flow bench idea?

[fiatfactory]

Hi all, first post, long time reader.

I have an FMA 400 flow bench, which I mainly do small european 4 cylinder cylinder heads. It uses a flow.com and software similar to the recent supaflow benches, in that it has pitot, swirl and tumble capabilities.

My question is this: I currently use a pitot tube to measure and record air speed, but feel that some useful information might be had if I could take air speed readings right at the valve head...to assess any air speed differences around the valves periphery.

My pitot tube doesn't allow me to reach that far and accurately around the corner.

My idea was to fabricate a dummy valve, with a small hole in one of the faces leading to a hole which carries on up the valves stem and allows me to connect my rubber hose to... but I'm stumped as to exactly where, and what orientation this hole (or pipe) should be. Any advice, ideas?

Thanks in advance,

SteveC

 

[MikeHalloran]

The first thing that came to mind is a hollow stem, with a small nipple projecting radially into the valve pocket, terminating in a short length of lead tubing that you can bend to orient and position near the valve seat.

Mike Halloran
Pembroke Pines, FL, USA

 

[tbuelna]

flatfactory,

If you are willing to spend some time and money, you can build a test valve body using the same techniques used on small scale wind tunnel models to measure local surface air pressures. First, machine a hollow open-ended valve body and drill small diameter ports at the surface locations you wish to measure air pressure. Then braze tiny stainless tubes to the backsides of each port and route the tubes up the valvestem. Finally, connect the tubes to a device that permits the air pressure in each tube to be measured. If you can index the test valve, you can probably use just a single surface port.