REFLECTOR: Update on Engine Upgrade

[Scott Derrick]

Maybe I should get my gun?  :-)

Chuck Jensen wrote:
> Scott, the swamp is rising and the alligators are getting hungery, but just keep your eye on the shore and keep plugging away.
>
>
>
> -----Original Message-----
> From: reflector-bounces at tvbf.org [mailto:reflector-bounces at tvbf.org]On
> Behalf Of Scott Derrick
> Sent: Saturday, March 28, 2009 10:16 AM
> To: Velocity Aircraft Owners and Builders list
> Subject: REFLECTOR: Update on Engine Upgrade
>
>
> Well, I thought I was basically done with my turbo woes after rebuilding
> the wastegate controller and installing new seals in the turbo.   A few
> prolonged high power runs blew that out of the water.
>
> 1.) The turbo still leaks though the engine is now running really
> sweet.  I finally located a table of limits for the series turbo I
> have.  I pulled the turbo, disassembled again and discovered the seal
> surface on the turbine side was four thousands out and somewhat oblong.
> There was some slight pitting also. It appears that even though it only
> had 1400 hours on it, the center housing was trash.  With my recent
> experience with  T210's  and the  horribly  inaccurate instrumentation,
> even if it was run by the book, the turbo was still fried by way too
> high an inlet temp.  I called the Garret dealer  that provided the
> seals, and through a process of measuring certain faces and inlet outlet
> sizes determined which specific housing I needed and got that and a full
> rebuild kit. cost $290 including shipping.  I have the new parts and
> will hopefully rebuild the unit today.
>
> I really hate that the aviation turbo industry is so closed minded and
> locked down.  There help factor is ZERO for DIY homebuilders.  They
> wanted $1000 to inspect my turbo, anything wrong was more $$. The center
> housing alone was an additional $1000.  They are crooks maintaining an
> almost monopoly on the industry. 
>
> 2.) During the high power runs a new oil leak started. I initiated the
> high power run at a temp just inside the low temp oil range and saw
> about 85-90 psi oil pressure, well within redline but I think it
> revealed a weak spot.  The leak of course is on the back of the engine
> up against the firewall! You can only see the area with a mirror and not
> very well at that.  I believe it is the oil pump, which I rebuilt per
> the overhaul manual.  I asked an experienced overhauler and he asked if
> I double threaded it. I said, no the manual calls for a single thread.
> He said he always doubled threaded those pumps because one thread failed
> to seal every now and then(no change to the TCM overhaul manual though)
> and he thought that was the reason for the leak. SO, I'm pulling the
> engine off to rebuild the pump. 
>
> 3.) I used silicon 90 degree 2.5" hoses to route the induction are from
> the controller to each side of the induction run.  I reworked the
> induction system to get this 520 to almost fit a Std Cowl which required
> longer induction runs. They work but have such a large outside diameter
> they are almost/barely rubbing in places.  I never really liked it but
> there are so many other issues I let it be.  Once installed they are a
> real PITA to get in and out as they are buried on the back side of the
> engine.  Since I am removing the engine to rebuild the oil pump  I
> started to think about this fitting issue again.  I found aircraft grade
> 90 degree induction elbows made from 6061 seamless tubing for $15
> apiece!  Of course they are auto racing parts...  They will have to be
> cut down and re flanged but will see if I can replace the larger
> silicone turbo hoses for these much more compact 2.5 inch aluminum
> elbows while i rebuild the oil pump.
>
> 4.)  95% done with the cooling plenum.  I can't believe hoow much of a
> time sink this has been!  Getting it to fit snug, be reasonably
> airtight, be easily removable is no small task.  Maybe since the plug
> was made for a 550 and I'm fitting it to a 520 contributed some, I don't
> know. 
>
> Spring is finally here, though we did have a cold front move through,
> dump a couple inches of snow and drag the temp down into the high 30's
> low 40's for a few days. I'm looking forward  to  a long spell of good
> building weather.
>
> Scott
>
>
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