astrowrench
Member
My God People Do That
/
Piston Rule
- Thread starter DirtRacer7
- Start date
/The rules don't specify how many attempts or rotations are allowed when checking the lift. Most competent and knowledgeable techmen are going to give a competitor a reasonable number of attempts to try to met the specification. Personally I normally will give mulltiple attempts, at least 3, or to the point that I'm confident I'm getting representative readings.
sCREamnClones
New member
hmmm you're close ... actually there is more concern with the minimum lift rather than the maximum lift, when checking at the pushrod.
The minimum lift specification serves as a means of controlling and limiting the practice of cutting lift off the nose of the cam lobe and then running an increased ratio rocker arm, while still complying with maximum lift specification at the retainer.
Ok Stoney....you just answered my 'WHY' and I DO appreciate that! There4....are these rules 'written' by guys that have a 'whole lot' of experince(?), or....guy's w/ guilty conscience?
astrowrench
Member
HAl you ain't GONE YET!!!!!!!!! Dave
hmmm you're close ... actually there is more concern with the minimum lift rather than the maximum lift, when checking at the pushrod.
The minimum lift specification serves as a means of controlling and limiting the practice of cutting lift off the nose of the cam lobe and then running an increased ratio rocker arm, while still complying with maximum lift specification at the retainer.
Ok Stoney....you just answered my 'WHY' and I DO appreciate that! There4....are these rules 'written' by guys that have a 'whole lot' of experince(?), or....guy's w/ guilty conscience?
sCREamnClones
New member
You'd think 'Tar'n Feather's' should be appropreate....right?My God People Do That
sCREamnClones
New member
the "telescoping leg" of your caliper works great for this, which is exactly what it was meant for, measuring the bore depth of things.
I'm assuming the tech mans is calibrated with mine? Ok Don what is the reason for this rule? Are they that much different or are they being modified?
There is likely a rule or spec on them because of both people modifying them because theyr out of spec, and because some came that way from the factory, but what do i know? It is not that hard to ask the tech man if you can check the accuracy of your calipers with his, by measuring a known part with both, when he is not busy of course. Im sure most would allow you to do so, if they care anything about racers who actually want to make sure they are legal.
DynoDon
Moderator
There were games being played in that area and that forced a spec on it.
DynoDon
Moderator
In my DVD I address the issue of calibrating the calipers. I purchased sever different size pin gauges and no go's from e-bay. Then I took them to a machine shop and ask them to verify the size as advertised. I have small medium and large. Everyone I had checked came out ok. I use them to calibrate my dial caliper before I check things. If I have an item out of spec, the first thing I do is check the calibration and measure it again.
Sometime ago in another situation a call I made was challenged, the opposition was the quality, brand, calibration, and method used for determining the legality of the part in question. They attempted to make a case on all fronts. In all fairness I will allow anyone to question the measurements, and I will reconsider. In order to verify on the spot I collected all of the measuring instruments I could in the pits.
We ended up with:
1 starret micrometer, 4 no name digital calipers, 1 mitutoyo digital caliper, 1 digital and 1 dial starret caliper.
My pin guages were questioned also.
So using one front wheel bearing each tool was used to measure, outside, inside and width of the bearing all tools except one, measured accurately to .001 including mine, the one that did not was the micrometer, as it was not zeroed correctly and the owner did not have the hook wrench and did not know what I was talking about. I know the calibration industry, yes it is needed in industry but many are abusing it in kart racing.
We ended up with:
1 starret micrometer, 4 no name digital calipers, 1 mitutoyo digital caliper, 1 digital and 1 dial starret caliper.
My pin guages were questioned also.
So using one front wheel bearing each tool was used to measure, outside, inside and width of the bearing all tools except one, measured accurately to .001 including mine, the one that did not was the micrometer, as it was not zeroed correctly and the owner did not have the hook wrench and did not know what I was talking about. I know the calibration industry, yes it is needed in industry but many are abusing it in kart racing.
well how do you calibrate the telescoping end of the caliper. I would use a .750 gage block and set the block on a flat surface and take a reading from there. micing over a pin or a hole only shows that the caliper end is calibrated not the telescoping end. although the depth mic or dial depth gage would be more suitable for checking the depth.
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If it is digital at least stand it on your flat plate and bottom the end before zeroing the guage, it does not matter if the jaws are slightly open or not. By simply using the block the end of the rod may not start flush with the bottom surface of the beam, So make it flush first, zero it and then measure the guage block.