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Tips On Finding Tdc On Kohler K Engine?


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#1 FilledTires OFFLINE  

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Posted October 02, 2014 - 06:32 PM

I am trying to do a leak down test on a Kohler K341.

 

I am having trouble finding precisely TDC. The spark plug is over the exhaust valve so I can't stick anything in there to feel the piston, right?

 

I have the breather cover removed and can bring it to the point where both valves are closed. I rotate the crankshaft by hand until they both close. Then I keep going until the exhaust valve begins to open, then I back it up to when they were both closed. How accurate is this?

 

Do I need it to be very precise to perform Valve Adjustments and Leak Test?

 

Also: How do you go about locking the crankshaft in place for the Leak Down Test? Vice Grips over the drive shaft? 100PSI seems to be like a lot of pressure, and I won't be able to hold that still.

 

Any thoughts?

 

Thanks!



#2 lyall OFFLINE  

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Posted October 02, 2014 - 08:26 PM

there is a hole in the flywheel cover for timing.

on the flywheel there are 2 marks - one is "T" for top dead center and "S" I do not know what the S stands for, I think start

 

But I do know  that when you use a timing light you should see the "S"  and not the "T" 

I always start by gapping the points to 0.020 then check it with a timing light.  then adjust the points so that the "S" is centered in the timing hole

 

find out this about the "S" 

  the "S" mark inicates when the points begin to break, firing the spark plug.


Edited by lyall, October 02, 2014 - 08:35 PM.

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#3 FilledTires OFFLINE  

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Posted October 03, 2014 - 12:37 AM

I can never see those marks through the sight hole. When I set my points on my other tractors, I just turned the crankshaft by hand until the plunger for the point came all the way out. Then I set my point gap. Has always worked fine for me. 

 

Back on topic though, determining TDC for a leakdown test. I am thinking I don't need to be at exactly TDC to perform this test. As long as both valves are closed.

 

Can anyone verify that is acceptable? I don't see why not.


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#4 Alc ONLINE  

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Posted October 03, 2014 - 05:29 AM

I can't see why a few degrees off either way and like you said as long as the valves are closed . Are you using one of those " Leak Down Tester " that measures  % of leakage ?   We used to have one in  the old garage at work but haven't see it since it closed .



#5 FilledTires OFFLINE  

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Posted October 03, 2014 - 07:13 AM

Yes I am using an OTC leak down tester. I just tested it and it is reading zero pressure in the cylinder.

I can hear air coming out but can't tell where because of all the engine ducting and covers. I think that means it is a blown head gasket. I will remove all of the tin and test again and see if I can see the source.
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#6 1978murray OFFLINE  

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Posted October 03, 2014 - 09:50 AM

make sure when you look for leaks the listen for air coming out of the intake and exhaust ports.  just incase a valve is not seating properly. 



#7 FilledTires OFFLINE  

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Posted October 03, 2014 - 06:14 PM

I made some progress on this project and since I have strayed some from my original question I have created a new thread here:

 

http://gardentractor...t-165/?p=498220

 

Please let me know if you any of you have any tips or advice!


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#8 skyrydr2 ONLINE  

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Posted October 03, 2014 - 07:42 PM

This engine has a compression release, all k series has this feature your going to need to dis- able it to perform your test. Also can't do a compression test either....

#9 GTTinkerer OFFLINE  

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Posted October 03, 2014 - 09:08 PM

I believe that if you bring the piston up backwards to TDC it will override the automatic compression release.  Also you may want to make sure you use some manner to lock the flywheel in place for the leak down test since if you don't have it real close to TDC the air will force the piston down hard..






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