Conference vicki::boats

    
    Your mechanic probably owns stock in the company that makes
    the $150 dwell meter that he's recommending.  There is no
    difference in setting the dwell in automotive or marine
    applications.  This is just another prime example of the 
    "Marine applications cost 3 times as much" mindset.
    
    I would recommend that you check the prices at Sears.  They
    sell some decent quality test equipment that is probably a 
    good compromise between the ADAP and the $150 meters.  You
    should be able to get a multifunction analyzer for much less 
    than $150.
    
    Rick W.

    Rick is absolutely right. your mechanic knows better.
    
    You may consider doing a lot more yourself, i certainly
    would not trust this person anymore..
    
    Jim.

    
    If you put in a new set of points, you can get pretty close (almost
    perfect) with simply setting the pointgap. Race car drivers did this
    for years on some pretty sophisticated modified engines. When the
    points are a little pitted- a dwell meter is more accurate- but any
    decent mechanic should be able to set a nerw set of points right on
    spec by setting the gap,
    
     A dwell meter is good when you have worn points or for detecting a bad
    bearing or worn lobes on the distributor cam. 
    
    A dwell meter tells yoy where the points are set- to adjust them, you
    have to stop the engine and adjust the points (late model GM
    distributors being the exception). Even there the fgactory manual 
    instructions were to do it either with a feeler gauge or counting turns
    from full closed on the point adjustment screw.
    
    If you want to go that route- a dwell meter is a dwell meter is a dwell
    meter.- an ADAP or sears special will work as well. 
    
    FIRST- find out what the factory manual says. My OMC manual says to use
    a feeler gauge- you have to really search to find the dwell spec.
    
  these are truck block based engine and with some minor exceptions, are
    identical to truck/autimotive engines. I would either get a manual and
    do the work myself  or:
    
     get a manual- and find a local mechanic who will "moonlight" from the
    local dealer. Sometimes a swap of a day's fishing for a tune-up and
    servicing is all you need

    C'mon Joe, get those fingernails dirty.  I used to do this stuff by
    eyeballing the point gap and then setting the timing by rotating the
    distributor until it sounded right.  I'm showing my age but way back
    when American big-block V8's were amazingly insensitive to fine
    adjustments of dwell and timing.  Don't know if yours are the same.
    
    This stuff is a lot more fun than painting the bottom.
    

    	Hi,
     
    	Chances are the engine in question needs the dwell meter because
    it has a GM style point distributor and you can adjust the dwell
    from outside the distributor with an allen wrench while the engine
    is running. Are the engines Mercruisers?
    
    	I have to agree with evryone else that $150.00 for a dwell meter
    is a lot of money! The only reason I can think of for the large
    price would be if it were a dual meter that was capabable of metering
    both distributors at the same time on a dual engine set-up. This
    might make synchronized dwell setting easier on a dual set-up. If
    it really is needed. But with a little patience the same could be 
    accomplished with a single dwell meter.
    
    PL

    re: .5:
    
     Even ifit is a GM type distributor with the adjustment on tye outside,
    the typical way you set the points (even the dealers did this) was to
    install the points, set the gap by eyeball, close it up and start the
    engine. You inderted an allen wrench into the adusting screw and closed
    the points until the engine started to skip(basically no clearance).
    
     Then you backed out the screw (x) turns - from the manual- and closed
    it up. When I checked this with a dwell meter, it was within spec. 
    
     The only time I saw a dwell meter to be easy to use was when the
    distributo was pulled and put into a distributor testing machine where
    the distributor was rotated by the machine and the cap was off- I used
    to use these when we'd rebuild a distributor and used it to check the
    centrifugal/vacuum advances and "wobble" or bearing slop.
    
     Only did this with the high performance/modified stuff- usually where
    we were fussing around with changing the advance curves.
    
     Most of the small/large block GM marine enines use a centrifugal
    advance distributor (no vacuum advance) made by Prestolite- the specs
    on this distributor are for point gap in the manuals. The DELCO
    distributor used on the cars I have onl;y seen when someone has
    replaced the whole engine with an automobile or truck complete assembly
    You can tell the prestolite distributor real easy- the cap is very flat,
    and the plug wires are in a horiziontal plane.
    
