On 09/15/2009 06:58 AM, C. E. White wrote:
> "jim beam"<me@privacy.net> wrote in message
> news:ba6dnexjW938CTLXnZ2dnUVZ_rOdnZ2d@speakeasy.ne t...
>> On 09/15/2009 03:53 AM, Elle wrote:
>>> On Sep 14, 9:04?pm, jim beam<m...@privacy.net> wrote:
>>>> ?even if the
>>>> valve guides are chronically worn, if the seals are sealing,
>>>> there's no
>>>> oil loss.
>>>
>>> A lot of auto maintenance sites (not just random people posting)
>>> state
>>> that either the valve stem seals or the valve guides may be
>>> failing.
>>
>> 1. your honda valve guides are not submerged.
>
> It doesn't matter. Oil is being flung all over the inside of the valve
> cover. If your guides are worn and your seals are worn, oil will be
> sucked in through the intake guides.

it does matter - submerged guides can leak literally pints.


>
>> 2. it's been known for internet "experts" to be full of it.
>
> True
>
>> 3. i've experimented with /no/ seals - you lose a little, but it's
>> not a massive source of loss.
>
> True as well. I've had engines that did not even use valve stem seals
> (Jensen-Healey 2.0L Lotus 4 cylinder) and others that only used them
> on the intake valves. However, when you say "you use a little," that
> might add up to a lot in the eyes of some people. For a new engine
> with minimal valve stem to valve guide clearance, the loss will be
> small. However, for an older engine with worn stems and guides, the
> loss can be significant. In the old days this was still trivial in
> many cases. However, with modern engines, severely worn guides can
> casue several problems - excessive air leakage will screw up the PCM's
> calculation for fuel delivery and excessive oil consumption can damage
> a catalytic converter.

right, but that's a whole different issue.


>
>>> I
>>> understand what you're saying but it is hard for me to say from the
>>> Civic shop manual drawing whether a new, properly installed valve
>>> stem
>>> seal alone will ensure no leakage in this area.
>>
>> unless it's lost flexibility, is worn or cracked, it will.
>
> New seals will help, but becasue of the excessive play, they won't
> last as long, and they will still let more oil past than seals on
> unworn guides and stems.

but they are literally weeks old - no "lasting" problem.


> Seals have to allow some oil past to keep the
> valve stems and guides lubricated, so they aren't perfect seals by
> design.

untrue - the stems and guides run dry. the seal is there to do just
that - seal.

>
>>> Regardless, for now I am going the route of trying to clean things
>>> up
>>> with continued use of Mobil 1 and/or maybe Auto-RX.
>
> If the engine is only using a half a quart per 600 miles, I'd just
> drive it. With 197,000 miles on the engine, it is not just the valve
> train that is worn.

a honda should be up there at at least 300k.