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Got a popped rotary?

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Old 10-26-08 | 01:13 PM
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Got a popped rotary?

I'm looking for someone in the Houston area with a blown rotary engine that can still turn it over with a starter. I've built a compression tester that I need to test on a bad engine. It's been tested on my car and an RX-8 but both cars have good compression. Post here or shoot me a PM. Thanks.
-John

Last edited by TwistedRotors; 10-26-08 at 01:41 PM.
Old 10-27-08 | 12:38 AM
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Sorry I didnt get back with your PM, I dont have any blown ones at this moment.

If you want a blown motor, or simulate it, pull the upper (trailing) plugs out and insert the tester, the open smaller plug hole will allot alot of compression out, this should make it look like a blown motor.
Old 10-27-08 | 01:11 AM
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Good idea Chuck, I'll give that a shot. Someone in the area has to have a chipped apex seal or worse though......hope I didn't just curse anybody. I need to see how this thing reads with 1 or 2 low pulses out of 3.
-John
Old 10-27-08 | 12:34 PM
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Darn, I wish you were around a month or two ago. I popped my motor and I could use a definitive compression test to tell for sure.
Old 10-27-08 | 02:45 PM
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lol, follow me around.... my motor is on its 9th life.
Old 10-27-08 | 03:32 PM
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Hah! Thanks for the offer Phil. Well while we're waiting for someone to lose an apex seal here's a pic of what I've been working on.

Tell me what you think.
-John
Old 10-27-08 | 04:26 PM
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I want........

It looks like it reads the compression and stores the reading for EACH rotor face... ?
Old 10-27-08 | 04:39 PM
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I really like that, I maybe in line for a prototype when you can get one done.

If you could get it to read RPM by counting the number of pulses/time, that would make it Bad ***.

Does it take the higher reading over a few rotations of the motor, Like Rotor 1 spins 5 full rotations so it will take te higher readings for each rotor?

Last edited by Rx7_Nut13B; 10-27-08 at 04:41 PM.
Old 10-27-08 | 05:30 PM
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It's actually simpler than that. All it does is count 3 compression pulses and then display them. If you keep turning the engine over, it'll just keep on counting pulses and displaying them. This is why I need a blown engine so I can make sure that it is able to differentiate between the low and high. I am working on adding an RPM readout to it. It'll display on the second line. This is actually my first prototype...the final tester will be in a much smaller case with some ruggedizing done. I've kept this thing simple to keep costs down and hopefully made a tool that anyone with a rotary can use.
-John
Old 10-27-08 | 06:37 PM
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The is there a way to stop the sampling while the motor is still turning over, if not then it may see the final few low pulses as compression and display it.

Well I will be first in line, I have a digital compression tester but I have to use my laptop for the display, a hand held display is nice.

That is the same type of Quick Connect that i used on mine, the simplest way to do something is to use something all ready made, right.
Old 10-27-08 | 07:04 PM
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Well I've used it quite a few times and haven't had a problem with it displaying low after you stop cranking. It only updates the screen when it has 3 new pulses to display. I guess it's possible to have a low reading on the final pulse if the timing is just right but honestly it's very easy to watch this thing and write down the readings as they are shown. Pen and paper datalogging FTW! :-) I have seen the swivel and quick disconnect used on a compression testing system before and I think it's an awesome idea. Keeps the sensor safe while you're threading in the adapter and makes it easy to connect the sensor at any angle. I do like the swivel I'm using as it allows you to really move the quick connect any which way you need it to face. The front leading sparkplug on that RX-8 almost got us...had to borrow someone with very small hands, but only cause we couldn't get the adapter to start threading. Once we got it started it was easy to hook up the sensor. Stupid RX-8 motor mounts. I'm not too impressed with that design....as if the FD's plugs weren't hard enough to get too. Anyway...now I'm just rambling.
-John
Old 10-29-08 | 07:36 PM
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DOPE!

id buy one for sure i live in bumF***cazoo in the middle of nothing and there 4 fc's
.... so thatd be sweet
Old 10-30-08 | 09:33 PM
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Well I'd love to sell them, but I really need to test this thing on a blown motor. It works by simulating a blown engine on my breadboard, but real world tests are the best. I'm adding the code for reading and displaying RPM and I've got a new case and connectors for the second prototype. Anyway, I'm still waiting for my custom PCB's but once I get those and make sure they work right then I should be able to start selling them. Maybe another month or so? In time for christmas hopefully! :-P
-John
Old 10-30-08 | 09:56 PM
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I think it is funny, when someone is trying to find a popped rotary you cant find one.

I tried today to pop mine but it held on strong like always.

9500RPMS
Old 10-30-08 | 11:46 PM
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No joke man. I mean, it's a good thing that no ones blowing there motor. I am still waiting for my boards though.....ordered just 2 for now to make sure they work. The turn around time is insanely long, but at least they're cheap. Glad your car's running good...you going to bring it to the next meet?
-John
Old 10-31-08 | 12:30 AM
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Nope, I have something else to bring to the next meeting, something more rare then a Ridiculous High HP FD.

You going to be at the next meet I would like to see the prototype.
Old 11-01-08 | 09:18 AM
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Oh, I'll be there for sure. The prototype is in peices, but hopefully I'll have it back together so I can at least show it off by then. I can't wait to see what you're bringing. It'll be like show-and-tell back in elementary school!
-John
Old 11-06-08 | 09:38 AM
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I like that tester. That looks pretty nice. Good work!

B
Old 11-06-08 | 01:27 PM
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Thanks Brian. I've already got a second prototype finished that I showed off at the Houston meet. Pic is below. If (when) I start selling them, this is what it will look like. Just waiting on my PCB's now.
-John

Old 12-01-08 | 11:11 PM
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You've got a PM, TwistedRotors!
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