Is Engine Dead
02-19-2003, 02:20 AM
#1
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Join Date: Feb 2003
Posts: 43
Hi all. First time user to the site. Glad to see there are other enthusiasts out there. I just picked up a 1988 RX-7 SE non turbo manual transmission for $175.00! The owner of the shop said that it was a customers car and the engine was shot. I planned on replacing the engine, but it runs! I drove it on and off the trailer, and into the shop. It runs rough and doesn't seem to idle. The battery was also dead so I had to jump it. It starts right up. The first thing I'm going to try is new plugs and a battery. It doesn't smoke or smell like anti-freeze or oil. I checked the oil and anti-freeze, both were full and looked new. The air cleaner also was in great shape. The shop owner didn't know rotaries and from the sound of it didn't even pull a plug, just assumed it was dead. Quote: "Those rotaries only last 60k." The car has 118k, he state it already had a different engine 67k ago. I have a '79 RX-7 since '89, and my dad bought his new in late '78. Never had any trouble. I also change an engine in a '86 back in '96, so I'm familiar w/ the engine components. Is the engine dead? What should I check? How do I check compression or a bad apex seal? Any help would be appreciated. Thanks in advance.
02-19-2003, 10:41 PM
#4
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Join Date: Feb 2003
Posts: 43
The new plugs and battery did nothing to improve, but the plugs were worn out. I'm next going to try and check compression. Has anybody had a plugged up catalytic convertor that caused power loss? I had this happen on a Saab 900. What about faulty MASS sensor? Thanks, Ryan. BTW I cleaned the interior, looks better already.
02-20-2003, 01:48 AM
#5
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Join Date: Apr 2002
Location: IL
Posts: 2,930
clogged cat will cause problems, but you can usually tell by high operating temps and/or glowing cat/manifold...
any old compression checker will work, but most piston motor checkers retain the pressure to hold a peak value, this is kindof useless when you're trying to get 3 readings from a single spark plug hole as on a rotary engine. So you have to remove the schraeder valve used to hold the pressure, so the needle can bounce with each rotor face. Looking for nice even bounces, somewhere between 60-150psi depending _greatly_ on rpm
most important is that there are 3 seperate spikes, and relatively even per rotor housing. Personally, I would crank for 15 seconds, and count the spikes during the 15 seconds. Multiple that # by 4 and you have your rpm count for a nice relatively useful compression check.
if compression checks out, other things would be coolant system pressure check, and if that checks out, and the car isnt low on oil and/or blowing oil smoke... she's probably something usable.
how's the oil pressure when you get her running?
any old compression checker will work, but most piston motor checkers retain the pressure to hold a peak value, this is kindof useless when you're trying to get 3 readings from a single spark plug hole as on a rotary engine. So you have to remove the schraeder valve used to hold the pressure, so the needle can bounce with each rotor face. Looking for nice even bounces, somewhere between 60-150psi depending _greatly_ on rpm
most important is that there are 3 seperate spikes, and relatively even per rotor housing. Personally, I would crank for 15 seconds, and count the spikes during the 15 seconds. Multiple that # by 4 and you have your rpm count for a nice relatively useful compression check.
if compression checks out, other things would be coolant system pressure check, and if that checks out, and the car isnt low on oil and/or blowing oil smoke... she's probably something usable.
how's the oil pressure when you get her running?
02-23-2003, 11:55 PM
#7
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Thread Starter
Join Date: Feb 2003
Posts: 43
I checked the compression. 3 even spikes and 95psi in the front. No compression in the rear rotor. I am trying the ATF trick in the rear rotor as I have nothing to lose before pulling the engine. Any one know of a good source for a used engine. I'd love to keep the car but I have a '79 RX-7, 3 other vehicles and a motor cycle, so my plan is to put an engine in and sell it. Thanks.
