Compression tool

[gp1200x]

If you have a newer style XP like a 97 XP or XPL unit, what compression tool are you using to check your compression? Years ago I had a very short stubby hand unit but can't locate it. I tried using a tool from one of the Amazon kits with a treaded hose but that hose is probably 16-18" long. My readings were about 128 -130 in both but that volume in hose (small diameter but still volume) bothered me. I then tried the 6 inch bent shaft in the kit but that is a hand held pressurizing type and I get readings abour 160-175 but I could not get a good seal and can hear the leaking due the angle because of the clearance.

Anyone recommend or know a good short tester with a super short maybe a 4" stubby on it with no quick connect on it? Just about every tester out there appears to be the same unit with quick connects in different kits and are all too long.

 

[Boyd12]

Grainger sells the gauges etc. You can make one to fit your needs.

 

[burtshaver2021]

Mine is just from Canadian Tire, it has a quick connect and a hose but I trust it. As for volume in the hose, that’s not an issue, it either makes it’s pressure or it doesn’t

 

[gp1200x]

I found an ordered an old style hand held one with a very short pipe. I want to get an accurate reading to see how high my compression is to determine whether I can run 91 no ethanol or need to stick to 93 with ethanol. I think it is going to come up between 180 and 190 since it was hitting 175 with the gauge using a straight metal stem but leaking on me. Heads were worked and milled years ago.

Those gauges with longer hoses will give you readings to compare to each cylinder but not an accurate true reading since you greatly increased the head volume due to that cable volume and they have no check valve in them to hold the air so it will lower the actual readings. (Double the volume half the pressure etc.) Using a very stuby hand held with the shrade valve right at the end usually gives a close reading of the actual pressure.

 

[mikidymac]

No, as long as the hose has a schrader valve at the tip that goes into the head you will get a completely accurate reading.
Mine is from AutoZone and been accurate for about 20 years.