bench vise valve spring compressor psi checker, accurate?
#2523928
07/19/18 03:34 AM
07/19/18 03:34 AM
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Joined: Nov 2003
Posts: 36,041 Lincoln Nebraska
RapidRobert
OP
Circle Track
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OP
Circle Track
Joined: Nov 2003
Posts: 36,041
Lincoln Nebraska
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how accurate are they & which one should I get? thank you for your time.
live every 24 hour block of time like it's your last day on earth
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Re: bench vise valve spring compressor psi checker, accurate?
[Re: RapidRobert]
#2524060
07/19/18 01:09 PM
07/19/18 01:09 PM
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Joined: Aug 2011
Posts: 2,865 Pattison Texas
CSK
master
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master
Joined: Aug 2011
Posts: 2,865
Pattison Texas
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The one I have is way off
1968 Charger COLD A/C Hilborn EFI 512ci 9.7 compression, Stealth heads, 4.10 gear A518 ODtrans 4100lb,10.93 full street car trim 2020 T/A 392 Stock 11.79 @ 114.5
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Re: bench vise valve spring compressor psi checker, accurate?
[Re: CSK]
#2524068
07/19/18 01:32 PM
07/19/18 01:32 PM
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Joined: Jan 2003
Posts: 16,376
dogdays
I Live Here
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I Live Here
Joined: Jan 2003
Posts: 16,376
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There are only two realistic factors for accuracy (or not). What you're looking at is a piston in a cylinder exactly 1.00 square inch in area, and a pressure gauge. Both have to be accurate and if they are, the device is accurate.
As it is much easier to produce a cylinder that is 1.000 square inches, the major source of inaccuracy is the pressure gauge. SO, if the pressure gauge is accurate to within 1%, that is what the device's accuracy is, as well. If one wanted to be idiotic, the distance the centerline of the gauge is above or below the centerline of the cylinder counts too, but it is usually much smaller than the gauge's inaccuracy.
IMHO it is much easier to be inaccurate about measuring the distance between the vice jaws than any other part of this process. If one wishes to be super accurate buy a super accurate gauge and have it calibrated by a deadweight tester traceable to the National Institute of Science and Technology, before the series of spring tests.
There are other less accurate ways to assure accuracy.
R.
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Re: bench vise valve spring compressor psi checker, accurate?
[Re: topside]
#2524090
07/19/18 02:27 PM
07/19/18 02:27 PM
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Joined: Jan 2003
Posts: 15,439 Val-haul-ass... eventually
BradH
Taking time off to work on my car
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Taking time off to work on my car
Joined: Jan 2003
Posts: 15,439
Val-haul-ass... eventually
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Used to sell one that was accurate within 1%. They're made by an old funny car racer friend of mine. Bench-tested every one. He also sells 'em to Summit, Jeg's, maybe Speedway, which they re-brand as theirs. You can PM me if you like for his phone #. The Proform tester I bought was JUNK. The one I bought from topside some years ago is consistent and pretty accurate, based on what my calibration spring and other "known quantity" springs read.
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Re: bench vise valve spring compressor psi checker, accurate?
[Re: RapidRobert]
#2524180
07/19/18 05:46 PM
07/19/18 05:46 PM
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Joined: Jan 2003
Posts: 14,506 So. Burlington, Vt.
fast68plymouth
I Live Here
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I Live Here
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Posts: 14,506
So. Burlington, Vt.
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A friend bought one of the Proform bench top units that uses the hyd cylinder with the pressure gage on it. Brought it down to the shop and we checked it against a PAC calibration spring...... it was waaaay off.
It got sent back.
68 Satellite, 383 with stock 906’s, 3550lbs, 11.18@123 Dealer for Comp Cams/Indy Heads
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Re: bench vise valve spring compressor psi checker, accurate?
[Re: lewtot184]
#2524352
07/20/18 02:03 AM
07/20/18 02:03 AM
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Joined: Nov 2003
Posts: 36,041 Lincoln Nebraska
RapidRobert
OP
Circle Track
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OP
Circle Track
Joined: Nov 2003
Posts: 36,041
Lincoln Nebraska
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Damn! I think I might try a bathroom scales in a drill press! (I read about that once).
live every 24 hour block of time like it's your last day on earth
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Re: bench vise valve spring compressor psi checker, accurate?
[Re: lewtot184]
#2524550
07/20/18 02:35 PM
07/20/18 02:35 PM
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Joined: Nov 2003
Posts: 36,041 Lincoln Nebraska
RapidRobert
OP
Circle Track
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OP
Circle Track
Joined: Nov 2003
Posts: 36,041
Lincoln Nebraska
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you just have to keep in perspective what your buying. Exactly
live every 24 hour block of time like it's your last day on earth
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