Snowmobile Fanatics banner

1 - 20 of 21 Posts

·
Registered
Joined
·
8 Posts
Discussion Starter #1
HELP!!! I just installed a new piston/ring and gasket on my '94 Vmax 600. Before I did I had 120PSI in good cylinder and 90PSI in bad cylinder. After installation I now have 90PSI in both cylinders. I amptly lubed cylinders with 2 stroke. Is this common or is something wrong? The cylinder gasket was a 3 piece riveted together. The old one was a single. I am wondering if this is the issue. I haven't run it yet and am wondering if everything needs to burn off and reseat??? Any help is appreciated.
 

·
Registered
Joined
·
8,842 Posts
I guess I would start it and see. what have you got to loose at this point by starting it. sometimes compression can be low. pour a little dribble of oil down one hole. and then check that hole. if the compression comes up there might be a chance the motor will work fine. I would run it on a stand. spray a little eather around the base gaskets to see if they are leaking. if not after some idle time on the stand recheck it.
 

·
Registered
Joined
·
8 Posts
Discussion Starter #5
Ok I started the sled and let it run 2-3 minutes and rechecked compression. 120 PSI in both. Rings did not look like there was a up or down so not sure if that would matter. Anyway I have 120 PSI both cylinders and hopefully wont blow it up next time out. Thanks to you 3 who gave some advice.
 

·
Registered
Joined
·
77 Posts
OK yes this is common if you have sleeves did you hone the and motor and rings on this sled can not be put in up side down. So you can relax and go have some fun. After a tank of fuel check compression a gain.
 

·
Registered
Joined
·
8 Posts
Discussion Starter #9
Thanks all. I got to say this is the coolest forum I've found. Now let it snow, let it snow, let it snow!!!!!!!!!!!!
 

·
Registered
Joined
·
985 Posts
not familiar with the vmax600 but, rings can most definitely be put in wrong.
it depends on the rings but wiseco's usually have the top marked right next to the split.
again not all rings have a top/bottom but almost all wiseco's especially the ones for nikasil cylinders do.




p.s. not that it would make much difference in compression initially. you really need to run the tank or two of break in fuel though it before worrying too much about compression.
 

·
Registered
Joined
·
4,755 Posts
most piston on sleds have pins in the ring lands to keep them from rotating
 

·
Registered
Joined
·
2,304 Posts
^^^^^^^^^^^^^^^^^^^^^^
True, but if the ring wasn't in the pin groove the piston wouldn't fit in the cyl.
 

·
Registered
Joined
·
4,755 Posts
thats for sure
 

·
Registered
Joined
·
2,304 Posts
^^^^^^^^
But it shouldn't affect the compression, it is so the ring dosn't turn and then hook a port and damage your cyl, piston, and ring
 

·
Registered
Joined
·
450 Posts
when i had my head of for machine work, when i re-installed it i couldnt get hardly anything on my comp guage before starting the eng up.. when she fired it up i checked again went to 150psi both sides. i got a little worried too at first.. but been 200 miles now with no problems.
 

·
Registered
Joined
·
2,304 Posts
Originally posted by daman
[br]
Originally posted by TeamNFG
[br]^^^^^^^^
But it shouldn't affect the compression, it is so the ring dosn't turn and then hook a port and damage your cyl, piston, and ring
it would if the ring end gaps were lined up....
[?][?][?][?]
I don't quite understand what you are saying, but the pin has no significance on compression, it only holds the ring in place on the piston.
 

·
Registered
Joined
·
198 Posts
rings just need to seat in,just as in any engine.they'll have to fill with oil and get set to the cylinder and then presser will come up..
 
1 - 20 of 21 Posts
Top