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Conference vicki::boats

Title:	Powerboats
Notice:	Introductions 2 /Classifieds 3 / '97 Ski Season 1267
Moderator:	KWLITY::SUTER

Created:	Thu May 12 1988
Last Modified:	Wed Jun 04 1997
Last Successful Update:	Fri Jun 06 1997
Number of topics:	1275
Total number of notes:	18109

437.0. "Unusual OMC V8 Problem" by BAGELS::MONDOU () Wed Jul 12 1989 13:18

    A friend is in process of having his OMCV V-8 repaired.
    It's a wierd problem and I'm entering it in the event
    other boaters experience similar problems.
     
    The engine is a Ford 460 c.u.
    
    Symptom is rough idle, vibration, loss of power.  The key is
    this occurs early in the season after the boat has been in
    storage for months. Usually within the first ten hours of
    operation - but not immediately upon initial use.  Tricky
    problem.
    
    Problem is a valve push-rod that somehow gets jammed in the 
    valve train mechanism. It gets jammed in such a way that it
    is stationary so there is no unusual noise.  The engine is
    running on 7 cylinders since one valve isn't working.
                                             
    A compression test will quickly locate the problem cylinder.
                                                               
    Repair is relatively simple - remove valve cover, replace the rod.
    
    Ford is aware of this problem but doesn't know the cause.  It first
    showed up in auto's belonging to people who store their cars over
    the winter while they go to Florida.

T.R Title User Personal
Name Date Lines

437.1 sticking valve???? BIZNIS::CADMUS Fri Aug 11 1989 13:37 53

T.R	Title	User	Personal Name	Date	Lines
437.1	sticking valve????	BIZNIS::CADMUS		`Fri Aug 11 1989 13:37`	53
	It has to be a sticking valve or lifter. For the pushrod to jump out, there has to be excessive clearance and since you have hydraulic lifters, and normal clearance is zero, a sticking valve ( very common in engines put up and stored is probably the culprit. On a v-8 one or more valves is always open. Withe the engine stopped, the valve stem is exposed to outside air coming in through the exhaust or intake manifolds. On a boat engine, if you use anti-freeze- in the block, moist air is present in the exhaust manifolds since they have a water dischsrge from the block in th reiser or exhaust elbow. A little bit of rust on start up causes the valve to stcick or drag ( move slower than the pushrod is dropping)-resulting in excessive clearance, gravity causes the pushrod to drop out of the way, the lifter tries to open the valve, and there tou are. I'd look at my storage techniques- really fog the engine - I also take out the plugs and pour some oil in the plug holes as well as through the carb intake. I use a good fogging oil while they engine is running and then use marvel mystery oil in the plugs/carburetor. I leave the coil wire off and crank her over a few times.I put the plugs back and then seal up the carb air inlet and the exhaust with duct tape. In the spring, I reverse the process- pull out the plugs, rtake off the duct tape and let the starter spin the engine over a few time to make sure everything is freed up. Put in new plugs, Turn on the fuel, and fire her up. Sealing the exhaust and intake made a big difference. TH first year I owned the baot, I did all of the above except closing off the exhaust/intake. That was a damp spring with a lot of temp changes, and I got enough rust in the engine(350 chev) to get three valves to stick REAL GOOD!- it took me a weekend just to get the engine running right. Since I began soaking everything AND keeping air from gettin to the manifolds- no problem. You may have some kind of weird problem- but Idoubt it, especially since this happens after the engine is stored. With a newer engine, the valve/guide clearances are pretty tight, and a litle bit of rust can really hang things up. The old clunkers get so loose that a little rust isn't even noticed. Dick

    
    
    It has to be a sticking valve or lifter. For the pushrod to jump out,
    there has to be excessive clearance and since you have hydraulic
    lifters, and normal clearance is zero, a sticking valve ( very common
    in engines put up and stored is probably the culprit.
    
    On a v-8 one or more valves is always open. Withe the engine stopped,
    the valve stem is exposed to outside air coming in through the exhaust
    or intake manifolds. On a boat engine, if you use anti-freeze- in the
    block, moist air is present in the exhaust manifolds since they have a
    water dischsrge from the block in th reiser or exhaust elbow.
    
     A little bit of rust on start up causes the valve to stcick or drag
    ( move slower than the pushrod is dropping)-resulting in excessive
    clearance, gravity causes the pushrod to drop out of the way, the 
    lifter tries to open the valve, and there tou are.
    
    
     I'd look at my storage techniques- really fog the engine - I also
    take out the plugs and pour some oil in the plug holes as well as
    through the carb intake. I use a good fogging oil while they engine is
    running and then use marvel mystery oil in the plugs/carburetor.
    I leave the coil wire off and crank her over a few times.I put the
    plugs back and then seal up the carb air inlet and the exhaust with
    duct tape.
    
      In the spring, I reverse the process- pull out the plugs, rtake off
    the duct tape and let the starter spin the engine over a few time to
    make sure everything is freed up. Put in new plugs, Turn on the fuel,
    and fire her up.
    
     Sealing the exhaust and intake made a big difference. TH first year I
    owned the baot, I did all of the above except closing off the
    exhaust/intake. That was a damp spring with a lot of temp changes, and
    I got enough rust in the engine(350 chev) to get three valves to stick
    REAL GOOD!- it took me a weekend just to get the engine running
    right.
    
     Since I began soaking everything AND keeping air from gettin to the
    manifolds- no problem.
    
     You may have some kind of weird problem- but Idoubt it, especially
    since this happens after the engine is stored. With a newer engine,
    the valve/guide clearances are pretty tight, and a litle bit of rust
    can really hang things up. The old clunkers get so loose that a little
    rust isn't even noticed.
    
    Dick