Just a quick PSA, I've already returned it and didn't take pics. We all know Harbor Freight can be hit or miss, but the compression tester is a MASSIVE miss. Dangerous even. I bought one to do a compression test on a 95 Wave Venture 701 I got to work on, and on a rebuilt engine it was only showing 80PSI on one cylinder and 70 on the other. That is obviously far too low and I was worried I was gonna have to ship it back to the rebuilder. I did some quick googling and came across a lot of info about the HF testers having a design flaw. They don't have a schraeder valve at the cylinder end of the hose- only at the other end, so you end up lots of PSI short of where it should be as the air in the hose gets compressed and the hose stretches. I rented one from O'reillys and it gave me 155PSI and 145PSI. For a similar price to the HF one you can get a Bosch one on Amazon that is spot-on with the oreillys one. Supposedly some of the HF ones *do* have schraeder valves on them but not all of them.
PSA: Harbor Freight compression testers are worthless
- Thread starter K.Aoi
- Start date
Nice unnecessary sarcasm- honestly the majority of stuff from HF is passable or even good- but there are stinkers, and this is the biggest one I've seen to date.
I already returned it so I cannot, but I believe it held pretty well what it did register.
Ya gotta do what ya gotta do, but I hate cheap tools.
do have a HF tester, just for comparison, one cylinder to the others, always thought the cheesiest thing about them was the O-ring sealing the threads at the sparkplug adapters. Mine measures proper but it's been used seven times, well three times on seven cylinders........ : )
three engines total. If mine lied to me I'd junk it too.
three engines total. If mine lied to me I'd junk it too.
Wonder if they sell defibrillators as that might be a future investment, bwahahaha...
Wouldn't be shocked if they do!
What?
I think it means that the pressure doesn’t build up as you crank, it just goes back into the cylinder, resulting in low readings (?).
Yeah I don’t get it. The valve is there to release the pressure in the hose prior to unscrewing it from the spark plug hole or to take a second reading. You want the valve up by the gauge since the other end is often buried down the plug well. It doesn’t affect the gauge reading no matter where it’s placed. You’re not “lots of PSI short” by any measure.
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It's not known as Hazard Fraught for nothing.
I bought a fuel rail pressure gauge from them. The first time I used it, the car cranked, the gauge filled with gas and it sprayed all over the engine and the firewall insulating pad, locking the unleaded smell into the hvac intake for weeks. that was a penny wise and 5 pounds foolish.
AKA Horrible Freight
Horror Fright
Never understood buying cheap gauges, micrometers, etc.
If it's important enough for precision, why buy imprecise tools?
If it's important enough for precision, why buy imprecise tools?
Harbor Freight is usually the last place I shop for tools that require any kind of measuring or accuracy. If I need a wrench I can cut in half or make a tool out of then I'll go there.
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