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  1. #1

    Default Crankcase Pressure

    I am getting a good amount of oil spewing out of my valve cover breathers only at full throttle... I am wondering if I need to slap on a crankcase evac system or what else to do. Any thoughts or help is appreciated

  2. #2
    FEP Super Member bwguardian's Avatar
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    More information needed...and pictures would help. However, do you not have a functioning pcv?
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  3. #3

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    347 stroker with Fast EZ EFI. Just had motor rebuilt... Never did this before rebuild

  4. #4
    FEP Super Member erratic50's Avatar
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    Sounds like a case of blow-by.

    It happens more-so on stroker motors due to the shorter piston height. It could be an indication of a rotating assembly problem like a broken or stuck set of rings or a broken/cracked piston though.

    You might want to do a leakdown test or a compression test and see if perhaps the rings on one specific cylinder are not sealing compared to the others. maybe put a scope down the hole and see what things look like on the cylinder wall. A cylinder head gasket blow into the oil return passage would do it too.

    Lots of variables on an engine that was recently tore apart for sure.

    Is the PCV valve and filter OK?

    Did you change something like valve covers to something different than you ran before?

    What year we working on? Can you post some pictures?

  5. #5

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    Seconds blow-by, but PCV isn't part of the equation at all at WOT (I suppose unless it's stuck open). Leak-down or compression tests tell what's up with compression rings, but aren't going to indicate the health of the oil control rings. Take the spark plugs out and look at them for a dark/wet/oily appearance. Anything slapped on would just be addressing symptoms instead of fixing the problem. An oil control problem will need whatever is wrong with the oil control rings corrected.
    Last edited by Walking-Tall; 04-17-2017 at 10:23 AM.
    Mike
    1986 Mustang convertible ---> BUILD THREAD
    Past Fox-chassis "four eyes":
    1983 Mercury Cougar LS
    1986 Ford Thunderbird ELAN
    1980 Capri RS Turbo

    Work in progress website ---> http://carb-rebuilds-plus.boards.net/

  6. #6

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    is this something I should address with the engine builder because I only have about 50 miles on rebuild or under

  7. #7

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    Quote Originally Posted by erratic50 View Post
    Sounds like a case of blow-by.

    It happens more-so on stroker motors due to the shorter piston height. It could be an indication of a rotating assembly problem like a broken or stuck set of rings or a broken/cracked piston though.

    You might want to do a leakdown test or a compression test and see if perhaps the rings on one specific cylinder are not sealing compared to the others. maybe put a scope down the hole and see what things look like on the cylinder wall. A cylinder head gasket blow into the oil return passage would do it too.

    Lots of variables on an engine that was recently tore apart for sure.

    Is the PCV valve and filter OK?

    Did you change something like valve covers to something different than you ran before?

    What year we working on? Can you post some pictures?
    Rebuild consisted of boring out the cylinder walls .10 over was already bored .30 over, as they were a little scored up from the piston breaking before. New CP Carillo bullet series pistons, rings and all that. Melling high volume oil pump put in and Custom grind cam from Comp. Valve covers are the same as before and they are baffled covers with R2C breathers. This is also an 86 mustang gt... Original motor was taken out and new block and everything was built which is why I don't have stock EFI set up

  8. #8
    FEP Super Member erratic50's Avatar
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    So this build is a "349" then. Cool.

    One outside the box scenario

    Those often heat up very fast and are hot running motors because the cylinder walls are so thin. That's a bad thing when when you talk about heat cycles because it can cause cracks.

    Also if your walls get too thin they distort more-so than normal with heat which will cause ring seal problems.

    Just one theory. You should be able to find evidence like chatter marks on the bores and piston skirts if this is what's happening. Usually when you bar a motor over with a old school dial torque wrench you can see it. And you can feel it.

    There might only one hole causing fits. Casting thicknesses vary. Sleeve it or build in another block if this is the case.

