Been doing some preliminary checking to decide what length and size valve springs I want/need to run. I have some gages I bought a loooooong time ago for checking assembled spring heights. So I ferreted them out and one of the scales had come loose. I have two guages so I can check two ranges of length. Its an easy fix once I decide just where it needs to be oriented. Probably a dab of super glue and then slide it back on the gage. This led me to checking length of the gage and it seems that the gages are not correct. Maybe I'm not thinking about this correctly. So here are some pictures to show what I'm thinking.........and I'm wondering if others may be checking incorrectly . Anyway, the scale on the one unit reads the "Overall" length of the guage from top to bottom.......but there is a recess where the spring retainer sets, and I think it should be reading that distance. Seems obvious to me but can't believe someone making a gage like this would do it wrong....so I must be wrong. Its about .150 difference, which is a he** of a lot on a valve spring length. Am I looking at this wrong???????? I can shorten the gages and make them right, but don't want to do it till I'm sure. The first picture shows a 1.800 reading on the scale and the micrometer at the "overall " length. I think the 1.800 should be to the recessed step inside the gage. Should have said "lengthen" instead of "shorten" the gage.
Yes...your "installed height", spring check tool...is correct. Been made that way for many years, still made that way. Mike
Mike, I usually agree with you on things and respect your knowledge. In this case I still feel that the gage is not giving me the correct reading. I reattached the scale to the gage at the point where the zero mark was best for each graduation. What I mean by that is on a micrometer when the zero point passes a linear graduation point, its just far enough past the mark so you can see the .025/.050/.075 etc. I got my Snap Gages out and checked the height between the heads guide boss and the spring retainer. Then took a dial caliper and checked the Snap Gage dimension. There is about .150 difference in the reading. There is no way to relocate the scale on the tool to get that or anywhere close to that reading. I just think they screwed up when they made it. I'm going to check the other (shorter) one later and see if it is the same way. It appears to me that they cut the bottom of the gage too short. I'll post some more pictures later after I have been out to the shop again.
Wrong size tool, retainer should not be down in the recess. You need one for the smaller o.d. retainer to sit on the tool where the micrometer is on. The tool is calibrated correctly for the retainer o.d. it was designed for.
Some (or many) of the valve spring installed height gages are poorly made and inaccurate and they don't match up correctly to many valve spring retainers. I was tied of messing with them and decided to machine a very simple gauge (for my application) that was intentionally made to a height below my installed height dimension. After adding this to the spring seat and under the retainer, I simply used feeler gauges on top of this gauge to correctly and accurately measure the remaining distance for my I.H. dimension.
I agree with Kenny and Eddy. I suspect you have the wrong tool for what you are trying to measure. I recently stripped down an aftermarket inline-6 Repco crossflow head for my FED project. The valves are canted, and I struggled getting accurate installed readings using a vernier gauge. Thought I would buy one of those thimble mikes. Took forever to find one that would read the small installed dimensions I was trying to measure. Finally found one from an O/T 4-banger race shop, and had to sell a kidney to get it imported from the US. Wrong part got sent, waited again. Finally arrived, and went to measure up. It will measure my exhaust valves OK, but not the inlets... will not compress short enough to get the collets onto the valve stem. Long story short, a lot of mucking around, and a lesson that not all thimble mikes do the same job. Cheers, Harv
OK, Mike was right.......as usual, so my apologies for doubting. The problem simply is that the gages I have are made for larger size retainers that should sit on the top surface. Then they would read correctly. What confused me was that the retainers that came on the head fit perfectly in the recess.........so thats where I thought was the correct place. The simple fix is to just subtract the depth of the recess from the reading I get. I think I will make a small spacer to set in the recess and put a note in the box to remind me next time. Thanks for the help guys, I just couldn't see the forest..................
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