Jd valves August 03, 2013 05:58AM
I'm building a 3000 rpm tractor. Put different cam in now need to adjust valves. Can't use the stock way. Got told to do each one separate. Could some one explain how to do this. It's on a john deere sbjd. I'm not a master builder and need all the help I can get.
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Re: Jd valves August 03, 2013 06:25AM
I have always done each sep at TDC on comp stroke.
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Re: Jd valves August 03, 2013 02:35PM
Never heard that before .. Set valves the same way the book said except fit the lash that is cam grinders call
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Re: Jd valves August 03, 2013 02:41PM
Do what LLS says he is correct
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Re: Jd valves August 03, 2013 04:13PM
Well if I'm wrong. I put my engine at tdc number 1 piston. The book said to do few groups but on group 5 exhaust mine it's already tight with the adjustment all the way out.
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Re: Jd valves August 04, 2013 12:39AM
First is the cam in the right spot? Did you degree your cam? If so then set #1 valves at TDC compression stroke. Then rotate 120 degrees so the next piston in the firing order is at TDC and set those valves. Then rotate to the next, one set at a time. Performance cams have more duration than stock cams, meaning valves are open longer. So when #1 is at TDC in a stock application other cylinders maybe closed, but not with the new cam.
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Re: Jd valves August 04, 2013 01:18AM
BM. What do you mean not with a new cam.
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Re: Jd valves August 04, 2013 01:32AM
He means that when #1 is at TDC you can adjust #1 valves, but not necessarily any other valves like you can with a stock cam. You need to put each cylinder at TDC to adjust those valves. The big question is, did you degree in the cam, in other words, is the center of the cam lobe where the cam card says it is supposed to be? If you have not done this before, the easy way to check is put a degree wheel on the crank, find top dead center and put a wire pointer on TDC on the degree wheel, then put a dial indicator on #1 INTAKE lifter or push rod and zero out the indicator, rotate the motor by hand slowly in the correct direction until the pointer is at .050 lift, then check on your degree wheel what degree it is at (presumable BTDC) and compare to the cam card on the .050 line, not the "advertised line". If you are close to what the cam card says, then adjust the lifters. If your number 5 is tight, make sure you are not confusing intake and exhaust valves.
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Re: Jd valves August 04, 2013 12:46PM
The cam did get degree in by a well known engine builder. He just came out and did it in my shop. The thing that bugs me is he said the timing marks on the cam gear where 180 degrees off and I'm sure he knows what he is talking about. I'm trying to do this work myself but I am new to it so please be kind. When the 1 piston is at tdc on the comp where should the timing marks be. Can you see them where the injection pump is at or should they be down by the crank. The only way I'm going to learn is doing it. So I need real good directions on how to and so far you guys have helped me a lot. Thank you very much and I hope to try to get it figured out. Just wish I new more
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Re: Jd valves August 05, 2013 02:00AM
This is how I have set the lash on a JD in the past. This may take longer but I know that I'm on the base circle(bottom of lobe when the valve is closed) of camshaft.
Assuming the camshaft has been installed correctly. I only adjust one cylinder at a time. I rotate the crankshaft and watch for the intake rocker arm to start opening the valve. At this point the exhaust should be moving to close the valve. I keep rotating the crankshaft until the exhaust is not moving, and the intake is all the way open or halfway closing. I then set the exhaust valve lash. After the exhaust valve lash is set. I rotate the crankshaft more. The intake will close and the exhaust will open. Once the exhaust is open the intake is surely closed. Now set the intake valve lash. Now move to the next cylinder that the intake valve is opening and the exhaust valve is closing, and repeat. This is how I have done it when the motor is installed in the tractor, and you have no markings for degrees on the balancer.

or

There also is a period where both valves are closed during the compression stroke. This is after the intake is opened and then closed, both intake and exhaust valves should be closed. You can find this by: First find the intake stroke. This should be when the intake starts to open. Right when the intake starts to open you should be near TDC. Rotate to TDC. Once at TDC rotate the crankshaft 360 degrees. This means you should be back at TDC during the compression stroke. Both valves should now be closed. You can set both intake and exhaust valves. Move to the next cylinder and repeat.
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Re: Jd valves August 05, 2013 12:57PM
I adjust one cylinder at a time with a performance cam as well. I watch one cylinder ahead in the firing order of the one I'm adjusting, once the intake valve closes, then adjust the two valves. So, 1-5-3-6-2-4, to start out with 1 you just watch the intake rocker on 5, for 5, you watch int rocker 3, etc. Seems to work for me. You are then essentially setting them both on that cylinder's tdc of compression stroke, just not worrying about watching marks. Obviously, you must turn the engine in the normal direction of rotation. Hope this helps! Ed.
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