Valve spring set up

IamGroot

New member
I’ve searched and found some threads about setting up valve springs but still don’t think I understand how to do it. I’m going to put down what I think I know and hopefully someone will verify I’m doing it right or set me straight.
1: determine the height of the spring at your desired pressure
2: determine the distance between the retainer where the spring touches and the pocket the spring sits in
3: make the spring match the height using shims or cutting pocket deeper, if necessary

If the above is correct how do you accurately measure from the distance between the retainer and pocket? And how exact do you have to be?
 
That's it!
You need a special caliper. Or a dial indicator and a 1 " tall tube , to simulate a valve spring, i used 3/4 pvc square cut on both ends. Install it as the spring put in retainer.
Mount indicator over valve , zero out .
Raise valve till it stops read indicator.
Add that too the one inch , that's your installed hieght.
 
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SORRY this is for OHV Clones.... but i didn't want to delete in case it helps someone
FOR OHV Clones Predators
here is how i do it... install the valve spring straight up no shims with your sliding micrometer... position it on top of your retainer where the part that comes out of the bottom goes down to the spring pocket... you can push your spring to one side to get an edge to hit... this will give you a measurement to the TOP of the retainer... now subtract the thickness of the retainer...... you now have the total height from the spring pocket to the bottom of the retainer, we race with a Minimum installed height... if the minimum installed height is .910 and you have .935 you now know you need to install a .025 shim... pretty simple I usually leave .002 on the table just to be safe since mine is not the standard way of doing it...
 
That would work for the ohv .
Not feasible on the flatty.
To add ; i May have used a 3/4 splice as the retainer has too fit inside . thin wall tubing would work also or compress spring in vice measure, then install and use dial indicator as described above. Only problem with this is it's hard to push the valve up till coil bind.
Accuracy is important.
 
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have you read the Final Assembly chapter of my book. it describes valve spring setup.


two things you really need

a way to measure spring pressure for a given height.. Simple way is to make an adapter for a drill press that will hold a 1" or 2" dial indicator and mount it in the press. it will have to depress the spring and measure how far it is going down after contacting the spring.. you have to know what the compressed(installed ) height is and then what pressure at that height for That spring..


then you have to know what your installed height is for both valves... I wright about a easy way to do that in the assembly chapter.

when I assembled any engine I cut the valve relief then find my exact installed height.. I then start sorting springs at that installed height looking for the spring that has the pressure I need. Generally I had the exhaust at 1.020 and the intake from 1.020 - 1.060 for installed heights.
 
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have you read the Final Assembly chapter of my book. it describes valve spring setup.


two things you really need

a way to measure spring pressure for a given height.. Simple way is to make an adapter for a drill press that will hold a 1" or 2" dial indicator and mount it in the press. it will have to depress the spring and measure how far it is going down after contacting the spring.. you have to know what the compressed(installed ) height is and then what pressure at that height for That spring..


then you have to know what your installed height is for both valves... I right about a easy way to do that in the assembly chapter.

when I assembled any engine I cut the valve relief then find my exact installed height.. I then start sorting springs at that installed height looking for the spring that has the pressure I need. Generally I had the exhaust at 1.020 and the intake from 1.020 - 1.060 for installed heights.


I have now. Was easy!!! Thank you ?
 
What do you use for shims to get you installed height just right? The thin upper shim is too thin and the thick one is too thick. The thin upper with a spark plug indexing washer is just right. Any issues with using that setup?
 
Is this a legal engine?
No the indexing washer won't work.
You either need to cut the pocket more.
Find a different springs , or sand the long one shorter.
Swap out retainers to find one that works with your spring.
 
Is this a legal engine?
No the indexing washer won't work.
You either need to cut the pocket more.
Find a different springs , or sand the long one shorter.
Swap out retainers to find one that works with your spring.

I had to dig the rule book out. I thought you could use multiple shims with a maximum thickness of .058. I was wrong, thanks for putting me back on track.
 
Well your doing good 80% don't have a rule book.
Decreasing the overall springs length seems simplest.
 
If at overhaul time your spring measures the correct tension at the correct height, or even the correct tension at an adjusted height (different shim) do you continue to use it? How often do you replace your springs? I change retainers every few weeks when I lap the valves but have been wondering about the springs for a while. In the 90's when I was doing this we replaced them every 3 weeks at overhaul but they sure don't seem to change much these days.
And just for verification, using a 96-3 cam for an example you want your intake spring at 20# at installed height and your exhaust at 18# at installed height, whatever that installed height may be, correct?
 
Scott,
Make sure that the nose pressure remained the same.
You're right that the aftermarket springs are considerably more consistent than the Briggs oem springs, but they still drop over time.
I've re-used them plenty of times (especially when the engine is just right with that particular set of springs) but eventually you'll need to find a duplicate set of those springs.

Are you replacing lower retainers with new heat treated retainers that often, or using stock retainers?


-----
?Thanks and God bless,
Brian Carlson
Carlson Racing Engines
Vector Cutz
www.CarlsonMotorsports.com
Carlson Motorsports on Facebook
30 years of service to the karting industry
Linden, IN
765-339-4407
bcarlson@CarlsonMotorsports.com
 
Scott,
Make sure that the nose pressure remained the same.
You're right that the aftermarket springs are considerably more consistent than the Briggs oem springs, but they still drop over time.
I've re-used them plenty of times (especially when the engine is just right with that particular set of springs) but eventually you'll need to find a duplicate set of those springs.

Are you replacing lower retainers with new heat treated retainers that often, or using stock retainers?


-----
?Thanks and God bless,
Brian Carlson
Carlson Racing Engines
Vector Cutz
www.CarlsonMotorsports.com
Carlson Motorsports on Facebook
30 years of service to the karting industry
Linden, IN
765-339-4407
bcarlson@CarlsonMotorsports.com

Well this will make me sound simple but I wasn't aware of heat treated retainers, I've only been using stock ones and I have a bunch of them on the shelf. I'll be in touch when I start getting low on them.
 
Well this will make me sound simple but I wasn't aware of heat treated retainers, I've only been using stock ones and I have a bunch of them on the shelf. I'll be in touch when I start getting low on them.

Good luck finding them -- that's why I asked.
I don't have any available for retail (only for customer rebuilds and new builds,) and I've re-used them on occasion since they are getting more and more scarce.
 
Always replaced lower retainers with new stock. Have seen a few heat treated snap in half By all means if you have a flathead that runs good don't fear re-using springs.
 
Good luck finding them -- that's why I asked.
I don't have any available for retail (only for customer rebuilds and new builds,) and I've re-used them on occasion since they are getting more and more scarce.

Well that's just a TERRIBLE thing to do to a guy!! It's like telling a little kid about some delicious candy and then saying, "but you can't have any!
;)
 
To take Groots question 1 step further:

Spring bind is measured in a vice with calipers and is .680 Coil bind is measured with dial indicator and is .385 Means installed height is 1.075
Find a spring or spring with shim that is 18# at a height of 1.075 correct???
I feel like I am so overthinking this
:unsure:
 
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