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Compression Testing 13b

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Old 04-08-12, 10:40 AM
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VA Compression Testing 13b

I am getting my GSL-SE back after ten years. It always ran well, but my uncle says the motor is blown. I know it would occasionally have a major starting problem after a brief run and shutdown (like moving it in the driveway). I need to verify the motor is blown before I take it out and rebuild. Will a compression test confirm this? I am thinking my uncle may have just run into the starting problem and given up. It has been sitting a while and has over 200 k miles. What steps should I take first?
Old 04-08-12, 08:42 PM
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http://www.banzai-racing.com/compression_test.htm

This the best guide for compression testing a rotary.

From your description, the problem may not be compression. Hot-start flooding is very common in FCs, and the GSL-SE has a very similar EFI system. If that's the case, leaky injections are a potential cause, but often times it's just a combination of engine age and the extra rich cranking map in the ECU.
Old 04-09-12, 12:34 PM
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Okay, assuming then that I need a re-build, what is the first step? I will be doing the work, but need a "rebuild kit". What is the difference between the OEM Mazda parts and for example the Adkins parts? I don't want to race this car, just get it back on the road.
Old 04-09-12, 01:20 PM
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first step is to pull the engine out.
Old 04-09-12, 01:23 PM
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Originally Posted by andernamen
Okay, assuming then that I need a re-build, what is the first step? I will be doing the work, but need a "rebuild kit". What is the difference between the OEM Mazda parts and for example the Adkins parts? I don't want to race this car, just get it back on the road.
first step is finding out if is blown,then next step is to pull the engine out of the car.
OEM Madza parts from the dealer?..2x expensive,if they have it.
best bet is too look around for vendors that carry a rebuild kit..like Atkins.(not ADkins)
Old 04-09-12, 06:24 PM
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Originally Posted by RotaryRocket88
http://www.banzai-racing.com/compression_test.htm

This the best guide for compression testing a rotary.

From your description, the problem may not be compression. Hot-start flooding is very common in FCs, and the GSL-SE has a very similar EFI system. If that's the case, leaky injections are a potential cause, but often times it's just a combination of engine age and the extra rich cranking map in the ECU.
X2
Definetly do some diagnosis before deciding to just tear it down for a rebuild. The last thing you want is to rebuild it and have the same problems due to bad injectors or some other issue.
Old 04-10-12, 09:15 AM
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if its a 3rd gen, and thats with a 20$ tester

1. Warm up engine to operating temperature, then allow it to cool for 10 minutes while you get the plugs out.
2. Remove the front and rear trailing (upper) spark plugs while the engine cools.
3. Disconnect the circuit opening relay, and the igniter connector. The CAS and EGI fuse are both unplugged so that no gas nor spark will occur during the test.
4. With both spark plugs out, fully depress the accelerator pedal to the floor, and motor the engine for 5-10 seconds. You should watch for 3 bounces of the needle (once for each rotor face). Specifications vary depending on the brand of shop manual. I’ve gone by 7.0 kgf/cm2 or 100 psi minimum @ 250 rpm as stated in my 93 RX-7 Workshop Manual. Other references say 6.0 kgf/cm2. Yes, you can compensate for higher cranking rpm during the test. There's a chart in the Workshop Manual.
Old 04-11-12, 07:39 AM
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Cant get it to operating tempurature as the engine won't start. I will definitely check a few things first, i.e. fuel pressure, plugs, etc. My uncle has had a few people look at it and they say the seals are gone. Speaking of seals, if I end up rebuilding, how about aftermarket apex seals? The OEM are super pricey. I'd like to find some that will last a while, don't cause chattering, and won't harm the housings. Do the atkins fit this bill?
Old 04-12-12, 08:30 PM
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there are plenty of companies out there with rebuild kits, my favorite ones are atkins and mazdatrix, pinneaple racing also sells some tools and parts. for the apex seals i like the rotary aviation classic for a dd and the super seals for something a little bit more powerfull.
Old 04-13-12, 01:35 PM
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this tread would have been helpful to me before i pulled the motor thinking there was no compression.
oh wellk life and learn, guess i just have to port it now lol

thanks for the link!
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