This was day 2 of fasting blood draws for the new trial I’m in with a 25 hour ambulatory blood pressure monitor between the draws. That means I went almost 20 hours with nothing but water and a torture device squeezing my arm every 15 minutes. And when I say torture device I mean that because of stress and pain from my back my BP was about 170/100, and the amount of pressure needed to get those readings was very painful. In fact I have a large bruise on my arm from the pressure, but interestingly it’s not where the measuring cuff was placed but right below the edge of the cuff on the inside of my elbow.
Something else interesting is I was looking at a bad cylinder head the other day when I got an image that showed a spark plug with 5 or 6 exposed threads sticking up in the combustion chamber and the tip extending past the surface of the head.
This one has the plug tip just slightly below the surface of the head and no exposed threads on the spark plug. I would need to angle mill a small amount from this head to get the combustion chamber CCs right but I should just be able to get a slightly cooler heat range for the plug to make it work on E85. I spent a lot of time thinking about that last night to distract myself from the blood pressure monitor squeezing the life out of my arm.
I was listening to the Peter Gabriel channel on YTM and while some of those videos look ridiculous now some are still avant guard even in 2017. They aged incredibly well even in the face of enormous changes in the state of the art for video.
Well I really need to shower and get to bed, I’m not even making sense to myself right now.
Someone mentioned an app on Twitter that did something I needed, tracking walks and estimating calories burned. So I looked it up at the Google Store and found out the price was right (free) and the basic version did in fact do everything I needed from such an app. So I now have “Map My Walk” installed on my phone.
What I learned is my “short walk” is 3.31 miles long instead of my estimated 2.5 miles I’ve been telling everyone, and that I burned 500 calories on my “short walk”. I’m thinking my “long walk” is closer to 5 or 6 miles than the 3.5 or 4 that I thought. This also explains how my shoes keep wearing out so fast, since I go for a walk almost every day. I’m also faster than I thought but still nothing to brag about.
Also while on my walk I contemplated the one remaining issue I have to solve with the rear suspension: keeping the rear wheels from steering the car under power because the toe angle changes. With the 2D Pratt truss the knuckle could have had enough bending torque to change the toe angle uncontrollably, so I had to make it 3D without adding to the weight or making it take up too much space behind or over the transmission. Thinking the problem through I realized the 4-link was going to be taking almost all of the forces that would be changing the toe, so all I really needed to do was give the 2D truss a fighting chance at using the depth of the structural members to resist toe change by using some diagonals connecting to the vertical member of the last bay before the knuckle, in as many planes as I could so the last bay would be 3D but everything else could remain 2D, only slightly increasing the weight of the truss and not changing the vertical stiffness needed to keep the wheel aligned on the other 2 axis. In doing so I would not be using a true Pratt truss in that the diagonal members will be under compression rather than tension, and the end bay would not have an upper horizontal member or terminating vertical member but would be similar to a kingpin truss in 3 planes, with another triangular bay under the truss from the bottom of the knuckle up to the bottom horizontal member in the plane of the main truss keeping the camber angle constant. I wish my CAD skills were good enough to draw this out and output a .gif or .jpg file to put in the blog, because words are only so good in describing this.
Another stab at it, the plate that holds the knuckle to the truss is going to be rectangular or maybe a right triangle with the hypotenuse facing down and forward and the right angle on the top rear side. Diagonal members will run from all 3 corners of the triangle to the first vertical member of the truss, one from the bottom corner to the bottom of the first vertical member from the bottom, one from the top front corner to the bottom of the vertical member on its front side, another from the top front to the top of the vertical member on its front side, and a last one from the top rear corner to the top of the first vertical member, that diagonal in the plane of the truss. That should be more than enough to keep the forces driving the wheel under control so the toe and camber don’t change. And none of the added members will interfere with the drive shafts or the lateral links of the Watts link that keeps the whole shebang located from side to side. That’s because all of the added structure is either behind or above the knuckle and therefore above or behind the driveshafts and lateral links.