    Eliminate more common scenarios first.
    Last edited by erratic50; 04-18-2017 at 07:47 PM.

  9. #9
    FEP Super Member xctasy's Avatar
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    Quote Originally Posted by StrokerSteve86 View Post
    347 stroker with Fast EZ EFI. Just had motor rebuilt... Never did this before rebuild

    Ok, its normal to talk problem, synmptoms, diagnosis, then remady.


    Its a normal problem with these systems. If its something like a 2.3 OHC to EFI conversion , it'll already have a balanced PCV system, so blow by is normally contained by the stock system.


    The 5.0 carb system isn't what you need for a Throttle Body EFI conversion. The cars original stock 1986 onwards Port EFI IAC takes care of all that.

    On 1979-1988 CFI's, there is another system which compensates, basically similar to the 2V and 4V GT system.

    Remady? There are three.

    Option 1

    In your case, normally, a breather cap will help. A lot of guys don't use PCV systems with Plug and Play TBI systems

    http://vb.foureyedpride.com/showthre...breather-setup

    Option 2

    Quote Originally Posted by Mike1157 View Post
    .......
    Installed a PCV system to try and get rid of some of the excessive oil vapor.






    I relocated the fidle valve to the intake, and got it off of the valve body to try and get it to stop whistling at idle,...Hopefully, it'll stop.



    I started the engine and ran it through a heat cycle. So far the thing isn't leaking...Hopefully,.like the mysterious cloud that wafts out from under the driver's side fender,...and like the whistle from the throttle body,...maybe I got all that crap fixed.

    Your other easy Option 3 is this

    https://fordsix.com//viewtopic.php?f=1&t=73925

    Quote Originally Posted by xctasy
    Quote Originally Posted by cr_bobcat
    So how do you like that adjustable PCV valve? Is it worth the money? I've been looking at the thing and it's definitely intriguing...
    https://youtu.be/nd92jPRH3YY?t=123

    Background.


    EFI requires different PCV system. When we drop from a Port EFI to a 4bbl intake EFI system like EZ, FAST or FITECH, we forget that it isn't a 4bbl carb system.

    So muxh vac is created, it can squish the 3/8" PCV hose, and Ford doesn't even show the PCV system in the VECI chart on most of its engines.


    All over the world, Ford Port EFI cars went to either an an Auxilary Air Valve (Bosch Pulse Width Modulation PWM-driven aux-air valve)




    or Idle Air Control with a PCV hose on the Big Sixes and all other EECIV Port Injection cars and trucks




    Only they didn't call it that, which makes it all a little bit hard.

    Since an aftermarket EFI mates the best of NASCAR 4-BBL or Pro Street Carb intake technogoy without the stock EECIV EFI port EFI manifold, you have have no PCV fit-up and an EFI engine will make awesome vacuum, and a will push the rings real hard from the get go.

  10. #10
    FEP Super Member erratic50's Avatar
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    Do make sure you have sufficient and functional PCV.

    You know your PCV is working a bit too well when the rear intake gasket ends up in the back side of the lifter valley. Yikes. Been there done that!

  11. #11

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    Quote Originally Posted by StrokerSteve86 View Post
    is this something I should address with the engine builder because I only have about 50 miles on rebuild or under
    Yes...........
    Mike
    1986 Mustang convertible ---> BUILD THREAD
    Past Fox-chassis "four eyes":
    1983 Mercury Cougar LS
    1986 Ford Thunderbird ELAN
    1980 Capri RS Turbo

    Work in progress website ---> http://carb-rebuilds-plus.boards.net/

  12. #12
    FEP Super Member erratic50's Avatar
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    Totally! Bore scope and compression tests and leakdown tests are the best place to start.

