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Old October 8th 08, 01:36 AM posted to rec.aviation.owning
150flivver
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Posts: 171
Default Can hydraulic lifters cause inadequate full power?

On Oct 7, 2:33*pm, wrote:
Drew Dalgleish wrote:

: * I Don't know the answer to your question but I'm wondering if the
: airbox was changed with The STC. Is it possible the engine is hungry
: for air at full throttle?

* * * * This engine upgrade is extra weird because the owner who did it
(the guy we bought it from) also got a field approval for changing it
firewall-forward to the fiberglass clamshell cowling like later-model
-180's. *So, it's got the mufflers and two exhausts that exit by the
nosewheel. *That and the updated air box should provide good power. *

* * * * We added and manifold pressure gauge to it as an optional STC
component, even though it's fixed-pitch prop. *As far as air restriction,
I've discounted that because the manifold pressure gauge reads about 1.5"
less than ambient pressure.... right about where it should be as far as
losses in the intake. For example, at the 2100' field elevation we're at,
a typical day would read 28" before starting. *Full-power static runup
shows about 26.5".

* * * * I've also discounted an improper (lean) mixture due to jetting,
carb float level, fuel pressure, etc because it requires leaning when the
DA reaches about 3500' in order to make max power.... right about where it
should. *If it were too lean, it wouldn't do that until quite a bit higher
DA (and we've have melted the pistons when we run autogas).

-Cory

--

************************************************** ***********************
* Cory Papenfuss, Ph.D. Electrical Engineering, PPSEL-IA * * * * * * * **
* Research Associate, Vibrations and Acoustics Laboratory * * * * * * * *
* Mechanical Engineering * * * * * * * * * * * * * * * * * * * * * * * **
* Virginia Polytechnic Institute and State University * * * * * * * * * *
************************************************** ***********************


Sometimes a weak valve spring(s) will manifest itself in a loss of
hp.