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Valve spring swap help!!!

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Old 03-26-2009, 11:03 PM
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Default Valve spring swap help!!!

The cam is in, it was so easy I couldn't believe it. Anyway I'm replacing the springs doing the TDC method and one of the valves doesn't stay up so I can't install the locks as the spring can't be compressed any more.

Tried to put some grease around the valve stem to see if it sticks out but the ****** keeps going down.

Other than an air spring compressor, what can I do?
Old 03-26-2009, 11:35 PM
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If you don't have air, you can do the old shade tree method of pulling the spark plug, feeding in some small rope through the spark plug hole and rotate the motor up to TDC compressing the rope up against the valves in that cylinder.
Old 03-26-2009, 11:57 PM
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Originally Posted by 1Bear
If you don't have air, you can do the old shade tree method of pulling the spark plug, feeding in some small rope through the spark plug hole and rotate the motor up to TDC compressing the rope up against the valves in that cylinder.
This method will work for you, it's the old school standard when compressed air is not available
Old 03-27-2009, 05:30 AM
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Top dead center method
This method requires you to put the piston at the highest position in the bore, so that when you start to compress the spring, the valve can only drop until it hits the piston. When the piston is at top dead center, the valve can't move very far at all.

There are several ways to accomplish this:
A) You can place a small stick/rod/straw/something into the spark plug hole and have a buddy turn the crankshaft by putting the stock 24mm crank pulley bolt in and turning the bolt with a wrench. You should be able to feel when the piston comes up to the top.

B) This method is a bit more elegant. Rotate your motor over by hand until your cam gear and crank gear are dot to dot like you set them up as earlier. At this position, piston 1 and 6 should be at top dead center. You can change the 4 springs on these 2 cylinders now using the instructions below. After you change those 4, then, rotate the crankshaft a full 90 degrees, and the cam gear dot will turn 45 degrees, as if it is pointing to 7:30 if it were a clock. Now piston 8 and 5 are at the top and can be changed. Rotate another 90 degrees on the crank and your cam gear dot will now be at 9 o'clock. Piston 7 and 4 can now have their springs changed. And FINALLY, rotate the crank another 90 degrees and the cam gear dot will be at 10:30. You can now change your remaining four springs on piston 3 and 2.

Once again, that's 1 & 6, rotate 90, 8 & 5, rotate 90, 7 & 4, rotate 90, 3 & 2.
From LS1Howto.com http://www.ls1howto.com/index.php?article=23#part3
Old 03-27-2009, 07:18 AM
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Valve not staying up with compressed air would worry me. Could indicate a weak cylinder.
Old 03-27-2009, 11:37 AM
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I don't think he has an air compressor or he does and he's just not using that method.
Old 03-27-2009, 12:39 PM
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Not trying to hyjack this thread but what type of valve spring compressor is everyone using for this? I'm probably going to put in some dual springs since i've heard stories about the new 918's breaking.
Old 03-27-2009, 01:42 PM
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Thanks, I'll try the rope thing.

I'm using a crowbar spring compressor, it's the first time I do a cam/springs swap and it's the last time I use the crowbar lol
Old 03-27-2009, 02:13 PM
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The crane valve spring tool works very well and does 2 springs at once!
Old 03-27-2009, 03:50 PM
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Vinci/Crane tool is by far the best...if it's still available now that Crane went under. Maybe Vinci still has them...
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