  13. #13

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    Yea I will have to post some pics when I get home and see what you guys think... but will most likely contact my engine builder in the A.M. and see if he has any insight as well

  14. #14

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    IMHO the builder is not going to willingly admit to rings or oil rings potentially clocked wrong, spreader not seated right between the oil rings or maybe overlapping the oil rings, etc.... but that's about all you have at this point, is to carefully and politely inquire with him...
    Mike
    1986 Mustang convertible ---> BUILD THREAD
    Past Fox-chassis "four eyes":
    1983 Mercury Cougar LS
    1986 Ford Thunderbird ELAN
    1980 Capri RS Turbo

    Work in progress website ---> http://carb-rebuilds-plus.boards.net/

  15. #15

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    Yea I agree on that 100% but they seem like decent people and said they were more than willing to cover anything if something were to happen so we will see what he wants me to do I guess

  16. #16

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    That's good to hear, good luck with it.
    Mike
    1986 Mustang convertible ---> BUILD THREAD
    Past Fox-chassis "four eyes":
    1983 Mercury Cougar LS
    1986 Ford Thunderbird ELAN
    1980 Capri RS Turbo

    Work in progress website ---> http://carb-rebuilds-plus.boards.net/

  17. #17
    FEP Super Member xctasy's Avatar
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    You'd be supprised just how long a long stroker will last if you manage blow by.


    In the A series 2ND Edition book, DV said that blow by from valves and pistons collectively defines remaining engine life. An Evacusump system should pull 1.85 to 2.65 inches of Hg suction at operating temperature. When the figure drops below that, it only has 15 to 30 minutes more operation time at full load.




    How-to-Modify-Ford-s-o-h-c-Engines-David-Vizard

    http://www.scribd.com/doc/26804743/H...-Vizard#scribd






    An Ecavusump and checking static leak down will ensure your engine is gonna last.


    Back with a really heavily turboed and giggle gassed 2.3 Mercury Capri owner who had a used but over bored engine block, engine tuner Steve asked the questions engine builders don't ask. That's becasue engine builders are professionals, and you treat 'em with kid gloves even when they put together your 5 to 8 grand or more engine.


    In chatt rooms, tho', its okay to ask the unaskable...


    Quote Originally Posted by Ethyl Cat View Post
    Blowby can only come from the rings.

    Hopefully you oriented the top and second ring correctly and they are in the right groove.

    If piston to cylinder wall is really .030" that is your problem. Surely you wrote it wrong?

    Maybe the cylinder walls got washed out from the rich low end.

    Do a cylinder leakage test.



    Blow by is in fact natural, and you can quantify it very acuratley with a CFM Flow Sensor Meter.

    Becasue a 342/347/349 is such an amazing engine, you'd be best off checking its blow by is under 2 cfm at peak torque after run -in.

    Maximum blow by should never get past 5 times the at birth, run-in value. 2.2 cfm at birth, 6.6 CFM at about 4000 rpm would be time to pull it down.


    However, David Vizard is on record for being able to predict how many hours engine life a used motor has got by reading blow by depression using a good twin 18 cfm per pipe AIR Backflow valve hooked to the rocker cover as per his diagrams in the above book.

    Quote Originally Posted by xctasy View Post
    Go to a library, and get this book if you can.



    http://www.amazon.co.uk/Tuning-Briti.../dp/0854297324


    Tuning British Leyland's 'A' Series Engine Hardcover – Aug 1989

    The problem with your high rpm air fuel ratio swing is blow by.


    The way to fix it is to remove it by an evacusump system, two 5/8" PCV valves to the intake manifold from the rocker cover.


    And then two anti back fire valves flowing in excess of 18 cfm each from the lower turbo manifold flange to a dedicated rocker cover catch can.

    David Vizard described on in pages 398 and 399 of his second edition of modifying BMCs A series engine, and discussed Turbo applications specfically. Diagrams 15.2a, and 15.2 nail the sysyem down.

    I'd guess any good 349 would make 380 lb-ft net flywheel at 3500 to 4500 rpm , or at least 235 rw lb-ft in an auto, or 310 lb-ft at the bags if T5.

