Valvespring replacement
Thread Starter
Joined: Feb 2015
Posts: 6,014
Likes: 2,294
From: Conroe, Texas
Joined: Apr 2006
Posts: 3,910
Likes: 1,158
From: Grand Rapids, Michigan
Get a BTR height mic and adjust with shims accordingly. I recommend the BTR mic because it works well with smaller diameter retainers, as other brand height mics tend to let the retainer sit inside the first step causing inaccurate readings. Figure out where coil bind is on the new springs, and add .050 to that measurement to determine where your installed height needs to be. Once you've figured that out, add whatever shims get you to that point.
Thread Starter
Joined: Feb 2015
Posts: 6,014
Likes: 2,294
From: Conroe, Texas
Get a BTR height mic and adjust with shims accordingly. I recommend the BTR mic because it works well with smaller diameter retainers, as other brand height mics tend to let the retainer sit inside the first step causing inaccurate readings. Figure out where coil bind is on the new springs, and add .050 to that measurement to determine where your installed height needs to be. Once you've figured that out, add whatever shims get you to that point.
I was looking at different spring height checkers and I like the one from BTR. Can you give me an example? The coil bind for the 1207x is 1.00" so are you saying that I'll need to add shims to reach 1.05 after max lobe lift? If the exhaust lift is .632 does that mean it will most likely need additional shim to reach the 1.05 after max lobe lift? Just trying to understand.
Thread Starter
Joined: Feb 2015
Posts: 6,014
Likes: 2,294
From: Conroe, Texas
According to LME the heads are setup with PAC .660 springs and have a .060 shim on the intake and .045 on the exhaust. My assumption is that this was what was needed to reach the desired install height and since I'm reusing the seats and retainers I just need to make certain that I have 1.80" between the seat and the bottom of the retainer and I"ll be okay to install the new springs.
Thread Starter
Joined: Feb 2015
Posts: 6,014
Likes: 2,294
From: Conroe, Texas
https://www.yellowbullet.com/threads...arance.101230/
Looks to me like 0.06 to 0.10 is exceptable clearance.
Looks to me like 0.06 to 0.10 is exceptable clearance.
Joined: Apr 2006
Posts: 3,910
Likes: 1,158
From: Grand Rapids, Michigan
I wasn't too worried about it when I set my springs up, as I'm not turning enough RPM to really be concerned about spring surge. I run BTR .660 platinum springs, and I merely shimmed mine to increase pressures a bit because of the turbo. On my Camaro, I just installed them at the suggested installed height. You're correct in your math, but you subtract your full ROCKER lift from your installed height and compare that to your coil bind height. I'm sure that's what you meant anyway, but someone reading this might get the math wrong, lol. I think I ended up with something like .065-.075 clearance at full lift on my cam. I was fine with that.
Thread Starter
Joined: Feb 2015
Posts: 6,014
Likes: 2,294
From: Conroe, Texas
So basically what I'll need to do is take my feeler gauges and find out what spacing I have between the coil springs at full valve lift. I think LME set the the valve spring height at 1.78" for the .660's and used the shims to create more spring pressure and if that's the case then it won't hurt anything to run the .700 lift spring with the way the heads are set up with the current shims. Ordered the BTR spring height checker from Summit Racing today and when I get some time I'll dive into it.
Thanks LS1Formulation!
Thanks LS1Formulation!
LS1 Tech Stories
The Best V8 Stories One Small Block at Time
Gas Monkey Built a 6-Wheel Ferrari Testarossa With a Corvette LT4 Engine
Verdad Gallardo
7 Most Reliable High-Performance Engines GM Has Ever Built
Verdad Gallardo
Amazing '71 Camaro Restomod Is Modern Muscle Car Under the Skin
Verdad Gallardo
6 Common C5 Corvette Failures and What's Involved In Repairing Them
Pouria Savadkouei
Retro Modern Bandit Pontiac Trans AM Comes With Burt Reynolds' Autograph
Verdad Gallardo
Top 10 Greatest Cadillac V Series Performance Models Ever, Ranked
Pouria Savadkouei
Top 10 Most Powerful Chevy Trucks Ever Made!
Hennessey's New Supercharged Silverado ZR2 Has 700 HP
Verdad Gallardo
Coachbuilt N2A Anteros Is an LS2-Powered C6 Corvette In Italian Clothes
Verdad Gallardo
TECH Apprentice
Joined: Jan 2023
Posts: 340
Likes: 47
From: Corpus Christi, TX
I'm glad you're covering this subject for me! My time of doing the same thing is coming soon. I have a question I just wanted to confirm, After looking for springs that are single setup and not dual I have found that I cannot find a high lift set. Is this due to the need of a thinner design for the dual so they can compress more without binding? It appears they have less coil per an inch but I've never actually worked with a set and kind of scared up how noisy the valve train could get. I don't know why I'm concerned about the noise with straight pipes
Joined: Apr 2006
Posts: 3,910
Likes: 1,158
From: Grand Rapids, Michigan
Why do you need a single spring setup? There are numerous reasons for duals for high lift set ups, and coil thickness can be part of that. However, I can tell you right now that even with .660 capacity duals in my Camaro, the valvetrain doesn't seem to be much noisier than stock. Just get duals.
