This Is So Fun It Must Be Illegal

7-27-2009 - With everything out and cleaned it was time to get down to the business of converting the Tracker. I started with the motor adapter and took a few basic measurements from the flywheel. Grabbed what I thought I would need and headed off to school and my lab of big tools. I started with a piece of 4” round T6061 aluminum and cut a 3” long piece. My old one was 2.7 inches long and I figured the new one would be about the same. I faced off both end to have a nice flat place to start and got to turning. I have a CNC lathe, but it has a very small capacity, so I did all of this on a manual lathe. I did the flywheel face first. The flywheel has a depression in it where it bolted to the engine and this really helps when you start drilling and tapping the bolt holes. Next I flipped it around to do the motor end. This requires a lot of turning to get it to a size that matches the face of the WarP9. Next a big hole in the middle to fit over the motor shaft and I then cut the keyway to match the motor and on to the bolt holes for the flywheel. Using that depression, I marked the first hole with a transfer punch and took it to the mill to drill and tap the hole. I inserted one bolt and tighten it and proceeded to mark the remaining five holes. The key is to get the first one and the rest follow like Lemmings over the cliff. I bolted up everything and put it back on the lathe (adapter and flywheel) to see how smooth it would turn. Much to my surprise, it was very smooth. I did a quick check and found it had a low spot on the flywheel, so it is now nice and round. All of this took about four hours – if school would have been in session, I would be able to knock off at least 1 hour because everything would have been set up in my lab instead of locked up for the summer. I rained most of Saturday, so I worked on other projects around the house.
Next up was the adapter plate – that piece of metal that can cost upwards of $800.00. As you know, I’m a bit on the cheap side. So I used the same method I used on the Fiero – what I like to call the “tap-and-cut” method. It starts a piece of thin plexiglass – my guess 1/16”. This is some stuff I had lying around the lab that has been there over seven years. It’s too thin for most everything that my students do, so it just sits there, but for what I do, it works great. Cut a piece about the size of the bell housing on the transmission and clamp it in place (I use spring clamps). Now take a hammer and start tapping. I start with the shaft coming out of the transmission because this is the critical point in the process. On the Fiero, this shaft actually stuck out beyond the face of the bell housing and I just made a hole in the Plexiglas and hung it from the shaft. On the Tracker, it sets in about ¼” so I made sure I had this point marked on the Plexiglas before I started marking the holes. You can go crazy and mark all of the holes and the entire profile of the bell housing if you desire, but I just went for the critical points and made sure I do not have points of interference (these points might be drive shafts on a front wheel drive car). On the Fiero I contoured everything to match the bell housing (boy was I stupid), but this time around I went for simple. By keeping straight lines and easy angles your cuts can be done with a number of saws (metal band saw, Sawsall, scroll saw…). This also cuts down on grinding and finishing. Once I had the template, I marked all of my centers for the holes (circle template from my drafting days) with a center punch and prepped the ¼” steel plate. First I traced the template outline and cut it to shape. Next I taped the template to the steel and marked the hole locations for the bell housing, motor and the cut out. On the WarP9 there is a flange that sticks up (4” diameter – they call it a pilot) - a big hole saw will get this out of the way. And finally some start holes to remove the cut out. This cut out will be the part that attaches to the motor and is separated by a spacer (2” x ¼” flat stock). It is a slow process, but I used a scroll saw to make this cut. It uses a thin blade and requires a 5/16” hole to get it started. I chose a hexagon, but a square or octagon will work as well. Doing it round requires bending metal or a really big tube, so to keep it simple, I stuck with straight lines.
With all of the pieces cut, it was time for a dry fit. Slide the flywheel/clutch/motor adapter on the transmission – check. Bolt the outer piece of the adapter plate to the bell housing – check. Mount the cutout to the motor – check. Attach motor to hoist and slide it all together – check. It all fit like a glove (baseball, not deerskin driving gloves) and now is the time to get a measurement for the thickness of the spacer – mine was 1.85 inches. This number is what you need to weld everything together.
And speaking of welding, that is what I did today (7-28-2009). My welder is at school and the Tracker is at home, so this requires a few trips. I welded the spacer pieces to the cutout. The next step is to align the cutout/spacer piece to the other plate attached to the bell housing. If I had the welder at the house (or the Tracker at school) I would get everything where I wanted it and tack weld it all assembled. That is not the case, so instead I will align the pieces and mark all the way around the plate. Then I will take it all apart, tack weld it and recheck it one more time. Just to make it clear, if it doesn’t line up, it might not work. And if it does work, it will probably be noisy. (Steve Clune has a method where he runs things at slow speeds and taps the adapter plate until the noise goes away – same thing on my part, just a different way.) Once everything is where I want it, it’s one more weld and the adapter plate is done. Did I save anything by not buying the pre-made adapter – I figure my time is cheap. Materials are minimal – maybe $10.00. The trips back and forth to school – maybe another $10.00. The satisfaction of making it myself – priceless!
So until then…