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How do I remove valve springs?
In order to try and avoid another lobe wiping episode I want to remove my valve springs this time around. I have Vic Jr heads with 7/16 studs and 3 springs per valve. Should I remove both inner springs for break in or just the innermost? Will I need to fabricate a shaft to pry on? Exactly what tools am I going to need to do this? If anyone could give me a run down of the procedure or direct me to the necessary information I would appreciate it.
Thanks, Mike |
It's likely you have TWO valve springs and the third item is the valve spring "dampner". A rather flat winding that looks like a spring. Proper breakin prodedure for a flat tappet cam is indeed to remove the inner round wire spring. Run the engine for 2o to 30 minutes at varying rpm never below 2000 or so. Vary the rpm some so that different parts of the cam get "splashed" during the break in. Re-install the inner most spring after breakin.
There is a valve compression "tool" you can buy (fairly cheap), which is what I used to do mine. Depending on your type of valve you may need to "fabricate" something in addition to work or use with the valve tool. Here is a picture showing one possible way to do it. I used an old rocker arm shaft and an actual valve tool. The picture just demonstrates another possible way. VERY important: You'll need an air compressor and will have to fabricate or buy an adaptor to fill the cylinder with air pressure. This will hold the valve firmly in place while you depress the springs to remove the keepers. I like to bring the cylinder up to TDC before I apply the air pressure. No air pressure will result in the motor "swallowing" the valve! More information on my "Engine Blog" thread: http://www.clubcobra.com/forums/show...4&pagenumber=2 http://www.clubcobra.com/photopost/d...cker_shaft.jpg |
You'll need a good magnet also to aid the removal of the valve locks.
Compress the spring, pull the valve locks and ease up on the compressor. Remove the spring. Just reverse process for assembly... Good time to check your valve seal condition....and make sure you have spring cups on aluminum heads. |
The air fitting for the sparkplug hole can be found here. http://www.mytoolstore.com/kd/kdengi14.html#901
Hey, Slick, that looks like the tool I have to remove ball joints. How's the undercoating holding up on that new engine? Tim |
Eh eh,,, that is in fact a pickle fork ball joint tool. I was just playing around one day.
The motor is doing great! Pulls strong, runs cool and doesn't use oil. Couldn't be better! |
valve spring tool
Desertson,
The best valve spring tool I have found is made by Moroso. Their tool will fit most any size stud and will lock in the compressed position so you can get the keepers in and out with no problems. Summit Racing has a copy for only 49.95 part #sum-906784. Also I do not try to keep the piston at TDC because most any air compressor will force the piston to the bottom of the bore anyway. |
Millenium, true enough! Really HARD to get the crank at exact TDC and if you don't the piston will move to the bottom. The whole valve spring thing IS a pain in the butt, but it beats loosing a cam lobe! :D
I feel "paranoid" with the piston so far away from the valve. I guess I have "hope" that if it all goes to hell and I loose my air pressure I have a prayer of recovering the valve which stopped moving down into the cylinder because it hit the piston top. Could be "false hope" and your screwed either way! :LOL: |
TDC+4th gear + E Brake =:)
Works without fail. Rick |
Ernie, that looks like a "pickle fork" we used to use on tie-rods and ball joints. Good thing you found a second use for it.:D
Mike, as you are doing this, you might want to rotate the engine for each chamber so it is closed. That way the air tool will hold the valve closed. Without it, the valve will drop into the chamber, on top of the piston. This means you should do all of the things you want to do to the spring at one time. put compressed air in chamber Compress spring. Pull locks Do whatever. Put locks back on. remove comressed air. next chamber. Rick's idea to make the car safe for work, will need to be modified. You might want chok the tires so you can turn the engine over with a breaker bar ( at the crank ). You can also use the breaker bar to keep the piston from moving to the bottom of it's stroke. Hope this helps. |
Cotton Rope
For those that do not have access to an air compressor, I have used 1/4" cotton rope to hold the valves closed!
With the piston on the way to TDC with both valves closed, stuff a good amount of this small rope through the spark plug hole and then "HAND" crank the engine to TDC. The rope will fill the area above the piston and hold the valves closed. Just remember to leave some rope hanging out of the spark plug hole so that you can remove it when you are done with your spring work. Terry |
Shall I use as much air pressure as possible here? As it is a 351 Windsor I plain to put a nut and washer on the stud and pry off that with a tie rod separator, Will that be all right? The engine is still on a stand, Probably should have pulled the springs while the heads were off but I guess I wanted to be sure that I can do it this way so I don't get in trouble when the engine is installed in my wee little 65 mustang engine compartment.
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I used a 120 psi from my compressor. I reckon less psi will still do a fine job, I'm just "paranoid" as hell. IF a valve DOES drop, "off with your head"! :D
I used a breaker bar to rotate the engine around to do each cylinder. One time I didn't quite get it at EXACTLY TDC. When I applied the air pressure the piston immediatly went "down", which rotated the crank (of course) and the breaker bar and socket got "launched" in the process! That was ugly, if your going to use TDC you got to be SURE of where it is. I kind of like that "rope trick", not sure I would use it, but I can see where it would work AND you wouldn't have to worry about loosing air pressure! |
Well she seems to have surviveda half hour at two grand, gotta put the springs back in now, that should be fun.
For some reason it fryed the cap on my unilite, was using a old accel supercoil and the old ballast resistorthat came with the car, just picked up a MSD blaster 2 (8202), also had to jump it off a charger to get it to start, perhaps the extra power from that caused this? It ran fine for a half hour despite the cap welding itself, any ideas? |
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