I really need to learn how to use the AutoCAD 360 program I downloaded to the laptop and not just so I can draw pictures of the car to post to the blog. Anyone know of some good tutorials to teach me to use it?
Billed @€0.02, Opus the Unkillable Badass
Yeah, the guy that has a bike safety blog that mostly blames cars is building a hot-rod. Let’s just say that “irony-poor blood” is not a big problem around Casa de El Poeta.
Anywho, I have been working on the adaptor design to run Wide 5 hubs on early Ford spindles so that I can use less expensive and easier to find commercial street rod or hot rod parts instead of custom fabricated axles to use what is essentially pure race spindles on the street. The Wide 5 hubs I’m using are rated for 5000 pound off-road racing trucks, so street use on a sub-1700 pound car is going to be extremely under-stressed. Ditto just about every suspension part on the car being under-stressed for street use at this weight, unlike the race spindles I mentioned earlier that are designed for a “heavy” pavement sprint car that comes in at about 1500 pounds because pavement sprinters use a lot more front brakes than dirt track sprinters that don’t even have a right front brake.
Getting back to that adaptor I have found a few things out by inference rather than by direct description. For instance I found out the inner bearing has a 2″ I.D. which means that the spindle adaptor has to be 2″ from the seal race out to the outer bearing which is 4.6″ from the outside of the seal race to the outside of the outer bearing. Somewhere along the line I need to gradually taper the adaptor from the 2″ inner bearing to the 1.813″ I.D. of the outer bearing, actually the 1 13/16” diameter of the spindle. The outer bearing is about .68″ wide, so the “landing area” for this bearing will extend from 4.6″ from the outside edge of the seal race (I know I’m using the wrong terms for these but I can’t find an article on the web describing the actual names of the various parts of the part of the spindle the hub runs on), to 3.85″ from the seal race and taper up to the 2″ diameter of the inner bearing over the next 3.1″ to 0.75″ from the bearing race, so there is a nice broad landing area for both bearings to slide in on. I also know the seal race is 2.375″ O.D. and at least 0.437″ wide, and that the entire adaptor is 5.687″ from the seal race (described as the “inner bearing shoulder” in this particular diagram) to the end of the piece, which will end up being 7.125″ long over all from where it bottoms against the Ford spindle to the end of the piece.
That’s the outside, the inside is much more fun from the designer’s (me!) standpoint. First of all the two main design parameters were to not introduce failure-inducing stress points into the design, and to have as little flex as possible. Fortunately the seal race on a Ford spindle is 1.5″ O.D. (edit: 15/8“) while the landing area for the inner bearing is 2″, meaning there will be a 0.250+/-” (edit: 0.1875″) wall thickness under the bearing if the I.D. cut is made straight across from the seal race to the end of the inner bearing landing area. This is acceptable if I use a high-strength aluminum alloy. Then the bearing shoulder on the Ford spindle for the outer bearing is 3″ from the bearing shoulder for the inner bearing, and 3.5″ from the face on the Ford spindle where the adaptor will be bottomed out. This will be the inside face of the bulkhead that runs from the Ford spindle outer bearing landing area to the landing area for the Wide 5 outer bearing, with generous radii where the bulkhead meets the I.D. of the adaptor after subtracting the 0.250″ (edit: 0.1875″) wall thickness from the bearing I.D.’s.
So basically there will be a Wide 5 spindle from aluminum on the outside, with a bulkhead the same I.D. as an early Ford outer bearing then and I.D. the same as an early Ford grease seal. The adaptor will have a shoulder on the bulkhead slightly larger than the O.D. of the washer of the early Ford spindle nut before going out to the end of the threaded area and the beginning of the Wide 5 outer bearing landing area on the adaptor. There should only be a tiny bit of added flex over machining the adaptor to rest against the Ford spindle solidly full length, but the adaptor will be much lighter and considerably easier to install than fitting against the spindle as a solid piece.
And it’s time for me to get ready for evening services now.