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Old 01-23-2003, 06:08 PM
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Post Valve Spring question

I was told by one guy that changing the springs with the heads still on the motor is no problem and will take less than an hour, another guy told me changing them that way is a major pain in the *** and will take several hours, what are your thoughts? Thanks.

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Old 01-23-2003, 06:28 PM
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you must put air in cyl have cylinder on top dead center [both valves closed] rap top edge/side of spring requires special spring tool cheap just be very careful not to push down on valve as air holds valve shut might want to replace seals if they are old only glinch is if you have bad valve leak down tester will put air in cyl eazy job don't rush good hunting
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Old 01-23-2003, 06:28 PM
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it depends on how fast and how experienced you are, i used to change 16 springs between rounds at the drags 25 min tops, but these days it takes a couple of hours, after you master the technique its simple.
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Old 01-23-2003, 06:45 PM
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It may be a hour for you guys who know what you're doing, but it sounds like a Saturday and a 6-pac to me!
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Old 01-23-2003, 07:08 PM
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From what I have heard you just need to have cylinder at top dead center with both valves closed as said before... If you drop a valve in the cylinder when it is at bdc you are gunna have to pull the head... I would plan on it as a weekend job just in case something goes wrong...
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Old 01-23-2003, 08:17 PM
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If you do not have air. You can feed some small rope into the cylinder and rotate the engine by hand until the piston pushes the rope against the valves. That will hold them while you change the springs. While you have it apart you might want to check these dimensions. How To Spring Set Up
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Old 01-23-2003, 08:31 PM
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Unless you have a standard tranny and have it in high gear with the E brake on, the motor will turn to BDC. I have done this many times with air, and they have always turned to BDC. The rope trick works best if you're worried about dropping a valve (but takes alot longer). You can make an attachment to pressurize the cyl. Get a compression tester from Autozone, the hose detaches from the guage. Take the hose off the guage and remove the schrader valve from the end that goes into the plug hole. The end that goes to the guage will be a "D" type coupler, the most common type for air hoses (it should work with your air hose coupler). Crank the regulator as high as it will go, and be sure to break the keepers loose before trying to remove the springs. Expect to take 2-3 hours your first time (maybe more, maybe less). Oh yeah, loosen the rockers on each cyl, to make sure both valves are closed.

[ January 23, 2003: Message edited by: BstMech ]</p>
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Old 01-24-2003, 06:55 AM
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I believe the actual time to do the "changing of the spring" part of the job is small. Where all the time comes in is how easy the access is. Changing springs on a race car with plenty of open area around the heads can go fairly quick. Changing springs on a 25 foot Bayliner with a 350 inboard could take a week.
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Old 01-24-2003, 01:53 PM
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Even if you drop the valve into the Cyl. it should'nt go far enough down that you can't just pull it up by the stem. After all the piston is a very short distance from the head at TDC. With the piston at EXACT TDC than rolling of the motor will not be a problem. But you will have to make sure the piston is sitting in the middle of the dwell period.
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