leak down testers

[FunkyfullWidth]

I need to get a leakdown tester. I want one that I won't have any doubt as to the results. Matco sells them for around 150, snap on for about 300 and the harbor freight one is less than 40.

Anybody have experience with any of them? I see the harbor freight one is only capable of 15 psi. I can see that being ok for small engines but i'm doing automobile engines mainly. will the lower pressure give you different readings? I understand with high pressure testers you may need to pin the crank in place to keep the pistons from moving. Any advice on a good one. And of course with most specialty tool purchases, I need it yesterday.

 

[driz]

It's a simple airplane engine tester. I got one 25 years ago to work on my 150 and still have it. Useful for other engines too as long as you absolutely make sure the thing won't turn over when you put the air to it. Guaranteed to spin that prop like a samauri sword or fling a half drive 50'if it slips off.
I don't remember the outfit i got mine from but it's some not so well known line of tools that a lot like HF work just fine but aren't quite as solidly made. Try looking for airplane tools , airplane engine tester and that sort of thing. The name of the outfit that sells those is , and I am spitballing............something like ATS or ATIS, something like that . Lonok around and you will find them, start with amazon then ebay. You will need to make up an adapter for the smaller plugs in autos though. I just made one out of a HF air ****** soldered or brazed onto an old auto sparkplug that got drilled out and the glass part broken off. I doubt you would pay more than $40 for one. If you don't find one on the net look up Trade A Plane. That is the mag to buy everything airplane bypassing the middle man.
Word to the wise, hanging onto a prop is still a bit hard but with a 4' leverage no real problem. THat 1/2" rathet sure is a problem so use a buddy and hang on tight

 

[gungatim]

I've got the HF one. only used it a couple times on my Goldwing, but it worked fine. I don't recall it being limited to 15psi, though, have to check.

 

[martin666]

I use the one made by Lang. Rebranded by others and reasonably priced. Easy to find

 

[sberry]

This is the place for HF, mine works great.

 

[signcrafter]

Buy the lang for 80 dollars.

 

[airrj]

The OTC 5609 I have and I have used others as well, and I am very pleased with the unit. They run between $70-$80 normally I think.

Good Luck.

 

[LandofRath]

I made mine, easy to find plans they are rather simple.. It reads almost exactly the same as my neighbors professional gauge.. It just sounded like a fun project and I wanted one to test old bikes I picked up. But I guess there not all that pricey to begin with.

 

[FunkyfullWidth]

I guess my main question though is the high vs low pressure. I can see where low pressures would be better for a small engine.

 

[gungatim]

I guess my main question though is the high vs low pressure. I can see where low pressures would be better for a small engine.

I looked it up and you are right the HF is regulated to 15psi...reading the reviews on their site explained the pros, good for 2-strokes, and good for not having to lock the crank/rod from high pressure moving the piston, and good for identifying valves leaking where high pressure MAY seal them...supposedly still measures the same leakage, just have to be a little more sensitive on the guage reading. main con is you may not "hear" a leak as easily. that's from their site, my only experience is was with my Goldwing so YMMV...

 

[maxpower_hd]

I got an OTC one for I think around $40-$50. I don't remember exactly but it works just fine. The gauge was inferior though. It broke when I dropped it only a foot off the ground and it barely impacted. I replaced the gauge with a nicer one and have had no issues since.

 

[Squankum]

I am happy with my OTC unit.

OTC 5609 Cylinder Leakage Tester Kit
http://amzn.com/B0030EVL60

... HF is regulated to 15psi... and good for identifying valves leaking where high pressure MAY seal them...

I can see that... almost. Isn't the engine while working generating much greater pressure than all of these gauge setups? I could see it being an issue on the compression stroke, but only at the very beginning.

.

 

[HaroRider]

I have the HF one and while it does work the low pressure does make it hard to tell where the leaks are coming from. But the % of leakage works fine.

After you find the percent you can rig up the tester to shoot shop air pressure (I used a regulator) in and pinpoint the actual leak. Thats what I did anyway..

 

[619DioFan]

I have the otc 5609 set. seems to be a pretty good quality tool.

 

[T45]

Another vote for OTC. This is a tool where the middle ground is good. The kit is handy, the way its put together works well and overall the unit is fit for the task at hand.

