Date:         Sat, 27 Oct 2018 18:07:49 -0700
Reply-To:     Neil N <musomuso@GMAIL.COM>
Sender:       Vanagon Mailing List <vanagon@gerry.vanagon.com>
From:         Neil N <musomuso@GMAIL.COM>
Subject:      Re: The value of instrumentation
Comments: To: dbeierl@attglobal.net
In-Reply-To:  <CAMOH8LJ3Wzt0MgdHqGvMRimx-Dp3oi8muxnhh82om48X1JZ_gA@mail.gmail.com>
Content-Type: text/plain; charset="UTF-8"

On 10/27/18, dbeierl <dbeierl@gmail.com> wrote:
>>
>> If
>> the lifters are quite worn and bleed down faster than normal, I wonder
>> if that causes the heads' oiling circuit(s) to lose its' prime.

> I wouldn't think lifters would wear much internally, since the piston
> basically only moves at starting time and then only if it was under an open
> valve.  But because of the extraordinarily small clearance between piston
> and bore they're subject to getting sticky.  The restoring force from 60
> psi of oil pressure is a lot less than you'd think given the small piston
> area.  When one does bleed down all it does is allow the valve to close and
> ooze ?half a cc? of oil out the end.
>
> Can't speak to the rest except to say I'm used to thinking of "prime" as an
> issue in suction systems rather than pressure one.


Right. I see your points regarding general lifter behaviour. I looked
online for an oil passage flow for this engine but didn't find one.

Ya, my mind was focused on "priming" because as far as I know, the
pump was allowing oil to seep out overnight due to "borderline" oil
pump gear end play. (a not uncommon issue per se when mating a diesel
Vanagon oil pickup tube to a I4 VW gas engine oil pump. Even with new
parts). As it was, oil pressure stayed at zero until the engine held
at ~ 2500 RPM. After reducing gear end play to ~ .002 (measured with
Plastigauge), even if the engine sat unused for 3 days, first start,
I'd see oil pressure right away. The difference was "night and day".


--
Neil n

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