Click for Alexseal Click for Cape Scott Click for McKinna Click for Westport Click for Walker

427's engine trouble

Discussion in 'Chris Craft Roamer Yacht' started by gravy, Aug 21, 2012.

  1. gravy

    gravy Member

    Joined:
    Aug 24, 2010
    Messages:
    52
    Location:
    River bend marina St. Clair MI
    Hello fellow roamer friends I have a 1966 37' roamer with 427 side oliers,
    and my port engine has oil comming out of the fill cap when I'm above 2200 rpms. I'm told that called blow by. Over the winter the engine was rebuilt and has compressen of 170 in all cylinders. What should I look for to solve this problem? Thanks Gravy
  2. K1W1

    K1W1 Senior Member

    Joined:
    Sep 30, 2005
    Messages:
    6,455
    Location:
    My Office
    Hi,

    If it was a big fumer before it may have blocked the breather.

    Check the crankcase vent line is clear and un restricted.

    What was done during the re build?
  3. alloyed2sea

    alloyed2sea Moderator

    Joined:
    Jan 28, 2004
    Messages:
    797
    Location:
    Alex, VA
    427 Gurus

    ONe of the best places for free (and yet valuable) advice on 427s is here:
    Chris Craft Commander Forum
    They pretty much know it all.
    Cheers!
    -Eric
    (didyouko nowthatthe427blockisthesameasthe390truckengineblock?)

    Attached Files:

  4. rcrapps

    rcrapps Senior Member

    Joined:
    Sep 8, 2004
    Messages:
    2,104
    Location:
    Jax FL
    I remember building LBCs and thought chrome piston rings were going to be the best. Boy did I almost mess that up. It took forever before the rings set and there was a lot of blow by. Then one day, Varoom and a clean bilge again. Compression always looked good and even. When they set it, it did go up just a little, say near 5psi.
    If it's been blowing crank fumes since the build, keep the vents open and run um..
    Keep us in touch.
  5. boatfxr

    boatfxr New Member

    Joined:
    Jun 8, 2012
    Messages:
    5
    Location:
    san antonio, tx
    Valve covers

    I used to race these in the sixties on drag strips. Once had this occur after installing aftermarket valve covers. If you did not reinstall the originals, the stuff available physically fits but they do not have the factory baffles below the breathers to deflect oil splash. Sometimes there is a left and right cover. Another item to check is the hose coming from the valve cover to to the carb base. If you did not have it replaced at overhaul there is a good chance it is either retricted or blocked all together. One more item is the design of aftermarket breather caps. Factory ones are larges and have a very dense screen to coalesce oil vapors and it will then drain back into the engine. If you have smoke coming out with the oil then it is blow-by related. If not then what I listed above should put you back on track.
  6. boatfxr

    boatfxr New Member

    Joined:
    Jun 8, 2012
    Messages:
    5
    Location:
    san antonio, tx
    Valve cover revisited.

    If the carb base plate was changed or the incorrect gasket beneath it or the carb will block off the vacuum port into the intake manifold. Easily checked by removing the breather hose running to the carb base at the valve cover while running to see if there is vacuum available. If not you've found your problem.
  7. rcrapps

    rcrapps Senior Member

    Joined:
    Sep 8, 2004
    Messages:
    2,104
    Location:
    Jax FL
    I can't remember if the Chris 427s used PVC or let case fumes blow into the flame arrester (air filter). Chris went both ways on some of their own marinations.
  8. gravy

    gravy Member

    Joined:
    Aug 24, 2010
    Messages:
    52
    Location:
    River bend marina St. Clair MI
    blow by

    Thanks for all the help. I will check all of the good tips out and let you know what I come up with thanks Gravy
  9. doompatrol

    doompatrol Member

    Joined:
    Feb 2, 2012
    Messages:
    35
    Location:
    Yachtforums sucks!
    Ford 427s have an exhaust crossover that runs through the intake manifold from the front exhaust port on one bank to the rearmost exhaust port on the other bank. The crossover rots out at a thin spot on the underside, which puts exhaust directly into the crankcase. You don't notice it so much at low RPM, but as you open the throttles the volume of exhaust pressurizing the crankcase overwhelms the PCV system and starts blowing oil mist and exhaust out the breather (and everywhere else it can find a way out).

    The fix for this requires pulling the intake manifold. There is no other way. You either replace the manifold with a new aluminum one (they're available online, just be sure to get the "non-EGR" version that doesn't have a crossover.

    Alternatively, get some thin stainless steel stock and trim it so it just fills the crossover port hole in the intake manifold gasket, thereby blocking off the crossover port. I've heard that SS butter knives are the perfect thickness.

