[SuziBlu]

Gday folks, thought I might be able to find which eare the head gasket was gone by doing a compression test.

As near as all are 150psi, seems low to me, shouldn't this be 180psi.

It goes like a scalded cat, so maybe the compression tester is out of whack, it is a well known brand, its called, Made In Taiwan.

As all are so very similar, are they all low, or is my tester ready for the floatation test. It hasn't been used in years.

Maybe if the VRS kit ever turns up, I'll be doing it at me mechanic mates shop, do a test there ?

[maloo11]

Yeah i think your high quality 'made in Taiwan' gadget is stuffed. Compression should be 170 minimum, so if all cylinders are at 150, no way would it be going like a scalded cat.

[SuziBlu]

Yea thats what I was thinking, the fact that they are all so similar tells me the donk is fine, the fact that they are all so low tells me my compression tester is terribly grimbo

I will test it against my mechanics quality gauge, but yea, its for the bin. Did its job years ago, past its use by date.

[fordem]

maloo11 wrote:

Yeah i think your high quality 'made in Taiwan' gadget is stuffed. Compression should be 170 minimum, so if all cylinders are at 150, no way would it be going like a scalded cat.

Do both wet & dry tests - you might be surprised - about two years back I asked a friend of mine to do a compression test on my G13BA, and it came back around 120 on all four - like you I felt the engine ran too well for the compression to be that low.

I went out and bought my own Equus tester and ran my own tests - 120 dry, 195 wet - I ran it for another year until the loss of power became readily apparent before rebuilding and it was actually down to around 90 on all four.

Also - the compression tester is nothing more than a pressure gauge with a non-return valve, you should also be able to check it's accuracy with any handy air source - just find a way to couple it up and compare the pressure gauges

[maloo11]

Yeah, so your rings were stuffed. Dry test should be 170 minimum for a g13, wet test will increase compression as it seals the cylinder/rings, therefore increasing compression. If it doesnt increase much between wet/dry tests, compression aint a prob. Im no mechanic, but thats how i understand compression tests should work

[fordem]

Exactly - but the compression tester was fully functional - and SuziBlu's might be also.

The point is that a dry test only tells you half the story, and all four cylinders CAN read low on an engine that runs well.