Thread: GIO & Leak Down Test Results
04-22-2008, 07:26 PM #1
GIO & Leak Down Test Results
I have a bad gas in oil problem on my 07. I have the R&D breather kit on the way but I just made up a leak down tester to check the condition of the engine before I install this kit. Since I made the damper valve in the tester by just epoxying a coupling and then drilling a 3/64" hole, I'm not too conserned about the accuracy of the results, just that they should all be the same and fairly low. A bought tester should be below 10%. Since the hole is a little bigger than the hole in a bought tester I would think anything less than 15% should be OK. Anyway here are the results:
#1 - 7%
#2 - 59%
#3 - 6%
#4 - 43%
In #1 and #2 cylinders the only air that could be heard escaping was the small amount getting by the rings and bubbling in the oil pan.
In #2 and #4 cylinders lots of air was escaping past the exhaust valves.
Does this mean I have a problem with the exhaust valves or just that they are not seated correctly at the moment? If a run the ski at WOT and re-test, would this help (maybe build-up on the exhaust valves?). If the valve clearance was off would this cuase the problem?
I'm assuming bad exhaust valves would not cause the GIO problem and this would only happen if there was an issue with the rings.
04-22-2008, 09:14 PM #2
I wanted to just give some of my comments to you.
I was just wondering how you peformed your test.
as form what I can see you may have done the test incorrectly.
when you do a leak down on a cylinder you HAVE to have it on TDC on the compression stroke ,
this will ensure that all valves are in the closed position in the cycle.
once you have got each cylinder at TDC then and only then can you perform a leakdown test.
cause if you do the test any ather way it aint going to work correctly.
does this make sence.
04-23-2008, 05:47 AM #3
Thanks Warren, but yes I ensured I was at TDC compression on each cylinder. In fact, for the two cylinders that were bad, I rotated the crank 360 degrees to get the other TDC stroke and got 100% leakdown in both cases with all the air leaking out the exhaust and intake valves.
04-23-2008, 05:57 AM #4
04-23-2008, 10:38 AM #5
Just have 10 hours on ski! Will probably check valve clearance anyway but this shouldn't affect valve sealing at TDC would it??
04-23-2008, 04:38 PM #6
if the valve clearance is wrong , riding , then yes it will make it leak.
and also give poor starting/running etc
iether way u will need to check them , in my opinion if they are out take t dealer to be corrected as they must have been set incorrectly from the factory.
04-24-2008, 08:13 PM #7
Leak Down UPDATE
Well, I took off the valve cover and checked the valve clearances which were all OK. About .007" on intake and .012" on exhaust.
I did the leak down again with same results.
I then tapped the top of #2 cylinder exhaust valve "push rods" with a plastic stick and a hammer a few times. I checked again and the leak down was improved drastically. I tapped the valves a few more times and when I tested it again it was at 6-7% same as #1 and #3.
I did the same with #4 and now all 4 cylinders have the same leakdown result of 6-7%.
Since the hole in the damper of my homemade tester is a little larger than it's supposed to be I'm guessing the leakdown would be less than 6% if using a store bought tester.
04-25-2008, 03:07 AM #8
not saying I would be happy with 8%,
but you have to remember that there are a lot of variable with leakdown reading ,
does the comp test still say the same results with 1 cyl at 135psi
that not good , but this is at cranking speed and dont forget at running rpm ther is a lot of pressure pushing that ring out So I feel your to speed wouldnt be affected that bad with these readings just my opinion
iether way the #'S should be closer than what they are , contact dealer and be the good old dripping tap
It will get fixed in the end
Last edited by sirbreaksalot; 04-25-2008 at 03:17 AM.
04-25-2008, 06:52 AM #9
Warren, not sure what you mean by numbers should be closer as all cylinders are now at 6-7% leakdown which is good. It looks like I just had some carbon build-up on the exhaust valves from idling/fogging in the garage prior to storage. When I tapped the exhaust valves as described above all cylinders were the same. I also suspect they would be even lower than 6% if I had a proper leakdown tester and not a home made one.
Thanks for the help
04-25-2008, 06:56 AM #10
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