Barrel Valve leakdown

I have a Enderle Square BV on a NA injected engine.
Idle check is set to 25 lbs. Throttle blades set at .010. I notice when we were leaking the barrel valve that air was coming from the idle check valve when throttle was wide open. Of course when I closed the throttle air blew out as it passed the set pressure and then continued to leak a small amount after the throttle was completely closed.
My question is, should the idle check leak at full throttle? The spool valve doesn't close the idle port?
If this is normal then should the leakage be added to the calculations in determining pill size?

This was the first time I noticed this and was curious. On my blower motor leak was set so high I never noticed.

Thanks
Dave

 

Thanks Mike. Yes I cap it when doing a leak down also. But when using it on a NA motor the main pill that is normally in the BV is a blank. Then a main pill is put in a check off the pump which is returned through the return line. I don't really understand why it isn't in the BV like I do on my blower motor. But this is what is recommended.
I set the pressure on the idle check with it attached to the leak down gauges. It's just I noticed at wide open throttle I was getting leak through the idle check and thinking it has to affect the amount of fuel being returned.
On the dyno we noticed the engine was running a little lean except at idle. I richened it up by going from an .085 to a .075 and it was still lean. This is with a -1 enderle pump flowing 7.8 gal and .036 nozzles in all 8 ports. I didn't have a smaller pill to change to and that's when we started looking at stuff. Noticing this made me curious as I thought the idle was closed off at full throttle.


Dave

 

Got it, so as I have already done I am compensating for the leakage by adjusting the main fuel return..

I was just curious as to this leak being normal or if something was going on. By your answer it is something that just happens because of machining tolerances. Kinda like blow by at the rings..

Thanks
Dave

 

I’ve never understood this schematic. What is the purpose of the idle bypass.? What size pills do you run in each poppet? I’m getting ready to use a square Bv for the first time and have the “idle” port plugged. Just using the “main”

 

Idle bypass is only supposed to be active when throttle is closed. Main purpose is to return excess fuel when you chop the throttle the poppet opens to prevent pump from dead heading.

Idle poppet does not have a pill, just a check. Mine is set to open at 25lbs. At idle the pump just trickles so it forces fuel to the nozzles and supposedly helps the engine to start. To me it is more to prevent dead heading the pump.
The other poppet is the main bypass (if you have a blank pill in the BV which I did to mine). The poppet for the main bypass is set to open at 3lbs on mine, and currently I have an .085 pill in the pill holder.
My pump is an -1 Enderly and I have 97lbs of fuel pressure at 7200 rpm.

I will tell you this is the same BV I use on my blower motor and it is set up totally different. I could not get any fuel pressure at all tops was 30-35lbs for some reason. This was on the dyno the first time. I had issues and brought the engine home and tore it down again.
Before I went back to the dyno I set the fuel system up as described in the picture and the pressures I've stated and everything worked as it should.
What you are going to do is similar to the way a Rons Injection is set up. And it works fine. But the Rons system uses a check in the return fuel line but is only there to aid starting. Or so I was told.

Long winded, and I hope it helps.
As you can tell by me starting this thread I definitely don't have all the answers.

Dave

 

NA Hilborn 40+ years ago usually had a ~3 psi idle bypass check and a ~20 psi secondary check that would close off at ~30% open throttle onwards ..... the pill was in the idle circuit.
A friend used to reverse the idle and secondary check pressures so it still idled at 3 psi but once the secondary closed off it would instantly create more back pressure and fatten the mixture slightly, a bit like an accelerator pump in a carb.
His car was an early footbrake Powerglide dragster setup with a less than optimal converter so it provided a clean idle but then helped him get off the line when he mashed it.

 

Now we have electronic lean outs...

I'm fat at idle right now, but I'm waiting to get to the track before tackling that issue..

Dave

 

Yeah, it's all totally different now but there's always more than one way to skin a cat.

 

Thanks Dave. Seems like the thing they call idle poppet on the square BV schematic has the same function as the pump saver poppet on a k valve (the top one).