I would be interesting in hearing everyone's preferences as far as brand/model. I'm not a professional and this tool probably won't get used very often.

Been using a Moroso for years.

I have a snap-on for 30 years. You can buy or even make a cheap one, lots of Youtube videos. Ebay has them for $35.00 https://www.ebay.com/itm/304592254582?chn=ps&_trkparms=ispr%3D1&amdata=enc%3A1txWD82BQSpO5rMr5kUpOBg18&norover=1&mkevt=1&mkrid=711-213727-13078-0&mkcid=2&itemid=304592254582&targetid=4580840332323346&device=c&mktype=&googleloc=&poi=&campaignid=441131611&mkgroupid=1235851352595866&rlsatarget=pla-4580840332323346&abcId=9300906&merchantid=51291&msclkid=7aeab19b263d12d5d47fd5731e906035

No real moving parts just pressure regulator, two gauges, and a fixed orifice.

FAA approved dual gauge aircraft tester from Aircraft Spruce is what I use now after using a Moroso single gauge for years

Dual guage Snap-on for many years. Never had an issue.

Never used one. Better? More accurate? More precise? More repeatable?

If it's better, I'm interested.

I bought the summit house brand years ago , does the job for me , like you I'm not a pro and I think friends have used it more than me .

Cab, it seems that aircraft air leaked at 70psi when most cars are tested at 100psi.

Any reason for that?

Thanks,
Bill

I have a MAC I bought off the tool truck probably 20 years ago or so.

I would just buy a lisle off of Amazon for $30 if you aren't going to use it a lot.


https://www.amazon.com/Cylinder-Lea...;hvtargid=pla-4584482475463938&psc=1

Most of the leak down meters I've seen and used call for 80 lbs., not 100
My air compressor kicks on at 75 lbs. and shuts off at 125 lbs. so when it kicks on so I have wait until it shuts off to continue testing
I set the pressure on every cylinder to make sure I'm getting semi accurate results, you can rock the crankshaft a couple of degrees with air pressure in the cylinders, not to many degree though and see a change, especially on a cold motor

Yep. Single gauge tool needs to have the regulator adjusted every hole.


Two ways to do this. Set it on TDC - valves closed - and check it, or plug the hose in, bar the engine over until it hits the compression, give it an extra push and hold it steady until the gauge settles.

Seen both used by pros. One better than the other?

https://www.ebay.com/itm/304592254582?

I got mine from Summit over 30 years ago and test at 100 pounds. One of the reasons I bought a 2 stage compressor.

Thanks for the info guys. It sounds like there may not be much difference in quality between the various brands .

FAA certified A&P mechanics do it with the piston down low on the firing stroke and then use the prop to rotate the crank and piston back up to get it sealed up and read what their gauge says, not real precise but they are making the FAA happy by using that method
I'm trying to remewmber the cutoff reading for failing the FAA guidelines, I'm thinking 70 % leakage was still flyable for another year on several cylinders(2 out of six )
I would go fly my plane for twenty + minutes before doing any engine tesing on compression, those air coll motors are really loose on the clearances

I warm engine, put it on TDC and hook up tester. Adjust inlet pressure to 100 PSI. Look at cylinder gauge. Subtract whatever it reads from the 100 PSI. That is your leak down percentage. Continue through firing order to do rest of cylinders.

"Please note: This cylinder leak tester is not suitable for shallow cylinder."

Never heard this term before. What is a shallow cylinder?

I bought one recently, just a cheap Sealey one. Compression test said it was low on #3. I thought it was just a cylinder head gasket. The thing with a leakdown test is you can narrow down where your issue is when you locate where the air is escaping from, for example exhaust or inlet valve, gasket, rings or bore.
We had air escaping from the breather, 100% leakdown so I thought maybe we'd nipped a ring ? Fault is below.

It may not be correct but I always set the gauge (dual gauge) to 100, connect it to the cylinder that is at TDC and bring it back up to 100 psi.

It makes the math easy on the leakdown percentage.

Sometimes I do have to trip the compressor to get back up to over 100 psi.

Probably the most important is that I do it the same way and record the results.

Had and used OTC for years with no issues.