This is where it all started really. The Mazda Miata Dipstick Top was the first project that I took from idea to finished parts and it worked out so well I've been able to provide them at low cost to other Miata owners. I actually didn't expect it to b as successful as it has been, in fact when I had a co-worker help me do the program he seemed the whole idea was a bit silly and figured I shouldn't waste my time and should just go buy a new factory part, or continue live with the yellow stub of a dipstick.

a little background

Over the past many years I have owned no less than three Mazda Miatas. They have proven to be reliable, cheap, easy to maintain and fun cars. So much so that my parents even bought one in addition to my three. Despite having so many I have really only had one entirely functional Miata at a time. The ones that weren't entirely functional I stripped down to the bare tub tossing the parts I didn't need (i.e; didn't have room for in my garage) and using what I did to keep the one working car, well, working. The one part that I simply couldn't get in good shape however always seemed to be the dipstick top. One car came with one already broken. Another was intact until i was adjusting something (probably the timing sensor) and the wrench slipped and completely shattered the plastic dipstick top. I figured there had to be a better way and since I had just gone through the trouble of swapping in a new engine and painted the valve cover, etc, I figured it was as good a time as any to see if I could fix the eyesore that was the yellow stubby dipstick stub.

A pretty common site among Miata engine bays.

The fix

Designing a replacement really didn't take too much time. I wanted the part to be basically as close to a factory replacement as I could get so I took what was left of the dipstick in my car, measured it, and used that as the basis for my design. As far as how one could grab it and pull it out of the engine I figured i'd just make something simple and straight forward, a shape easy enough to grab between two fingers and pull. The most challenging part really was programming the part in Mastercam since I hadn't done anything like that before but with some help I had a working program and learned a bit as well.

Installing the new tops really wasn't a big deal. The toughest part about the installation process was removing the old yellow top and grinding down the dipstick a bit. Since the shape of the new top matched that of the old one, at least in terms of how it interacted with the dipstick tube, I simply had to make sure I lined up the new top approximately where the old one was and glue it in place. Like magic, I had fixed an old annoying problem that bugged me each time I popped the hood on my car to do any work. As an added bonus it would never break like the old factory one and actually looks very purposeful in the engine bay, as if that's how the car came from the factory.

other options

Early on I realized that while it might be OK for some people to remove their broken dipstick top and replace it with one of my new ones, not everyone wanted to invest that sort of effort or time and would rather just pull a ready to go dipstick out of a box and slip it in the car, job done. Figuring out how to create the actually stick part of the dipstick was far more challenging than just creating the top. It had to be the same diameter as the factory dipstick so I could use my tops, had to be strong, corrosion resistant and incorporate a calibrate way to measure the level of oil in the engine. Choosing the material was reasonably easy. Stainless steel would provide the strength, rigidity and corrosion resistance I needed, but stainless steel was also very hard to work with. I thought of and discarded many ideas for marking indicators for the oil level on the end of the stick eventually deciding on trying to flatten the stainless rod in and then drilling two tiny holes calibrated at distances taken from a "master dipstick". If the holes were drilled on center (which more often than not they weren't) I then would take the straight dipstick rod to a custom bending die I milled manually and add the characteristic bends found in the Miata dipstick. Typically if I started with 10 dipstick rods, by the time I was done drilling the holes I would have maybe 2 or 3 that I felt were good enough to make into complete dipsticks. The rest had off center holes that provided a weak point where the end could get bent and break off in someones engine, which nobody wants and simply looked unprofessional.

I sold complete dipsticks for about a year but eventually realized that it was just too much effort and I really wasn't happy with the quality or consistency. I decided that for the time being, until I could find a way to improve the quality of the complete dipstick solution, it would be best to shelf this product and just sell the replacement tops on their own. While I might be missing out on sales, i'd rather sacrifice sales then sell a product that I feel is lacking in quality or execution. The dipstick tops however have never been better. I have found the best way to put a great finish on each part and I typically keep enough on hand that often when someone places an order the shipping label is printed and I have their replacement top in the mailbox within 15 minutes. Nobody likes waiting around for parts to ship.