2nd Generation Specific (1986-1992) 1986-1992 Discussion including performance modifications and technical support sections.

compression test results.

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Old Dec 12, 2005 | 11:06 AM
  #1  
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compression test results.

well i cant seem to get my 86 gxl to start.. (ive had it started before and so has my friend)..

so i decided to do a compression test. i used a piston type compression tested.. i help in the button.. remove both trailing plugs.. floored the gas and took my reading... imediately i was shocked.. the neddle didnt go higher than 35 at the most.. on both rotors... now my question is..the engine was cold..but anyways..how can a motor with 120k..have that bad of compression when it was running last summer? did i do something wrong lol...


so yea.. u guys think i should just pull the motor and port it and prep it for rebuild?
this kinda bums me out cuz it was running then the alt went out and ym friend let it sit all summer then i bought it and towed it to m,y place and been working on it..i was hoping to get it running but with compression that low i dont think theres any chance...even though it has started and ran before.

oh well just wanted to let yall know whats up..

just to repeate.. the compression was reading no more than 30-35psi on both rotors.
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Old Dec 12, 2005 | 11:32 AM
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Have you tried putting something in there to possibly lubricate the seals again? i know you shouldnt let a rotary sit without some kind of lubricant inside the engine and without turning it over every day or couple days (my personal opinion there)... maybe you could put some sort of lubricant in there to raise compression, marvel mystery oil or ATF.... just a thought if you wanna see where you cn get compression numbers...

- chris
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Old Dec 12, 2005 | 11:56 AM
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Originally Posted by zerogrips13
well i cant seem to get my 86 gxl to start.. (ive had it started before and so has my friend)..

how can a motor with 120k..have that bad of compression when it was running last summer? did i do something wrong lol....
Because as it sat, the Carbon and oil gummed up on the apex seals and cause them not to move properly intheir grooves...

Originally Posted by zerogrips13


so yea.. u guys think i should just pull the motor and port it and prep it for rebuild?


just to repeate.. the compression was reading no more than 30-35psi on both rotors.

Yes
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Old Dec 12, 2005 | 12:01 PM
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try the ATF trick to see if it can bring the apex seals back to life, but I'd start saving for a rebuild and porting templates.
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Old Dec 12, 2005 | 01:09 PM
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well i figured the rebuild would be soon or a junk yard motor...hile i port and save for a rebuild (i can offord 150$ for a junk yard motor easier than 600 for a rebuild)

but do u really think i should try the atf trick???
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Old Dec 12, 2005 | 01:56 PM
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compression is low so why not? if it doesnt work then it usually means something's wrong with either the seals, springs, or the rotors (or all of the mentioned). and to diagnose that you have to pull the engine apart. i'd say it can't hurt
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Old Dec 12, 2005 | 03:56 PM
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Try all the ATF. MMO, steam cleaning tricks before you pull the engine. The worst thing for a rotary engine is sitting for long periods of time.
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Old Dec 13, 2005 | 06:13 AM
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anyone got a god link to the atf trick.. im bout to go for school and wont have time to look it up till this afternoon...

thanks for your help guys.. ill try it out


p.s. if it saits for a while would that cause it to burn alot of blue smoke when it starts?? about 4 months ago i got it started and it was burning some nice clouds of blue smoke....
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Old Dec 13, 2005 | 06:49 AM
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Best thing you can do for this is tow the car around in 5th gear for about 20 minutes. Then pull over take the car down and start it and drive away, problem solved.

zerogrips I will guarantee this will work.
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Old Dec 13, 2005 | 07:02 AM
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do u mean hook it to a car and tow it?? cuz i dont really have anything that could pull it lol...and it doesnt have brakes..since i disassembled them to do some maintainence to them... is there a way i could simulate this procedure???

and i just have to ask ..how did u come up with this solution>?? related experience?? lol..
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Old Dec 13, 2005 | 07:32 AM
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put the brakes back on and pull it with a truck or another car in 5th gear on the highway and your motor will break free and you will be able to start it no problem. And yes this has been done many times.\

***There are a few people this morning thinking "damn I sold my car for a few hundred bucks because I thought the motor was seized and needed a rebuild." hahaa
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Old Dec 13, 2005 | 09:43 AM
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Originally Posted by Bukwild
Best thing you can do for this is tow the car around in 5th gear for about 20 minutes. Then pull over take the car down and start it and drive away, problem solved.

zerogrips I will guarantee this will work.

lol...i do have to say it worked for me too...thought i left it on 2nd gear and was towed 1 block. though the situation was a lil different
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Old Dec 13, 2005 | 10:55 AM
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the motors not seized though.. it turns over good and attempts to start but just continues to turn over..and the brakes have been tooken apart for good reason..they dont work lol.. for atleast 6 years this car has been on the same brake pads... a 1/2 frozen caliper..and rip boots..i think ill try to atf trick first...i got it to start a week ago with starter fluid it started reved to 1200 then to 800 and died...havent had any luck since..

thanks for all the advice, and i will get back to u after i do the atf trick...im also thinkin it might be out of gas.. :P ...(the gauge says empty but the previous owner said it didnt work anyways..(sending unit??) ..so i might go get 2 gallons and see if that helps...well see.
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