     There is no technical reason to synchronize dwell- only rpm.Dwell
    (point gap) only needs to be within spec. As was
    mentioned in one of these notes, these big V/8's are very tolerant on
    point adjustment and small variances in timing. They aren't nearly as
    sophisticated as some of today's elecronic ignition/fuel injected /
    computer controlled engines.
    
     Changing points /plugs/ and adjusting timing is oe of the more simple,
    basic maintenence tasks- I agree with .4- get your hands dirty and try
    it- it really is pretty simple. Tking the distributor OUT completely
    and getting it back in can be tricky if you don't know what you are
    doing, but there si no need to do this if you are only changing
    points/condensor.
    
    BTW: your local auto parts store usually carries the points/condensor/
    rotor and distributor cap for these marine distributors.
    
     I'd get a manual on the engines and roll up my sleeves and go at it-
    you can save yourself lots of $, be assured of the quality of the work
    you are doing, and hopefully develop enough engine smart to do some 
    repairs at sea.  Getting a manual is a first step-I've had one on every
    engine/vehicle/outdrive >I have owned- makes things go a lot
    quicker/easier and keeps you from making those really dumb mistakes
    
    my 2 �
    
    Dick
    . 
    
    

    Thankyou gentlemen,
    
    I am off to Sears to get a cheap dwell meter and attempt the operation
    myself. By the way the engines are crusader 350s - GM 454 Buick (I
    believe) big blocks.
    
    How do I know what manual to get if I don't know the engine maker?
    (ie Buick, Olds etc...) Is there a straight GM 454 manual?
    
    
    Thanks for all your replies
    
    Joe D.

    The heartbreak of america   CHEVY!

    I've appreciated this discussion because I tried to give my boat a tune
    up last summer. I have a Sears "Engine Analyzer" which includes Dwell
    but was unable to reconcile the setting of the points with a feeler
    guage to the Dwell. And since this is a Ford engine it drove me crazy
    because, as has been explained, only GM (type) distributors allow the
    Dwell to be set on a running engine. I'd set the points with the guage,
    start the engine, check the dwell. Stop, take apart, adjust. and again
    and again. I couldn't ever find a place where the points were set to
    proper spec and the dwell read correctly. It runs, but I am just not
    confident I did it any good. Should I just forget the dwell and use the
    feeler guage to properly adjust the gap?
    
    john 

    No you don't wish you had a chevy. 
    
    Yes you should forget the dwell meter, and use a feeler guage.
    Most specs call out for a range such as 17-19, or whatever.
    Get a good feeler guage, and take good care of it, its not 
    hard at all.
    
    Where is the boat now...
    
    
    JIm.

    You mean geographic location, like someone might be willing to help a
    maladriot if close enough? That would be real nice, except the boat is
    on the Cape, in Harwich, not too close huh? Been spending a lot of
    money running down there to get it ready this spring.
    
    You mean is it in or out of the water? It is out of the water on a
    trailer right now. I plan on putting in a outside water tap at the
    cottage this weekend so I can hook up those water muffs for running it
    there. Hoping it might be easier to tune it there then while rocking
    and rolling with wakes of passing boats.
    
    I think that my feeler guage is a good one. 
    
    Re. my comment. It's just that my family has never had good luck
    with Ford motors, GM's have been good to us.
    
    john

RE: Note 662.10  

>>    Yes you should forget the dwell meter, and use a feeler guage.


Sorry Jim, I disagree on this one.  If you can't get the correct gap to 
coincide with the correct dwell, I would go with the dwell.  Electrically 
the points are either just open or closed, how wide they open really is 
not important.  What *is* important is that the points open at the correct
time and are open for the correct length of time.  A properly set gap on 
an unworn distributor cam should yield the correct dwell.  But if they don't
match then the dwell is the correct measurement to use.

