REFLECTOR:Rough Rider

Sun, 20 Jul 2003 08:10:43 -0500

We use updraft cooling and we moved the spider to the bottom.  Our engine
runs smooth even when hot on the ground.  Dwane Swing suggested that we put
the spider on the bottom to eliminate just the type of problem that several
of the velocity flyers are having with rough running engines when hot.

Mike

-----Original Message-----
From: reflector-admin@tvbf.org [mailto:reflector-admin@tvbf.org]On
Behalf Of Scott Derrick
Sent: Saturday, July 19, 2003 9:05 PM
To: reflector@tvbf.org
Subject: Re: REFLECTOR:Rough Rider

Spider is on top and I'm using updraft cooling. I thought about putting
a piece of insulation in the bottom side of the spider to keep it
cooler.  Think it would help?

Scott

Mike Pollock wrote:
> Is your fuel injector spider on the top of the engine?  Are you using
> updraft or downdraft configuration?
>
> Michael Pollock
>
>
> -----Original Message-----
> From: reflector-admin@tvbf.org [mailto:reflector-admin@tvbf.org]On
> Behalf Of Chuck Jensen
> Sent: Saturday, July 19, 2003 11:26 AM
> To: 'reflector@tvbf.org'
> Subject: RE: REFLECTOR:Rough Rider
>
>
> Well, maybe the booster pump is enough to overcome the vaporization in the
> injection line because it will run pretty smooth even down to 700 rpm
after
> flight, if the booster is run. But won't smoothly at 1100 rpm wo/booster.
>
> I can see how the temp/conditions in the injection lines would be pretty
> consistent after power operations so the booster pump would have the same
> salutory effect after pretty much any flight.
>
> Good thought on not increasing the idle speed.  The brakes already have
> enough work to do without having to overcome a fast idling engine pushing
it
> down the runway on landing.
>
> My concern that "this ain't right" grew out of comments from a couple
> mechanics and a CFI that thought smooth engine ops, even at low rpms,
should
> not be dependent on the booster pump.
>
> Nonetheless, Scott gets the Southern Comfort(ing)Award, even though I
still
> have a tiny bit of residual doubt.
>
> Chuck XL/RG
>
>
>
>
>
> -----Original Message-----
> From: reflector-admin@tvbf.org [mailto:reflector-admin@tvbf.org]On
> Behalf Of Scott Derrick
> Sent: Saturday, July 19, 2003 10:54 AM
> To: reflector@tvbf.org
> Subject: Re: REFLECTOR:Rough Rider
>
>
> Sounds pretty normal for an injected lycoming.
>
> I have a IO360 which isn't the same engine but the injection system is
> very similar. I also have a Mag/IE combo. My plane runs exactly the
> same.  Very smooth idle when cold, idles rough as a cob when hot unless
> I increase the fuel flow to about 5 gph. I can do this using the
> electric fuel pump or just idle it at 1000 rpm instead of the normal
> 600-700 which is what I do when hot.  DO NOT increase your idle speed!!
> Bad idea. You want that low idle speed when landing so you can slow down.
>
> This rough idle is worse in the summer for my plane. Its just the fuel
> vaporizing in the injection lines, no biggie as it only happens at low
idle.
>
> First time it happened to me I ran to my friend an A&P/IA.  He said, no
> problemo. Just Lycomings injection system design.
>
> Your fuel pressures sound right on to me, I think the other pressures
> you are referring to were for a Franklin.
>
> The A&P that enrichened the idle mixture was probably right in doing so
> but that won't effect the vaporization of fuel in your injection lines
> when the cylinders are hot.
>
> Sounds like your setup is right on, keep flying!
>
> Scott
>
>
> Chuck Jensen wrote:
>
>>I have an engine issue that two mechanics have looked at...and that's all
>>they've done.  I wondered if anyone has ideas on avenues of
>>investigation/solution.  I'm running a 540 with mag/EI combo.  The engine,
>>particularly after a long flight (less so after starting cold), runs rough
>>at ramp speed (1,000 rpm).  Here are the symptoms with a hot engine after
>>flight:
>>
>>As long as the booster pump is on, runs smooth as glass.  VM-100 indicates
>>30 psi (from another post, is that way too high??) and approx. 4.0 gph
>
> @1000
>
>>rpm.  If the booster pump is secured, fuel pressure drops to 28 psi, fuel
>>flow shows 1.7 and engine bounces between 650-700 and just barely stays
>>running.  Turn the boost back on, and it immediately goes back to smooth
>>operations with the first set of values.  Turn the boost off, and it's
>
> right
>
>>back in the dumps.
>>
>>At cruise or high power operations, the boost pump on/off makes no
>>difference in fuel pressure, fuel flow or smoothness of operations.
>>
>>One mechanic suggested that the idle speed needed to be increased.  ??
>>Seems he was missing the point.  I'm intentionally setting it at 1,000 rpm
>>with the booster, then engine goes in the toilet when the booster is cut.
>>
>>The second mechanic increased the richness setting which may have been too
>>lean since I did not get a temporary rpm increase when cutting off the
>>mixture, but the reliance on the booster pump did not change for smooth
>
> ramp
>
>>operations (especially when hot).
>>
>>Induction plenum has been checked thoroughly but that would seem to be
>>unrelated to the observed symptoms.
>>
>>Questions:  1) are my fuel pressure values way out of line (earlier post
>>talked about 5-6 psi)?  		2) if my numbers are bogus, do I
>>have a bad fuel pressure sensor or ground?
>>		3) what do others run for fuel pressure/flow at 1,000 rpm on
>>a 540?
>>		4) is the main fuel pump going in the crapper? (its been
>>this way for a long time 				with no further
>>degradation/change)
>>		5) is this type of poor low power performance characteristic
>>of deterioration of the 			positive displacement type
>>fuel pump?
>>		6) is there a way to check the main fuel pump performance?
>>
>>I was in the camp that the main fuel pump is going downhill but I don't
>>understand why, if it is putting out that much pressure, why the fuel flow
>>should fall so much when the booster pump is secured.
>>
>>By all rights, these questions should be investigated and fixed by a good
>>mechanic (which exempts me), but since that avenue has been unproductive,
>
> I
>
>>thought I'd check out the collective wisdom/experience of the
>
> Reflectorites.
>
>>Best idea wins an official Atta Boy award; redeemable wherever good ideas
>>are sold.
>>
>>chuck
>>N27GV
>>
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