Valve Spring Checker

[FElony]

As I try to round out my building tools, I am at a standstill with the above device. A few years ago a friend of mine bought one of those spring pressure gauges that you see around 70 bucks or so, designed to be used in a vice. He measures a set and gets x lbs. Wondering about the accuracy, he takes his springs to a machine shop, and they give a value that is less than what he got. Then he goes to another one, and they give him a number higher. There was, IIRC, about a 14 lb. spread from one shop to the other, with his value somewhere in between. He was not happy.

So, what are some experiences you've had? Is the actual number super critical, or is it just used to compare one spring to another on the same gauge, much the way dyno figures work? How long do the vice units last? Is there a "measuring spring" for calibration, and can those testers even be calibrated?

Although I may wind up doing a bunch of springs over a period of years, the prices of some stand-alone upright testers are somewhat prohibitive. If the vice types are junk, what is a reasonable alternative?

[wayne]

I have one i use in a drill press it works ok and you can buy a test  spring i have  one.Comp cams sells the spring i got mine from amazon.

[machoneman]

The test spring really does level the playing field no matter what device is used.  Add +/- and your good to go!

[C6AE]

Easy to make one with a small lathe.
A brake cylinder cup and piston for 1-1/8" bore is pretty darn close to 1 sq.inch (area .994")
Bore out a short piece of 1-1/2" aluminum bar to 1.128" (area =  9993", close enough), add a snap ring groove, drill and tap a port for an oil pressure gauge, make up a 1.125 piston with a 1/2" stub to chuck in the drill press, hold that in with a snap ring, fill it with fluid, screw in the gauge and Bob's your uncle! A spring pressure testing gauge.
 Just pull it down in the drill press to a predetermined stop. A travel dial is a handy thing right here!
The accuracy will be determined by the quality of your gauge.
A fun evening shop project, 5 easy pieces, 3 of which you can buy over the counter.

Even if you don't you don't have a lathe, in this hobby you have to have a friend with one...

[Katz427]

Well FElony having spent some time in a metrology lab you have a problem as most gauges are not that accurate. Most gauges have an accuracy characterised usually as a percentage of the full scale reading.
If you use a gauge of 1000 lbs to check a 150 lbs. seat pressure spring you can get a fair amount of inaccuracy.
If one needed better accuracy , you have to work closer to " full scale".
Many times I would generate a calibration curve, so a correction factor could be applied at the lower scale readings.
You also need a good known traceable calibration standard, if you insist on absolute accuracy.
On torque wrenches I would usually go every 20 ft/lbs, unless the wrench was really wired and needed more points. It took time and not everyone wanted that accuracy. Low, middle and Full scale, thank you

[66FAIRLANE]

Heres something I made a few years ago you may be interested in.

http://fepower.net/simplemachinesforum/index.php?topic=424.msg3237#msg3237

[Falcon67]

I use a Harbor Freight 1 ton arbor press.  I made a plate for the base that hold the tester using the screw in the back and a plate that replaces the face plate.  Removed the ram and drill/tapped the center of it for another plate.  Both plates stick a bit out the left side (facing the press).  Use a valve retainer height mic, set to open or closed height, place on the plate and pull the handle until the upper plate touches the height mic.  Read pressure.  Easy, quick, repeatable.  Can run through a full set of springs in minutes.

Have to get some pics LOL.

[FElony]

Heres something I made a few years ago you may be interested in.

http://fepower.net/simplemachinesforum/index.php?topic=424.msg3237#msg3237

Very smart. You no makee for buy-buy? How's the Profrom gauge holding up? Looking at the ones Jegs has. Not sure if I should get 0-300 (more accurate in the lower pressure range??) or the 0-600 (not sure if any cams I have will get over 300??). I have "tdoelerich"'s on-head valve spring compressor, but I don't think anything can be rigged off that.

[Katz427]

My only experience with the Proforma gauge was in the lab. A fellow gear head brought one  a 600lbs valve spring gauge and the supervisor of the lab said it was reading about 10% low.  So off 60 lbs at full scale. He calibrated a few points to give the fellow a calibration curve to correct the readings.

[jayb]

I have one of those Proform valve spring checkers and it is off almost exactly the same amount, about 10% low. 

[FElony]

I have one i use in a drill press it works ok and you can buy a test  spring i have  one.Comp cams sells the spring i got mine from amazon.

Izzit this one?  https://www.ebay.com/itm/132475035280

[wayne]

Yes that is the one i have.

[FElony]

Yes that is the one i have.

Thanks!

[steinauge]

I used one made by Sturtevant tool at work for 40 years.It was mechanical and used a threaded center shaft and a marked rotating plate on the shaft.It had a moving upper arm that bore against the valve spring and had a 1\2" square hole in it to accept a beam type torque wrench.You simply set your installed height with the plate ,put the spring in and pulled on the torque wrench until the "clicker" in the top arm went off.The pressure was 2X what the torque wrench read.When I retired in 2015 we were still using the same one I ordered in 1975. Every student I had for 40 years used that tool.I imagine it is still in production? 

[Falcon67]

I have one of those Proform valve spring checkers and it is off almost exactly the same amount, about 10% low.

Mine is dead on per the Crane check spring.  SO if we are using ProForm sourced items for this work, are we playing Chinese Checkers?