Rick W.

re            <<< Note 662.12 by FAIRWY::WILSON "Moe, Larry, Cheese!" >>>
>                             -< Dwell on this.... >-

> RE: Note 662.10  

> >>    Yes you should forget the dwell meter, and use a feeler guage.


> Sorry Jim, I disagree on this one.  If you can't get the correct gap to 
> coincide with the correct dwell, I would go with the dwell.  Electrically 
> the points are either just open or closed, how wide they open really is 
> not important.  What *is* important is that the points open at the correct
> time and are open for the correct length of time.  A properly set gap on 

	WRONG_O again

	It is how long they are  *_CLOSED_*  for that matters  - 
remember why ?  (-:, (-:  and the time at which they open is set by
rotating the distributor, and is checked with a timing light...etc.

	Its been my experience that if dwell and points gap don't 
agree there's something else wrong.  Check the points gap at EACH 
opening to see if the cam that opens them is worn unevenly, also check 
the distributor shaft for slack/wear/looseness.  According to who has 
been mucking with it the distributor shaft could be bent, but thats 
very unusual though still worth checking for.

	Reg	{but I'm not very good with water pumps, so ask 
		somebody else anyway (-: }

RE: Note 662.13

>> 	WRONG_O again

>>	It is how long they are  *_CLOSED_*  for that matters  - 
>>remember why ?  (-:, (-:  and the time at which they open is set by
>>rotating the distributor, and is checked with a timing light...etc.


Gee Reg, nice of you to put it so eloquently.  Yes, I do remember why it
it is important how long the points are closed.  Keep in mind that not
everyone who reads this conference also knows.  Briefly, the charge is 
built up during the time that the points are closed.  When the points 
open the field collapses and is released through the system to the spark 
plug.

This is exactly why the dwell is more important than the gap.  The points
must remain closed long enough for the charge to build up, and open long
enough for it to fully collapse.  Since you pointed out Reg that the time 
points are closed is very important, you should know that if gap is set 
to factory spec on a worn distributor, the points may not be closed long
enough for the field to fully charge.  To take it even further, a severely 
worn distributor with the gap set to factory spec might not ever allow the 
points to close at all.  

My "point" (pun intended) is this: if the correct gap does not give the 
correct dwell then yes, there is a problem.  But short of replacing the 
distributor, the correct fix is to go by the dwell, not the gap. 

Rick W.

    You guys are getting a little caried away. 
    
    All he wanted to know is if he was getting ____ without getting
    kissed.
    
    Yes he was.
    
    Does he need a dwell meter NO.
    
    Can he use a feeler guage. YES
    
    But its nice to have both..
    
    Jim (who's getting out of this)
    
    

    
    
     If the point setting is correct, and the dwell is wrong,
    then I suspectyou either have a worn bearing in the distributor
    (which should be reapired), or the points are not new.
    
      |___________________|
               V
      _________ __________
     |         V          |
    
    The scketch above shows a typical problem on used points- material is
    deposited on one of the points, making a high spot- the feeler gauge 
    covers the whole surace and gives a falsoe reading (usually setting the
    points at the correct gap results in too low a dwell angle.
    
     Setting the gap with a new set of points corrects the problem
    ,provid4d the distributor bearing is O.K.
    
     Another possible problem is that your dwell meter is not calibrated
    correctly. MOst of them need the two leads tied together and the meter
    zeroed before hooking up to the engine (the "dwell set" position on the
    meter")-.
    
     If the distributor is o.k- the dwell and the point gap should both be
    in spec .
    
    
    D............
    

    Re. .16, and the other possibility is that I am a complete Bozo who
    shouldn't be allowed within a screwdriver's reach of an engine.
    Actually the points were brand new ($20+ !!!!) as I was attempting a
    tune up for improved starting. And I think that meter was set
    correctly, though I have no idea on its absolute accuracy. 
    
    
    My explanation for the difference was that it seemed to be impossible
    to adjust the gap and then tighten everything without having the points
    move a little. You guys are really scaring me with ideas of a bad/worn
    distributor. I will look at the lobe tomorrow to see if it looks worn.
    With everything else happening this weekend I am not sure I'll get a
    chance to much more than that this time around. Let you know if I am
    more successful at some point in getting the correct dwell reading.
    
