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1987 RX7 with oil consumption problems

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Old Nov 24, 2012 | 10:07 AM
  #1  
mdavidson101's Avatar
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From: Michigan
MI 1987 RX7 with oil consumption problems

I'm giving you all the complete story, It might be slightly long.
I picked up a 7, it was blown up. I yanked the motor, found a 88 motor with "15,000 miles." The motor was in some guys Suzuki Samurai.
I ended up swapping various parts from my motor to the 88 to make it work.
The exhaust has been replaced, the pre-cats eliminated, but has regular cat.

I drove the car home from my shop, with open manifold, It ran like crap.
The exhaust has since been replaced, the pre-cats eliminated, but has regular cat. Once I popped the hood, clutch fan pieces were everywhere. I Bought an electric fan for it, and plugged it into the secondary tach feed. Bad idea, it made the car run even worse. I started playing with the tuning and timing after reading some on here. It ran slightly better.

Well one sunny hot afternoon day, I drove it into town, and it was running GREAT, better than it ever did. It also got hot. It was slowly climbing slightly above normal, then BAM maxed the gauge out. I shut it down immediately, checked that it had water, hoses hooked up, electric fan plugged in and working. Well the fan was not hooked up any longer, as well as lower radiator hose. I had it towed back home, and after some playing around, I figured that if the e-fan is plugged into the tach feed it runs like crap, I found another source of power, the idle circuit feed? The 6 plug green connector, middle plug on the bottom row. The car runs great, it doesn't over heat. The problem is, even when I got it first running, It uses a ton of oil, and it doesn't run like it should. It runs great up to about 3K runs okay to about 4, and around 5-7.5-ish, it wants to fall on its face.
On a normal week, it will use about 2-3 quarts, daily driving. Last week it was slightly better about 1 quart. I drove around 400 miles.

I'm worried that its about time for a rebuild. I don't have the money to, or the time and knowledge to do it myself.

What could my problem(s) be, and is there anything I can do to make it use less oil?
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Old Nov 24, 2012 | 10:24 PM
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Is the car losing any oil externally?
Put a piece of cardboard on the driveway and park over it and examine it in the morning.
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Old Nov 25, 2012 | 10:25 AM
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mdavidson101's Avatar
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Originally Posted by misterstyx69
Is the car losing any oil externally?
Put a piece of cardboard on the driveway and park over it and examine it in the morning.
No, the oil pan is dry, the oil cooler line has a little residual oil on it, it doesn't leave a spot. I was just wondering, what is the correct length of the oil dipstick? I'm wondering if I might be under-filling it.
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Old Nov 25, 2012 | 10:42 AM
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length of the dipstick? you mean the marks to fill it?
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Old Nov 25, 2012 | 10:59 AM
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If you are sing 3 quarts a week then there is a problem.
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Old Nov 25, 2012 | 01:04 PM
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From: Michigan
I realize there is a problem, I was wondering what it could be and if I can do anything to use less oil until I can rebuild.

I was wondering the actual length of the dipstick, in case I don't have the right one.
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Old Nov 25, 2012 | 01:39 PM
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From: Pump Handle, SK. Canada
Originally Posted by mdavidson101
I realize there is a problem, I was wondering what it could be and if I can do anything to use less oil until I can rebuild.

I was wondering the actual length of the dipstick, in case I don't have the right one.
On my 86 13b stick from the very top of the rubber stopper to the full mark is 13 inches right on the button . Being as the bottom end is not open to the engine workings like a piston engine you would need a lot of extra oil in the pan before it started to burn as much as you are , you must have some kind of oil control problem . If it burns that much oil you should be able to check the plugs to see if it is coming from front , rear or both rotors . Gerald m. If they didn't replace the o rings on the oil control rings you might have this problem . also if you are going to run a e fan you should run it from an independent power source with a temp switch in line , not sure weather it should have a relay or not
Attached Thumbnails 1987 RX7 with oil consumption problems-img_0002.jpg   1987 RX7 with oil consumption problems-img_0004.jpg  

Last edited by gerald m; Nov 25, 2012 at 01:54 PM.
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Old Nov 25, 2012 | 03:44 PM
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I just started it, the first winter snow is upon us here in Michigan. It appears that my back rotor has a lot of carbon build up in the leading plug only. I also noticed that it sounds like its knocking. It doesn't sound metallic, and its off the exhaust side. Maybe the auxiliary port diaphragm is broken and fluttering? It makes the sound around 2500 to 2200 under deceleration. It does it under load as well as not.
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Old Nov 25, 2012 | 06:53 PM
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Originally Posted by gerald m
If they didn't replace the o rings on the oil control rings you might have this problem . also if you are going to run a e fan you should run it from an independent power source with a temp switch in line , not sure weather it should have a relay or not
How hard would it be to replace the O-rings? What source of power should I go to? It doesn't over heat at its current power source.
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Old Nov 25, 2012 | 09:25 PM
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From: Pump Handle, SK. Canada
Originally Posted by mdavidson101
How hard would it be to replace the O-rings? What source of power should I go to? It doesn't over heat at its current power source.
It's never a good idea to STEAL power from another source if you don't know what that source operates. For all you know that circuit may run important components that require a steady source . You need to go here Foxed.ca find what you need for your car and do some reading so you understand the basics of the little engine and electrical . That said the Oil control O rings are as much work as a rebuild to change as they are located on the sides of the rotors and to remove the rotors you need a full tear down . Good luck .. Gerald m.
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