HF Compression gauges

[Dr Honda]

Hi Guys,

I've been a firm believer in the HF compression gauge. I have a few, and they work great. But... over the last year or so, guys have gotten them, ans said how low they read.



SO.... today, a buddy came to my shop with a brand new HF gauge, and wanted to see how to use it. So we plugged it into my Polaris, and it was only reading 80 psi in all 3 cyl's. Since that is crazy low, I grabbed my older HF tool... and check it... and I was 130 psi in all 3 cyls. (Factory spec)


At that point... I hooked his gauge to my shop air.... and the gauge was reading basically the same pressure as my regulator. So, I decided to try it again. AND... again, I got 80 psi.


After a little head scratching... I realized something........


HARBOR FREIGHT DECIDED TO REMOVE THE SCHRADER VALVE AT THE TIP OF THE HOSE !!!!!!!!!


Without that valve.... the air, trapped in the hose, is simply expelled when the piston goes down. In turn, adding the volume of the hose, and fittings to the chamber of the engine. With a valve in the tip... the pressure in the hose will build over a few revolutions, and it would work.





SO.... unless you can find the older HF number 92697 gauge.... don't bother with the HF gauge anymore. It looks like the gauge that Advance auto sells, is the old HF version. (for $29) It's $10 more than HF sold them for... but it's still cheaper than most others.

 

[Sportster-2001-951C-Stock]

LOL, I guess they moved the schrader to the top of the hose?

So the HF gauge WAS worth $19, NOW it's worth $5, if that. We should see a flurry of these being dumped on fleabay soon when they discover they don't work.

 

[Cyclopse]

Any comment on this compression gauge? I've had it for ages but never used it. It was a friends fathers, I got it when he passed away fifteen years ago. It's got the shrader valve at the bottom end where the rubber tip is. Do most compression gauges thread into the spark plug hole or do they have the rubber cone like this one? I'll try it out when I get my ski out of storage. It runs great but the motor is seventeen years old with no rebuild as far as I know.


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[Dr Honda]

I have an old push in gauge like that, and it works well. The only drawback is... you normally need a helper, since you may need 2 hands to hold enough pressure on the tool to keep it from leaking.

 

[LouDoo]

I also have a push-in type gauge, I've had it for over 30 years, I replaced the sharder valve in it about 5 years ago. The gauge is very accurate and still works well, however, it works fine for 717's but with a 787 (the engine being slanted) there's not enough clearance between the bulkhead and the engine to use the gauge. I'll bet you're gonna have the same problem with your GTX.

Lou

 

[Cyclopse]

Thanx for the advice, I'll see if I can rig it with a plug thread fitting and hose.

 

[Spimothy Leary]

i'll have to look in my garage now but I must have the older version of HF gauge.
my ski reads 151,151,153 on the gauge, i'm guessing that its about 24 months old.