    John
    

RE: Note 662.15   

>>                          -< OK OK OK OK OK OK OK OK >-
>>    You guys are getting a little caried away. 
 
>>    Jim (who's getting out of this)
    
  
Jim,
You'd better call security!  Someone else is using your account!

8^) 8^) 8^) 8^) 8^) 8^) 8^) 8^) 8^) 8^) 8^) 8^) 8^) 8^) 8^) 

Rick W.

I have had a number of Ford engines in both cars and boats (302's and 351's)
and I agree that using the feeler gauge is the simplist and most straigtforward
way to set new. When I want to adjust with a dwell meter, rather than use
the "remove cap/adjust/start/measure" iteration routine, I have found another
method that works well, though it requires another pair of hands.

There apprears to be a constant relationship between the dwell reading when
the engine is just cranking and when it is running for a given set of points,
distributor, and dwell meter. To adjust: I check the dwell running. If it
needs adjustment, I note the amount, stop the engine, remove the coil wire
(to prevent arcing) and the distributor cap, and then adjust the dwell while
the engine is being cranked. Though the dwell will read lower the amount
needed to adjust it is typically the same, and certainly within the range
of the spec. Finally, I put it back together and recheck.

    Everyone in this note who is talking about adjusting dwell on the
    454 through the window usually supplied on automobile 454 distributors
    is forgeting something. Marine distributor caps have no window because
    they are sealed to prevent the spark from causing an explosion of
    gas vapors. Setting gap and checking dwell is the only option.
    
    If you have a windowed distributor cap, junk it and buy a marine
    one or seal it up with silicone.
    

    
    
      One could always use the "windowed" dist cap to adjust the dwell,
    then replace it with the proper "windowless" cap.
    
    BTW - if the dwell is adjusted with a good (preferably the same)
    dwell meter each time the points are changed, the timing should
    never have to be adjusted (providing it is right in the first place).
    
    				Kenny

    
    
    re: .21- The "windowed cap only comes with the DELCO distributors- the 
    Distributors in most marine engines are either Prestolite or Mallory-
    cap and points are different.
    
     The original intent of this note was to identify how to adjust the
    points and get the correct dwell-clarifeied by the most recent note 
    that the problem is the poit move when they are tightened down.
    
     Most poits (other than the externally adjusted DELCO distributors have
    a slot wher you can use a screwdriver as a "lever" to move the points
    in
    the adjustng slot with the hold down screw "snug". I've adjusted points
    in this manner and then fisnish by socking down the hold down screw-
    if the hold down screw is loose,I agree that adjusting poinyts is
    impossible. 
    
    AS far as distributor wear is concerned, I was more concerned about the 
    bearing wear rather than a lobe being off- this is not a big deal to
    repair-any machine shop or good auto electric shop can do it. 
    
     If the engines have a lot of hours- bearing wear is a possibility-
    check by shaking the distrubotor shaft from side to side while the
    points are open and see if the gap changes by mor than .001-.002
    
    
     Another alternative to the problem is to convert to a CD breakerless
    ignition , or add a CD ignition to work with the existing points.
    
     How far off is the dwell from specs when it is set?  Other than high
    speed performance, most engines are pretty tolerant of being off spec
    for starting and other than high speed running. I would tend to look
    for  fuel problems for hard starting rather than ignition, particularly
    if you have new points and plugs.
    
    
    

    RE: .20---Way to go, Steve!!! I was reading this wondering when the
    BOOM would come from using an automotive distributor in a marine
    conversion.
    
    This is such a simple operation with a meter---why all the fuss? Put
    the points in, take the cap off, pull the plugs, set up the meter and
    crank it. Put back together and go like hell!!! (after you set the
    timing)
    
    I'm on the water and your still screwing around with the points!
    
    Give me a holler on the radidio when you finally get the bottom wet.
    
    Go For It !