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General Information => General => Topic started by: Smoker on April 23, 2014, 10:51:13 am

Title: Harbor freight compression tester?
Post by: Smoker on April 23, 2014, 10:51:13 am
To buy or not to buy? I did a quick Google search and found advice both ways as usual. Figured I'd check with you guys specifically.

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Title: Re: Harbor freight compression tester?
Post by: vanbcguy on April 23, 2014, 11:53:53 am
Most folks say it tends to read a bit low.  The real purpose of a compression tester though is to track changes over time and to identify differences from one cylinder to the next.  It'll do those things just fine.
Title: Re: Harbor freight compression tester?
Post by: ORCoaster on April 23, 2014, 12:59:09 pm
They make several kits so be careful in comparison shopping.  I have one and it seems to do fine.  Like is said, for comparing across the engine and approximate values only.

Title: Re:
Post by: Smoker on April 23, 2014, 01:25:13 pm
Thanks. That was my thought as well... that a compression tester is meant to show major problems, not extremely precise numbers. I think I'll grab one.

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Title: Re: Harbor freight compression tester?
Post by: TimpanogosSlim on April 23, 2014, 10:27:00 pm
indeed, it seems ok but test it against pressure gauge you trust perhaps?
Title: Re: Harbor freight compression tester?
Post by: Wayland on April 24, 2014, 11:12:16 am
I bought one off ebay, but as far as I know, it's the same as the one HF sells. I have used it several times, and while I have nothing to compare it to, the results have always seemed believable. It seems like a decent quality tool.
Title: Re: Harbor freight compression tester?
Post by: vanbcguy on April 24, 2014, 11:25:38 am
My understanding is that the reason they tend to read low is due to the volume inside the adapters rather than any issue with the gauge itself.  23:1 compression means the volume of the adapter itself is fairly substantial so it will cause a lower "apparent" reading than a different gauge with less space inside the fittings.