VAF Forums

VAF Forums (http://www.vansairforce.com/community/index.php)
-   RV General Discussion/News (http://www.vansairforce.com/community/forumdisplay.php?f=2)
-   -   Silver hawk Fuel Injection Question (http://www.vansairforce.com/community/showthread.php?t=135666)

Robb 03-13-2016 07:36 PM

Silver hawk Fuel Injection Question
 
I am in the process of doing my first annual inspection on my RV7. I am removing all the panels and so far I have not see any type of fuel filter in the system. I do have the electric fuel pump between the seats on the lower console. I checked all the previous logs and do not see any mention of it. I am used to a gascolator in my Husky. If not it sure looks like it should have some type other than the one inside the fuel injection system.

rzbill 03-13-2016 07:50 PM

Quote:

Originally Posted by Robb (Post 1061978)
I am in the process of doing my first annual inspection on my RV7. I am removing all the panels and so far I have not see any type of fuel filter in the system. I do have the electric fuel pump between the seats on the lower console. I checked all the previous logs and do not see any mention of it. I am used to a gascolator in my Husky. If not it sure looks like it should have some type other than the one inside the fuel injection system.

There is a fine screen filter in the AFP pump system (between the seats). Its the big gold anodized cylinder. Contact Airflow Performance in Spartanburg, SC for details if you do not have original documentation.

There is also a VERY VERY fine screen filter in the SilverHawk fuel injector servo body. Contact Precision Airmotive for documentation regarding maintenance.

Both of these filters should be inspected and cleaned at the annual condition inspection.

RickWoodall 03-14-2016 07:19 AM

Fuel fliters
 
In Canada our regulators make us also install a gascolator. My annual, the afp filter comes out in tunnel between knees, as well as all fuel connections there checked. Also, the fuel servo is inspected for and the screen pulled on that and the gasket/ring replaced. My andair gascolator pulled and cleaned/inspected.

If you bought the plane, I would contact the previous owner/builder. Pretty important stuff. He can surely tell you what there is,where it is, and what they did as normal annual routine. Not something to skip or not fully understand.

DanH 03-14-2016 07:47 AM

With the EX-5, Precision requires a 35 micron filter installed downstream of all pumps and valves except the engine driven pump.

In contrast, the cylindrical AFP filter supplied with their boost pumps is 125 micron, and is installed upstream of the electric boost pump. As such, a builder may have deleted it.

Robb 03-14-2016 12:29 PM

Thanks for the info

ILikePike 03-14-2016 03:15 PM

I have this on my list of things to figure out. Dan are you saying that the 125 filter is ok or should a 35 be installed IAW the Precision recommendation? I installed the Vans supplied filter/pump and FWF kit on my IO-360-M1B.

DanH 03-14-2016 04:03 PM

Quote:

Originally Posted by ILikePike (Post 1062226)
I have this on my list of things to figure out. Dan are you saying that the 125 filter is ok or should a 35 be installed IAW the Precision recommendation? I installed the Vans supplied filter/pump and FWF kit on my IO-360-M1B.

I don't think a 125 micron filter prior to the electric boost pump can be a bad thing, regardless of Precision's instructions. Besides, I'll bet Don at Airflow wants that 125 micron filter in front of his boost pump, just to protect the pump.

I would not put a 35 micron screen in that AFP canister without careful fuel flow checks with the engine compartment hot, hot, hot.

rzbill 03-14-2016 04:07 PM

Quote:

Originally Posted by DanH (Post 1062068)
With the EX-5, Precision requires a 35 micron filter installed downstream of all pumps and valves except the engine driven pump.

In contrast, the cylindrical AFP filter supplied with their boost pumps is 125 micron, and is installed upstream of the electric boost pump. As such, a builder may have deleted it.

Now that's got me curious. Specifically about the mesh of the finger screen installed in the EX-5 servo. I see the note about 32 micron filtered fuel supply by Precision but I have not found reference to what the internal screen is. Just by observation, I have a hard time believing it is finer than 32. I guess if it is, I will have learned something.

No intent to change anything since my system has had very little debris on the last 4 annuals (480 TT). Hardly worth the disassembly (but yes I will continue to do it). :)

ILikePike 03-14-2016 07:39 PM

I was not actually thinking about changing out the 125 micron filter before the pump. The question was about the wisdom of adding a 35 micron filter somewhere after the boost pump?

RV7A Flyer 03-14-2016 09:15 PM

Quote:

Originally Posted by DanH (Post 1062239)
I don't think a 125 micron filter prior to the electric boost pump can be a bad thing, regardless of Precision's instructions. Besides, I'll bet Don at Airflow wants that 125 micron filter in front of his boost pump, just to protect the pump.

I would not put a 35 micron screen in that AFP canister without careful fuel flow checks with the engine compartment hot, hot, hot.

I note that the Andair pump that I and many others have has their filter before the pump. So the pump manufacturer wants it *before* the pump, the FI manufacturer wants it *after* the pump, and none of them, as far as I can tell, are small enough. :)

I don't know what the upshot of all this is...I'm not changing my system, as it's worked flawlessly for nearly 400 hours now and I've not found anything in any filter since the first 25 hours (just a hint of some blue paper fibers from initial assembly). YMMV.


All times are GMT -6. The time now is 04:22 PM.