Tigges Talk - Getting Fit

Part 2 of Building a TAFC.

For Part 1, go here: Tigges Talk - Pipe Dreams

In the last update, the new chassis was still on the jig in the shop, with the spindles & front wheels all assembled, the rear axle housing installed, the steering hooked up, and a plan in place for a lot of small part fabrication before it came off the jig.

After a few weeks, I took more vacation days & drove the 150 miles from Maine through New Hampshire to the Tigges complex in Holbrook, Massachusetts. Depending on traffic, this trip takes as little as 2-1/2 hours or as long as 4 hours. As usual, the trip down was as it should be, reasonably uneventful, although the trip back needed a little Yankee ingenuity.

In my absence Fred & Mark had completed a lot of detailed small part fabrication & fitting. All of the brake lines had been formed & run, along with the requisite tabs & mounts welded in place. The decision had been made to go with the old fuel & oil tanks, so the lower tank support rods had been bent up & welded in & the tank basket repaired & fitted with tabs. The upper tank support trees had been cut out of the old chassis & welded in as well as fabrication of a new top strap & tabs to hold the tanks down. All the support brackets for the fire bottles & actuation hardware, the brake handle & fire bottle lever & steering wheel had been fabricated, fit & installed. There was also the weight bar & mounts, ignition component plate brackets & rail drain bungs that had been installed… many hours spent on the lathe, in the Bridgeport vice & behind the torch to design & install what is needed to make everything work. Since the chassis came in the door, there have been 44 pieces added & 51 welds done on just the front half of the car.

From a functional point of view, not too much has changed from the old car. Little things like the top rail drains being relocated to the front of the car & the oil tank overflow being routed directly to the frame rail instead of a dedicated tank will simplify servicing. It is really cool to be involved with every step of the build, as it makes it much easier to understand exactly how all the parts work together & what they do. An example is how the rear brake hard lines are routed very tightly to the axle housing, so that if the chutes get pulled under the car & wrap around the axle they will not sever the lines (leaving you with no chutes or brakes - not good).

Before taking the car off the jig, we made some adjustments which would ensure everything fit perfectly, expediting servicing at a race. Jig removal was a three guy operation, Mark & me on the rear of the car, Fred up front. We lifted it up and over the jig & placed it outside the shop, then released the jig from the tie downs & carried it past the chassis. We then numbered & cut the jig legs off for storage in the shop. The car went back into the shop, now supported with jack stands.

Mark went to work with the TIG torch, finishing off bottom welds on brackets & tabs that had not been accessible while the car was on the jig, while Fred & I worked on bleeding the brakes. There is a 2PSI residual pressure valve on the rear brake system that keeps the brake pads in light contact with the rotors during the run. This is so when the driver hits the brakes at the finish line they have no excess play. I got fooled into thinking the front & rear master cylinder lines were swapped because some air in the front lines had been compressed & made the brakes act just like they had a residual valve in them. Another learning experience, things are not always as they seem.

Learning experiences aside, another time sink is the issue of disappearing parts. We all spent too much time looking for the rear end chuck mounting nuts & the brake lever. Mark could still see the chuck nuts image in his brain, right where he put them in the tray a few weeks earlier. We couldn't find the tray or the nuts. We looked everywhere, eventually finding them on the floor in the shop where they had come to rest after being knocked off the bench. The brake lever however is almost two feet long… how do you lose that? It was hiding in a blanket of plastic wrap that had been set over the engine in the old chassis to protect it from dirt. Mark & I both picked up this plastic to check under it, but neither of us looked in the plastic… there it was!

With the car off the jig, it was time to start adding the heavy stuff. The 10" ring & pinion chuck assembly was installed into the rear axle along with the hubs & drive axles. The really exciting part was mounting the rear wheels & slicks. Now the chassis was actually starting to look like a racecar! Every step is like a little discovery. The Murf McKinney chassis is narrow in the rear, so we had better clearance between the tires and the chassis, even without wheel spacers, but not having the spacers means we will need to buy shorter wheel studs.

The next day Kevin dropped over to help with the body fitting, something we have all been waiting for. We had purchased the body from Tony Bartone, who had McKinney build his car. Mark & Fred had compared build sheets, gone out to McKinney's shop in Indiana to be fit to the new chassis, and discussed the differences in the chassis measurements, so I thought this would be a drop-it on and go deal... I’m showing my inexperience building a car again! With the nice removable body tree bolted onto the chassis & the car ready to roll out into the driveway, the fun began.

Mark & the girls had spent the morning removing the go-around & body struts from the body, which was stored in the race trailer. The go-around is an aluminum frame that is bolted into the body. It fits around the driver's compartment, sealing the upper frame rails and the firewall at the engine plate. The go-around needed to be adjusted to fit the cage on our chassis, which we did by marking the places where the roll cage passes through it then cutting and grinding the openings to fit. Once modified, it was re-installed into the body & we were ready to roll.

Mounting the body is a four person job, one on each rear corner, one in the front, and one under the car to guide the body onto the rear hinge mounts on the body tree. We lifted the body over the chassis only to hear Fred exclaim from under the car 'It doesn't fit!' The hinge brackets were thicker than the old ones and were dragging on the outside edges of the body supports… a minor issue fixed with some time on the milling machine.

NHRA specifications call for three critical body measurements on a Top Alcohol Funny Car. The front lip to the track surface must be 3" minimum, the rear bumper opening to the track surface cannot exceed 29", and the overhang from the front wheel spindle to the nose of the car cannot exceed 40". After much measuring, re-measuring, adjustments and clearancing, the body was fit with the body support saddles in place on the frame rails, the go-around resting on the chassis, and the rear hinge mounts & front latch working properly. There are still minor tweaks to do to get it all perfect, but we are in race trim 'attitude' with the car within class specifications. My idea of 'drop it on & go' is almost laughable in retrospect. Every small adjustment takes a long time to make, then fit, then measure & re-adjust, especially when the body needs to keep coming on & off to test fit.

Somewhere in there we took a day off to do the trailer brakes in the race trailer, a messy job that is pure misery in the heat of summer and always too much to do in the spring… more required work to go racing that is 'behind the scenes'. It was pretty cool to see how electric brakes work. It would be more accurate to call them 'electrically actuated mechanical brakes'.

We will be moving on to the next steps in the build, stuff that we will be able to do inside the shop over the winter. I'm looking forward to these next steps in this process, fitting & adjusting more parts (like the slick carbon fiber electronics & timer box), installing the go-power between the rails, and mapping out the plumbing & wiring. See you next installment, thanks for reading!

Detailed pictures (with descriptions) of the ongoing build & Yankee ingenuity here:

Tigges New Car - Round Two - Getting Fit


Chris Saulnier - Team Tigges
Mechanic Falls, Maine