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Discussion Starter #1
It seems like there was a way I read on here on how to change out valve springs with the heads on. It seems like it involves using a compressor to put air in the cylinders to hold the valves up.....but I can't be sure. Is there a way??? It would sure save some time and $$$. Thanks!!!
 

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Or thread a long piece of blind pull cord in through the sparkplug hole w/ the piston down and then bring the piston up to TDC. Cord will squeeze up and hold the valves in place so they can't fall.

pdq67

PS., just tie a big nut to one end so you CAN'T lose it in the cylinder.
 

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long ago what I did was take the ceramic out of an old sparkplug and have an air fitting welded to it.
used compresser to pressurize the cylinder.
I seen another method same as above but having a tire valve installed on the plug and use a bicycle air pump.
but wait there still is another method!
get some clothesline and feed it into the cylinder via the sparkplug hole until you cant get anymore in there.
that will keep the valves from falling.
once done remove the rope.
(thats an old school trick)
 

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Basically all you do is hook the lower half of a compression tester tool to your air supply and this will charge the cylinder and hold the valves up in that cylinder while you remove the springs. Use the spring removal tool designed to grab the spring and compress it then you can remove the keepers, now the spring will come right off. You must keep the air pressure on the cylinder until the new spring is installed and the keepers are installed. Remove the spring compression tool from the spring. At this point I generally give the top of the valve a tap with a rubber hammer to make sure the keepers are seated and then you can release the air pressure. Repeat for the other valve in this cylinder. Then move on to the next cylinder and repeat the process.
 

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I am doing a spring change right now and I used the lower half of a compression tester just like scott mentioned but I also used clothes pins to hold the valves in place. I bought one of those nice spring removal tools from summit and I must say it has paid for itself already.
 

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Discussion Starter #7
Can the compressed air hurt anything??? I have a compression tester that has a bunch of fittings. I could sacrifice one of those.


Maybe even easier.....I could just do the cord/rope trick but just start the motor up and let the cylinders burn up the material and move it out the exhaust system!!!!!!! :clonk::D
 

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Can the compressed air hurt anything??? I have a compression tester that has a bunch of fittings. I could sacrifice one of those.


Maybe even easier.....I could just do the cord/rope trick but just start the motor up and let the cylinders burn up the material and move it out the exhaust system!!!!!!! :clonk::D
No the air charge holding the valves won't hurt anything, it's just like the piston coming up the cylinder wall on the compression stroke holding both valves closed.
 

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We change a lot of valve springs during the racing season and on the dyno when breaking in solid lifter cams and so far we have not needed any air to hold the valves in place the valve seals seem to wrik fine after you break the retainers loose. and we go right through the firing order that way we can install the springs and lash the valves.

Using rope in the cylinder makes for a good chance of bending a valve and just when you think you have heard it all.
 

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Probably will be able to break the keepers OUT using a deepwell socket to contain them and a 3 pound Ford Tool.

A couple a whacks and go!!

pdq67
 

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Also keep in mind that the air pressure might turn the engine, not a problem it just kinda surprises you if it happens. And your air compressor needs to be turned on and ready even after pressurizing the cylinder, as it will leak down while you're working.
 

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Actually....that makes sense. I'm guessing that my compressor can't come close to the presser created in the cylinders when it's running???
You are correct, your air compressor probably can't develop as much air pressure as the engine does while running. Most home air compressors won't make over 125 PSI.
 
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