The correct kind of compression guage

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I have this one and it works just fine.
EEPV303A.jpg

Snap-On makes it and the part # is EEPV03A
I think it was around $250 off the truck but that was a few years ago.
 
I had a Star Products gauge that has a schader valve in the end of the hose that would not read more than 50lbs on any saw...It is sold by Snap-on and the reason I wanted to try it was b/c of price and the size of the hose...It was small and flexible enough to fit in the 041's which the Snap-on gauge I use at work would not fit in...So the schader valve at the end is not a tall tell sign...
 
I read somewhere, (probably here), that compression testers with long hoses don't give an accurate reading because of the volume of compression within the hose itself. Apparently it's enough to throw off the reading.
 
BuddhaKat said:
I read somewhere, (probably here), that compression testers with long hoses don't give an accurate reading because of the volume of compression within the hose itself. Apparently it's enough to throw off the reading.
Click to expand...

That my friend is the whole reason of this post. The schrader valve is a one way valve, which lets subsequent strokes build the pressure to the maximum the motor is capable of, and takes the variation of the amount of gas that needs to be compressed out of it.

BTW, I just got a cheapo (says IEC on the gauge face), $27 at Bumper to bumper, with a schrader valve and 3 or 4 adapters. I haven't tested it against a compressor yet, but seems close based on how hard different engines pull over.
 
basic calibration says to use a known to be correct gauge.
highest quality gauge I've got is a German made Drager.

compression gauge is snap-on

FATGUY said:
I have the same guage you do. Now, how do you know it's not reading high and the lisle is reading correctly?
Click to expand...
 
Damn good topic.
Having said that before i got my gauge i did a search rather than asking a thrashed out question and fully understand the reasons for the correct valve placement.
Fwiw i got an ABW (probably only sold in oz - make a lot of mechanic tools) gauge, they are made in the US by "US gauge" which according to my research make the gauges for snap-on, but cost a lot more.
Funnily enough the super dear ABW gauge with all the fittings and plastic case has the valve where the quick release fitting for the hose extensions are and not at the tip, the cheaper one I picked only has 14 and 18mm fittings and no case - but has the valve at the tip!!
 
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outdoorlivin247 said:
I had a Star Products gauge that has a schader valve in the end of the hose that would not read more than 50lbs on any saw...It is sold by Snap-on and the reason I wanted to try it was b/c of price and the size of the hose...It was small and flexible enough to fit in the 041's which the Snap-on gauge I use at work would not fit in...So the schader valve at the end is not a tall tell sign...
Click to expand...

I don't know what the deal was with your guage, but it is a fact that you must have the Schrader valve at the tip. To indicate anything otherwise is to only mislead someone.
 
I'm going to ask Greg to chime in here. I've never seen the tester Baileys sells but am told that it does no have the required valve at the tip. Maybe Greg can clarify this for us. They're always looking to improve their product so it's only fair for him to know what the end users are experiencing.
 
Funny no one would mention the importance of a proper seal at the end you tap the hose fitting on the gauge into the cylinder head. I purchased a brand new KD compression tester and there is no seal of any kind on either of the fittings included in the kit. Tried an O ring still no good. Dismantled and Welded up a spark plug to fit on the testers hose still no good. Tested the KD on my compressor and it registered nearly the same. Just can't get the seal to the cylinder head. I am repeatedly using my fathers old HOLD THE SAW WITH ONE HAND..... HOLD THE GAUGE tightly to the cylinder head .....POSITION YOUR FOOT IN THE SAWS HANDLE PULL 3 OR 4 TIMES .......(IF COMPRESSION IS HIGH I NEED TO ALSO USE MY KNEE TO HOLD DOWN THE SAW) Provides what appears to be an accurate reading. Have done the compressor test on the old gauge and it does register nearly the same. I am leary of anyone providing compression test results over 160 pounds. Best I ever registered on my gauge was 150+/- lbs. :chainsawguy:
 
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almondgt said:
Funny no one would mention the importance of a proper seal at the end you tap the hose fitting on the gauge into the cylinder head. I purchased a brand new KD compression tester and there is no seal of any kind on either of the fittings included in the kit. Tried an O ring still no good. Tried mounting a spark plug washer on the fitting still no good. I am repeatedly using my fathers old HOLD THE SAW WITH ONE HAND..... HOLD THE GAUGE tightly to the cylinder head .....POSITION YOUR FOOT IN THE SAWS HANDLE PULL 3 OR 4 TIMES .......(IF COMPRESSION IS HIGH I NEED TO ALSO USE MY KNEE TO HOLD DOWN THE SAW) Provides what appears to be an accurate reading. Have done the compressor test on the old gauge and it does register nearly the same. I am leary of anyone providing compression test results over 160 pounds. Best I ever registered on my gauge was 150+/- lbs. :chainsawguy:
Click to expand...

Never been an issue. Both of my guages have o-rings seals at the end. Are you using a guage that threads into the head or one of the push on types?

Why do you have a problem believe readings over 160 PSI? I've got several, one at 200. I've got some that are under 150.
 
blsnelling said:
I'm going to ask Greg to chime in here. I've never seen the tester Baileys sells but am told that it does no have the required valve at the tip. Maybe Greg can clarify this for us. They're always looking to improve their product so it's only fair for him to know what the end users are experiencing.
Click to expand...

Called Baileys and they said it was at the tip. Apparently its inside about 1/2 in. so its hard to see w/o shining a light in opening. Kinda thought my Baileys was somewhat accurate but know I know
 
redunshee said:
Called Baileys and they said it was at the tip. Apparently its inside about 1/2 in. so its hard to see w/o shining a light in opening. Kinda thought my Baileys was somewhat accurate but know I know
Click to expand...

Good deal. I just couldn't imagine them selling the wrong kind of guage as their only option. Puts that old myth to rest.
 
The KD tester utilizes a rubber hose and threads into the cylinder head and has been useless to me to date. Both of my testers utilize the Schrader tips. I trust the gauge that works for me and have tested approximately 30 saws, tired, saws, newly rebuilt saws, saws that I rebuilt and have run in the bush for extended periods of time and new saws. To my knowledge all the saws are stock. None have registered over 155 PSI. I did change seals in an Echo 500vl recently. I tested the saw prior to disassembly and it was 150 PSI on the money. I damaged the base gasket so I cut several of my own with the material I had on hand. The best reading I get now is 135. I will leave the 500vl at such until I find an OEM gasket to fit. Just my personal experience on the subject. I would be interested in further observations regarding same.:greenchainsaw:
 
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