some guy is selling me a jspec motor. he says the comepression in rear is 115psi and front like 105 twice and then a lower one number.

i wanna go there and test it and see if its good. what can i look for or tell if it has a stuck seal?

you could check the apex seals thru the exhaust port with your finger tips and see if there is a sharp edge to them if it does it could be high mileage , push on the apex to check the tension on apex springs . check the exhaust side to make sure no oil has been burnig do to oil seals and if the engine is out of the car look with a flash light thru the exhaust port with a flash light to check the rotor housing for any scores and the side plates for extensive wear . Good Luck with your purchase https://www.nopistons.com/forums/pub...DIR#>/wink.gif

Also, if the motor is out of the car you can crank the motor over by hand and listen to the exhaust cycles. YOu should get 3 nice puffs per rotor. If you only have one good puff than more than likely you have a bad apex or a stuck apex seal. Do like 13bt starlet says and check the apex seal through the exhaust ports as you crank the motor by hand. I just tore down a motor that had only one compression cycle on the rear rotor and all the apex seals looked ok through the exhaust ports but when i tore the motor down one of the apex seals was broken off at the end so you could not tell from outside the exhaust port. Also, if like you said in your post that the front rotor had two good compressions and then one bad one than you may have a stuck or broken side seal.

hmm too bad i cant see a side seal if its broken or not. ha

if your keen on this motor then go buy yourself a surgical mirror (those ones that are used in dentists)



they fit nicely through the exaust port and can twist/bend the way you want them

with a nice torch and this mirror you will see all aspects of the apex seal, aswell as the bottom of the rotor housing, side's and top

u may even be able to see abit of the side seals if your lucky depending on if the engine is ported n how big the exaust ports are



My 12a J port i could see alot

Those surgical mirrors work great How did I missed that one out https://www.nopistons.com/forums/pub...IR#>/blush.gif . Thanks for dropping by brappin7 and refreshing my memory https://www.nopistons.com/forums/pub...#>/biggrin.gif

well i picked one up. it has 3 good pulses out of rear. 1 strong and 2 weak in front. apex seals look intact thru spark plug hole. they all seem to "stick out" like apex seal springs are pushing them towards housing. motor has been sitting for about half a yr.

i thru some 2 cycle oil in it and will let it sit and see what happens. any opnions?

anyone?

sounds like a stuck corner seal, a good run after being soaked with some thing like penitrate can bring them back to life, depending on how bad it is