    Oh, and change your oil. You've got a lot of byproducts of combustion going through the engine.
  10. rcrapps

    rcrapps Senior Member

    Joined:
    Sep 8, 2004
    Messages:
    2,104
    Location:
    Jax FL
    I did not think about that. Good advise.
    This is something to seriously check into.
    ,rc
  11. gravy

    gravy Member

    Joined:
    Aug 24, 2010
    Messages:
    52
    Location:
    River bend marina St. Clair MI
    Thanks for the tip, we are going to take the intake manifold off in a few days and i'll tell you I find Gravy
  12. gravy

    gravy Member

    Joined:
    Aug 24, 2010
    Messages:
    52
    Location:
    River bend marina St. Clair MI
    Well I've pulled the moter and started to break her down and found that the chamber did rotout on the intake manifold and I would like to replace it with a used one that is a cast one for my 1965 427 ford side oiler. so if anyone has one or knows where one is please let me know. Thanks Gravy
  13. watjam

    watjam New Member

    Joined:
    Feb 2, 2006
    Messages:
    77
    Location:
    We hail from Huron, Oh.
    427 parts


    You could not be in a better area for 427 marine parts.


    Marine sales & Repair Inc.
    Marine Sales & Repair, New & used engines & equipment - ask for Earl.
    30134 S. River rd.
    Harrison township, MI


    Total Performance
    Mt. Clemmons, MI
    Groesbeck, ave. -ask for John Versmeerch, tell em' Jim sent ya!


    Both these outfits have what you need and more, they are like a candy store for
    Vintage motors, earl's place is unbelievable for anything you need on a Chris.
  14. Oneiros

    Oneiros New Member

    Joined:
    Dec 17, 2006
    Messages:
    289
    Location:
    lulea Sweden the land of the midnightsun
    hey!
    How are you, are you working on your boat yourself, I have not started yet, but in the spring we will replace four square meters of the hull plates
  15. watjam

    watjam New Member

    Joined:
    Feb 2, 2006
    Messages:
    77
    Location:
    We hail from Huron, Oh.
    Hello oneiros!

    Finding a shop that could get my motors done right and done by late May has been an ordeal, But we are getting it done,
    For now, I am concentrating on items in the engine compartment that I can access now with the engines removed, ie, air conditioning, bilge pump, maybe some soundproofing.

    I really wanted to replace steering system with a Seastar unit but money is very tight with the rebuilds.

    The present system is not so bad as long as I remember to keep the turnbuckles tightened
    On the upper helm cables.

    Hope all is well.
  16. gravy

    gravy Member

    Joined:
    Aug 24, 2010
    Messages:
    52
    Location:
    River bend marina St. Clair MI
    I found a good repair shop for my motor and we have most of her torn down, I will take some photos of her and post them. I've pulled the old flooring on the back deck and will be installing new striped vinyl floor. I also picked up a pair of bennet trim-tabs and will install them over the winter. That should keep me going all winter long. Gravy
  17. Oneiros

    Oneiros New Member

    Joined:
    Dec 17, 2006
    Messages:
    289
    Location:
    lulea Sweden the land of the midnightsun
    Ok I have restored my engine 2007 has passed 130 hours the Detroit Diesel 8.5 l we here in Sweden find that gasoline engines are not as good .petrol is expensive and explosive, I have isolated the engine compartment with sheet metal that has micro small holes absorb sound, it works perfectly
    Erik the swed
  18. Oneiros

    Oneiros New Member

    Joined:
    Dec 17, 2006
    Messages:
    289
    Location:
    lulea Sweden the land of the midnightsun
    Ok I have restored my engine 2007 has passed 130 hours the Detroit Diesel 8.5 l we here in Sweden find that gasoline engines are not as good. Petrol is expensive and explosive, I have isolated the engine compartment with sheet metal that has micro small holes absorb sound, it works perfectly
  19. watjam

    watjam New Member

    Joined:
    Feb 2, 2006
    Messages:
    77
    Location:
    We hail from Huron, Oh.
    :eek:Yes Eric, I too would like diesels. But there is a dirty little word called "tuition" that prevents me from going down that very coveted road.
  20. watjam

    watjam New Member

    Joined:
    Feb 2, 2006
    Messages:
    77
    Location:
    We hail from Huron, Oh.
    That sounds like a very productive winter lay-up!
    I did the Bennett conversion, probably the most bang for the buck of anything I've done to date.
    They give added speed with less drag, but the real pay-off comes when running with a heavy fuel load. I have to believe they have paid for themselves in one season.

Share This Page