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-   -   Help: lack of compression problems (https://www.rx7club.com/2nd-generation-specific-1986-1992-17/help-lack-compression-problems-721063/)

panterarules42069 Jan 14, 2008 02:17 AM

Help: lack of compression problems
 
i bought a used japanese engine and it doesnt seem to have any compression in it, i can hold my fingers over the spark plug holes when the engine rotates and it doesnt even push my fingers off. I know it means that my engine is bad... is their any use in keeping this engine in and around or am i totall skrewed? any hope of rebuild? i need a guru!!

RyosukeD Jan 14, 2008 05:09 AM

Rebuild it.

beefcake Jan 14, 2008 07:15 AM

is the engine in the car or just being rotated on a bench, but if its in the car get some oil into the engines plug holes, dont be shy either, then crank it again, it should pick up some compression, try using atf oil as well, clear it all out and give a go at firing up, if it sat for a while the seals could just be stuck, the motor most prob will be short lived after that but it may give you some fun runs in the mean time:)

RotaryResurrection Jan 14, 2008 11:56 AM

Ah, you got one of those lovely junk jspec engines that are not useable from the get-go. Sounds like every seal in it is stuck. You can try a liberal amount of lubricants but it is not likely to ever be "right" without a full teardown.

People think I am talking shit in an effort to generate more rebuilding business for myself when I tell them that jspec junkyard engines are hit or miss and if they want a quality engine with warranty they had better do a rebuild. There is always one or 2 of the lucky people that come and post "I got mine from XXX and it runs great for 2 years now" but there are 10 other people who either got a bad one or tell them to rebuild instead. Who do they listen to? :ugh2:

The Wankler Jan 14, 2008 02:29 PM


Originally Posted by RotaryResurrection (Post 7737557)
Ah, you got one of those lovely junk jspec engines that are not useable from the get-go. Sounds like every seal in it is stuck. You can try a liberal amount of lubricants but it is not likely to ever be "right" without a full teardown.

People think I am talking shit in an effort to generate more rebuilding business for myself when I tell them that jspec junkyard engines are hit or miss and if they want a quality engine with warranty they had better do a rebuild. There is always one or 2 of the lucky people that come and post "I got mine from XXX and it runs great for 2 years now" but there are 10 other people who either got a bad one or tell them to rebuild instead. Who do they listen to? :ugh2:



Kevin is correct. I was on of the unlucky ones. Mine had a blown rear rotor.

Rebuild it!

KompressorLOgic Jan 14, 2008 03:28 PM

yeah u never know what happend to that engine in japan...

one tip if you have to get a jdm engine. only buy it local, with some kind of warentee. If it was shiped from far away its very easy for them not to honor your warentee...

then as soon as u get it home compression test it out of car... then if its bad bring it right back asap. and get your money back.

then if they wont take it back at least you know whos shop to burn down...LOL

K-Tune Jan 14, 2008 05:46 PM

before i even turn over a jspec i normally let its insides soak in MMO, then slowly rotate it forward and backward by hand.

it will take a few turns to wake all the seals up, but you should be able to hear audible CHUGS as the rotors turn, as well as some resistance as you try to rotate it as the motor tries to compress.

panterarules42069 Jan 14, 2008 09:03 PM

All great stuff thanks fellas the engine is in the car i might try the lubricants as a last chance effort so itll hopefully run till i can get it somewhere better for work, but if not then ill try to rebuild it. This is a first for me so it should be interesting ive always wnated to crack one open to actually see the inner workings. FB what is this MMO? cant recall what that is. thanks

RotaryResurrection Jan 14, 2008 09:42 PM

MMO is marvel mystery oil.

I recommend *thin* motor oil, atf, or even 2 cycle.

panterarules42069 Jan 14, 2008 09:47 PM

oh ya duh! i wanted to try that stuff. try tomorrow as last ditch effort before rebuild project starts... not lookin forward to that! thanks for the help

1.3mazda Jan 14, 2008 09:50 PM

MMO or atf is the way to go if you attempt this method which i would try because you have nothing to lose and everything to gain.

panterarules42069 Jan 15, 2008 01:06 AM

compression problem
 
ya i checked and when the engine spins it puts out 1 bigger than 2 smaller puffs that are all too weak to even push my fingers from the hole on both rotors. I read in the book that means bad inner seals and stuff so im F---ed basically!!

Looks like a rebuild but what was this i heard about thin oil maybe breaking the seals loose?

panterarules42069 Jan 15, 2008 01:07 AM

and when i first got the engine i soaked atf in it and spun it every now and then for like a day so...


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