 

[BillK]

ffw,
I didn't look at the HF one but it must be a single gauge type ?? Stay way from them and stick with a two gauge unit. You can use the two gauge type at any pressure and I feel it is more accurate. Mine is an ancient Moroso one, probably 30 years old and still does the trick even though I rarely use it.

 

[gungatim]

ffw,
I didn't look at the HF one but it must be a single gauge type ?? Stay way from them and stick with a two gauge unit. You can use the two gauge type at any pressure and I feel it is more accurate. Mine is an ancient Moroso one, probably 30 years old and still does the trick even though I rarely use it.

nope. twin gauges...

 

[jgorm]

I have the HF version. It's just a regulator and 2 gauges. You don't need anything fancy. Why would you need higher psi? The purpose of a leak down is not to measure compression, it's to find out why you have low compression. You just need to hear where the air is coming out so you know if its rings, exhaust valves, or intake valves.

 

[LandofRath]

I have the HF version. It's just a regulator and 2 gauges. You don't need anything fancy. Why would you need higher psi? The purpose of a leak down is not to measure compression, it's to find out why you have low compression. You just need to hear where the air is coming out so you know if its rings, exhaust valves, or intake valves.

Not completely true, sometimes you need to know how much compression your losing not just where. On some larger engines a leak of 20% might be considered perfectly sealed while on another that is a catastrophic failure... If it was only about hearing where the air is going you would not need the gauges just a air chuck and a hose that screws in.

Higher PSI can make it easier to locate a leak as stated earlier. But low pressure ones do the work as well. Many use 100 psi mainly just to make the math easy, 100 base point is 100% you lose 15psi its 15% ect ect.

 

[pi_guy]

In my years of using one the purpose was more directed towards the percent loss of each cylinder in relation to the other cylinders. Race motors do not make as much power if imbalanced and also leads to implosion or other unhappy results. The ideal situation is 5 to 15% of each other. That depends on motor type and lifespan.
If you are hearing air it time for a rebuild. Many of the units I have worked with use 100psi and there is a restriction so you do not move that much volume if you do have a leak or get the motor spinning if you do not have it locked.

 

[driz]

Not completely true, sometimes you need to know how much compression your losing not just where. On some larger engines a leak of 20% might be considered perfectly sealed while on another that is a catastrophic failure... If it was only about hearing where the air is going you would not need the gauges just a air chuck and a hose that screws in.

Higher PSI can make it easier to locate a leak as stated earlier. But low pressure ones do the work as well. Many use 100 psi mainly just to make the math easy, 100 base point is 100% you lose 15psi its 15% ect ect.

For small planes they regulate it to 80 on the first gauge then read the farther one. Why 80 I dunno. but that is the number they use for the usual 125 PSI engine that got designed sometime around the 30's. It works . For airplane purposes 75 is great , about all you get in real life. 70 is very good 65 is getting there , time to listen for the leak and below 60 you got problems, fix me now. Something like that.
BIG thing to remember if all the other one's numbers are good with ONe bad one run it a bit and test that poor one again. Rings do sometimes go into alignment with all the others momentarily. That will give you one temporarily blown looking set of rings that are really still as good as the others. It happens all the time you just never feel it before it goes away.
you listen for the blow by at the oil filler (rings), karburator (intake valve,yea my see key is still %^$^), exhaust (ex valve leak). Nothin to it really just an old fashioned method that was invented long before the Sun analyzer and followers dropped in.

 

[justme-]

Fwiw a couple weeks ago I did a Kawasaki engine update school, they covered lots of things including recommended tools. Many companies recommend tools they themselves sell, Kawi does not.
They actually recommend a NAPA unit.
They said they test in house various tools, these included and found the napa to be fas more reliable and repeatable than any other including the truck brands and the very popular otc. It should also be much cheaper than most but I can't verify as my napas near by are all the same guy and way overpriced compared to the average Napa.

 

[rhandwor]

http://www.tooltopia.com/search.aspx?find=otc-5609

 

[FunkyfullWidth]

If time wasn't a factor here I would have bought the otc one. I ordered the napa line and should have it today. It's labeled as a balkamp, but I was told is made by OTC just rebranded for napa. No idea as to the validity of that.

I'm going to pick it up today and take a look. for kicks i'll post results of what I find.