    It goes on up from there. A within range DT3-BLB3 3 CFM Blowby Sensor is $599, and still needs a data logger to read it, although you will get by with the right catagory of Fluke meter.

    DMC-BL DataMite Micro Logger for Blowby is $299





    Quote Originally Posted by xctasy View Post
    ....
    Just a note. The removal of blow by is based on the dyamic leak down rate of 3 cfm at 5000 rpm overall for a Formula 5000 or TransAm or AVESCO 630 hp 302 SB Ford or Chevy making 450 lb-ft of torque at 5000rpm. Thats 3/8ths of a cfm per piston for an engine making about 630 hp at 7500 rpm.

    David Vizard allowed for a heck of a lot more blowby than most Americans would be confortable with. The tiny A series 78 cube 1275 4 cylinder engines taken up to 145 hp would have to have a 37% leakdown rate to pass 18 cfm of blow by, but that is how the Evacusump system is oversupplied by the suction force of the exhaust, and that gives depressions of 1.85 to 2.60, and the vaccum really unloads the rings to reduce flutter.........


    I'd expect a static leakdown of 80% to yeild those kind of 2cfm figures at about 4000 to 5000 rpm. Engine health is best measured by blow by pressure if Evacusump, as the rings are unloaded by the system. The life remining can be drastically increased by having a little think, and then deciding to incorporate some kind of Evacusump stratergy.

    Like everything, its your car, and you don't have to incorporate a xctasy grocery list of wack job ideas...but it sure as heck is an awesome indicator of engine health, a barometer which if used, will allow you to confidently lean a little harder on your 349.


    See http://performancetrends.com/Blowby_...owby-CFM-Table

  18. #18

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    Far be it from me to disagree with Dave, but a mess haze on top of valve covers of a freshly built engine with ~50 miles on it, isn't acceptable.
    Last edited by Walking-Tall; 04-18-2017 at 11:42 PM.
    Mike
    1986 Mustang convertible ---> BUILD THREAD
    Past Fox-chassis "four eyes":
    1983 Mercury Cougar LS
    1986 Ford Thunderbird ELAN
    1980 Capri RS Turbo

    Work in progress website ---> http://carb-rebuilds-plus.boards.net/

  19. #19
    FEP Super Member xctasy's Avatar
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    Hmmm, I agree. not good. Maintain the relationship. Go back.


    I've had some issues with ring bed in... 50 miles, well you to teat it like your micro fibering your new brass knobed bed end. No crazy antics untill a moderate bedding in phase. Engine run in is like paint buffing. A liitle hard and fast, some long and sustained. The running in phase is just like fetting a nice wooden scuplture, don't wanna go goriila balls all at once.


    If the engine is designed to go to 6 k, you'd notice blow by at peak torque, 3.5 to 4.5 k, so you wouldn't be giving it full revs so soon.

    I'd say just be mindfull of the engine builders expectations of run in.

  20. #20
    FEP Super Member erratic50's Avatar
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    Did you fire it initially with synthetic or conventional oil? Precisely what type of rings were used? I've had issues with synthetic when breaking in rings personally.

    Ive used file fit before and got too aggressive with tight ring gaps. I ended up with broken rings in the oil pan the very first time I heat cycled it.

  21. #21

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    Engine builder put in 15W40 Brad Penn oil... the green oil... unsure of rings as he did not put specifics on the invoice

  22. #22

  23. #23

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    I'm also not sure if this Fast system makes a lot of injector noise but once the motor is warm I can he some racket... can even hear it over the exhaust and the exhaust is f'n loud or I'm hearing something that I would rather not here after spending this much on a rebuild

  24. #24

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    Contacted the engine builder today and he doesn't like what I'm telling him so I'm bringing the car out to him to let him hear it run... hopefully didn't break another piston somehow

  25. #25

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    Definitely thinks there is something wrong with it

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