1st Generation Specific (1979-1985) 1979-1985 Discussion including performance modifications and technical support sections

low compression HELP

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Old Jul 8, 2008 | 08:26 PM
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low compression HELP

so i got my 83 compression tested today and the apex seals on the rear rotar are shot...there is no compression on it...now i know i could rebuild the entire motor but couldnt i just replace the seals...my uncle says he could get the parts/seals for about 200 bucks...also does anyone know of any mechanics that can and or will do this in wisconsin...

also how can i tell what sub-model my rex is if it doesnt have any badges clarifying that.
thanks for any and all help


---Sam
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Old Jul 8, 2008 | 08:34 PM
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Originally Posted by 81gen1
a GSL will have rear disc brakes, not much else to tell. if no disc brakes then it's either a S or GS. pretty much the same thing though.

what color is it and what rims does it have?

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Old Jul 8, 2008 | 08:34 PM
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i believe it's only down to s, gs, or gsl......is the only difference between gs and s that the gs has a sunroof basically?...this is a harder question than i thought lol.
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Old Jul 8, 2008 | 08:53 PM
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The 200$ kit will only come with soft seals. This will not solve your problem, as you will just reuse the apex seals you already have. Best to just get a master kit from Mazda.
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Old Jul 8, 2008 | 08:56 PM
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Originally Posted by Jeezus
The 200$ kit will only come with soft seals. This will not solve your problem, as you will just reuse the apex seals you already have. Best to just get a master kit from Mazda.
how much would that be(ballpark)and is there an online site that sells them
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Old Jul 8, 2008 | 09:00 PM
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http://www.atkinsrotary.com/store/pr...cat=590&page=1
would this work
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Old Jul 8, 2008 | 09:21 PM
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the only way to know what you need is to take the engine apart and measure everything to see if it is in spec or not
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Old Jul 8, 2008 | 09:31 PM
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well the car runs good, its just slow, it doesnt overheat and the oil pressure is always good.
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Old Jul 8, 2008 | 09:33 PM
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Originally Posted by RX7_4_LIFE
Yes that would work, I would opt for their Master Rebuild Kit, as if you just bought the hard seals you would still need the soft seals.
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Old Jul 8, 2008 | 09:37 PM
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Also, although you didnt give us any info on the age of motor. There are alternatives.

Has the motor been sitting/last time if was driven.

Could the seals be stuck and not gone.

If you do a rebuild are you prepared to try and find housings if yours are shot. How about rotors (broken apex usually means broken **** inside)

All things to consider.
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Old Jul 8, 2008 | 09:42 PM
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Originally Posted by djessence
Also, although you didnt give us any info on the age of motor. There are alternatives.

Has the motor been sitting/last time if was driven.

Could the seals be stuck and not gone.

If you do a rebuild are you prepared to try and find housings if yours are shot. How about rotors (broken apex usually means broken **** inside)

All things to consider.
He will have to replace the housings if he tears it down, unless his motor has very very few miles...
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Old Jul 8, 2008 | 09:44 PM
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I know this but does he?
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Old Jul 8, 2008 | 09:53 PM
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110k original...was parked and not run for 5 years
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Old Jul 8, 2008 | 09:57 PM
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Originally Posted by RX7_4_LIFE
well the car runs good, its just slow, it doesnt overheat and the oil pressure is always good.
i would recommend doing the ATF/MMO/seafoam thing to see if by some chance your seals are just stuck, it'll save you some money if they are just stuck.
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Old Jul 8, 2008 | 09:59 PM
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how can the car run good if you say it has no compression on 1 rotor.......
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Old Jul 8, 2008 | 10:11 PM
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Originally Posted by djessence
how can the car run good if you say it has no compression on 1 rotor.......
i know, the guy at the dealer said its a dream that it runs...
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Old Jul 8, 2008 | 10:18 PM
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+1 on the seafoam treatment. Let it soak for a couple days. Ray Green has a thread on this a month or 2 ago. He thought his engine was toast and it was just a stuck seal
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Old Jul 8, 2008 | 10:47 PM
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+1 on seafoam. I tore down one of Ray's old engines and it had barely any carbon in it at all!
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Old Jul 9, 2008 | 05:38 AM
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No sunroof means it's an S model, lightest model for each year. It can't have zero compression on the rear rotor and run good, just doesn't work that way. Add another vote for seafoam, which I seem to remember suggesting once before to you.

The kit you listed is fine for the internals, but you'll need a gasket kit too, they run around 200, unless you can fid a Felpro kit which run less, but I've never used one so I can't say if everything needed comes in the kit.
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Old Jul 9, 2008 | 12:42 PM
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I favor a cautious approach. Try the MMO treatment first. MMO should dissolve/loosen oil residue buildup that may cause stuck seals, and it's pretty harmless when it goes through the engine, even if it's bearing debris and goo. Repeat if necessary. If that doesn't do it, try seafoam. I'd hold off on ATF because it seems so radical and I'd worry about the bearings and gears in the engine as well as the walls of the combustion chambers.
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Old Jul 9, 2008 | 04:35 PM
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can anyone give me step by step instructions on the seafoam...i got 3 cans today and i have a general conception on how to do it but i dont want to screw anything up...pics would be great also
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Old Jul 9, 2008 | 04:41 PM
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alright, you can either put it in the gas tank: get about 1/8th of gas left in the tank, pour the whole can in the tank, then go for a ride, until you've burnt most of it, then go refill, it will be very very very smoky, so make sure you keep a can with you in case you get pulled over.

2)(what i recommend since your case seems severe) turn the car on and use a vacuum hose to suck in the seafoam. or take the plugs off and use something to squirt it in the engine. let it soak for about a day or two, then crank. let it iddle until it stops smoking.

hopefully that will fix it
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Old Jul 9, 2008 | 04:43 PM
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Originally Posted by blackdeath647
alright, you can either put it in the gas tank: get about 1/8th of gas left in the tank, pour the whole can in the tank, then go for a ride, until you've burnt most of it, then go refill, it will be very very very smoky, so make sure you keep a can with you in case you get pulled over.

2)(what i recommend since your case seems severe) turn the car on and use a vacuum hose to suck in the seafoam. or take the plugs off and use something to squirt it in the engine. let it soak for about a day or two, then crank. let it iddle until it stops smoking.

hopefully that will fix it
thank you very much...although there is one more thing, where is the vacuum line and where do i disconnect it.
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Old Jul 9, 2008 | 04:49 PM
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i disconnected the cruise control from the carb (there's a nipple right above the air/fuel mix screw, that's where the cruise control goes) then i used a small rubber hose and attached it to the nipple and inserted the other end in the can. ... i'm sure you can use your cruise control hose if you don't have one, just make sure all the liquid inside the hose is gone before you connect it back to the C.C. just for safety.

i don't have pics anymore or i would show you. (you could also slowly pour it through the carb, but it takes a lot longer cuz you gotta be careful not to put too much or it'll stall the car)
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Old Jul 9, 2008 | 04:51 PM
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Originally Posted by blackdeath647
i disconnected the cruise control from the carb (there's a nipple right above the air/fuel mix screw, that's where the cruise control goes) then i used a small rubber hose and attached it to the nipple and inserted the other end in the can. ... i'm sure you can use your cruise control hose if you don't have one, just make sure all the liquid inside the hose is gone before you connect it back to the C.C. just for safety.

i don't have pics anymore or i would show you. (you could also slowly pour it through the carb, but it takes a lot longer cuz you gotta be careful not to put too much or it'll stall the car)
oooo, mine doesnt have ps
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