Date:         Fri, 27 Apr 2007 18:28:11 -0700
Reply-To:     Keith Hughes <keithahughes@QWEST.NET>
Sender:       Vanagon Mailing List <vanagon@gerry.vanagon.com>
From:         Keith Hughes <keithahughes@QWEST.NET>
Subject:      Re: vanagon Digest - 27 Apr 2007 - Special issue (#2007-438)
Content-Type: text/plain; charset=us-ascii; format=flowed

Jake,

>Date:    Fri, 27 Apr 2007 15:34:04 -0400
>From:    Jake Beaulieu <jbeaulie@ND.EDU>
>Subject: Re: vanagon Digest - 26 Apr 2007 to 27 Apr 2007 - Special issue
>         (#2007-436)
>
>
>>There's really only a couple of ways you can get gas in the oil, and if
>>you don't have a dead cylinder (i.e. does not fire at all), there's
>>really only one.  You have to be dumping gas into the cylinders when the
>>engine is not running, and about the only way that can happen is with
>>seriously leaky injectors.  Pull the injectors and check the spray
>>patterns, and look especially for fuel leaking when they shut off.
>>There should not be more than a drip or two. My guess is that you'll
>>find one or more injectors leaking significantly.
>>
>>
>
>I have pulled the plug wires one at a time while the van is running and
>the rpms drop by about the same amount on all cylinders, suggesting that I
>don't have a dead cylinder.  I have checked all four injectors and the
>cold start valve for leaks (several times), there are none.  Injectors
>were recently reconditioned by Cruzin Performance
>(www.cruzinperformance.com) and all have a beautiful spray pattern.
>Thermo-time switch is working correctly, thus the cold start valve is only
>injecting when it should (i.e. for the first 7 sec while the starter is
>engaged).
>
>
The pattern may be fine, but do they 'weep' when closed (with the system
pressurized)?  I've seen lots of reconditioned stuff fail.

>>Well, according to your earlier description, you're not "at idle" when
>>it's first started (i.e. the throttle is open to keep it running).  With
>>the throttle opened past normal idle position, and the engine RPMs in
>>idle range, the vacuum will be very low.  You're only going to have high
>>vacuum when you generate a high pressure drop across the throttle plate.
>>
>>
>
>Oh, didn't know that.
>
>
>
>>>I would like to see the vacuum higher.
>>>
>>>
>>If the idle adjustment (air bypass) is adjusted to allow more air around
>>the throttle plate - which is almost certainly the case given how rich
>>you're running - you can't get any higher.
>>
>>
>
>hmm...good point.  I am running a brand new AFM from Bus Depot and I
>haven't touched the initial settings.  I also have a working spare.  Maybe
>I'll screw around with the air bypass screw in the spare and see if it
>effects the vacuum.
>
>
Has nothing to do with the AFM per se.  The idle is set using the air
bypass screw; irrespective of the condition of the AFM.  If, for
whatever reason, you have to open the bypass screw significantly to idle
correctly, the 'manifold' vacuum will suffer as a result.  Means nothing
relative to performance, however, just an artifact of lowering the
pressure drop across the throttle plate.

>>>Lifters are set at 0 lash warm,>>>*Really* bad idea IMO.
>>>
>>>
>
>Well, one could put together a novel from all the lifter adjustment posts
>on the list.  People seem to have strong opinions on this matter.  I
>simply defer to Boston Bob, the proffessional who built my motor and has
>posted his hydraulic lifter sermon on his website (www.bostonengine.com).
>
>
>
Which, as I read it, says nothing about zero lash.  He recommends 0.006"
until breakin is complete (2 years ought to do it), then experiment with
preloading.  Personally, with my '78 I ran about 3/4 turn past zero
lash.  Worked OK for me...well, until the damn injector hose blew and
the thing burned to the ground...arggghhhh.

>>>I set the lifters to 0 lash when hot which is equivalent to 0.006 cold
>>>
>>>
>as I understand it.
>
>
>>Nope.  There's no way to infer that.  Zero lash *warm* will equate to
>>valves not fully closing when *hot*.  Now, I assume that since you're
>>talking valve lash, you have solid lifters in you motor.  If you have
>>hydraulics, you're way off base on adjustment.  Hydraulics should be set
>>to zero lash (i.e. just touching the pushrod and valve stem surfaces),
>>then tightened two turns (or 1 1/2 turns per some folks).  Make sure you
>>run the motor for several minutes to pump up the lifters, then allow to
>>cool for 4-6 hours prior to adjustment.
>>
>>
>
>I didn't realize "lash" was specific to solid lifters.  Sorry for the
>confusion.  I do have hydraulic lifters.  I think I will go back in and
>set them to 0.006 cold.  Again, I defer to Boston Bob's advice for setting
>the lifters.  Note that the Bentley manual now says that preloading the
>lifters is optional.
>
>
True, if you don't mind the clack, clack, clack, clack, clack,... :-)

>
>
>>First, check your injectors.  If you're really getting gas in the oil,
>>that's the first problem to tackle and fix.  Then adjust the valves
>>correctly (Cold for solid lifters) and see where you're at.  Hope this
>>helps,
>>
>>
>
>My oil reeks like gasoline within a couple hundred miles of an oil
>change.  I have always thought that gas was washing past the cylinders
>while the motor was just barely chugging along while it warmed up.  I'll
>talk with Bob, adjust the valves, then get back to the list.  Thanks for
>your advice Keith.
>

Gas can't 'wash past the cylinders unless you have *very* low
compression, which you don't have, or if gas is leaking in while the
motor is not running.  The rings only seal under dynamic conditions.  At
rest, there are gaps in the rings (they're there under dynamic
conditions too, but they do not act as though they are there- another
story) that allow the gas to seep past.  This just does *not* happen
when the motor is running, and the cylinder is firing.  Now, you can get
combustion products in the oil that smell similar to gas, but if you
really have 'gas in the oil', you should see a rise in "oil" level,
instead of a drop.  You will also see the viscosity decrease visibly.
Good luck,

Keith Hughes
'86 Westy Tiico (Marvin)