Valvespring replacement
Thread Starter
Joined: Feb 2015
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From: Conroe, Texas
Valvespring replacement Who's done this on the heads while still in an Fbody and what have you found to work best? I've been looking at spring pressure testers from Proform and LSM Racing that work by attaching to the rocker arm on the head but not sure if those will work with the T&D billet steel adjustable rocker arms for the Brodix BR7 heads. I have the LSM Racing spring compressor that mounts to the head and compresses both springs at the same time and looking to run a stiffer spring this time around.
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From: Central Cal.
I'm guessing the last time anyone considered this, it sent them on a hopeless illegal substance spiral, that once recovered from, they sold the car... LOL!
Last edited by G Atsma; Apr 26, 2024 at 03:04 PM.
Thread Starter
Joined: Feb 2015
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From: Conroe, Texas
That's funny right there..Heads were built by LME in 2018 with PAC .660 spring. The car has a .661 lift cam and in 2019 I installed the heavier T&D rocker arms and been driving it around for several years now so It's long been time. I'm switching to the PAC 1207X .700 lift springs. From what I've gathered so far I just need to get the piston to TDC, put the car in first gear with the e-brake engaged and then load the cylinder with 55-60 psi. Just wondering if a cleaned spark plug wire fed into the spark plug hole would be better. Either way I'm gonna go for it!
I have an 04 goat, I/m pretty sure its tighter than an F-body but not sure. I used rope, as I do not have a large compressor. Was no problem. I do not have any insight on your head setup for a compressor but I did the trick flow on head compressor.
Joined: Apr 2006
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From: Grand Rapids, Michigan
I've done it to both of my cars, just fed a rope into the cylinder and gently turned the engine to TDC on the compression stroke until I felt resistance. A clean spark plug wire might work, I'd only worry that it would be too stiff and follow the contours of the cylinder and coil up on the edge. A piece of rope ends up just wadding itself up in the middle, which works great for holding the valves up.
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I've always used rope also. Never had any luck with compressed air even though I have the fittings. The keepers were always tighter than the pressure on the valve head from the air. 
Never heard of using spark plug wire, butt hay, sounds like it might work; just, costs AHELLUVALOT more than a foot or 2 of 3/8" rope. OTOH if you're in your garage at 2 in the morning, and you have no rope butt some fornicated plug wires laying around, ... you do you. Me, I'm a bit of a marine person, so I always have rope around, butt of course not everybody is that way.
Never heard of using spark plug wire, butt hay, sounds like it might work; just, costs AHELLUVALOT more than a foot or 2 of 3/8" rope. OTOH if you're in your garage at 2 in the morning, and you have no rope butt some fornicated plug wires laying around, ... you do you. Me, I'm a bit of a marine person, so I always have rope around, butt of course not everybody is that way. Trending Topics
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From: Missouri
ive always used the air method and it works fine, i use the snap on 14mm adapter (with valve removed). when you take the rockers off all valves are up any ways i dont even turn engine over at all. hook it straight to my compressor (mines at 150 psi) . also keep a pen magnet right next to keepers when they get ready to come out in case one tries to make a run for it. when laying em back in sometimes ill use a small dab of greese on the inside to help em stay there as i un compress the spring . the back two cylinders suck the worst.
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From: Wilmington, De
That's funny right there..Heads were built by LME in 2018 with PAC .660 spring. The car has a .661 lift cam and in 2019 I installed the heavier T&D rocker arms and been driving it around for several years now so It's long been time. I'm switching to the PAC 1207X .700 lift springs. From what I've gathered so far I just need to get the piston to TDC, put the car in first gear with the e-brake engaged and then load the cylinder with 55-60 psi. Just wondering if a cleaned spark plug wire fed into the spark plug hole would be better. Either way I'm gonna go for it!
Thread Starter
Joined: Feb 2015
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From: Conroe, Texas
Just pull some of the front springs that are accessible and test their pressures. If they check out, then you are good to go. I also wouldn't fret about being .001" over the springs lift rating. There is around .050" of coil bind clearance baked into that rating, so you would now be .049" from coil bind. Adding another .040" of clearance could negatively impact the spring's performance, especially if the spring's seat and open pressures remain the same. Your cam is still only going to open the valve by .661", so if the spring's rate isn't stiffer, then all your doing is decreasing the spring's ability to control the valve by increasing the clearance to coil bind. If you need to change the springs, but you haven't experienced any issues with valve control after adding the T&D rockers, then I would replace with another set of the same valve springs. If you have been experiencing valve control issues, then do some math and get a spring with a stronger rate for a higher open pressure at .661" of lift.
Thread Starter
Joined: Feb 2015
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From: Conroe, Texas
The thought of dropping a valve when a piston is down in the hole is not something I want to deal with. It's going to be one at a time with each one at TDC.
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From: TX
Ive done it many times. Using both air and the rope at tdc method. Both work well, but I prefer the rope method. Quicker to set and dont have to work around an air hose in an already tight engine bay. I use a Crane or Comp tool. The one that threads into the rocker bolt hole and does 2 springs at once. I have both tools for LS and LT motors so I dont remember which one is which lol
Thread Starter
Joined: Feb 2015
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From: Conroe, Texas
Springs I'm looking at are CamMotion LS High Performance .700 lift springs or PAC 1207x. Good for hydraulic camshafts with aftermarket rocker arms.
155 lbs @ 1.800
436 lbs @ 1.150
457 lbs @ 1.100
Coil bind @ 1.000
I really don't see any issues with these over the PAC .660 springs as they have similar spring pressures. CamMotion suggested their .685 spring which has 170 lbs @ 1.800 and 450 lbs @ 1.115
155 lbs @ 1.800
436 lbs @ 1.150
457 lbs @ 1.100
Coil bind @ 1.000
I really don't see any issues with these over the PAC .660 springs as they have similar spring pressures. CamMotion suggested their .685 spring which has 170 lbs @ 1.800 and 450 lbs @ 1.115
On The Tree
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From: Colorado
You want springs with minimal (~0.050") space left at max lobe lift. Giving a spring more room can lead to it going into wild oscillations as it comes off max lift. Minimal space at max lift helps damp out the oscillations. The CamMotion suggestion was wise.
Thread Starter
Joined: Feb 2015
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From: Conroe, Texas
I talked to the powers that be over at CamMotion and they suggested the 1207x for what I got going on.