So basically what I'll need to do is take my feeler gauges and find out what spacing I have between the coil springs at full valve lift. I think LME set the the valve spring height at 1.78" for the .660's and used the shims to create more spring pressure and if that's the case then it won't hurt anything to run the .700 lift spring with the way the heads are set up with the current shims. Ordered the BTR spring height checker from Summit Racing today and when I get some time I'll dive into it.
Thanks LS1Formulation!
Thanks LS1Formulation!
You cannot measure between coils to find out your clearance.
You must take the spring down to full solid and record that measurement. You then take you installed height, subtract your valve lift, then subtract your coil bind number. This will give you your coil bind clearance.
Example
Spring coil bind # is 1.00"
Installed height is 1.800"
Calve lift is 0.700"
1.800"-0.700"=1.100"
1.100"-1.000"= 0.100" coil bind clearance.
I'm glad you're covering this subject for me! My time of doing the same thing is coming soon. I have a question I just wanted to confirm, After looking for springs that are single setup and not dual I have found that I cannot find a high lift set. Is this due to the need of a thinner design for the dual so they can compress more without binding? It appears they have less coil per an inch but I've never actually worked with a set and kind of scared up how noisy the valve train could get. I don't know why I'm concerned about the noise with straight pipes
Duals usually have a lower coil bind # than singles due to the design. A single spring with a 400lb rate will require a larger wire diameter than 2 springs collectively making 400 rate.
The biggest advantage of a single over a dual, is it usually has a much higher frequency (can handle more RPM before hitting its natural frequency) along with a much lighter retainer/spring package.
I have a pretty aggressive bullet cam 0.650" lift 232/242 @ 0.050"
I went from a PAC-1206X with Ti retainers to a PAC-1276X with Ti retainers. My total weight with spring/retainer went from 100g with a dual to 70g with the beehive. Spring weight does matter in the total package.
Thread Starter
Joined: Feb 2015
Posts: 6,014
Likes: 2,294
From: Conroe, Texas
After some frustration I was able to feed 3/8" inch ropes into 1&6 and then brought it back up to TDC. I ended up having to melt the ends some to get enough stiffness in the rope to feed it into the spark plug holes. Next up is to remove the rocker arms and replace the springs. My arms and hands aren't as limber as they used to be.
Thread Starter
Joined: Feb 2015
Posts: 6,014
Likes: 2,294
From: Conroe, Texas
I'm seeing that the LSM Racing SC-167 valve spring compressor dosen't mount to the Brodix BR7's. I had called them several months back to verify and they said it would work. Maybe they've made some revisions to the original design and that may be the problem. This one does not fit over the boss for the center bolt valve covers and then lay flat on the rocker pedestals with the bolt holes aligned.
TECH Addict
Joined: Dec 2017
Posts: 2,191
Likes: 977
I have found a few whacks ... on the tool itself (I don't like whacking on the retainers) will shock the keepers into saying goodbye to the valve stems.
I use a socket as the "drive" device. That way, I can whack SO hard if I want, that the keepers fly off; but the socket keeps them contained so they don't spoioioioioioinnnnggg off into space somewhere. Obviously you have to hold on tight to everything because the spring and retainer come loose then too. A deep-well socket, maybe a 5/8" or so, is about right.
I haven't the vaguest foggiest dimmest remotest hint of a whiff of a glimpse of a clue about the Brodix heads.
Thread Starter
Joined: Feb 2015
Posts: 6,014
Likes: 2,294
From: Conroe, Texas
Just found that Summit Racing sells an adapter made by LSM Racing for this tool when working with aftermarket heads but I don't see how that could be because when you install the tool and get it onto the boss for the valve cover bolts the holes do not line up by about an 1/8". I looked at the one made with steel from Comp Cams and I'm certain it will work but none in stock. Proform makes a similar one made of aluminum but I'm skeptical. TSP sells a neat valve spring compressor tool that mounts to the rocker arm pedestal and you use a 3/8 drive ratchet or breaker bar to compress the spring and it's made of aluminum but not a whole lot of working room to get my fingers in there to install the keepers.
Don't be concerned about them being aluminum. I bought one made of aluminum, I think from Pro-Form, and it has no problems compressing my 170lb seat pressure PAC duals. Now, whether or not it will work on an Fbody, IDK........