Help! compression tester stuck in miata : Grassroots Motorsports forum: Grassroots Motorsports Magazine

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Oct. 11, 2011 12:28 p.m. mw HalfDork

About two weeks ago, I tested the compression in my miata. When I did the cylinder, the adaptor that screws on the end of the tester, did not come out and just unscrewed from the tester. I decided to put a drop of locktite on the tester and screw it into the adaptor. I then went on vacation and forgot about it until now. Now neither of them will turn. The only turning Im getting is the rubber hose on the metal end of the tester.

I realize that locktite may have been a bad idea. In the miata, theres no room to get any tools down there to turn the adaptor. I was considering, (and this may be stupid) trying to run the engine to heat it up hoping it would expand and loosen. I was going to pull the injector wires for that cylinder and ground the plug and then let it run on 3 cyl until warm. I was also going to tape down the release on the tester so the compression tester doesnt get a big workout. Thoughts...

Also, its a harbor freight $15 tester, so Im not that concerned about it.
Oct. 11, 2011 12:35 p.m. MG_Bryan Reader

Is there enough room to grab onto the metal part with something? I had to modify of set of pliers for a similar situation at one point, but that was because a larger than needed sparkplug socket was stuck in the head.
Oct. 11, 2011 12:46 p.m. mw HalfDork

Nope. It's about 3 1/2" down and the hole is about 1.1" around.

It turns out the car won't start on 3 cyl anyway, so that plan is out.
Oct. 11, 2011 12:56 p.m. mw HalfDork

It's fixed. I ended up cutting the hose. I then took a small flat screw driver that I ground into a bit of a point and hammered it down the hose. It unscrewed.
Oct. 11, 2011 1:58 p.m. ansonivan Dork

A brutal solution to a brutal problem, I shall drink to your success this evening.
Oct. 11, 2011 2:03 p.m. TRoglodyte HalfDork

mw wrote:

It's fixed. I ended up cutting the hose. I then took a small flat screw driver that I ground into a bit of a point and hammered it down the hose. It unscrewed.

You are a lucky man, so lucky I am buying a lottery ticket just reading about how lucky you are.
Oct. 11, 2011 2:17 p.m. mw HalfDork

I do feel lucky. The car is my dd and I have to go to work tomorrow.
Anyone car to comment on my compression numbers? 170,155,155,160. It's a 97 with 130k. I think it's down on power, but wasn't sure if compression was the main culprit.
Oct. 12, 2011 6:24 a.m. 44Dwarf Dork

I was going to say stick the longest philips screw driver down the hose and tap the end when it gets to the fitting and unscrew, no need glad you got it out.
Oct. 12, 2011 8:05 a.m. mike Reader

Those comp numbers sound fine for a 100k+ Miata engine. I've daily-driven a Miata with worse numbers than that for a year or two before pulling the head for a quick-and-dirty valve job (and the 150k shortblock is still stuck with the original pistons and rings).

Also, I've had real concerns about compression testers getting stuck in the spark plug holes. I'm glad you managed to find a way to get one back out!