DanS26
Performed the necessary maintenance on my 2008 Model 5502 10kW Generac today since I can't go any where.

Big shout-out to 78buckshot for his helpful post on the valve adjustment procedure.  See this post:

https://www.zillerstore.com/post/valve-adjustment-procedure-author-78buckshot-10165545?pid=1308803294

On my 10kW machine though a few changes are necessary.....your hand cannot fit in a 10kw machine without pain in the front of the machine to move the engine to top dead center.....so I removed the screen on the other end to access the cooling blades to rotate the engine. Worked great. I was gentle to not break any of those plastic blades.

As 78buckshot observed from his experience the exhaust valves were tight......yes I know I last adjusted valves in 2010.  200 hrs on the machine so the reason for the long delay.

A little tricky to adjust those valves because as 78buckshot advised as you torque to 173 in lbs the gap increases. So after a few failures to get to .004mm I bladed to .002mm then torqued to 173 in lbs and presto it went right to .004mm.

I was a little concerned with the torque on that little 10mm nut but it held.  I used a crowsfoot and a torque wrench and watched very carefully to not slip off or engage nearby metal.

Thanks to all you guys here to help us DIY'ers.


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Birken Vogt
I hate the valve adjustment on these things.  I stick a gauge in and get an idea where it is.  Loosen nut, rotate stud a good guess, tighten nut.  Check clearance.  Loosen nut, turn stud a fraction of a flat in proper direction, tighten nut.  Repeat measurement.  Repeat procedure until it's right.

On diesels and larger gas engines you set the clearance, tighten the nut and the clearance stays the same.  Thankfully.  Doing the above procedure on more than 2 cylinders would be excruciating.
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DanS26
Technique is the key.

What I mean by bladed is to put a .002 blade over the valve stem. Tighten the nut slightly at that point and remove the blade.  Then torque the nut. Amazingly it works. Most techs know this trick.  But for us DIY'ers it is trial and error.
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78buckshot
I have been able to turn the engine from the alternator end on all of the machines that I service, yes I agree that it's tight and painful, glad we could be of some help.
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Birken Vogt
There are certain models I can't get to the fan somehow.  Exhaust pipe or something, can't remember.  Maybe it is the newer 530 models?  Anyway I will just hook a starter bumping switch up to the starter and rotate the engine that way.  Crude but it works.  Sometimes you have to try a couple times to get the engine to stop at the right place.
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DanS26
78buckshot wrote:
I have been able to turn the engine from the alternator end on all of the machines that I service, yes I agree that it's tight and painful, glad we could be of some help.


You must have small hands and wrists to get into that small space.  I was about to call my wife to help....then I decided to attack from the opposite end.
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Peddler
There is absolutely no reason to worry about TDC when adjusting the valves, none!  Bump the engine over with the starter until one of the valves on the cylinder you are working on starts down and then adjust the other.  Repeat until the one you adjusted starts down and then adjust the remaining valve.  Repeat for the other cylinder if there is one.  You are more likely to make a mistake at TDC then by using this method.
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Cobranut
Peddler wrote:
There is absolutely no reason to worry about TDC when adjusting the valves, none!  Bump the engine over with the starter until one of the valves on the cylinder you are working on starts down and then adjust the other.  Repeat until the one you adjusted starts down and then adjust the remaining valve.  Repeat for the other cylinder if there is one.  You are more likely to make a mistake at TDC then by using this method.


The valves are still in overlap when the intake is just starting to open.  
Better to have the other valve fully open to avoid the overlap area. 
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DanS26
Peddler wrote:
There is absolutely no reason to worry about TDC when adjusting the valves, none!  Bump the engine over with the starter until one of the valves on the cylinder you are working on starts down and then adjust the other.  Repeat until the one you adjusted starts down and then adjust the remaining valve.  Repeat for the other cylinder if there is one.  You are more likely to make a mistake at TDC then by using this method.


Generally I agree with your method but by not using TDC you are assuming that the camshaft is machined perfectly.  The factory grind on those camshafts are not always within specs or the specs can be loose right out of the factory.

If I was in a hurry your method is satisfactory.....but I had plenty of time.
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grsthegreat
if one valve is compressed and you adjust the loose valve, you cant cause any issues with engine. doesnt matter how the cam is machined.
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Birken Vogt
Any place on cam base circle be it the 1-up-1-down method or the TDC method should give the same result.  If the cam base circle is machined incorrectly then it will always be wrong no matter how you do the adjustment, there is no way to use adjustment to compensate a bad cam.
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DanS26
Birken Vogt wrote:
Any place on cam base circle be it the 1-up-1-down method or the TDC method should give the same result.  If the cam base circle is machined incorrectly then it will always be wrong no matter how you do the adjustment, there is no way to use adjustment to compensate a bad cam.


You are thinking circle....I'm thinking oval.
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Birken Vogt
The base of the cam is a circle and has to be for proper operation.  The opening lobe is the only part non circular.

All larger engine manuals tell you to bring up a particular cylinder to TDC and then you can adjust a bunch of other valves/injectors that are also on base circle but not TDC.  This way you don't have to reposition the engine once for each cylinder which would be prohibitive with 6 or 8 cylinders or more.  But the 1-up-1-down method works for all engines if you can't get the manual or are otherwise in the dark.
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78buckshot
I'm sorry that my post on valve adjustment has caused discontent. Everyone here is correct, there is more than one way to skin a cat. ( I haven't skinned a cat in a couple of years and have always use only one procedure). When I instruct young guys at work on the valve adjustment I want to follow Generac's procedure so they have reference material when I'm not around, same reason I posted the procedure per Generac instructions. Also, not having studied the cam specs on these little motors I don't want to guess at when the lifter is on the base circle, Generac has already said "find TDC on the compression stroke and adjust the valves on that cylinder". My intent was and is to help those that are not doing this stuff on a daily basis and not intended to be an in-depth class on internal combustion engines. It does make interesting forum material.
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