Rotary Compression Tester?

Brigdh · Postby **Brigdh** » Tue Jun 24, 2014 9:14

I figure its a long shot, but does anyone have a rotary compression tester? The RX-8 is making angry noises, and I'm trying to narrow down the issue.

Postby **RX-7 Chris** » Tue Jun 24, 2014 9:14

there are ways to do it with a piston one.

Brigdh · Postby **Brigdh** » Tue Jun 24, 2014 9:14

Its a wee bit hard to watch the e-shaft pulley, a piston tester display, and crank the engine without any assistants

speedjunkie · Postby **speedjunkie** » Tue Jun 24, 2014 9:14

No but I plan on buying one sometime soon. Well, after buying rebuild parts lol.

Postby **RX-7 Chris** » Wed Jun 25, 2014 9:14

Brigdh wrote:Its a wee bit hard to watch the e-shaft pulley, a piston tester display, and crank the engine without any assistants

very true.

speedjunkie · Postby **speedjunkie** » Wed Jun 25, 2014 9:14

I hadn't thought of it, but why do you have to watch the e-shaft pulley?

Brigdh · Postby **Brigdh** » Wed Jun 25, 2014 9:14

Because I'm not sure my seals are all working as they should be, so I'd like to correlate the number of pulses to the rotation of the e-shaft.

GR-8 · Postby **GR-8** » Wed Jun 25, 2014 9:14

There was a guy that had one but he moved to Texas. It was the TwistedRotors TR-01. Worked great. I'm looking to buy one as well. Especially since I felt the Grey 8 misfire a few weeks ago at 7k while getting on to the highway.

Apparently the TR-01 V2 is sold out. It's been like that for over a year. Not sure where to pick one up now. Know of anyone else that makes one? The last time the guy visited his own forum was back in Nov.

I may just end up doing it wit a piston tester. To much hassle finding one. Especially for the price. That's a used AP for the grey 8.

Brigdh · Postby **Brigdh** » Thu Jun 26, 2014 9:14

Yeah, I've been trying to get a TR one for a while now. I rented one from a guy on RX-7 club a while ago and I liked it.

I don't have the link handy, but there is a company that makes one, but its kinda pricy for what you get (like $600 if I recall correctly). You basically hook up the sensor to a laptop, and their software graphs the pressure readings from the sensor. You have to calculate the compression and RPM manually from the graph output.

I've narrowed down my problem to the engine, which is still under warranty, so its now the dealership's problem.

Brigdh · Postby **Brigdh** » Sat Jul 26, 2014 9:14

So, the Twisted Rotors compression testers are back (sort of). The guy behind TR has been making 5 testers a week, and then selling them online for $350 + $20 shipping every Friday at 5pm CST (aka 4pm here). The first 3 rounds of this had the testers selling out within minutes, but the batch that started selling yesterday was not sold out until sometime this afternoon (so almost 24 hours). I managed to snag one, but if anyone else is looking to get one, it seems like you'd probably get one from the batch to be sold on the 1st without too much trouble. Seeing as how the TR guy seems to promise a lot and take forever to execute, I wouldn't wait too long, he might stop doing this 5 every Friday routine if he thinks the demand has vanished.

speedjunkie · Postby **speedjunkie** » Sat Jul 26, 2014 9:14

Thanks for the heads up! I might have to jump on that. It only does one rotor at a time, right?

GR-8 · Postby **GR-8** » Sat Jul 26, 2014 9:14

Brigdh wrote:So, the Twisted Rotors compression testers are back (sort of). The guy behind TR has been making 5 testers a week, and then selling them online for $350 + $20 shipping every Friday at 5pm CST (aka 4pm here). The first 3 rounds of this had the testers selling out within minutes, but the batch that started selling yesterday was not sold out until sometime this afternoon (so almost 24 hours). I managed to snag one, but if anyone else is looking to get one, it seems like you'd probably get one from the batch to be sold on the 1st without too much trouble. Seeing as how the TR guy seems to promise a lot and take forever to execute, I wouldn't wait too long, he might stop doing this 5 every Friday routine if he thinks the demand has vanished.

Sweet Thanks. Going to have the Blue 8 up and running sometime this week. I will get one as soon as I get the funds.

Brigdh · Postby **Brigdh** » Sun Jul 27, 2014 9:14

speedjunkie wrote:Thanks for the heads up! I might have to jump on that. It only does one rotor at a time, right?

Yep. It has one sensor that you plug into a spark plug hole, and then it displays the PSI on each face, and the cranking RPM until you turn it off or run a new test. So remove spark plug, put the tester where it won't fall, disable spark and fuel (usually a fuse in the engine bay on the RX-7s), hop in the drivers seat, foot on the gas pedal to open up the intake all the way, and crank for 5-10 seconds. Then look at the readings.

The tool displays your raw readings. You'll need to normalize them for cranking RPM (the spec assumes the starter will spin at exactly 250 RPM) and altitude (the spec assumes sea level). You can use this online calculator to do the conversion: http://foxed.ca/index.php?page=rotarycalc

speedjunkie · Postby **speedjunkie** » Sun Jul 27, 2014 9:14

That's not a bad price. I'm gonna have to get one. Do you take out the spark plug on both rotors when you do it, or just one? I take both of them out.

Brigdh · Postby **Brigdh** » Mon Jul 28, 2014 9:14

speedjunkie wrote:That's not a bad price. I'm gonna have to get one. Do you take out the spark plug on both rotors when you do it, or just one? I take both of them out.

I usually take one spark plug out of the front rotor, run the test, replace the spark plug, then take a spark plug out of the rear rotor and test. However that's generally to prevent me from mixing up sparkplugs or sparkplug wires. Technically there wouldn't be a problem with taking out both leading plugs or whatever at the same time.

Rotary Compression Tester?

Rotary Compression Tester?

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