achimha wrote:
You can’t afford a cabin pressurizer for your workshop, Michael?
If the shop got one, it’s the best tool for the job.
Nope. It’s grossly over-szed for the simple job of testing a turbo for air leaks.
Don’t remember having ever seen a model where that can be done.
You’re not looking hard enough any decent utility/shop vac has a blower function.
Michael,
Trying to do a little research myself, could the pressure relief valve cause this.
Rob
Rob – Cause what ? The in-balance between R&L engines ?
The pressure relief valve is extremely simple – just a spring holding a cover shut and virtually never “fails”.
You need to hook up a shop vac lower side to the exhaust pipe then start spraying the pipes with soapy water to find leaks. This is by far the most likely scenario.
Wouldn’t hurt to pop the hose leading to the turbo inlet off to check the turbine is free turning and has no play while your’e at it..
Thanks
Replaced the turbo- problem fixed
What was wrong with the turbo ?
Not had a chance to ask, I think it was a lot tighter to spin than the replacement. Now holds 40/2600 all the way to 12500’ after that went to FL180 at 33/2600 with no split between the throttles.
I think it was a lot tighter to spin than the replacement.
That would suggest that the bearings were coked-up .
This can be remedied by soaking the bearings in solvent and if the bearings aren’t in too bad shape you should be able to get a few hundred more hours out of it.
Did the plane have a long spell not flying ?
Save-A-Turbo
with Berryman’s B12 Chemtool
Turbochargers are simple one-moving-part machines that provide immense increases in piston-powered aircraft performance and capability. Pressurization, pressurized heated air, and sea level horsepower at altitude are efficiently available for turbocharged piston engine aircraft.
Turbochargers will usually last through the life of the engine with good maintenance such as: proper leaning, ample run-down time for bearing and lubricant cool-down, timely engine oil and filter changes.
Since maintenance and operational practices are not always known qualities, the following is recommended on an annual basis to help keep the turbo bearings and seals clean.
Following these steps may save your turbo from premature replacement.
To apply B12, cap the turbo scavenge port and fill the turbo oil cavity with
Berryman’s B12 Chemtool.
Cap the turbo oil supply port and allow the solution to remain in the turbo cavity
for at least 24 hours.
Turn the turbo through several revolutions by hand at least twice during the soaking process.
After the soaking period is completed, drain the turbo cavity and flush with mineral spirits.
Hook up the oil scavenge line. Prime the turbo cavity with a cup of engine oil and connect the oil supply line. The turbocharger depends on engine oil pressure for lubrication and cooling of the bearing and seals.
Taxi at idle, or idle the engine for a minimum of three minutes before shutdown.
This allows time to cool the turbo bearings and seals so as to minimize and prevent coking of the oil. Coking causes stuck bearings and results in a dragging turbo with probable oil leaks.
This same procedure will often correct an oil leak at the compressor or at the turbine bearing seals.
Berryman B12 is available at most Auto Parts Houses, or through RAM.
See Berryman B12
For further information:
Berryman Products, Inc.
3800 E. Randol Mill Road
Arlington, Texas 76011
817-640-2376
The turbo was fitted in 1993 it was not replaced at the engine overhaul in 1997.soit has done around 1900 hrs , I believe the blade tips were worn as well, I think it was time to change.
