Thread: Rings or Valves?
08-03-2008, 05:39 PM #1
Rings or Valves?
I did a routine compression test today and found the last cyl had 70lbs . the center and fist had 130 140lbs. that last cyl has always been low around 115 120. I also did wet test with 1 oz of 30wt and the last cyl
jumped up to 180lbs the center was 200 and the first was 200 also.
so what do you guys think rings or valves? Im guessing rings.
08-03-2008, 08:54 PM #2
If you add oil to the cylinders and the compression goes up, it's the rings amd not the valves... Ron
08-03-2008, 09:13 PM #3
Nice! At least I wont have to spend 500+ dollars on just valves! I should porlly change the timing chain too.
08-04-2008, 07:55 AM #4
what do you guys think i will spend on parts? Will I have to get the block machined and put new pistons or just slap new rings and go?
08-04-2008, 08:33 AM #5
ur gonna have to measure the bore
an 03 GTX SC... with low compression in a cylinder... u must have some good hours on there... u gonna split cases and re-use old bearings? i'd hope not, do it all while you are in there...
Full gasket kit
balance shaft bearings
re-ring all three
measure the bores, for all you know you might be going oversized
examine the rod in that cylinder (why did only that cylinder low a bit of compression)
how many hours on this motor?
08-04-2008, 08:51 AM #6
If you consider 100 hours a lot than yea its got a lot of hours. This skis has had low compression in that cyl since i bought it @ 65 hours. It had 115 than
that was last August. It just recently dropped drastically like 3 months ago
it was still around 110 115 psi. Last month there was this time it made 1 long beep and the rev limiter kicked in and wouldn't let it go past like 3500 rpm.
I limped it back to shore and checked every thing and it was like almost 2 qts
low on oil. My gauges are still broke so I cant tell if there are any codes.
08-06-2008, 02:23 PM #7
08-06-2008, 02:39 PM #8
You can check the OEM price on www.ronnies.com. If it was me, I would also put in the SCIC forged pistons. But you need to break down the engine to see what's bad, and like Shibby said, you need to measure the bores to see if you need oversized pistons/rings. There was an '03 GTX SC on PPGs site that had low compression on one clylnder - it turned out to be a cracked piston - the weaker cast piston... Ron
08-06-2008, 03:18 PM #9
I guess I should get to pulling the motor out. And tearing it down to see wtf is going on in there. What could have gone wrong to cause this to happen? Like I said the compression was kinda low in that cyl when i got it.
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