM the engine after the end of the year.
  17. vacuum 6

    vacuum 6 I have chuckers

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    What no pics yet?
  18. vacuum 6

    vacuum 6 I have chuckers

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    Don,

    Question: Before relieving the engine pressure (blow-by) were you having issues with boost, meaning maintaining boost in 2nd and 3rd gear?
  19. Alky V6

    Alky V6 Let's go racing, boyz!

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    Sorry. My service manager is on vacation this week, and I'm having to fill in. I'm having to work. :( I'll try to get the pics posted soon.
  20. Alky V6

    Alky V6 Let's go racing, boyz!

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    Funny you should ask. The boost has been ramping down around 1 psi after the shift into 3rd. If I'm losing exhaust energy to the crankcase, that would explain the drop in turbine speed and boost level.

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