Leak testing

[Mouse]

How is a leak test performed. Do most testing devices actually read down to zero cfm with any accuracy, or is there another method used?

Thanks

John

[98-1074649673]

When u say "leak testing" are you refering to leaks between the head and adaptor, valve seats and just making sure you have no leaks on your test fixture?

I use a seperate probe/wand hooked to a digital manometer that I use for velocity testing. I run it around my sealing surfaces with flow depression applied. It will show a leak, if you put it in the port with valves closed and sweep it around the valve seat area it will show a leak there also. The same can be done with a water manometer.

Hope I addressed your question?

[Mouse]

Bruce,

Well, I was wondering about the SF600. I have seen mention of running it with everything closed and recording the cfm. Then deducting that figure from your readings. I recall seeing a reference to leak testing on the FlowQuik too, in that article by Sean Brown.

So I am assuming that these machines can accurately read down to zero?

John

[maxracesoftware]

i just switch over to the smallest # 1 Orifice
and with all cyl head valves seated and closed
and flow contol knob closed

turn on SF-600 and look at PerCent (inclined manometer)
for any reading above zero

you might have to adjust flow depression knob in very small increments to get test pressure to climb to at least 28 inches to check for leakage CFM...and when you do this, its best if you turn off flowbench ..then very slightly open flow contol knob in tiny increments..then turn bench on again.

you don't want to open flow contol with bench on at so very small amounts, there will be too much rubbing effect/friction on seal with that much test depression

as far as leakage, i wouldn't recommend you accept leakage in your tests ... i'd find source of leakage and correct it to zero as much as possible

i use headgasket and bolt cyl head down on flow fixture , located and centered on bore .